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Natural habitats are being altered and destroyed worldwide due to urbanization, leading to a decrease in species abundance and richness. Nevertheless, some species, including tawny owls, have successfully colonized this novel habitat. Consequences at the population level have not been described, thus, our main objective was to describe the effects that urban structure have on the tawny owl population at local and landscape levels. Data were obtained from 527 survey points over 7 months in a large-scale owl survey in the Basque Country (northern Spain) in 2018. At the local scale, the interaction between forest and urban cover affected tawny owl abundance, the optimum being in medium forested areas. The interaction between urban cover and clumpiness index (urban patch distribution) showed a generally negative effect. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. In conclusion, at the local scale, when a minimal forest structure is present in urbanized areas, the species can exploit it. At the landscape scale, it prefers smaller urban towns to cities. Thinking ahead, the current tendency toward “green capitals” should benefit tawny owl populations.

Eutrophication is a widespread environmental change that usually reduces the stabilizing effect of plant diversity on productivity in local communities. Whether this effect is scale dependent remains to be elucidated. Here, we determine the relationship between plant diversity and temporal stability of productivity for 243 plant communities from 42 grasslands across the globe and quantify the effect of chronic fertilization on these relationships. Unfertilized local communities with more plant species exhibit greater asynchronous dynamics among species in response to natural environmental fluctuations, resulting in greater local stability (alpha stability). Moreover, neighborhood communities that have greater spatial variation in plant species composition within sites (higher beta diversity) have greater spatial asynchrony of productivity among communities, resulting in greater stability at the larger scale (gamma stability). Importantly, fertilization consistently weakens the contribution of plant diversity to both of these stabilizing mechanisms, thus diminishing the positive effect of biodiversity on stability at differing spatial scales. Our findings suggest that preserving grassland functional stability requires conservation of plant diversity within and among ecological communities., Eutrophication has been shown to weaken diversity-stability relationships in grasslands, but it is unclear whether the effect depends on scale. Analysing a globally distributed network of grassland sites, the authors show a positive role of beta diversity and spatial asynchrony as drivers of stability but find that nitrogen enrichment weakens the diversity-stability relationships at different spatial scales.

Globally, sandy beaches are subject to coastal squeeze due to erosion. Soft-sediment strategies, such as sand nourishment, are increasingly applied to mitigate effects of erosion, but have long-term negative impacts on beach flora and fauna. As a more ecologically and sustainable alternative to regular beach nourishments, a mega-nourishment has been constructed along the Dutch coast by depositing 21.5 Mm(3) of sand, from which sand is gradually redistributed along the coast by natural physical processes. The 'Sand Motor' mega-nourishment was constructed as a long-term management alternative for coastal protection and is the first large-scale experiment of its kind. We evaluated the development of intertidal macroinvertebrate communities in relation to this mega-nourishment, and compared it to species composition of beaches subject to regular beach or no nourishment. We found that a mega-nourishment resulted initially in a higher macroinvertebrate richness, but a lower macroinvertebrate abundance, compared to regular beach nourishment. As there was no effect of year after nourishment, this finding suggests that colonization and/or local extinction were not limiting macroinvertebrate richness at the mega-nourishment. In addition, a mega-nourishment does not converge to an intertidal macroinvertebrate community similar to those on unnourished beaches within a time scale of four years. Beach areas at the mega-nourishment sheltered from waves harbored a distinct macroinvertebrate community compared to typical wave-exposed sandy beach communities. Thus, a mega-nourishment temporally creates new habitat for intertidal macroinvertebrates by enhancing habitat relief of the sandy beach. We conclude that a mega-nourishment may be a promising coastal defense strategy for sandy shores in terms of the macroinvertebrate community of the intertidal beach. (C) 2018 Elsevier Ltd. All rights reserved.

Caves are excellent model systems to study the effects of abiotic factors on species distributions due to their selective conditions. Different ecological factors have been shown to affect species distribution depending on the scale of analysis, whether regional or local. The interplay between local and regional factors in explaining the spatial distribution of cave-dwelling organisms is poorly understood. Using the troglophilic subterranean spider Artema nephilit (Araneae: Pholcidae) as a model organism, we investigated whether similar environmental predictors drive the species distribution at these two spatial scales. At the local scale, we monitored the abundance of the spiders and measured relevant environmental features in 33 caves along the Jordan Rift Valley. We then extended the analysis to a regional scale, investigating the drivers of the distribution using species distribution models. We found that similar ecological factors determined the distribution at both local and regional scales for A. nephilit. At a local scale, the species was found to preferentially occupy the outermost, illuminated, and warmer sectors of caves. Similarly, mean annual temperature, annual temperature range, and solar radiation were the most important drivers of its regional distribution. By investigating these two spatial scales simultaneously, we showed that it was possible to achieve an in-depth understanding of the environmental conditions that governs subterranean species distribution.

Beta diversity describes the variation in species composition between sites and is often influenced by both local and regional processes. Partitioning beta diversity into turnover (species replacement between sites) and nestedness (richness difference between sites) components may enhance our understanding of the mechanisms behind the local and regional drivers determining species composition across spatial scales. We sampled macrophyte communities in 24 lakes in two regions (Yangtze River basin and Yunnan-Guizhou plateau) of China covering broad climate and nutrient gradients. Based on both species and functional approaches, we calculated multiple-site beta diversity using the Sorensen dissimilarity index and partitioned it into turnover and nestedness coefficients crossed with two nested spatial scales: among depths within transects (transect scale) and among transects within lakes (lake scale). The overall species beta diversity and functional beta diversity (i.e. Sorensen coefficient) were significantly lower and thus more homogeneous at lake scale. Across spatial scales, species beta diversity was mainly explained by turnover patterns (56–61%) and functional beta diversity primarily by nestedness patterns (58–65%). Both local and regional drivers contributed to structuring species and functional beta diversity patterns, largely through changes in species turnover and functional nestedness, respectively. Overall, we observed a significant increase in species beta diversity and its turnover component while a decreasing trend in functional beta diversity and its nestedness component at high altitude. Our results further emphasized that the species beta diversity and its turnover component decreased at high total phosphorus concentration (TP) across the two spatial scales, while the functional beta diversity and its nestedness component decreased at high TP at the transect scale. We conclude that understanding of the relative role of local and regional drivers in determining macrophyte diversity patterns may help managers to select the most appropriate conservation strategies for preservation of biodiversity varying with the scale in focus.

There is growing evidence that biodiversity is important for ecosystem functions. Thus, identification of habitat requirements essential for current species richness and abundance to persist is crucial. Hollow oaks (Quercus spp.) are biodiversity hot spots for deadwood-dependent insect species, and the main objective of this paper was to test the effect of habitat history and current habitat distribution at various spatial scales on the associated beetle community. We used a gradient spanning 40 km from the coast to inland areas reflecting historical logging intensity (later and lower intensities inland) through 500 years in Southern Norway, to investigate whether the historical variation in oak density is influencing the structure of beetle communities in hollow oaks today. We trapped beetles in 32 hollow oaks along this gradient in forested and seminatural landscapes over two summers. We found higher species richness and total abundance inland consistent with our expectation based on historic logging intensity. Scale-specific environmental variables also affected the response; beetle abundances were controlled by local conditions, whereas beetle species richness responded to habitat on the landscape scale. This indicates that long time continuity as well as large areas of favorable habitat is necessary to maintain beetle species richness through time in these highly long-lasting structures. Coleoptera, extinction debt, historical logging, Quercus, saproxylic, spatial scales, temporal scale, veteran tree

In order to better explore the maintenance mechanisms of biodiversity, data collected from a 40-ha undisturbed Pinus forest were applied to the Individual Species–Area Relationship model (ISAR) to determine distribution patterns for species richness. The ecological processes influencing species abundance distribution patterns were assessed by applying the same data set to five models: a Log-Normal Model (LNM), a Broken Stick Model (BSM), a Zipf Model (ZM), a Niche Preemption Model (NPM), and a Neutral Model (NM). Each of the five models was used at six different sampling scales (10 m × 10 m, 20 m × 20 m, 40 m × 40 m, 60 m × 60 m, 80 m × 80 m, and 100 m × 100 m). Model outputs showed that: (1) Accumulators and neutral species strongly influenced species diversity, but the relative importance of the two types of species varied across spatial scales. (2) Distribution patterns of species abundance were best explained by the NPM at small scales (10 m–20 m), whereas the NM was the best fit model at large spatial scales. (3) Species richness and abundance distribution patterns appeared to be driven by similar ecological processes. At small scales, the niche theory could be applied to describe species richness and abundance, while at larger scales the neutral theory was more applicable. Keywords: Species richness, Species abundance, Spatial scales, Niche theory, Neutral theory

Las riberas son ecosistemas espacial y temporalmente heterogéneos que favorecen una alta diversidad, pero que se podrían ver afectadas por la intensificación de ciertas perturbaciones antrópicas. Con el propósito de aportar información de base, que permita evaluar los efectos sobre la biodiversidad de eventuales disturbios, se caracteriza la vegetación por sus grupos biológicos y se analizan tres aspectos: la diversidad a tres escalas (margen, tramo y cuenca), su relación con características topográficas y edáficas y los cambios asociados a la presencia de ganado. Se identificaron 130 taxa; entre ellas, Cynodon dactylon y Eleocharis spp. tuvieron una frecuencia cercana al 100% y fueron los de mayor cobertura. Se halló 51% de especies herbáceas perennes, 27% de hidrófilas, 18% de anuales y 3% de árboles. En cuanto al origen, la proporción de exóticas no es menor a la mencionada para pastizales pampeanos, aunque las hidrófilas, propias de estos ambientes, son casi en su totalidad nativas. La diversidad beta calculada como el cociente entre tramo y márgenes fue 1.37, y entre cuenca y tramos fue 1.89. Por esto, la diversidad beta contribuye de manera importante a la biodiversidad regional. La diversidad se correlacionó con el eje que representa las variables edáficas en un análisis de componentes principales, a pesar que las pendientes explicaron una mayor proporción de la variabilidad entre sitios. La vertiente del Río de la Plata es la más diversa, y en un análisis discriminante se separó del resto. La densidad aparente del suelo fue la variable que más contribuyó a la distinción. Se sugiere que al momento de diseñar investigaciones y estrategias de manejo, la interpretación del funcionamiento de las riberas se realice en la escala de cuenca. Riparian areas are temporally and spatially heterogeneous ecosystems which favor high species’ diversity; however, they may be affected by the intensification of certain anthropogenic perturbations. With the aim of generating basic information to assess the effects of possible disturbances, riparian vegetation is characterized in terms of growth form, and three of its aspects are analyzed: diversity at three scales (bank, reach, and watershed), relationship with topographic and soil variables, and changes associated with livestock presence. In this study, 130 taxa were identified; among them, Cynodon dactylon and Eleocharis spp. exhibited frequencies close to 100% and the highest coverage level. Of all the species, 51% were perennials, 27% macrophytes and amphibious plants, 18% annual plants and 3% trees. The proportion of exotic species is not lower than that of pampean grasslands, but macrophytes and amphibious plants are almost all natives. Beta diversity, calculated as the ratio between reach and stream-banks, was 1.37, and for watershed/reachs, 1.89; thus, beta diversity contributes significantly to regional biodiversity. In a principal component analysis, bank slopes explained the greater proportion of variability among sites. Nevertheless, diversity was correlated to the soil-variables axis. The Río de la Plata watershed was the most diverse, and was differentiated from the other watersheds in a discriminant analysis, primarily on the basis of soil-bulk density. We suggest that the functioning of riparian areas be considered at the watershed scale for the design of research projects and management strategies.

Agricultural expansion and intensification is driving rapid landscape modification in the South American Gran Chaco, affecting biodiversity at multiple spatial scales. Research on biodiversity change in modified landscapes has focused mainly on remnant habitat patches. However, the habitat quality of the matrix is increasingly recognized as a key element for planning conservation in agricultural landscapes. We employed a multi-model selection approach to test 13 hypotheses about the influence of spatial scales and structural attributes on the richness of bird assemblages and forest specialist species within matrix types at the Argentine Dry Chaco. We selected 27 cattle ranches where six structural attributes of vegetation operating at different spatial scales (plot, edge and landscape) varied independently across a matrix intensification gradient in the agricultural frontier. We found that structural attributes operating at the plot, edge and landscape scale have significant influence on overall richness, with plot-scale attributes being more important than edge and landscape-scale attributes in driving bird occurrence in the grazing matrix. Factors operating at the plot scale had the largest influence on the richness of forest specialist species in the matrix. These results suggest that planning for the long-term conservation of Dry Chaco forests avifauna should pay attention to the effects of local agricultural management. Where further cattle production intensification cannot be avoided, implementation of highly selective clearing methods can mitigate the degradation of habitat quality for birds. Where cattle production intensification has already occurred, native tree plantings on cleared areas can restore significant bird diversity. Fil: Mastrangelo, Matias Enrique. Victoria University of Wellington; Nueva Zelanda. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Gavin, Michael C.. State University of Colorado - Fort Collins; Estados Unidos

The importance of spatial scale has been acknowledged as one of determining factors of species diversity in local and regional diversity. The aim of this study was to evaluate contribution of alpha (α) and beta (β) diversity across land-use type to gamma (γ) diversity at the margins of tropical forest in Central Sulawesi using dung beetles (Coleoptera: Scarabaeidae) as a focal group. Baited pitfall traps set in four land-use types ranging from natural forest through cacao agroforestry systems to open areas during two years of sampling (2009 and 2012). A total of 28 dung beetle species belonging to four genera were captured during the study period. The results showed that contribution of β diversity was higher than that of α diversity of dung beetles. Each land-use type contributed about 56.5 to 62.5% of the total species richness (γ diversity). The similar pattern of biodiversity between each spatial scale and during the two sampling years emphasized the large contribution of each land-use type to maintaining a high portion of the regional species richness. It suggests the importance of managing other land-use types, such as secondary forest and agroforestry as well as protecting the remaining natural forests.

International audience; We investigated the interacting impacts of urban landscape and gardening practices on the species richness and total abundance of communities of common butterfly communities across France, using data from a nationwide monitoring scheme. We show that urbanization has a strong negative impact on butterfly richness and abundance but that at a local scale, such impact could be mitigated by gardening practices favoring nectar offer. We found few interactions among these landscape and local scale effects, indicating that butterfly-friendly gardening practices are efficient whatever the level of surrounding urbanization. We further highlight that species being the most negatively affected by urbanization are the most sensitive to gardening practices: Garden management can thus partly counterbalance the deleterious effect of urbanization for butterfly communities. This holds a strong message for park managers and private gardeners, as gardens may act as potential refuge for butterflies when the overall landscape is largely unsuitable.

International audience; Agri-environment schemes (AESs) were implemented to reduce the loss of biodiversity in agro-ecosystems. This study aimed to assess whether AESs at either local or landscape scale increase the carabid abundance-activity and species richness. Carabids were sampled in 496 fields in a 430 km2 study area of central-western France. Based on the extensiveness of the agricultural practices involved, the different AES types were aggregated into three categories (AESEXT+, AESEXT++ and AESEXT+++) forming a gradient of extensiveness in farming practices. We sampled 20 fields in each of the three AESs categories. Each AES fields was paired with conventional fields. A series of statistical models were built to test the balance between the effects of AESs on either the carabid abundance-activity or species richness. AESs affected carabid abundance-activity and species richness both locally and at landscape scale (local characteristics having a greater effect than landscape composition). Carabid diversity benefited from AESs only when the most extensive practices were implemented, i.e. organic farming in cereal crops and delayed cutting in alfalfa. In addition, the local effects of organic farming and delayed cutting coverage interacted positively with these AESs at landscape scale. These results demonstrate that non-targeted organisms can benefit from AES management. They further emphasize the need to consider both local and landscape conditions when studying the effects of AESs on biodiversity. As only the most extensive practices had significant effects at both local and landscape scales, management must be planned strategically in space to ensure that AESs are distributed within the landscape to amplify their positive effects.

For over 150 years, ecologists have been striving to explain fundamental patterns of biological diversity, such as the observation that communities invariably consist of common and rare species, and to unravel the processes that underpin these patterns. This task is increasingly urgent given the accelerating loss of biological diversity. Although fishes are the most diverse vertebrate taxon and fish communities occur in a wide range of habitats, they have been relatively little studied in the quest to elucidate the processes that shape patterns of biological diversity. Here, some of the topics that investigations of fish assemblages can illuminate are highlighted. These include the characteristics of ecological communities and the role that dispersal limitation plays in structuring them, the distinction between core and occasional species, the insights that evaluating abundance in different currencies can bring and the assessment of community capacity. Questions are identified that future investigations of fish communities might tackle and a case study of a biodiverse ecoregion (Thailand and Peninsula Malaysia) is used to illustrate the need for better links between these ecological questions and effective conservation practice. Postprint

Our aim was to analyse changes in species turnover and structure of macrofaunal assemblages associated with intertidal coralline algal turfs at 4 spatial scales along the coast of Argentina (southwestern Atlantic): provinces (∼106 m), localities (∼104 m), sites (∼10 2 m) and replicate quadrats (∼1 to 3 m). Corallina officinalis was by far the dominant algal species in most samples, but C. elongata and Jania rubens var. rubens were also frequent. Frond density was 3 times higher in the southern, cold-temperate Chubut province than in the northern, warm-temperate Buenos Aires province. Macrofaunal species richness, diversity and evenness were also significantly higher in samples from Chubut than in those from Buenos Aires, with 'province' explaining 86 to 98% of the variance in the analytical model. In total, 118 macrofaunal taxa belonging to 11 invertebrate phyla were found. Mytilid bivalves and polychaetes were the most important groups contributing to differences between provinces. Brachidontes roddguezii was extremely abundant in Buenos Aires province, while Rhynchospio glutaea and Perumytilus purpuratus were dominant in samples from Chubut. Changes in assemblage structure were significant at the scale of provinces, localities and sites in Patagonian localities. Measures of beta diversity showed that taxonomic turnover was correlated with distance between samples at scales of 10 4 m or higher, with the highest at the scale of provinces. Higher biodiversity in the Magellan assemblage than in warmer areas of the northern coast of Argentina may be related to the Pacific origin of the Magellan fauna, which entered the southwestern Atlantic during the Tertiary period. Fil: Liuzzi, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: López Gappa, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina

Trawling has been reported worldwide to alter seabed structure, and thus benthic habitats and ecosystems. Usually, a decrease in species richness and biomass is observed, and community structure is modified towards more opportunistic species. The Gulf of St Lawrence (Canada) has been intensely exploited since the 17th century, including net, longline, dredge and trawl fishing activities. Recently, the collapse of groundfish stocks induced a shift in fishing practices toward shrimp trawling, which is currently considered a sustainable fishing activity in the region. However, no long-term study has evaluated the potential effects of trawling disturbances on benthic mega-invertebrates. We investigated whether shrimp trawling had long- (ca. 20 years), mid- (ca. 10 years), and short-term (ca. 4 years) impacts on benthic mega-invertebrate taxa richness, biomass, and community structure. Scientific and fishery trawling data analyses showed that no significant long-, mid-, or short-term effect was detected on taxa richness. Significant but weak effects on biomass and community structure were detected at the mesoscale, i.e. at the scale of fishing grounds. In this long-exploited ecosystem, we suggest that a critical level of disturbance was attained by the first gear passages, which occurred decades ago and had irreversible impacts on the seabed by removing vulnerable taxa and structures that provided three-dimensional habitats. It is likely that benthic communities have subsequently reached a disturbed state of equilibrium on which current trawling disturbance has limited or no further impacts.

The importance of disturbance and the subsequent rate and pattern of recovery has been long recognised as an important driver of community structure. Community recovery is affected by processes operating at local and regional scales yet the examination of community level responses to a standardised disturbance at regional scales (i.e. among regions under different environmental conditions) has seldom been attempted. Here, we mechanically disturbed rocky intertidal lower shore algal dominated assemblages at three locations within each of three different regions within the Lusitanian biogeographical province (Azores, northern Portugal and the Canary Islands). All organisms were cleared from experimental plots and succession followed over a period of 12 months at which time we formally compared the assemblage structure to that of unmanipulated controls. Early patterns of recovery of disturbed communities varied among regions and was positively influenced by temperature, but not by regional species richness. Different components of the assemblage responded differently to disturbance. Regional differences in the relative abundance and identity of species had a key influence on the overall assemblage recovery. This study highlights how regional-scales differences in environmental conditions and species pool are important determinants of recovery of disturbed communities.

There is substantial evidence that environmental changes on a landscape level can have dramatic consequences for the species richness and structure of food webs as well as on trophic interactions within such food webs. Thus far, the consequences of environmental change, and particularly the effects of invasive species and the fragmentation and isolation of natural habitats, have most often been studied in a purely ecological context, with the main emphasis on the description of alterations in species abundance and diversity and trophic links within food webs. Here, we argue that the study of evolutionary processes that may be affected by such changes is urgently needed to enhance our understanding of the consequences of environmental change. This requires an approach that treats species as dynamic systems with plastic responses to change rather than as static entities. As such, phenotypic plasticity on an individual level and genotypic change as a population level response should be taken into account when studying the consequences of a changing world. Using a multidisciplinary approach, we report on recent advances in our understanding, identify some major gaps in our current knowledge, and point towards rewarding approaches to enhance our understanding of how environmental change alters trophic interactions and ecosystems. [KEYWORDS: evolutionary processes ; phenotypic plasticity ; genotypic change ; trophic interactions ; invasive species ; habitat fragmentation]

This study identified the main biological mechanisms governing the diversity of ants on different ecological time scales. Ants were sampled in 15 plots distributed in early, intermediate and late stages of succession (five plots per stage) at the Parque Estadual da Mata Seca, Brazil. At each sample point, unbaited pitfall traps were installed in hypogaeic, epigaeic and arboreal strata. We collected 95 ant species from 26 genera and nine subfamilies. Our results indicated that there was an increase in species richness in advanced stages of succession. We also observed that ant assemblages were different among successional stages. For the arboreal and epigaeic strata, species richness did not change with succession progression, but species composition of these two strata differed among successional stages. Unlike to arboreal and epigaeic ants, hypogaiec ant species richness was higher in the intermediate and late stages of succession and the composition of hypogaeic ants differed among successional stages. Similarity between ant species foraging in arboreal and epigaeic strata decreases with succession progression and β-diversity was higher in advanced successional stages. Additionally, species richness was higher in the dry season, whereas the composition of ant assemblages did not change between seasons. A considerable fraction of the ant assemblage was found only in advanced stages of succession, demonstrating the importance of secondary habitats in maintaining biodiversity in dry forests.

Copyright © Marine Biological Association of the United Kingdom, 2014. In this study we examined the epibiont assemblage on shells of the living limpet Patella aspera. Limpets were collected at two sites at each of the nine islands of the Azores, totalling 707 individuals examined. Shells were measured and all the epibiota identified to the lowest taxonomic resolution possible. 190 taxa were recorded, of which 97% were algae, including 17 new records for the Azores. Only five shells were devoid of fouling organisms. The assemblage was dominated by a few algal taxa, whereas the majority of species occurred on less than 10% of the shells. A significant and positive relationship was generally found between basibiont size (shell length) and epibiota richness. The strength (slope) of the relationship, however, varied between islands and sites. These results suggest that a range of processes operating at multiple spatial scales influenced epibiont assemblages. Many features identified in these assemblages resemble, in many ways, those examined in island biogeography, suggesting that basibionts may be considered as 'islands' and may provide a suitable model system to test ecological hypotheses about ecosystems that are not so amenable to experimentation.

International audience; Wetlands, especially ponds, and their associated amphibian biodiversity are threatened by agricultural intensification. To improve conservation planning of these ecosystems, we need to understand at which scales biodiversity responds to human-induced disturbances. This study aims to assess the level-dependence of environment-amphibian biodiversity relationships in 150 ponds in an intensive agricultural landscape in Seine-et-Marne (France). Amphibian diversity surveys, site characteristic measurements and landscape descriptions are analysed. The hierarchy of the effects of local and regional variables on species richness, regional heterogeneity of species composition and species occurrences is investigated at three spatial levels: pond level, 1-, and 4-km(2) level. Species richness is negatively influenced at all levels by the fish presence. Water quality and pond density, which emphasize level-dependent effects, significantly increase species richness at the local and regional levels, respectively. With few exceptions, species occurrence analysis shows similar patterns, confirming, locally, the importance of fish avoidance, and, regionally, the need for increasing pond density. Environmental variables have no effect on the regional heterogeneity of species composition, questioning the potential existence of dispersal processes at scales above 1 km(2). This study highlights the relevance of a pond-group-centred approach compared to a pond-centred approach with regard to pond conservation in agricultural landscapes.

Agricultural intensification may result in important shifts in insect community composition and function, but this remains poorly explored. Studying how groups of species with shared traits respond to local and landscape scale land-use management can reveal mechanisms behind such observed impacts. We tested if ground beetles (Coleoptera: Carabidae) divided into trait groups based on body sizes, wing morphologies and dietary preferences respond differently to farming practise (organic and conventional), farming intensity (measured as yield) and landscape complexity (measured as the proportion of arable land within a 1,000 m radius) across Europe. We used data from 143 farms in five regions in northern and central Europe. Organic farms did not differ in abundance or richness of any trait group compared to conventional farms. As farm scale intensity (yield) increased, overall abundance of beetles decreased, but abundances of small and medium sized beetles, as well as that of wingless beetles, were unaffected. Overall species richness was not affected by yield, whereas consideration of traits revealed that phytophagous and omnivorous beetles were less species rich on farms with high yields. Increasing the proportion of arable land in the landscape increased overall beetle abundance. This was driven by an increase in omnivorous beetles. The total species richness was not affected by an increase in the proportion arable land, although the richness of wingless beetles was found to increase. Potential effects on ecosystem functioning need to be taken into account when designing schemes to maintain agricultural biodiversity, because species with different ecological traits respond differently to local management and landscape changes.

Despite the widely recognised importance of reserve networks, their effectiveness in encompassing and maintaining biodiversity is still debated. Species diversity is one of the most affordable measures of biodiversity, but it is difficult to survey such data over large scales. This research aimed to perform a sample-based assessment of species richness of groups of plants with different conservation value (alien species, protected species, and all species) within a reserve network, testing the use of partitioning as a tool for assessing diversity at different spatial scales, from the plot to the entire network. Plant diversity patterns differed for the groups of species for most of the investigated spatial scales. Despite these patterns assumed divergent tendencies when different species groups were considered, most of the species richness within the network was given by larger scale β-diversity for both alien and protected species, as well for all species. Diversity partitioning proved an effective tool to quantify the role of spatial scales in structuring the total species richness of the network, and is helpful in planning reserve networks.

International audience; The conservation of biodiversity has gained prominence in ecological research for the last decades. Conservation actions require a measure of biodiversity such as species richness, but its assessment is very difficult, even for small areas and therefore the search for surrogates (i.e. indicators) of biodiversity has emerged as an active research topic. We investigated the relationships between butterfly species richness and landscape structure and composition in two pine plantation sites in Southwest France. We assessed the correlation between butterfly species richness and a set of 15 landscape metrics computed for 18 land-uses at 10 different spatial scales. Spatial scales were accounted for by computing landscape metrics for circular buffers with radius ranging from 100 to 1000 m. The joint use of the Partial Least Squares Regression (PLSR) and a stepwise regression procedure revealed strong correlations between butterfly species richness and various landscape metrics in both study sites. The selected landscape metrics differed from one site to another and mostly involved measures of landscape fragmentation. We found a very strong effect of the spatial scale of investigation upon the perception of the landscape–butterfly richness relationship. Our main conclusions are that (i) certain landscape attributes can potentially serve as indicators for butterfly species richness at the landscape scale; (ii) future indicators of biodiversity based on landscape features should consider various spatial scales.

Reforestation of ex-arable land in temperate regions increases the area of potential habitat for forest plants. However, the herbaceous plant layer of these plantations contains fewer forest species than comparable plantations at continuously forested sites. One of the reasons for this might be differences in recruitment. The present study addresses post-dispersal seed predation, mainly of woody plants, as the factor limiting the recolonization of young oak plantations in southern Sweden. Our objectives were to investigate differences in dispersal and post-dispersal seed predation between first-generation forest plantations on ex-arable land and re-planted clear-cuts on continuously forested land. There was no recruitment following the experimental sowing of six commonwoody species (Alnus glutinosa, Betula pendula, Frangula alnus, Sambucus nigra, Sorbus aucuparia and Sorbus intermedia). Thus, the colonization of forest plantations by native shrubs and trees appears to be habitat-limited; the only exception being Rhamnus catharticus, for which poor dispersal ability may be more important. Post-dispersal seed predation of forest shrubs and trees was marked, especially in relatively small and isolated plantations on ex-arable land. There was a high seed predation of Crataegus monogyna, Sorbus aucuparia and Viburnum opulus on ex-arable land, while that of Frangula alnus and Sambucus racemosa was not associated with site placement and land-use history. Seed predation is probably a more important factor limiting restoration of near-natural forests than previously thought.

The impact of a bottom trawl fishery on fish or benthos is often determined by multiplying the frequency of the passing of the trawl by a factor for the effect (i.e., % mortality) of the singular passing of the gear. As fishing intensity in an area is not homogeneously distributed, it is necessary to determine the proportions of the area that are fished with dif- ferent trawling frequencies, as these subareas together contribute to the overall species' mortality. In this study, we show that the perceived proportion of the area fished with a specific trawling frequency depends upon the spatial and temporal scale used. A smaller spatial scale results in an increased perceived patchiness of the fishing intensity, while a longer time period does the opposite. The implication is that to determine the fishing-induced mortality of a particular species, the trawling frequency needs to be determined at those spatio-temporal scales that are appropriate considering the species' spa- tial processes (e.g., dispersion) or temporal processes described by life history characteristics. Resume´ : L'impact de la peche au chalut de fond sur les poissons ou sur le benthos se determine souvent en multipliant la frequence de passage du chalut par un facteur representant l'effet (par ex., % de mortalite´) d'un passage unique de l'engin. Comme l'intensitede peche dans une region n'est par repartie de maniere homogene, il est necessaire de deter- miner les proportions de la surface qui ont etesoumises aux differentes frequences de chalutage, puisque ces sous-surfaces contribuent ensemble ala mortaliteglobale de l'espece. Dans notre etude, nous montrons que la perception de la propor- tion de surface soumise aune intensitespecifique de chalutage depend de l'echelle spatiale et temporelle utilisee. Une echelle spatiale reduite a pour resultat la perception d'une contagion accrue de l'intensitede peche, alors qu'une periode de temps plus longue a l'effet contraire. Les consequences de cette observation est que, pour determiner la mortalitereliee ala peche chez une espece en particulier, il est necessaire de determiner la frequence de chalutage aux echelles spatiotem- porelles appropriees, compte tenu des processus spatiaux (par ex. la dispersion) et temporels de l'espece decrits par les car- acteristiques de son cycle biologique. (Traduit par la Redaction)