63 results on '"Common species"'
Search Results
2. Restoring diversity of thermophilous oak forests: connectivity and proximity to existing habitats matter
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Lanta, Vojtěch, Mudrák, Ondřej, Liancourt, Pierre, Dvorský, Miroslav, Bartoš, Michael, Chlumská, Zuzana, Šebek, Pavel, Čížek, Lukáš, and Doležal, Jiří
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- 2020
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3. Bumble bee species distributions and habitat associations in the Midwestern USA, a region of declining diversity
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Andrew H. Lybbert, Megan Varvaro, Karen Goodell, Jessie Lanterman Novotny, Randall J. Mitchell, Paige Reeher, and Jesse Smith
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0106 biological sciences ,education.field_of_study ,Ecology ,biology ,Population ,Biodiversity ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Bombus impatiens ,010602 entomology ,Geography ,Common species ,Habitat ,Abundance (ecology) ,Conservation status ,Species richness ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Bumble bees (Bombus spp.) are important pollinators, yet rapidly declining globally. In North America some species are thriving while others are nearing extinction. Recognizing subtle differences in species’ biology and responses to environmental factors is required to illuminate key threats and to understand their different population trajectories. We intensively surveyed bumble bees in Ohio, USA, along the receding southern boundary of many species’ ranges, to evaluate current conservation status of the state’s species. In 318 90-min field surveys across two consecutive years we observed 23,324 bumble bees of 10 species visiting 170 plant species. Habitat, landscape, latitude, and their interactions significantly influenced bumble bee abundance, species richness, and community composition during peak season. Sites planted with flowers yielded more bumble bee individuals and species than did sites not planted with bee food plants. Bombus impatiens, B. griseocollis, and B. bimaculatus comprised 93% of all observations. Their abundances all peaked in habitats planted with wildflowers, but there were species-specific responses to local and landscape factors. Three less common species (B. fervidus, B. vagans, and B. perplexus) were more likely to be found in forested landscapes, particularly in the northeastern portion of the state. Bombus perplexus was also affiliated with planted urban wildflower patches. These results provide a strong starting point for future monitoring and conservation intervention that targets less common species. A quantitative synthesis of detailed state-level and regional datasets would allow additional insight into broad scale patterns of diversity in bumble bee communities and species conservation trajectories.
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- 2021
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4. Using Red List species in designating protection status to forest areas: a case study on the problem of spatio-temporal dynamics
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Lise Tingstad, John-Arvid Grytnes, Ivar Gjerde, and Magne Sætersdal
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0106 biological sciences ,Ecology ,Frequency of occurrence ,biology ,010604 marine biology & hydrobiology ,Zoology and botany: 480 [VDP] ,VDP::Zoologiske og botaniske fag: 480 ,Biodiversity ,Site selection ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Common species ,Polypore ,VDP::Zoology and botany: 480 ,IUCN Red List ,Species richness ,Zoologiske og botaniske fag: 480 [VDP] ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Global biodiversity - Abstract
Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species afected the rank order of plots regarding richness of red-listed species, using two diferent national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the efect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation efectiveness over time than for more common species, and particularly at fner scales. Red-listed species · Site selection · Spatio-temporal dynamics · Temporal turnover
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- 2020
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5. Restoring diversity of thermophilous oak forests: connectivity and proximity to existing habitats matter
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Pavel Sebek, Lukáš Čížek, Miroslav Dvorský, Zuzana Chlumská, Ondřej Mudrák, Vojtěch Lanta, Jiří Doležal, Pierre Liancourt, and Michael Bartoš
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0106 biological sciences ,Habitat fragmentation ,Ecology ,010604 marine biology & hydrobiology ,Rare species ,Endangered species ,Woodland ,010603 evolutionary biology ,01 natural sciences ,Geography ,Habitat destruction ,Common species ,Threatened species ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The habitat fragmentation and isolation threaten populations of rare species. Organisms become endangered because of the primary habitat loss, but also due to limited dispersal capacity. Whether threatened species are limited more by their dispersal capacity or by lack of suitable habitats is an unresolved question critical to effective conservation. To address the question, we investigated patterns of colonisation by light demanding woodland plants in patches (clearings) of broadleaf forest where open canopy conditions were restored by partial cutting. Six pairs of identically sized (40 × 40 m) clearings were created in closed canopy thermophilous oak forest. Each pair included a clearing isolated in the closed forest and a clearing connected to an alluvial meadow and migration corridor along a river. Within each clearing, we followed colonization success by threatened and common species for 8 years. To assess the relative role of species pool, dispersal limitation and niche-based competition processes (viewed through the plant functional traits), we compared vegetation composition of the clearings to that of surrounding habitats (closed forest, open forest, meadow, forest edge). Clearings hosted more threatened species than closed forests, forest edges and meadows. Existing patches of open forest harboured the highest diversity of threatened species. Their proximity increased colonization success of threatened plants in clearings. Higher colonization rates by threatened plants were associated with shorter distances to source habitats and higher light, higher pH and lower moisture values in the clearings. Clearing type affected composition and ecological strategies of threatened species. Connected clearings were colonized by taller light-demanding species with higher seed mass, more suitable for establishment in a highly competitive environment, while the isolated clearings were colonized by shorter species with higher specific leaf area, better equipped for a more shaded environment. Species richness of threatened species increased in the first 3 years and decreased in last years, indicating that forest thinning creates only a short-term regeneration window with tree and shrub canopy closing back relatively fast. Active intervention should be therefore repeated in short intervals, preferably as shifting mosaics of differently aged stands. Our results bring novel information on the relative importance of habitat quality, isolation, and biotic filtering on communities of threatened species and their colonization success.
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- 2020
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6. Species richness is a surrogate for rare plant occurrence, but not conservation value, in boreal plant communities
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Varina E. Crisfield, Lingfeng Mao, Catherine K. Denny, Scott E. Nielsen, and Jacqueline M. Dennett
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0106 biological sciences ,Ecology ,Environmental change ,010604 marine biology & hydrobiology ,Rare species ,Biodiversity ,Plant community ,010603 evolutionary biology ,01 natural sciences ,Geography ,Common species ,Habitat ,Disturbance (ecology) ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Rare species are an ecologically important component of biological communities, but may be at risk of decline as a result of human disturbance and other sources of environmental change. Rare species are also ecologically idiosyncratic, making their occurrence difficult to predict a priori, and leading to efforts to find surrogate measures of rare species occurrence to inform conservation decisions. Using floristic data collected at 602 sites in the western Canadian boreal forest, we studied relationships between rare species occurrence, species richness and habitat type, with rarity defined according to the classification system developed by Rabinowitz (in: Synge (ed) The biological aspects of rare plant conservation, Wiley, Somerset, 1981). Relative to similar studies in other temperate regions, we found that a smaller proportion of species were classified as rare in our study region, and that common species dominate the flora. Regional-scale relationships were positive between richness and the occurrence of rare species; however, due to variation in these relationships among habitat types, richness is not a suitable surrogate for a site’s conservation value with respect to species rarity.
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- 2019
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7. Diversity indices or floristic quality index: Which one is more appropriate for comparison of forest integrity in different land uses?
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Z. Mirazadi, K. Abrari Vajari, and Babak Pilehvar
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0106 biological sciences ,Ecology ,Land use ,Biodiversity ,Forestry ,04 agricultural and veterinary sciences ,Vegetation ,010603 evolutionary biology ,01 natural sciences ,Diversity index ,Geography ,Common species ,Abundance (ecology) ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Alpha diversity ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Zagros forest in Iran has been heavily altered by anthropogenic disturbances such as farming, grazing and other activities. In this study, we first estimated the herbaceous plants coefficient of conservatism within this region. Forest integrity of different land uses was then assessed by common measures of plant diversity and the indices were specifically developed to estimate vegetation integrity (conservatism coefficient, floristic quality index and modified floristic quality index). As complementary approaches, some soil physiochemical properties were applied to judge forest integrity. A total of 81, 82, 88, native species were recorded in understory grazing (UG), abandoned fields (AF), and protected area (PA) land uses, respectively. Common species had higher abundance in AF land use, whereas specialized species were found in PA land use. Diversity indices and modified floristic quality index values were higher in AF land use compared to UG and PA land uses, and fisher alpha diversity index highlighted the significant differences in the plant diversity among land uses, while PA land use had high species richness with greater number of sensitive species and floristic quality index. Soils under PA land use showed the highest organic carbon, nitrogen and pH. Based on results, floristic quality index and mean coefficient of conservatism can be more informative than species-diversity measures in assessing floristic integrity and in contradiction to diversity indices, are accurate tools to determine differences in the integrity of land uses. Results indicate that PA land use have indeed progressed ecologically toward a vigorous ecosystem as observed by the development of its vegetation community.
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- 2017
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8. Is livestock grazing compatible with biodiversity conservation? Impacts on savanna ant communities in the Australian seasonal tropics
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Alan N. Andersen, Samantha A. Setterfield, and Gabriela B. Arcoverde
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0106 biological sciences ,Ecology ,Agroforestry ,010604 marine biology & hydrobiology ,Biodiversity ,Biology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Common species ,Abundance (ecology) ,Grazing ,Iridomyrmex ,Species richness ,Monomorium ,Conservation grazing ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Grazing by domestic livestock is one of the most widespread forms of anthropogenic disturbance globally, and can have a major impact on biodiversity and therefore conservation values. Here we use ants to assess the extent to which livestock grazing is compatible with biodiversity conservation in a tropical savanna of northern Australia, where there is growing pressure to intensify pastoral production. We focus on the extent to which ant responses conform with four general patterns identified in a recent global review: (1) soil and vegetation type have a far bigger impact on ant community composition than does grazing; (2) grazing modifies ant species composition but often not species richness or total abundance; (3) a species’ response often varies among habitats; and (4) between 25–50% of the species that can be statistically analysed are responsive to grazing. We sampled ants using pitfall traps at 38 sites in two land systems, based on cross-fence comparisons of areas of different grazing intensities. A total of 130 ant species from 24 genera were recorded, with the fauna dominated by species of Iridomyrmex and Monomorium. Land system was the primary driver of variation in ant species richness and composition, and grazing intensity was related to neither species richness nor total abundance. Only 10% of common species appeared to be impacted by grazing. Overall, ant responses to grazing in our study region were generally consistent with the four global patterns, except that the local fauna seems to be particularly resilient. Such resilience indicates that current grazing management practices are compatible with the conservation of ant biodiversity.
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- 2016
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9. The effect of fire history in shaping diversity patterns of flower-visiting insects in post-fire Mediterranean pine forests
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Spyridon Papakonstantinou, Thanassis Kyriazis, Theodora Petanidou, Stefanos P. Sgardelis, Vangelis Mizerakis, Athanasios S. Kallimanis, Jelle Devalez, Thomas Tscheulin, and Maria Lazarina
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0106 biological sciences ,Ecology ,Pollination ,010604 marine biology & hydrobiology ,fungi ,Biodiversity ,Biology ,010603 evolutionary biology ,01 natural sciences ,Common species ,Pollinator ,Abundance (ecology) ,Guild ,Species richness ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Fire affects diversity and structure of flower-visitor communities. We explored the effect of fire history on the diversity patterns and structure of the flower-visitor guilds (bees, beetles, flies, sawflies, and wasps), across a post-fire regeneration sequence of pine forests in Rhodes Island, Greece. Fire history was defined by fire frequency and post-fire age of sites. We did not find significant differences in species richness and abundance per guild between fire-history regimes except for the abundance of flies, sawflies and the entire flower-visitor community. Fire strongly affected the community structure of bees, beetles, and sawflies. Some of the most abundant and common species responded significantly to fire in terms of abundance; yet, we observed no significant variation in the abundance of the common species of bees, the most prominent pollinator group, implying that provision of pollination services may not be considerably affected by fire. Long-unburnt sites displayed higher heterogeneity in species composition compared to recently-burnt sites (either burnt once or twice). This pattern deviated significantly from null expectations when analyzing the abundance-based metric of β-diversity and was obscure in the case of the presence/absence-based metric, indicating that fire affected mainly the spatial distribution of individuals, i.e. the main change is not due to species turnover but to changes in relative abundance. Furthermore, the species composition in recently-burnt sites (burnt once in 2008) were more similar than in twice-burnt sites (including areas burnt once between 1984 and 1992, and in 2008), indicating that fire frequency affected post-fire heterogeneity of species composition.
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- 2016
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10. Rareness starts early for disturbance-dependent grassland plant species
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Robert J. Warren and M. Candeias
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0106 biological sciences ,Ecology ,010604 marine biology & hydrobiology ,fungi ,Biodiversity ,Endangered species ,food and beverages ,Plant community ,Interspecific competition ,Biology ,010603 evolutionary biology ,01 natural sciences ,Common species ,Habitat ,Abundance (ecology) ,Threatened species ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Ecological communities always contain a few common species and an abundance of uncommon species. Given that most plant mortality occurs in seeds and seedlings, recruitment success often predicts plant community assemblage and patterning, but observational patterns do not reveal whether plant populations are seed or habitat limited. Grassland plant species make up a sizable portion of the overall native flora in northeastern North America (N.A.), but approximately 30 % of the area’s threatened and endangered flora are grassland species, possibly leftovers from the post-glacial landscape. Yet, close relatives of many rare grassland species thrive in the same range. We investigated whether seed or habitat limitation explained rarity and commonness in remnant grassland species. We used seed addition experiments coupled with microhabitat manipulations (burning and herbivore exclusion) in three different habitat types to evaluate recruitment (germination and seedling survival) limitation for three rare and three common grassland species. Rare grassland species successfully recruited where burning reduced initial competitor density, but seedling survival suggested they were severely limited by interspecific competition. Both the rare and common plant species survived equally well in forest habitats where herbaceous density was low whereas neither survived in the edge habitats. Only the common plants thrived in the high-competition meadow habitat, further suggesting that the rare grassland species are poor competitors. Commonness and rarity are temporal designations that can change as disturbance alters the landscape. Glacial retreat and low precipitation in northeastern N.A. created a landscape suitable for poor competitors that tolerated poor conditions. Our results suggest that rare remnant grassland plants, unlike their close relatives, display more biotic than abiotic limitation as they do not compete well with other plants. These results suggest that suitable habitat is not a spatial location but a temporally transient assemblage of species requirements.
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- 2016
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11. Recovering mountain Mediterranean grasslands for breeding birds: ecology and population status shape species responses to management
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Guglielmo Londi, Simonetta Cutini, Giuditta Miniati, T. Campedelli, and Guido Tellini Florenzano
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0106 biological sciences ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Ecology ,Biodiversity ,010603 evolutionary biology ,01 natural sciences ,Biodiversity hotspot ,Grassland ,Shrubland ,Geography ,Common species ,Abundance (ecology) ,Conservation status ,Species richness ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
The Mediterranean basin is considered one of the most important biodiversity hotspots. This extraordinary richness originates mainly from thousands of years of human activities that deeply modified the landscape. Safeguarding the so-called cultural landscapes plays a key role in biodiversity conservation. In this paper we present the results of our monitoring of the effects of the life project “Preservation of mountain grasslands of the Tuscan Apennines”, mainly characterized by shrub-cutting actions, on bird populations in the Pratomagno pasture, one of the two areas where the project was implemented, a SPA in eastern Tuscany. The monitoring plan covers a period of 5 years. We tested the effects of shrub clearing on a series of bird community parameters, such as abundance and richness of common species and of some ecological guilds. We also tested the timing of the response to the interventions (immediate or drawn out over time). Our results show a dramatic decrease of birds associated with shrubland, while there were no important increases in grassland species, with the sole exception of Woodlark. Regardless of their positive or negative effects, our results show different response times for individual species or groups of species. Moreover, species with a bad regional conservation status increased less than those with a good one. Broadly speaking, these results suggest that the efficacy of such projects depends on a careful preliminary assessment of a number of aspects, encompassing the nature of the interventions themselves and the characteristics of the target sites, but also the type of response of target species and the conservation status of target populations.
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- 2016
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12. Diversity patterns of seasonal wetland plant communities mainly driven by rare terrestrial species
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Damien A. Fordham, David C. Deane, Corey J. A. Bradshaw, and Fangliang He
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0106 biological sciences ,geography ,geography.geographical_feature_category ,Ecology ,010604 marine biology & hydrobiology ,Rare species ,Biodiversity ,food and beverages ,Introduced species ,Wetland ,Biology ,Native plant ,010603 evolutionary biology ,01 natural sciences ,Common species ,Nestedness ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
In cleared landscapes, wetlands can represent important reservoirs of native plant diversity, which include terrestrial species. Depending on study aims, non-wetland plants might be removed before analysis, affecting conclusions around biodiversity and community structure. We compared the native plant communities of seasonal wetlands in a predominately agricultural landscape as defined geographically (including all species) with that of the obligate wetland assemblage. We were primarily concerned with determining how this design decision affects ecological and conservation conclusions. We analysed a survey database containing >12,900 flora records from South Australia, developing a new area-based method to remove sampling bias to include only wetlands with a near-complete census. We modelled occupancy, species-area relationships, β-diversity and nestedness under our contrasting community definitions. Terrestrial species were 57.4 % of total richness. Removing these species reduced wetland α-diversity by 45 %, but did not affect the scaling of richness with area (power-law species-area relationship z = 0.21 ± 0.01). Occupancies for wetland plants were relatively uniform, but were heavily dominated by rare (satellite) species when terrestrial plants were included, and this also increased β-diversity. Nestedness for terrestrial species occupancies was marginally lower than predicted under null models, suggesting that rare species often do not co-occur with common species. An implication of these occupancy patterns is that twice as many wetlands (and 50 % more wetland area) would be needed to include every native species within at least one wetland compared with wetland-only species.
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- 2016
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13. Industrial and post-industrial habitats serve as critical refugia for pioneer species of newly identified arthropod assemblages associated with reed galls
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Petr Heneberg, Petr Bogusch, Miroslav Mikát, Petr Janšta, Jan Macek, Petr Baňař, Alena Astapenková, Igor Malenovský, Štěpán Kubík, Milan Řezáč, and Kamil Holý
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0106 biological sciences ,Pioneer species ,Ecology ,010604 marine biology & hydrobiology ,Rare species ,Biodiversity ,Biology ,Reed bed ,010603 evolutionary biology ,01 natural sciences ,Ecosystem engineer ,Phragmites ,Common species ,Habitat ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Gravel-sand river terraces were nearly eliminated from central European landscape by river channelization. Monotypic stands of common reed (Phragmites australis) growing on such terraces are often stressed by drought, which makes them vulnerable to Lipara spp. (Diptera: Chloropidae) gallmakers. Although Lipara are considered ecosystem engineers, only fragmentary information is available on the biology of their parasitoids and inquilines. We analyzed the assemblages of arthropods (Arachnida, Collembola, Dermaptera, Psocoptera, Thysanoptera, Hemiptera, Raphidioptera, Neuroptera, Coleoptera, Diptera, Lepidoptera and Hymenoptera) that emerged from 17,791 Lipara-induced galls collected in winter from 30 reed beds in the Czech Republic, 15 of which were situated at (post)industrial sites (gravel-sandpits, tailing ponds, limestone quarries, colliery dumps, and reclaimed lignite open-cast mines) and 15 were in near-natural habitats (medieval fishponds, and river and stream floodplains). The Chao-1 estimator indicated 229.3 ± 18.1 species in reed galls at (post)industrial and 218.1 ± 23.6 species at near-natural sites, with the Sorensen index reaching only 0.58. We identified 18 red-listed species and four new species for the Czech Republic (Gasteruption phragmiticola, Echthrodelphax fairchildii, Haplogonatopus oratorius and Enclisis sp.), representing mostly obligate (64 %) or facultative (9 %) reed specialists. We propose that Lipara gall-associated assemblages undergo a long-term cyclic ecological succession. During first 10 years after reed bed formation, only Lipara spp. and several other species occur. During next decades, the reed beds host species-rich assemblages with numerous pioneer species (Singa nitidula, Polemochartus melas) that critically depend on presence of prior disturbances. Middle-aged reed beds (near medieval fishponds) are prevalently enriched in common species only (Oulema duftschmidi, Dimorphopterus spinolae). Habitats with the longest historical continuity (river floodplains) host again species-rich assemblages with several rare species that probably require long-term habitat continuity (Homalura tarsata, Hylaeus moricei). Landscape dynamics is thus critical for the persistence of a full spectrum of reed gall inquilines, with (post)industrials serving as the only refugia for pioneer species ousted from their key nesting habitats at once cyclically disturbed gravel-sand river terraces.
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- 2016
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14. Large mammal diversity and their conservation in the human-dominated land-use mosaic of Sierra Leone
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Anita McKenna, Roger Mundry, Bala Amarasekaran, Hjalmar S. Kühl, and Terry Brncic
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Ecology ,biology ,Biodiversity ,Species diversity ,biology.organism_classification ,Sierra leone ,Geography ,Common species ,Duiker ,Spatial ecology ,Species richness ,Transect ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Like elsewhere in West Africa, the landscapes of Sierra Leone are strongly human-dominated with consequences for large mammal distribution and diversity. Sierra Leone is currently going through a phase of post-war recovery, with accelerating development of the mining, forestry, agricultural and infrastructure sectors. As environmental issues are increasingly considered, comprehensive biodiversity information is required. Here we evaluate spatial patterns of large mammal diversity throughout Sierra Leone to make inferences about species persistence. We used systematic line transect sampling for assessing large mammal distribution. GLMs and canonical correspondence analyses were used to evaluate the relative importance of human impact for every species while controlling for environmental gradients and to make countrywide spatial model predictions. We further developed an algorithm to identify core distributional ranges for the most common species. A total of 562 km of transects were surveyed and 35 large mammal species encountered. Species diversity was impoverished in the country’s south and center and strongly increased towards the north and east. Human impact did not determine the distribution of four species (brushed-tailed porcupine, bushbuck, giant rat, warthog), but was very influential on chimpanzee and yellow-backed duiker occurrence with U-shaped and negative responses, respectively. The remaining species showed mixed responses to human impact and environmental gradients. Predicting species persistence in West African human-dominated landscapes is complex. Pooling of species for land-use planning is therefore not recommended. Our study provides key information for land-use planning to separate areas with post-depletion species assemblages from more diverse regions with high conservation value.
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- 2015
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15. Landscape-scale distribution and density of raptor populations wintering in anthropogenic-dominated desert landscapes
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Adam E. Duerr, Tricia A. Miller, Michael Lanzone, Amy Fesnock, Kerri L Cornell Duerr, and Todd E. Katzner
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Ecology ,business.industry ,Rare species ,Conservation Plan ,Biodiversity ,Wildlife ,Distribution (economics) ,Geography ,Common species ,Abundance (ecology) ,Ecosystem ,business ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Anthropogenic development has great potential to affect fragile desert environments. Large-scale development of renewable energy infrastructure is planned for many desert ecosystems. Development plans should account for anthropogenic effects to distributions and abundance of rare or sensitive wildlife; however, baseline data on abundance and distribution of such wildlife are often lacking. We surveyed for predatory birds in the Sonoran and Mojave Deserts of southern California, USA, in an area designated for protection under the “Desert Renewable Energy Conservation Plan”, to determine how these birds are distributed across the landscape and how this distribution is affected by existing development. We developed species-specific models of resight probability to adjust estimates of abundance and density of each individual common species. Second, we developed combined-species models of resight probability for common and rare species so that we could make use of sparse data on the latter. We determined that many common species, such as red-tailed hawks, loggerhead shrikes, and especially common ravens, are associated with human development and likely subsidized by human activity. Species-specific and combined-species models of resight probability performed similarly, although the former model type provided higher quality information. Comparing abundance estimates with past surveys in the Mojave Desert suggests numbers of predatory birds associated with human development have increased while other sensitive species not associated with development have decreased. This approach gave us information beyond what we would have collected by focusing either on common or rare species, thus it provides a low-cost framework for others conducting surveys in similar desert environments outside of California.
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- 2015
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16. Ecological grouping and edge effects in tropical dry forest: reptile-microenvironment relationships
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J. Nicolás Urbina-Cardona and Juan E. Carvajal-Cogollo
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Tropical and subtropical dry broadleaf forests ,geography ,geography.geographical_feature_category ,Ecology ,Biodiversity ,Biology ,Old-growth forest ,Edge effects ,Common species ,Habitat ,Abundance (ecology) ,Transect ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
We evaluated the effect of tropical dry forest edges in fragments on reptile structure and ecological groups, and their relationship to 15 environmental variables in the Caribbean Region, Colombia. We used 15 pasture-edge-interior gradients and 12 permanent linear transects per gradient, sampling them on three occasions between January and December 2006. We recorded 35 species (pasture: 15, forest edge: 28, forest interior: 16). Reptile structure was different along the pasture-edge-interior gradient and the magnitude of the influence of the edge effect on the abundance of the most common species changed from the dry to rainy season. We identified seven ecological groups based on three fixed functional traits: species habit, size and reproductive mode. The proportion of species belonging to each ecological group was different between the pasture and forest habitats, but there were no differences between the forest edge and its interior. Four of the seven ecological groups inhabited pasture and the forest interior, and all of the ecological groups were represented in the forest edge. The ecological group with oviparous small and diurnal species accounted for the 50 % of the species inhabiting the forest interior. Reptile structure and ecological groups were both related to patch size, elevation, herbaceous cover, percentage of bare soil and temperature, but explanatory power differed. We suggest that the conservation and management of tropical dry forest reptiles should take into account species traits so that rather than using information for a single species, a more generalized community approach is used.
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- 2015
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17. Analysis of a decade of trade of tortoises and freshwater turtles in Bangkok, Thailand
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Chris R. Shepherd and Vincent Nijman
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Ecology ,biology ,Tortoise ,Species diversity ,Radiated tortoise ,Southeast asian ,biology.organism_classification ,Wildlife trade ,Geography ,Common species ,Threatened species ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The illegal and unsustainable trade in tortoises and freshwater turtles in Asia is a clear impediment to their conservation, leading to steep population declines and what has become known as the Asian Turtle Crisis. We focus on the trade in tortoises and freshwater turtles for pets in one of Southeast Asia’s largest wildlife trading centres, the Chatuchak Market in Bangkok, Thailand. Between November 2004 and December 2013 we surveyed Chatuchak 12 times, recording all species and quantities of tortoises and freshwater turtles openly for sale. In total, 2,667 individuals representing 55 species, were observed with 97 % of the individuals belonging to species not native to Thailand. African, South Asian and Southeast Asian species made up the largest numbers. The number of individuals recorded per survey ranged between 110 and 522 of between 11 and 24 species; species richness, species diversity and evenness did not show any clear temporal pattern. New species were added after new surveys suggesting a continual increasing supply of novel species. The most common species in trade over this period were Indian star tortoise Geochelone elegans (653 individuals), African spurred tortoise G. sulcata (536) and radiated tortoise Astrochelys radiata (320). Globally threatened species were observed during every survey, totalling 1,235 individuals of 20 species. These included Critically Endangered radiated tortoises and Burmese star tortoise G. platynota. Non-native CITES I listed species, i.e. species that should not be traded internationally, such as black spotted turtle Geoclemys hamiltonii from northeastern India and Bangladesh, were observed during all but one surveys, totalling 417 individuals of seven species. The observations of large numbers of species that had clearly entered the country illegally was clear evidence that unscrupulous traders are taking advantage of the loopholes in Thailand’s legislation. Legal reform in Thailand is urgently required, so that the Wild Animal Reservation and Protection Act can function as an effective piece of legislation to be used to bring an end to the illegal trade in tortoises and freshwater turtles in Thailand.
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- 2014
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18. Long-term decline of a winter-resident bird community in Puerto Rico
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W. Andrew Cox, John Faaborg, Katie M. Dugger, Wayne J. Arendt, Miguel Canals Mora, and Judith D. Toms
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Tropical and subtropical dry broadleaf forests ,Ovenbird ,education.field_of_study ,Ecology ,biology ,Population ,Biodiversity ,Tropics ,biology.organism_classification ,Population decline ,Geography ,Common species ,Netting ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Despite concern expressed two decades ago, there has been little recent dis- cussion about continuing declines of migrant bird populations. Monitoring efforts have been focused almost exclusively on the breeding grounds. We describe the long-term decline of a winter-resident bird population in Guanica Commonwealth Forest, Puerto Rico, one of the last remaining tracts of high-quality tropical dry forests in the Caribbean. The winter bird community has exhibited dramatic declines, with constant-effort mist netting now capturing about one-third as many birds as it did 20 years ago. Population estimates for the three most common species have declined dramatically, even though
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- 2012
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19. Biodiversity of man-made open habitats in an underused country: a class of multispecies abundance models for count data
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Seigo Asanuma, Yuichi Yamaura, Shun’ichi Makino, J. Andrew Royle, Tamotsu Sato, Naoaki Shimada, and Hisatomo Taki
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geography.geographical_feature_category ,Ecology ,Agroforestry ,fungi ,Biodiversity ,Introduced species ,Grassland ,Geography ,Common species ,Disturbance (ecology) ,Habitat ,Abundance (ecology) ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Since the 1960s, Japan has become highly dependent on foreign countries for natural resources, and the amount of managed lands (e.g. coppice, grassland, and agricultural field) has declined. Due to infrequent natural and human disturbance, early-successional species are now declining in Japan. Here we surveyed bees, birds, and plants in four human-disturbed open habitats (pasture, meadow, young planted forest, and abandoned clear-cut) and two forest habitats (mature planted forest and natural old-growth). We extended a recently developed multispecies abundance model to accommodate count data, and used the resulting models to estimate species-, functional group-, and community-level state variables (abundance and species richness) at each site, and compared them among the six habitats. Estimated individual-level detection probability was quite low for bee species (mean across species = 0.003; 0.16 for birds). Thirty-two (95% credible interval: 13–64) and one (0–4) bee and bird species, respectively, were suggested to be undetected by the field survey. Although habitats in which community-level abundance and species richness was highest differed among taxa, species richness and abundance of early-successional species were similar in the four disturbed open habitats across taxa except for plants in the pasture habitat which was a good habitat only for several exotic species. Our results suggest that human disturbance, especially the revival of plantation forestry, may contribute to the restoration of early-successional species in Japan.
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- 2012
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20. Mapping from heterogeneous biodiversity monitoring data sources
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Dani Villero, Henk Sierdsema, Stuart E. Newson, Francesc Sardà-Palomera, Frédéric Jiguet, and Lluís Brotons
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0106 biological sciences ,Data collection ,Ecology ,010604 marine biology & hydrobiology ,Species distribution ,Context (language use) ,15. Life on land ,010603 evolutionary biology ,01 natural sciences ,Common species ,Sample size determination ,Data quality ,Statistics ,Environmental science ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Downscaling - Abstract
Field monitoring can vary from simple volunteer opportunistic observations to professional standardised monitoring surveys, leading to a trade-off between data quality and data collection costs. Such variability in data quality may result in biased predictions obtained from species distribution models (SDMs). We aimed to identify the limitations of different monitoring data sources for developing species distribution maps and to evaluate their potential for spatial data integration in a conservation context. Using Maxent, SDMs were generated from three different bird data sources in Catalonia, which differ in the degree of standardisation and available sample size. In addition, an alternative approach for modelling species distributions was applied, which combined the three data sources at a large spatial scale, but then downscaling to the required resolution. Finally, SDM predictions were used to identify species richness and high quality areas (hotspots) from different treatments. Models were evaluated by using high quality Atlas information. We show that both sample size and survey methodology used to collect the data are important in delivering robust information on species distributions. Models based on standardized monitoring provided higher accuracy with a lower sample size, especially when modelling common species. Accuracy of models from opportunistic observations substantially increased when modelling uncommon species, giving similar accuracy to a more standardized survey. Although downscaling data through a SDM approach appears to be a useful tool in cases of data shortage or low data quality and heterogeneity, it will tend to overestimate species distributions. In order to identify distributions of species, data with different quality may be appropriate. However, to identify biodiversity hotspots high quality information is needed.
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- 2012
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21. Genetic diversity of six arable plants in relation to their Red List status
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Stefan Meyer, C. Brütting, Isabell Hensen, and Karsten Wesche
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Conservation genetics ,Genetic diversity ,education.field_of_study ,Consolida regalis ,Ecology ,Population ,Biodiversity ,Biology ,biology.organism_classification ,Common species ,Genetic structure ,IUCN Red List ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
In Central Germany and throughout Europe, arable plants count among some of the most endangered plant species. Over the last few decades, the number and size of populations have been in sharp decline due to modern land use techniques, including the application of fertilizers, herbicide use and seed cleaning procedures. As arable plant species are underrepresented in population genetic studies, it is unknown whether agricultural intensification has affected the extant populations, and whether genetic structure varies among species with differing vulnerability in respect of their Red List status. We sampled 53 populations from 6 arable plant species throughout Central Germany. Random amplified polymorphic DNA analyses (RAPD) were applied to calculate measures of genetic diversity at the population level and genetic differentiation. Genetic diversity was found to be lowest in Bupleurum rotundifolium and Anagallis foemina, and highest in Consolida regalis and Nigella arvensis. The highest levels of genetic differentiation were observed among populations of An. foemina and B. rotundifolium but within populations in all other species. ΦST values differed strongly ranging between 0.116 for C. regalis and 0.679 for An. foemina. Patterns of genetic structure were related to the Red List status for all the species studied except An. foemina, for which it should consequently be raised. Our data confirm that even relatively recent threats are accompanied by detrimental genetic structure. As losses of populations and increased fragmentation have occurred in all common and uncommon species, the situation for arable plants could change for the worse in the following decades, highlighting the need for consistent monitoring.
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- 2011
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22. The efficacy of common species as indicators: avian responses to disturbance in British Columbia, Canada
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Kathy Martin, Amelia J. Koch, and Mark C. Drever
- Subjects
Intermediate Disturbance Hypothesis ,Ecology ,Common species ,Abundance (ecology) ,Indicator species ,Rare species ,Guild ,Biodiversity ,Species richness ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Common species can be major drivers of species richness patterns and make major contributions to biomass and ecosystem function, and thus should be important targets for conservation efforts. However, it is unclear how common species respond to disturbance, because the underlying reasons for their commonness may buffer or amplify their responses to disturbance. To assess how well common species reflect changes in their community (and thus function as indicator species), we studied 58 bird species in 19 mixed conifer patches in northern British Columbia, Canada, between 1998 and 2010. During this time period two disturbance events occurred, stand level timber harvest and a regional-scale bark beetle outbreak. We examined relationships among densities of individual species, total bird density and overall species richness, correlations in abundance among species, and responses to disturbance events. We found three broad patterns. First, densities of common species corresponded more strongly with changes in total bird density and overall species richness than rare species. These patterns were non-linear and species with intermediate-high commonness showed similar or better correspondence than the most common species. Second, common species tended to be more strongly correlated with abundances of all other species in the community than less-common species, although on average correlations among species were weak. Third, ecological traits (foraging guild, migratory status) were better predictors of responses to disturbance than species commonness. These results suggest that common species can collectively be used to reflect changes in the overall community, but that whenever possible monitoring programs should be extended to include species of intermediate-high commonness and representatives from different ecological guilds.
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- 2011
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23. Ant diversity and bio-indicators in land management of lac insect agroecosystem in Southwestern China
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You-qing Chen, Yan-lin Chen, Qiao Li, Zhi-Xing Lu, and Xing-yin Zhou
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Agroecosystem ,Geography ,Ecology ,Common species ,Habitat ,Abundance (ecology) ,Biodiversity ,Land management ,Secondary forest ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The segregation of land-use intensity signifies an important change in land use in lac insect agroecosystem of Southwestern China. Farming conversions have led to a highly diversified landscape, with a mosaic made up of patches of land with different succession, from cultivated lands to closed forest. Our aim here is to characterize ant assemblages within this mosaic and identify key ant community metrics and species that can be used for bioindication. The habitats supported different level of ant species richness and abundance. For ants captured by pitfall trapping, the mean plot species richness in lac plantation was significantly higher than that in dry land (deforestation land-use). For ants captured by sweep netting and foliage shaking, there was significant difference among lac plantation, dry land and secondary forest occurring from afforestation of lac plantations, with lac plantation having greatest species richness. Ant species composition was different among the three land-use habitats. Seven of the fifteen most common species had statistically different abundances or occurrence within the three land-uses. Thirteen species had statistically significant different distributions among land-use habitats (among them three species were captured by sweep netting and foliage shaking). Ten species had statistically significant habitat associations determined by IndVal analysis. Among these ten species, five ant species were associated with secondary forest, two with lac plantation, and three with dry land. Lac plantation integrated with lac-production and farming is clearly an important land-use protecting ant diversity, and thus having great conservation potential. The use of ants as bio-indicators is a promising method for determining ecological responses to human land use in China.
- Published
- 2011
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24. Private forest reserves can aid in preserving the community of medium and large-sized vertebrates in the Amazon arc of deforestation
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Anah Tereza de Almeida Jácomo, Carlos Fonseca, Eloy Revilla, Leandro Silveira, Nuno Negrões, and Amadeu M.V.M. Soares
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Wet season ,Ecology ,Amazon rainforest ,Activity period ,Fauna ,Biodiversity ,Camera-trapping ,Geography ,Common species ,Deforestation ,parasitic diseases ,Tropical mammals and birds ,Protected area ,Amazon ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Due to the advancing agricultural frontier in the Brazilian Amazon, the present rate of deforestation engenders a pessimistic scenario for vertebrate diversity in the area. Protected areas are an essential conservation tool to limit biodiversity loss, but their efficiency have yet to be proven. Here, we used camera-trap data on the presence of medium and large-size vertebrates in a protected area (Canta˜o State Park) and a neigh- bouring private forest reserve (Santa Fe´ Ranch) to evaluate their effectiveness in protecting biodiversity. We also gathered information on seasonality and activity patterns. A total sampling effort of 7929 trap-nights revealed a diverse vertebrate fauna in the region. A total of 34 mammal species, belonging to 8 different orders was detected in the study area, some of which have a high level of conservation interest and value. The photographic index showed that diversity was more abundant outside the protected area of Canta˜o State Park, where seasonality could play a major role in vertebrate occurrence. Overall, the influence of seasonality on distribution appears to be species-specific. During the wet season around 40% of the common species were not detected inside the park, whereas in Santa Fe´ Ranch most species (62.5%) suffered only a slight decrease in relative abundance probably due to changes in the availability of food resources. Our results highlight the importance of private land for vertebrate conservation in the Amazon and alert to the need for increased law enforcement in these areas to secure biodiversity preservation
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- 2010
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25. Forms of rarity of tree species in the southern Brazilian Atlantic rainforest
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Alessandra Nasser Caiafa and Fernando Roberto Martins
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education.field_of_study ,Ecology ,Population ,Biodiversity ,Small population size ,Rainforest ,Biology ,Habitat ,Common species ,Threatened species ,education ,Endemism ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The assessment of species rarity considers local abundance (scarce or abundant population), habitat affinity (stenoecious or euryecious species), and geographic distribution (stenotopic or eurytopic species). When analyzed together these variables classify species into eight categories, from common species to those having small populations, unique habitats, and restricted geographic distribution (form 7), as proposed by Rabinowitz in 1981. Based on these categories, it is possible to calculate the frequency of the different forms of rarity of the species present in a given site. The Brazilian Atlantic rainforest is considered a hotspot of the world biodiversity harboring many endemic species, which have restricted geographic distribution. Our objective was to identify the forms of rarity of tree species and their proportions in the southern portion of the Brazilian Atlantic rainforest using Rabinowitz’s forms of rarity. All the seven forms of rarity are present in the 846 tree species we analyzed: 46% eurytopic and 54% stenotopic, 73% euryecious and 27% stenoecious, 76% locally abundant and 24% locally scarce species. Eurytopic, euryecious locally abundant species accounted for 41.1%, whereas 58.9% were somehow rare: 4.5% eurytopic, euryecious locally scarce, 0.2% eurytopic, stenoecious locally abundant, 0.1% eurytopic, stenoecious locally scarce, 19.5% stenotopic, euryecious locally abundant, 8.0% stenotopic, euryecious locally scarce, 15.6% stenotopic, stenoecious locally abundant, and 11.0% stenotopic, stenoecious locally scarce. Considering that the most restrictive forms of rarity precedes extinction, the application of Rabinowitz’s system demonstrated that most tree species of the southern Brazilian Atlantic rainforest are threatened due to their restricted geographic distribution, restriction to a single habitat, reduced local abundance, or even to a combination of these variables.
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- 2010
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26. Correlates of vulnerability among arthropod species threatened by invasive ants
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Rosemary G. Gillespie and Paul D. Krushelnycky
- Subjects
Evolutionary Biology ,education.field_of_study ,Ecology ,Plant Sciences ,Population ,Rare species ,Vulnerability ,Biodiversity ,Life Sciences ,Zoology ,Introduced species ,Extinction ,Biology ,Tree Biology ,Hawaii ,Invasive species ,Common species ,Threatened species ,education ,Endemism ,Arthropods ,Ecology, Evolution, Behavior and Systematics ,Invasive ants ,Nature and Landscape Conservation - Abstract
Invasive species are causing population declines and extinctions of native species worldwide. Correlates of species vulnerability, which help identify at-risk taxa, are not well developed for arthropods, particularly with respect to threats from invasive species. At five sites undergoing invasion by ants in the Hawaiian Islands, we assessed body size, population density, trophic role and provenance (introduced or endemic to the Hawaiian Islands) as potential correlates of vulnerability for 300 arthropod species. Among rare species, prove- nance was the most important factor associated with absence from invaded plots, with endemic species much more commonly absent. Trophic role was also important, but only when interacting with provenance: endemic carnivores were by far the most vulnerable group, followed by endemic detritivores. For non-rare species, Hawaii endemics were sig- nificantly more reduced in invaded plots compared to introduced species. In addition, species that occurred at lower population densities were more vulnerable than those occurring at higher densities. Body size did not correlate with vulnerability for either rare or non-rare species. Despite these trends, there was relatively high variability in responses to invasion among species in many taxonomic orders, as well as among populations of particular species at different sites. While the consideration of additional intrinsic traits might increase pre- dictive ability to some degree (e.g., intrinsic traits only explained 21% of the variation in impact among non-rare species), community-specific extrinsic factors appear to play a large role in influencing outcomes for many species, making prediction substantially more difficult.
- Published
- 2010
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27. Case studies on decapod crustaceans from the Philippines reveal deep, steep underwater slopes as prime habitats for ‘rare’ species
- Author
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Bertrand Richer de Forges, Tohru Naruse, S. H. Tan, Tin-Yam Chan, Peter K. L. Ng, and Jose Christopher E. Mendoza
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Ecology ,biology ,Decapoda ,Rare species ,Biodiversity ,Intertidal zone ,Marine invertebrates ,biology.organism_classification ,Fishery ,Common species ,Habitat ,Abundance (ecology) ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Relatively few studies have been done to define or assess rarity in the marine environment. Published studies have focused on shallow-water and intertidal habitats, and the available information appears to reflect the same pattern observed in terrestrial environments, i.e., that there are many rare species and few common species in any one given area. However, our studies of the abundance of new and/or supposedly rare taxa of decapod crustaceans from the deep, steep slopes of the island of Balicasag, in the central Philippines, have raised questions on how rarity should be defined in marine invertebrates. Examples of such supposedly rare species of crabs and lobsters (Crustacea: Decapoda) are presented here. That these animals come from deep, steep slopes, a relatively under-studied habitat, highlights the major gaps in current knowledge of marine biodiversity that are in part due to the inadequacy of both traditional and high technology sampling methodologies and the limited habitat types that the former can target. Low-technology, artisanal tangle nets have proved to be an optimal capture technique for deep-water decapod crustaceans on deep, steep slopes; many new taxa have been discovered and, in other cases, perceptions of rarity and endemicity have been corrected.
- Published
- 2009
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28. Influence of harvest gaps and coarse woody material on click beetles (Coleoptera: Elateridae) in Maine’s Acadian forest
- Author
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Shelly L. Thomas, Robert G. Wagner, and William A. Halteman
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Canopy ,Ecology ,Common species ,Abundance (ecology) ,Forest management ,Biodiversity ,Species diversity ,Coarse woody debris ,Species richness ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
In order to maintain biodiversity in forests, it has been recommended that harvests be designed after patterns of natural disturbance. Using a long-term study that includes harvest treatments designed to emulate tree-fall gap disturbances in Maine’s Acadian forest, we examined how the species richness, abundance, diversity, and assemblage similarity of click beetles inhabiting coarse woody material (CWM) were affected by gap harvesting and CWM characteristics (diameter, degree of decay, and type of wood). There were few differences in beetle assemblages between 0.07 and 0.12 ha harvest gap treatments. Four of the most common species had higher abundances under a closed forest canopy than within harvest gaps. Species richness and total abundance were higher in CWM that had larger diameters and were more decayed. Species assemblages also differed with the degree of wood decomposition. Diversity was higher in CWM from softwood trees than hardwood trees. Results from this study suggest that small ( 35 cm).
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- 2009
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29. Fuelling the biodiversity crisis: species loss of ground-dwelling forest ants in oil palm plantations in Sabah, Malaysia (Borneo)
- Author
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Carsten A. Brühl and Thomas Eltz
- Subjects
Ecology ,biology ,Agroforestry ,Anoplolepis ,Biodiversity ,Rainforest ,biology.organism_classification ,Invasive species ,Habitat ,Common species ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Undergrowth - Abstract
Oil palm plantations today cover large areas of former tropical lowland rain forest in Southeast Asia and are rapidly expanding on the island of Borneo. Study of the community of ground-dwelling ants in different plantations in Sabah, Malaysia, over 2 years using tuna baiting, revealed that the oil palm plantation ground ant community was severely reduced in species richness in comparison to the forest interior, regardless of age, undergrowth cover, or proximity to neighbouring forest. The results indicate that oil palm plantation habitats, now covering more than 15% of Sabah’s land area, can sustain only about 5% of the ground-dwelling ant species of the forest interior. Nine of the 23 ant species baited in the plantations were never recorded inside forest. All numerically dominant ants were non-forest species. The most common species was Anoplolepis gracilipes, an invasive species present at 70% of all bait sites and known to cause ‘ecological meltdowns’ in other situations. The low frequency and species number of forest ground ants indicates that oil palm plantations act as effective dispersal barriers leading to community isolation in rain forest remnants. The replacement of natural forests with oil palm plantations poses a serious threat to the conservation of biodiversity on Borneo if similar results are confirmed in other taxa.
- Published
- 2009
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30. Non-random sampling and its role in habitat conservation: a comparison of three wetland macrophyte sampling protocols
- Author
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Melanie V. Croft and Patricia Chow-Fraser
- Subjects
geography ,Marsh ,geography.geographical_feature_category ,Ecology ,Wetland ,Macrophyte ,Common species ,Habitat ,Environmental science ,Species richness ,Quadrat ,Ecology, Evolution, Behavior and Systematics ,Nursery habitat ,Nature and Landscape Conservation - Abstract
Aquatic macrophytes provide essential spawning and nursery habitat for fish, valuable food source for waterfowl, migratory birds and mammals, and contribute greatly to overall biodiversity of coastal marshes of the Laurentian Great Lakes. Two approaches have been used to survey the plant community in coastal wetlands, and these include the grid (GR) and transect (TR) methods. These methods have been used to identify the average species richness at different sites, but their suitability for determining total species richness of a site has not been tested. In this paper, we compare the performance of these two established methods with that of the Stratified method (ST), which uses the sampler’s judgment to guide them to different habitat zones within the wetland. We used the three protocols to compare species richness of six coastal wetlands of the Great Lakes, three pristine marshes in eastern Georgian Bay (Lake Huron) and three degraded wetlands in Lake Ontario, Canada. The greatest species richness was associated with the ST method, irrespective of wetland quality. The ST method was also more efficient (fewer quadrats sampled), and revealed the most number of unique (those found with only one method) and uncommon species (those found in
- Published
- 2009
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31. Why the crested ibis declined in the middle twentieth century
- Author
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Dianmo Li, Xinhai Li, and Huidong Tian
- Subjects
Ibis ,geography ,geography.geographical_feature_category ,Ecology ,biology ,Biodiversity ,Wetland ,biology.organism_classification ,Altitude ,Common species ,Habitat ,Nipponia nippon ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Wildlife conservation - Abstract
The crested ibis (Nipponia nippon) had declined severely from a common species to only two pairs in last century. To analyze the declining process, we established a GIS database with historical occurrences of the crested ibis based on published literatures, and layers of environmental factors such as elevation, wetland, and human activities. We compared the environmental factors at the occurrence sites in different periods to quantify the changes of habitat use across time. To address the spatial deviation of the occurrences and check the effect of measuring scale on habitat use, we calculated the environmental factors in a serial measuring scales from 1 to 161 × 161 km2. Our results indicated that the crested ibis traditionally lives in habitat with higher wetland density and higher human impact, then it gradually moved to areas with higher elevation and lower human impact in last century. In 1980–2000 the crested ibis stayed at a very high elevation, lower wetland density and lower human impact as possible consequences of human activities such as using fertilizer and pesticide, drying the over wintering rice paddies, and direct hunting. Our quantitative analysis of the habitat use matched well the previous published statements (which have no numerical evidences) on the declination of the crested ibis. We suggest to reestablish the habitat with traditional farming practice that the bird has adapted as a major solution for applications such as conservation planning and reintroduction.
- Published
- 2009
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32. Tree seedlings: how do they establish in spontaneously developed forests? A study from a mountainous area in the Czech Republic
- Author
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Alena Dostalova
- Subjects
Altitude ,Ecology ,Common species ,Biodiversity ,Ecological succession ,Tree (set theory) ,Site tree ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Global biodiversity ,Woody plant - Abstract
The aim of this study was to find out which tree species can establish in spontaneously developed forests (SDFs) on mesic stands and how many tree seedlings are present there. The influence of different factors was examined and an attempt made to find out if there are some general trends true for groups of species typical for different stages of succession or with different types of distribution. All tree seedlings present in 48 permanent plots were counted (100 m2). The following factors were tested: altitude, slope and exposition, distance from the nearest forest, age and species composition of tree layer, species composition of herb layer, light conditions and soil reaction. The species composition was dependent on altitude and soil reaction. There were surprisingly high numbers of seedlings (in average 145 tree seedlings per 100 m2) and species (in average 5) present in SDFs. Not only species common in the area were found, but also uncommon species were present there, although in low numbers. Nonspecific species are the best colonisers of SDFs, and the anemochorous trees are better colonisers than zoochorous ones. The establishment of different tree species is influenced by different factors. The SDFs most probably shift toward forest with a number of species in the tree layer. The dominant species tend to be spruce and maple, but species typical for early stages of succession will be common in these growths.
- Published
- 2008
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33. The contribution of common and rare species to plant species richness patterns: the effect of habitat type and size of sampling unit
- Author
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John D. Pantis, Stephanos P. Sgardelis, Antonios D. Mazaris, Athanasios S. Kallimanis, Yiannis G. Matsinos, and Joseph Tzanopoulos
- Subjects
Ecology ,Common species ,Rare species ,Species distribution ,Biodiversity ,Species diversity ,Rank abundance curve ,Species richness ,Body size and species richness ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Understanding how overall patterns of spatial variation in species richness are affected by distributional patterns of species has been an area of growing concern. In the present study, we investigated the relative importance of common and rare species as contributors in overall plant species richness. We further examined if the effects of common or rare species in richness patterns are affected by the size of the sampling units and if the observed patterns hold at different habitats. We used a dataset of 5,148 higher plant species distributed across 16,114 sampling plots located in 240 sites of the NATURA 2000 network of Greece. We ranked all species based on the number of sites they occupied and we developed a common to rare and a rare to common sequence. We correlated those sequences with cumulative species distributions. We performed this analysis in nine different sizes of sampling units and in three different datasets referring to (a) all habitat types together, (b) coniferous habitats only and (c) alpine habitats only. Our analysis showed that despite the proportionally higher numbers of restricted species, widespread species make a greater contribution to overall richness patterns and that this observed pattern does not depend on the size of the sampling units. Moreover, the observed pattern stands for different habitat types. Our findings support the generality of this pattern and highlight the importance of widespread species as adequate indicators of biodiversity patterns at various habitat types.
- Published
- 2008
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34. Diet breadth, coexistence and rarity in bumblebees
- Author
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Gillian C. Lye, Ben Darvill, and Dave Goulson
- Subjects
Forage (honey bee) ,Ecology ,biology ,media_common.quotation_subject ,Biodiversity ,biology.organism_classification ,Competition (biology) ,Common species ,Abundance (ecology) ,Species richness ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Bumblebee ,Nature and Landscape Conservation ,media_common - Abstract
Factors that determine the relative abundance of bumblebee species remain poorly understood, rendering management of rare and declining species difficult. Studies of bumblebee communities in the Americas suggest that there are strong competitive interactions between species with similar length tongues, and that this competition determines the relative abundance of species. In contrast, in Europe it is common to observe several short-tongued species coexisting with little or no evidence for competition shaping community structure. In this study we examine patterns of abundance and distribution in one of the most diverse bumblebee communities in Europe, found in the mountains of southern Poland. We quantify forage use when collecting nectar and pollen for 23 bumblebee species, and examine patterns of co-occurrence and niche overlap to determine whether there is evidence for inter-specific competition. We also test whether rarity can be explained by diet breadth. Up to 16 species were found coexisting within single sites, with species richness peaking in mountain pasture at ~1,000 m altitude. Results concur with previous studies indicating that the majority of pollen collected by bumblebees is from Fabaceae, but that some bee species (e.g. B. ruderatus) are much more heavily dependent on Fabaceae than others (e.g. B. lucorum). Those species that forage primarily on Fabaceae tended to have long tongues. In common with studies in the UK, diet breadth was correlated with abundance: rarer species tended to visit fewer flower species, after correcting for differences in sample size. No evidence was found for similarity in tongue length or dietary overlap influencing the likelihood of co-occurrence of species. However, the most abundant species (which co-occurred at most sites) occupied distinct dietary niche space. While species with tongues of similar length tended, overall, to have higher dietary niche overlap, among the group of abundant short-tongued species that commonly co-occurred there was marked dietary differentiation which may explain their coexistence.
- Published
- 2008
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35. Eutrophication and fragmentation are related to species’ rate of decline but not to species rarity: results from a functional approach
- Author
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Christine Römermann, Anne-Kathrin Jackel, Peter Poschlod, and Oliver Tackenberg
- Subjects
Climax species ,Ecology ,Common species ,Indicator species ,Threatened species ,Rare species ,Fragmentation (computing) ,Biodiversity ,Biological dispersal ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Due to ubiquitous eutrophication and fragmentation, many plant species are actually threatened in Europe. Most ecosystems face an overall nutrient input leading to changes in species composition. Fragmentation is effectively influencing species survival. We investigate if two different measures of species performance of 91 calcareous grassland species–rate of decline and rarity—are related to comparable traits and hence processes. On the one hand we expected that species rate of decline is mainly determined by the processes of eutrophication and fragmentation. On the other hand we hypothesized that the importance of site characteristics may overwhelm the effect of eutrophication and fragmentation for species rarity. Hence, we compared persistence traits responding to eutrophication, dispersal traits being related to fragmentation and ecological site factors for decreasing and increasing species and for rare and common species. The results suggest that increasing species had better means of long-distance dispersal and were more competitive than decreasing species. In contrast, there were hardly any differences in traits between rare and common species, but site characteristics were related to species rarity. Rare species were in the main those with ecological preferences for warm, dry, light and nutrient poor conditions. This study may represent a basis for the assessment of plant species threat. Applying the deduced knowledge about the life history of decreasing versus increasing species to habitat-scale approaches it is possible to predict which species may become threatened in the future simply from the combination of their trait values.
- Published
- 2007
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36. Plant communities on ironstone outcrops: a diverse and endangered Brazilian ecosystem
- Author
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Regina de Castro Vincent, Flávio Fonseca do Carmo, Claudia Maria Jacobi, and João Renato Stehmann
- Subjects
Ecology ,Outcrop ,Biodiversity ,Endangered species ,Plant community ,Vegetation ,engineering.material ,Ironstone ,Geography ,Common species ,engineering ,Endemism ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Mountain areas are recognized centres of endemism and diversity on account of their isolation and altitudinal diversity. In tropical regions, mountain tops usually stand as islands of xeric vegetation among mesophytic assemblages. Unlike the vegetation growing on other rock outcrops lithologies, such as inselbergs (granite/gneiss) or campos rupestres (quartz/arenite), ironstone outcrop plant communities still lack systematic studies in Brazil. These outcrops (locally known as canga) share most of the characteristics of other rock outcrops, such as isolation and edapho-climatic harshness, but differ in that they are the object of opencast mining, and thus subjected to irrecoverable degradation. In addition, they are expected to harbour metal-tolerant and hyperaccumulator plant species. A botanical survey of two ironstone outcrop locations in the most important mining region of southeastern Brazil, the Iron Quadrangle, revealed a high within-site (138 and 160 species per site), and between-site diversity (only 27% of common species), totaling 64 families and 234 species among basal families and eudicots (154 species), monocots (68 species), and ferns (12 species). Canga crusts are rich in dicots, several of which play an important role in community structuring, together with the more usual monocot aggregations. Distinct plant communities are found associated to different microhabitats within the iron crust, depending primarily on the amount of soil and moisture retention in the different microtopographies. The environmental uniqueness, high diversity, lack of studies and rapid destruction of these ecosystems pose an immediate challenge for their conservation.
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- 2007
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37. Implications of collection patterns of botanical specimens on their usefulness for conservation planning: an example of two neotropical plant families (Moraceae and Myristicaceae) in Peru
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Euridice Honorio, Mathias W. Tobler, Carlos Reynel, and John P. Janovec
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Ecology ,biology ,Amazon rainforest ,Biodiversity ,Species diversity ,biology.organism_classification ,Floristics ,Myristicaceae ,Herbarium ,Geography ,Common species ,Rarefaction (ecology) ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
We evaluated the usefulness of herbarium collection databases for assessing patterns of species diversity and distribution based on a dataset from the flowering plant families Moraceae and Myristicaceae from the Peruvian Amazon. For Moraceae, a total of 3523 collections were used representing 134 species. The Myristicaceae were represented by 2113 collections of 46 species. We evaluated the distribution of collections based on 252 grid cells (0.5° size) covering all lowland rainforest in the Peruvian Amazon. We found that collections were concentrated in a few cells and that species diversity clearly increases in relation to collection density. Moraceae were collected in only 45% and Myristicaceae in only 31% of the 252 grid cells. Fifty percent of the collections came from just six and three cells, respectively. Most species were represented by only a small number of collections and collected only in a few grid cells, meaning a few widespread common species tend to dominate the collection records. Not surprisingly, most collections were made close to towns and transport routes. We evaluated the usefulness of rarefaction curves and diversity estimators for comparing diversity between regions. These techniques seem to be of little use for botanical collections due to violations of underlying assumptions. Problems such as accuracy of geographic and taxonomic data and strong bias in the spatial representation of the whole dataset are important to consider when basing conservation analysis, planning, and decision-making on seemingly large databases of biodiversity collections and are discussed in detail.
- Published
- 2007
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38. Rarity and abundance in a diverse African forest
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David Kenfack, George B. Chuyong, Richard Condit, and Duncan W. Thomas
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Habitat destruction ,Ecology ,Common species ,Rare species ,Biodiversity ,Dominance (ecology) ,Species richness ,Biology ,Endemism ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Basal area - Abstract
We censused all trees ‡1 cm dbh in 50 ha of forest in Korup National Park, southwest Cameroon, in the central African coastal forest known for high diversity and endemism. The plot included 329,519 individuals and 493 species, but 128 of those taxa remain partially identified. Abundance varied over four orders of magnitude, from 1 individual per 50 ha (34 species) to Phyllobotryon spathulatum, with 26,741 trees; basal area varied over six orders of magnitude. Abundance patterns, both the percentage of rare species and the dominance of abundant species were similar to those from 50-ha plots censused the same way in Asia and Latin America. Rare species in the Korup plot were much less likely to be identified than common species: 42% of taxa with
- Published
- 2006
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39. Long-Term Changes of a Coastal Bird Breeding Community on a Small Island – Does Natural Succession Compromise Conservation Values?
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Steffen Oppel
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Ecology ,Common species ,Disturbance (ecology) ,Endangered species ,Ecosystem management ,Biodiversity ,Species evenness ,Umbrella species ,Species richness ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Limited spatial resources available for conservation lead to controversy about whether to apply single-species management or ecosystemary approaches in order to maintain biodiversity. In this study I analyse changes in a community of breeding coastal birds over a 90-year period, in order to examine whether natural processes on an unmanaged island are in accordance with requirements to save endangered species. Both diversity and species richness of the community increased significantly over time, and evenness increased after having been severely reduced by human impact. Diversity, evenness and species richness seemed to approach an equilibrium in the past decade, but number of breeding pairs declined as a consequence of altered natural disturbance regime. Species identity changed over time, with two initially very common species recently becoming locally extinct. These species are of high conservation concern, and their disappearance causes a problem for the concept of naturalness on islands. I conclude that natural processes need to be applied to the entire landscape in order to maintain dynamic processes that are essential for the survival of these species. The natural changes on the island should not be interrupted, but rather demonstrated to the public in order to increase conservation mindedness and gain support for changes in anthropogenic influences on a larger spatial scale.
- Published
- 2005
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40. Management Effects on Bryophytes in Estonian Forests
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Nele Ingerpuu and Kai Vellak
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Species groups ,Ecology ,Common species ,Management effects ,Forest management ,Biodiversity ,Bryophyte ,Species richness ,Epigeal ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Bryophyte species richness and composition of six different forest types and three different management rates was analysed in 36 Estonian forests. Analyses were done separately for six different bryophyte species groups: total species number, hepatic, hemerophobic, common, non-epigeic and epigeic species. The differences in species richness between unmanaged and moderately managed forests were significant for all species groups, while the differences between moderately and intensively managed forests were significant only for total species number, and numbers of common and non-epigeic species. Our results showed also that in comparison of unmanaged and moderately managed forests, management effect was significant for species richness of all species groups except non-epigeic species, while in comparison of moderately and intensely managed forests, management rate remained significant only for total species richness and richness of common species. Also the species composition was affected by forest management. Only the compositions of unmanaged forest types were found to be significantly different between each other. In conclusion, even moderate management eliminates a significant number of bryophyte species, and the species composition of different forest types become more similar.
- Published
- 2005
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41. Cryptogam communities on decaying deciduous wood – does tree species diversity matter?
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Jacob Heilmann-Clausen, Erik Aude, and Morten Christensen
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Ecology ,Biodiversity ,Species diversity ,Biology ,Cryptogam ,biology.organism_classification ,Deciduous ,Common species ,Botany ,Bryophyte ,Alpha diversity ,Species richness ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Bryophyte and fungal communities were investigated on fallen trees representing seven deciduous tree species in a mixed near natural nemoral forest. Bryophytes were represented by 41 taxa, including several very frequent species. Of the 296 fungal species, most were recorded with very low frequency and the share of high frequent species was much lower than among the bryophytes. Species turnover was bigger in the fungal communities, compared to the bryophyte communities, and related to a higher extent to measured differences in environmental conditions. Tree species diversity was found to be an important factor for fungal species composition, while only small differences in bryophyte species composition were found between the different tree species. On the other hand bryophyte species richness showed distinct relations to tree species and microclimatic variables, a tendency which was not evident for fungal diversity. It is concluded that the two organism groups to some extent differ in their conservation demands. Thus, conservation of wood-inhabiting bryophytes requires prioritising of large, coherent forest stands in which a stable humid microclimate and a reasonable supply of dead wood is secured. Successful conservation of fungi requires that substantial amounts of dead wood are left for natural decay in a variety of natural forest environments representing different tree species, so that heterogeneity in dead wood types is secured.
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- 2005
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42. Inferences from Common Species Communities for Selecting Conservation Areas
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Romain Julliard and Frédéric Jiguet
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Ecology ,Common species ,Rare species ,Spatial ecology ,Biodiversity ,Umbrella species ,Species richness ,Rank abundance curve ,Biology ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
We aimed at identifying probabilistic areas of high biodiversity value over a large spatial scale, e.g., an entire country (France) within the temperate region, that could work as valuable conservation areas for both rare and common species. We aimed at identifying areas where four measures on bird community overpass a selected threshold value, by using probability interpolation models. The four variables considered were the rare species number, and three measures related to common bird community: relative abundance, estimated species richness and composition originality. For the latter, we developed an indicator that discriminates original from more ordinary compositions of common bird communities, accounting for the number of representatives in each species. This indicator was positively correlated to rare breeding species number, so that original composition of common bird communities allows us to identify areas also supporting the rarest species. Areas with high probabilities of two indicators reaching their threshold values represented 2.9% of continental France. Most double-indicator areas were those with high species richness and high relative abundance, then with original communities and high rare species number. The originality indicator was revealed valuable to identify the most suitable areas that could ensure the preservation of both rare and common species, at a national scale. By preserving sites supporting original common bird communities, conservationists would ensure the protection of rare and common species.
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- 2005
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43. Rare plants at the extremes of distribution: broadly and narrowly distributed rare species
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Mark W. Schwartz and Michele H. Mills
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Ecology ,Rare species ,Biodiversity ,food and beverages ,Herbaceous plant ,Biology ,Flora of North America ,Common species ,Habitat ,Eudicots ,Endemism ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The flora of North America north of Mexico was used to study rare species at the two extremes of geographic distribution: endemic species, those with large local populations but small geographic ranges, and suffusively rare species, those with small local populations but large geographic ranges. The taxonomic distribution, geographic distribution, and life history characteristics of the two groups were compared. Only 2% of North American species are suffusively rare, while 22.6% of species are endemic to one state or province. Suffusively rare species are significantly more likely to be seedless vascular plants and monocots than expected, and are less likely to be eudicots. Conversely, endemic species are more likely to be eudicots, and less likely to be monocots. Suffusively rare species are most abundant in Canada and the northeastern United States, whereas there are few endemic species in those areas. The highest proportions of endemic species are found in California, Florida, and Texas. Wetland habitats support many suffusively rare species, but few endemic species. Neither are common in alpine habitats. Suffusively rare and endemic species also differ in the dominant growth form. Suffusively rare species are most likely to be herbaceous eudicots, and less likely to be shrubs or shrub-herbs. Endemic species are also likely to be herbaceous, but are also frequently shrubs. A high proportion of endemic species exhibit plasticity in growth form, whereas few suffusively rare species have plastic growth forms. While both groups contain rare species, they differ considerably in geographic distribution and life history traits.
- Published
- 2005
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44. Is a biology of rarity in primates yet possible?
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Alexander H. Harcourt and Stephanie A. Coppeto
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Taxon ,Ecology ,Common species ,Habitat ,Rare species ,Biodiversity ,Zoology ,Sampling error ,Biology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
If we lack data on the biology of rare species, then understanding of the biology of rarity will be incomplete at best, biased at worst. However, the extent of potential under-study is mostly unknown. We therefore ask for primates, one of the better known orders of mammals, whether data are lacking on rare species. The measure used is published data on a crucial aspect of biology, namely density. Rare species are here defined as those with both geographic range sizes and habitat breadths less than the median for primates; common species are at or above the median for those two measures. Globally, nearly half, 47%, of the 32 rare species lack data on their density, compared to only 10% of the 83 common species (χ2corr. = 17.1, p < 0.001). Within realms, Asia and Madagascar show a particularly strong bias, missing density data for over 50% of their rare species. Thus, rare species are indeed severely under-studied compared to common species, even in this well-studied mammalian taxon.
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- 2005
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45. Abundance of two threatened woodpecker species in relation to the proportion of spruce plantations in native pine forests of western Norway
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Ivar Gjerde, Magne Sætersdal, and Trygve Nilsen
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Ecology ,biology ,Dendrocopos minor ,Dendrocopos leucotos ,Picus viridis ,Woodpecker ,biology.organism_classification ,Deciduous ,Common species ,Dendrocopos major ,Picus canus ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
In a comparative study we investigated woodpecker abundance in forest landscapes with different proportion of native pine forest and spruce plantations in western Norway. In 100 circular study plots of 100 ha each we recorded 38 white-backed –Dendrocopos leucotos, 22 grey-headed –Picus canus, 13 great spotted –Dendrocopos major, 6 green –Picus viridis, and 2 lesser spotted –Dendrocopos minor woodpeckers in the breeding season. The mean number of recorded woodpecker species peaked at 20–40% spruce plantations. The two most common species in the study, the white-backed and the grey-headed woodpeckers are both Red-listed species in Norway and among the rarest woodpeckers in Europe. The white-backed woodpecker preferred plots with higher than average proportions of standing dead trees and deciduous trees, and low proportions of spruce plantations in the plots. The grey-headed woodpecker preferred plots in the western (coastal) parts of the study area with presence of large aspen Populus tremula trees. Logistic regression models did not reveal any clear threshold values with respect to proportion of spruce plantations in plots, although both woodpecker species were extremely rare in plots with >60% spruce plantations. We recommend spruce plantations to be kept at moderate levels to ensure viable populations of woodpeckers in western Norway.
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- 2005
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46. Biogeographic patterns, -diversity and dominance in the cerrado biome of Brazil
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José Felipe Ribeiro, S. Bridgewater, and J. A. Ratter
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Geography ,Ecology ,Common species ,Biogeography ,Biome ,Biodiversity ,Dominance (ecology) ,Phytogeography ,Ecology, Evolution, Behavior and Systematics ,Floristics ,Nature and Landscape Conservation ,Global biodiversity - Abstract
From a total woody flora of ca. 1000 species, a suite of 121 species forms an oligarchy dominating the cerrado biome. This mirrors patterns of dominance described in western Amazonian rain forests. Widespread sampling shows that across the biome this suite of species contributes on average 66% of the total species composition, and 75% of the total Importance Value Index in cerrado communities. An analysis of the floristic similarity between six cerrado phytogeographic provinces (southern, central and south-eastern, central-western, far-western, north-eastern, disjunct Amazonian) reveals great heterogeneity within the biome, principally of the less common species. Of the 951 species recorded from 375 floristic surveys across the biome, 494 species (more than half of the total) are found in only one of the provinces, with very few species (37, i.e., 3.9%) found in all six provinces. Each of the provinces contains a significant number of species which are apparently confined to it, ranging from 15 species (1.6% of the total woody cerrado flora) in the far-western province (primarily in the state of Rondonia) to 162 species (17%) in the central-western province. At the local level, floristic similarity can be very high. An analysis of the floristic composition of 13 sites within the Federal District shows a woody flora of 236 species, indicating that 25% of the total woody flora of the cerrado biome is represented in 0.3% of its area, illustrating the great conservation importance of this region. Floristic similarity between sites within the Federal District is high, although much of this similarity is accounted for by ‘oligarch’ species which account for between 59 and 89% of total species recorded per site. Informed conservation judgements within the cerrado need to take account of regional floristic patterns to ensure maximum protection of biodiversity, as the majority of species are not geographically widespread within the biome.
- Published
- 2004
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47. Long-term tree population dynamics and their implications for the conservation of the Kakamega Forest, Kenya
- Author
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Marina Cords, Peter J. Fashing, Christina Scully, and Alison Forrestel
- Subjects
education.field_of_study ,Pioneer species ,Ecology ,Population ,Biodiversity ,Vegetation ,Biology ,Common species ,Disturbance (ecology) ,visual_art ,visual_art.visual_art_medium ,Trampling ,education ,Ecology, Evolution, Behavior and Systematics ,Tree stump ,Nature and Landscape Conservation - Abstract
Long-term studies of tree population dynamics play an important role in identifying the conservation needs of tropical forest ecosystems. We examined changes in tree population structure and composition over an 18-year period (1981–1999) in three plots located at the center of the Isecheno study site in the Kakamega Forest, Kenya, a forest with a history of logging and other anthropogenic disturbance. DBH size class distribution took the shape of an ‘inverse J’ curve in both 1981 and 1999 and did not differ significantly between the two study periods. Stem density increased significantly during the study with most of the increase occurring in the smallest stem size class (10–14 cm DBH). Nearly all of the most common species in 1981 remained among the most common in 1999, though the density of pioneer species decreased by 21% during the study. Our results suggest that forest in the study plots remained relatively undisturbed and in good condition over the study period. Forest in the plots also appeared still to be recovering from the selective logging of large trees that took place at Isecheno in the 1940s. In addition to our longitudinal study, we compared tree population parameters at three additional Isecheno sites spread over a distance of ∼1 km that have experienced different histories of disturbance: (i) a lightly human disturbed site (LHD), (ii) a heavily human disturbed site (HHD), and (iii) a cattle disturbed site (CD). While all three sites were selectively logged in the 1940s, the main signs of disturbance today are footpaths at the LHD site, tree stumps at the HHD site, and wide cattle paths at the CD site. Not surprisingly, of the disturbed sites, the LHD site was in the best condition. Trees at the HHD site exhibited extremely poor recruitment into the small size classes, a condition that can probably be attributed to human exploitation of small trees for poles. The CD site appeared to be at an earlier successional stage than the other disturbed sites with its low mean DBH, high overall stem density, and high pioneer species stem density. Browsing and trampling of vegetation by cattle may be the source of the light gaps that have led to the abundance of pioneer species at this site. We conclude that conservation measures applied to central Isecheno, including the establishment of a forest station nearby and ranger patrols, appear to have succeeded, but that the prognosis for the Kakamega Forest in general is bleak if protection efforts are not increased in other parts of the forest, where anthropogenic disturbance remains high. We also note the considerable variation in tree population structure and composition that can occur within a small area depending on the local history of disturbance.
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- 2004
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48. [Untitled]
- Author
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Nicolas Gaidet, Hervé Fritz, and Claudius Nyahuma
- Subjects
0106 biological sciences ,Ecology ,business.industry ,010604 marine biology & hydrobiology ,Environmental resource management ,Biodiversity ,Wildlife ,Participatory monitoring ,15. Life on land ,Census ,010603 evolutionary biology ,01 natural sciences ,Geography ,Common species ,Abundance (ecology) ,11. Sustainability ,Sustainability ,Wildlife management ,business ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The sustainable use of wildlife resources within community-based programmes is considered as a valuable option to enhance development and conservation objectives. The application of such a concept in communal lands requires the strong support of local communities through their active involvement in wildlife management. Precise and regular information on wildlife abundance is also essential for effective conservation. In this paper, we present an innovative participatory monitoring method based on bicycle counts developed within the framework of an integrated conservation and development project in the Zambezi Valley, Zimbabwe. Results from the 1999 count of population density and structure of common species as well as diversity of large to medium size species are presented. We demonstrate the efficiency of this method, which allowed a high census intensity with efficient animal detection, and hence appeared appropriate for use in a non-protected area. The method gave high levels of precision for the density estimates obtained (10–30% cv) and is therefore useful as a repeatable monitoring tool. In addition, this method is inexpensive to run and is easy to implement for local people. We emphasise the technical and financial autonomy offered by the bicycle counts for communities to monitor their wildlife resources, and we discuss the contribution of this method to the wildlife management process.
- Published
- 2003
- Full Text
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49. [Untitled]
- Author
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Susan J. Richardson-Kageler
- Subjects
Herbivore ,Stocking ,Ecology ,Common species ,Biodiversity ,Species diversity ,Species richness ,Biology ,Relative species abundance ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,Woody plant - Abstract
Study sites from various tree savannas and miombo woodland with adjacentareas with different herbivore species (game and cattle) and stocking rates wereselected from around Zimbabwe. Using the fence-lines separating the adjacentareas, 60 m2 plots were placed on both sides of thefence at 18 randomly chosen positions. The identity and number of plants of eachwoody species were recorded in paired 60 m2 plots. Therewere no significant differences in the woody species richness between pairedplots for any of the fence-line contrasts. For only two of the fence-linecontrasts were there significant differences (P < 0.05)in the relative abundance of woody species. For the first fence-line contrast,the stocking rates were the same, but the herbivore species present weredifferent, while for the second fence-line contrast, the numbers of herbivorespecies present were the same, but the stocking rates differed. Even thoughthere were no differences in the numbers of woody plant species present, therewere differences in the woody plant species and the numbers of plants of eachspecies: the second most common species was different for three fence-linecontrasts and the third most common species was different for four fence-linecontrasts.
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- 2003
- Full Text
- View/download PDF
50. [Untitled]
- Author
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Nevin Keskin, Selcuk Hazir, Servet Özcan, Harry K. Kaya, and S. Patricia Stock
- Subjects
Veterinary medicine ,geography ,Marsh ,geography.geographical_feature_category ,Ecology ,biology ,Biodiversity ,biology.organism_classification ,Grassland ,Nematode ,Common species ,Loam ,Botany ,Heterorhabditis bacteriophora ,Rhabditida ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The diversity and distribution of entomopathogenic nematodes in thefamilies Steinernematidae and Heterorhabditidae were assessed throughout anextensive soil survey in Turkey during 1999 and 2000. Entomopathogenic nematodeswere recovered from six out of seven regions sampled, with 22 positive sites(2%) out of 1080 sites sampled. A single nematode isolate was recovered at eachof the positive sites, of which 15 were steinernematid isolates and seven wereheterorhabditid isolates representing a total of four species. Based onmorphometric and molecular data, the nematode species were identified asHeterorhabditis bacteriophora, Steinernemafeltiae, S. affine, andSteinernema n. sp. The most common species was S.feltiae, which was isolated from 10 sites in six regions, followed byH. bacteriophora from seven sites in five regions,S. affine from four sites in two regions, andSteinernema n. sp. from one site. Heterorhabditisbacteriophora and S. feltiae have been found inmany parts of the world, whereas S. affine, so far, hasonly been recovered in Europe until our survey. Steinernemaaffine was isolated from the European (Marmara) as well as theAsiatic region (Middle Anatolia) of Turkey. A new undescribedSteinernema sp. was isolated from the most eastern region(East Anatolia) of Turkey. Soils of the positive sites were classified as sandy,sandy loam, or loam (68.2%) and sandy–clay–loam or clay loam (31.8%) and the pHranged from 5.6 to 7.9. The habitats from which the entomopathogenic nematodeswere isolated were broadly classified as disturbed (59.1%), which includedagricultural fields and poplar planted for lumber and wind breaks, andundisturbed (40.9%), which included pine forest, grassland, marsh and reed sites.Steinernema feltiae, S. affine, andH. bacteriophora were recovered from both disturbed andundisturbed habitats. The new Steinernema sp. was recoveredfrom grassland. Our survey showed that these nematodes occur widely throughoutTurkey, but at a frequency below that reported for other parts of the world.
- Published
- 2003
- Full Text
- View/download PDF
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