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For the Caatinga vegetation, it has not yet been definitively established which adaptive strategies best define the functional groups of woody plants and which syndromes emerge from the relationships between functional traits to achieve success in a semi-arid tropical region. To fill some of these gaps, we analyzed a specific set of characteristics that make up the LHS scheme of the plant ecological strategy (leaf-heigh-seed). The LHS scheme captures the functional niche of plants regarding the functional traits specific leaf area (SLA), plant height (HE), and seed mass (SM). We associate wood density (WD) to this scheme because this trait is a key feature for the identification of functional strategies in seasonally dry vegetation such as the Caatinga. We measured these characteristics in eight woody species and classified them according to their leaf phenology into deciduous and evergreen. The experiment was carried out between December 2017 and November 2018 in Caatinga areas located in the municipality of Barra de Santana, PB, a semiarid region of Brazil. Using cluster analysis, principal component analysis (PCA) and Pearson correlation analyses, we found significant relations between SLA and SM, and HE and WD. The SLA was the main predictor of plant strategy in the Caatinga. According to this characteristic, we identified two functional groups: species with a low SLA and species with a high SLA. We also recognized differences between deciduous and evergreen species based on the same trait. The traits measured, which represent the axes of the plant ecological strategy scheme LHS and wood density, are efficient in the discrimination of functional groups in the Brazilian semiarid. These groups relate to leaf phenology of woody species in this vegetation.

We aimed to characterize the adult and regenerating tree components and their relationships with soil characteristics of a native vegetation remnant in Cuiabá, Mato Grosso, Brazil. The area of the fragment is stratified into "dry area" (lithic neosoil) and "damp area" (gleisoil). We conducted a forest inventory with a random distribution of 25 parcels. We analyzed the physical and chemical components of the soil. We evaluated the vegetation's horizontal structure, diversity, and sample sufficiency using the Bootstrap richness estimator. We classified the species according to dispersal syndrome and ecological group. Overall, we found 93 species in the adult layer and 70 species in the regenerating layer. The similarity dendrograms based on the two evaluated indices demonstrated the existence of the two initially stratified environments in both strata. The IndVal (%) indicated that the set of indicator species differed between the strata. Thereby, the fragment is in an intermediate stage of successional progression. PCA showed that plots in the wet area had higher pH values and Ca, Zn, and Fe levels, while plots in the dry area did not clearly distinguish, varying in terms of K, B, and organic matter content. In CCA, a set of species that occurred exclusively in the damp area showed a strong relationship with the analyzed variables. The area is a diverse ecosystem that efficiently provides ecosystem services to society and should be the subject of long-term conservation and research.

Amazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO 2 are declining, as deforestation and climate-change-associated droughts 1-4 threaten to push these forests past a tipping point towards collapse 5-8 . Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone 9-17 . Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes 18,19 (defined by water-table depth, soil fertility and texture, and vegetation characteristics). In higher-fertility southern Amazonia, drought response was structured by water-table depth, with resilient greening in shallow-water-table forests (where greater water availability heightened response to excess sunlight), contrasting with vulnerability (browning and excess tree mortality) over deeper water tables. Notably, the resilience of shallow-water-table forest weakened as drought lengthened. By contrast, lower-fertility northern Amazonia, with slower-growing but hardier trees (or, alternatively, tall forests, with deep-rooted water access), supported more-drought-resilient forests independent of water-table depth. This functional biogeography of drought response provides a framework for conservation decisions and improved predictions of heterogeneous forest responses to future climate changes, warning that Amazonia's most productive forests are also at greatest risk, and that longer/more frequent droughts are undermining multiple ecohydrological strategies and capacities for Amazon forest resilience., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Here we studied the entire Atlantic Forest hotspot to investigate whether the effect of different environmental predictors depends on the phylogenetic extension and the biogeographical history of different Atlantic Forest sectors. We used occurrence data of 3,183 plant species with arboreal or arborescent habits. We reconstructed climatic stability across 120,000 years using the Random Forest method. Then, we compared the effect of biogeographical history, topographic, and climatic variables on species richness and phylogenetic diversity using Geographically Weighted Regression (GWR) models. Niche conservatism drives the strength and direction of environmental correlates with tree diversity, interacting with the biogeographical and phylogenetic extension considered. Low current climate seasonalities were the main drivers of species richness and phylogenetic diversity variation across the Atlantic Forest. Whereas in higher phylogenetic extension, topographic heterogeneity increased the number of tree species independent of the sector, deep-past climate stability favored phylogenetic diversity by increasing relict lineages of distant clades in all forests, but with anomalies in the southern sector. This investigation yields substantial evidence that the response of the northern and southern sectors of the Atlantic Forest to identical environmental conditions diverges significantly, providing compelling support for the imprint of phylogenetic heritage in generating non-linear diversity patterns.

Non-structural carbohydrates (NSC) are major substrates for plant metabolism and have been implicated in mediating drought-induced tree mortality. Despite their significance, NSC dynamics in tropical forests remain little studied. We present leaf and branch NSC data for 82 Amazon canopy tree species in six sites spanning a broad precipitation gradient. During the wet season, total NSC (NSC T ) concentrations in both organs were remarkably similar across communities. However, NSC T and its soluble sugar (SS) and starch components varied much more across sites during the dry season. Notably, the proportion of leaf NSC T in the form of SS (SS:NSC T ) increased greatly in the dry season in almost all species in the driest sites, implying an important role of SS in mediating water stress in these sites. This adjustment of leaf NSC balance was not observed in tree species less-adapted to water deficit, even under exceptionally dry conditions. Thus, leaf carbon metabolism may help to explain floristic sorting across water availability gradients in Amazonia and enable better prediction of forest responses to future climate change.

In general, insect herbivore diversity is positively correlated to plant diversity since plant assemblages structure different microhabitats and provide food resources for such insects. Although poorly studied, insect herbivores in tropical dry forests are positively affected by tree species richness and the structural architecture of vegetation. In this study, we analyzed whether true weevil and woody plants present similar patterns of diversity across different landscape units in a Neotropical tropical dry forests located in Brazil, and if there is a correlation among their assemblages. We used Hill numbers according to species richness and the inverse of Simpson to compare the taxonomic diversity of true weevils and plants in nine landscape units located at the São Francisco river basin in the states of Sergipe and Alagoas, north-eastern Brazil. All trees and shrubs with diameter at breast height (1.3 m) ≥ 5 cm were sampled, and true weevils were collected using a modified Malaise trap. We used co-correspondence analysis to test if plants and true weevil species tend to co-occur. A total of 538 true weevils from 60 species was collected, and a total of 1419 plants belonging to 49 species was recorded. There is no general pattern of co-occurrence and diversity among true weevils and plants, indicating that the plant community is not structuring true weevil assemblage in the Caatinga. However, there was positive relationship between Sibinia sp4 and Fabaceae-Mimosoideae. These results suggest true weevil-plant relationships in the Caatinga differ from that of more mesic ecosystems. Therefore, we observed that the mechanisms that regulate herbivore-plant diversity relationships do not always follow a positive relationship, as observed in previous studies.

Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come.

The emissions, deposition, and chemistry of volatile organic compounds (VOCs) are thought to be influenced by underlying landscape heterogeneity at intermediate horizontal scales of several hundred meters across different forest subtypes within a tropical forest. Quantitative observations and scientific understanding at these scales, however, remain lacking, in large part due to a historical absence of canopy access and suitable observational approaches. Herein, horizontal heterogeneity in VOC concentrations in the near-canopy atmosphere was examined by sampling from an unmanned aerial vehicle (UAV) flown horizontally several hundred meters over the plateau and slope forests in central Amazonia during the morning and early afternoon periods of the wet season of 2018. Unlike terpene concentrations, the isoprene concentrations in the near-canopy atmosphere over the plateau forest were 60% greater than those over the slope forest. A gradient transport model constrained by the data suggests that isoprene emissions differed by 220 to 330% from these forest subtypes, which is in contrast to a 0% difference implemented in most present-day biosphere emissions models (i.e., homogeneous emissions). Quantifying VOC concentrations, emissions, and other processes at intermediate horizontal scales is essential for understanding the ecological and Earth system roles of VOCs and representing them in climate and air quality models., Competing Interests: The authors declare no conflict of interest.

To provide an empirical foundation for estimates of the Amazonian tree diversity, we recently published a checklist of 11,675 tree species recorded to date in the region (ter Steege H, et al. (2016) The discovery of the Amazonian tree flora with an updated checklist of all known tree taxa. Scientific Reports 6:29549). From this total of plant records compiled from public databases and literature, widely used in studies on the Amazonian plant diversity, only 6,727 tree species belong to the first taxonomically-vetted checklist published for the region (Cardoso D, et al. (2017) Amazon plant diversity revealed by a taxonomically verified species list. PNAS 114:10695-10700). The striking difference in these two numbers spurred us to evaluate both lists, in order to release an improved Amazonian tree list; to discuss species inclusion criteria; and to highlight the ecological importance of verifying the occurrence of "non-Amazonian" trees in the region through the localization and identification of specimens. A number of species in the 2016 checklist that are not trees, non-native, synonyms, or misspellings were removed and corresponded to about 23% of the names. Species not included in the taxonomically-vetted checklist but verified by taxonomists to occur in Amazonia as trees were retained. Further, the inclusion of recently recorded/new species (after 2016), and recent taxonomic changes added up to an updated checklist including 10,071 species recorded for the Amazon region and shows the dynamic nature of establishing an authoritative checklist of Amazonian tree species. Completing and improving this list is a long-term, high-value commitment that will require a collaborative approach involving ecologists, taxonomists, and practitioners.

Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate-induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long-term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO 2 concentrations): maximum tree size, biogeographic water-deficit affiliation and wood density. Tree communities have become increasingly dominated by large-statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry-affiliated genera have become more abundant, while the mortality of wet-affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry-affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate-change drivers, but yet to significantly impact whole-community composition. The Amazon observational record suggests that the increase in atmospheric CO 2 is driving a shift within tree communities to large-statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change., (© 2018 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.)

Macroinvertebrate shredders consume preferably leaves conditioned by fungi and bacteria which offer greater palatability to them. Plant species in Cerrado present high concentration of chemical elements such as lignin and cellulose, phenols and tanins thus making them less attractive for shredders consumption and limiting the palatability. This study aimed to evaluate the feeding preference of a macroinvertebrate shredder of the genus Phylloicus for plant material from two different biomes (Cerrado and Mata Atlântica), after conditioning in a stream of Mata Atlântica and observing their physical and chemical characteristics. Senescent leaves were collected, monthly from the litterfall of riparian vegetation in a 500 m stretch of a stream in each biome from August 2014 to January 201. The most abundant species in each stream was selected for the experiment. The experimental design consisted in with two treatments. The first (T1) comprised leaf discs from Chrysophyllum oliviforme (Cerrado species) together with leaf discs of Miconia chartacea (Atlantic Forest species) which were conditioned in the Atlantic Forest stream. The second treatment (T2) involved leaf discs of Miconia chartacea conditioned in Mata Altlântica and Cerrado streams. Both tests had showed significant differences between the two treatments (T1 and T2). For T1, there was consumption of M. chartacea leaf discs by Phylloicus sp., but there was no consumption of C. oliviforme discs. For T2, there was preference for M. chartaceae leaves conditioned in a stream of Mata Atlântica than in Cerrado stream. The results showed that Phylloicus sp., had presented preference for food detritus of the Mata Antlântica biome and rejection to the one from Cerrado biome.

Precise identification of plant species requires a high level of knowledge by taxonomists and presence of reproductive material. This represents a major limitation for those working with seedlings and juveniles, which differ morphologically from adults and do not bear reproductive structures. Near-infrared spectroscopy (FT-NIR) has previously been shown to be effective in species discrimination of adult plants, so if young and adults have a similar spectral signature, discriminant functions based on FT-NIR spectra of adults can be used to identify leaves from young plants. We tested this with a sample of 419 plants in 13 Amazonian species from the genera Protium and Crepidospermum (Burseraceae). We obtained 12 spectral readings per plant, from adaxial and abaxial surfaces of dried leaves, and compared the rate of correct predictions of species with discriminant functions for different combinations of readings. We showed that the best models for predicting species in early developmental stages are those containing spectral data from both young and adult plants (98% correct predictions of external samples), but even using only adult spectra it is still possible to attain good levels of identification of young. We obtained an average of 75% correct identifications of young plants by discriminant equations based only on adults, when the most informative wavelengths were selected. Most species were accurately predicted (75-100% correct identifications), and only three had poor predictions (27-60%). These results were obtained despite the fact that spectra of young individuals were distinct from those of adults when species were analyzed individually. We concluded that FT-NIR has a high potential in the identification of species even at different ontogenetic stages, and that young plants can be identified based on spectra of adults with reasonable confidence.

We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide.

Local variation in the abundance and richness of vascular epiphytes is often attributed to environmental characteristics such as substrate and microclimate. Less is known, however, about the impacts of tree and branch turnover on epiphyte communities. To address this issue, we surveyed branches and epiphytes found on the forest floor in 96 transects in two forests (Atlantic rainforest in Brazil and Caribbean rainforest in Panama). In the Brazilian forest, we additionally distinguished between edge and core study sites. We quantified branch abundance, epiphyte abundance, richness and proportion of adults to investigate the trends of these variables over branch diameter. Branches <2 cm in diameter comprised >90% of all branches on the forest floor. Abundance and richness of fallen epiphytes per transect were highest in the Brazilian core transects and lowest in the Panamanian transects. The majority of epiphytes on the floor (c. 65%) were found attached to branches. At all three study sites, branch abundance and branch diameter were negatively correlated, whereas epiphyte abundance and richness per branch, as well as the proportion of adults were positively correlated with branch diameter. The relationship between branch diameter and absolute epiphyte abundance or richness differed between study sites, which might be explained by differences in forest structure and dynamics. In the Panamanian forest, epiphytes had been previously inventoried, allowing an evaluation of our surveying method by comparing canopy and forest floor samplings. Individuals found on the forest floor corresponded to 13% of all individuals on branches <10 cm in diameter (including crowns), with abundance, richness and composition trends on forest floor reflecting canopy trends. We argue that forest floor surveys provide useful floristic and, most notably, demographic information particularly on epiphytes occurring on the thinnest branches, which are least accessible. Here, branchfall acts as an important demographic filter structuring epiphyte communities.

Background: The Araucaria Forest is associated with the Atlantic Forest domain and is a typical ecosystem of southern Brazil. The expansion of Araucaria angustifolia had a human influence in southern Brazil, where historically hunter-gatherer communities used the pinhão, araucaria's seed, as a food source. In the north of the state of Santa Catarina, the Araucaria Forest is a mosaic composed of cultivation and pasture inserted between forest fragments, where pinhão and erva-mate are gathered; some local communities denominate these forest ecotopes as caívas. Therefore, the aim of this study is to understand how human populations transform, manage and conserve landscapes using the case study of caívas from the Araucaria Forests of southern Brazil, as well as to evaluate the local ecological knowledge and how these contribute to conservation of the Araucaria Forest., Methods: This study was conducted in the northern plateau of the state of Santa Catarina, Brazil in local five communities. To assess ethnoecological perceptions the historical use and management of caívas, semi-structured interviews, checklist interviews and guided tours were conducted with family units., Results: In total 28 family units participated in the study that had caívas on their properties. During the course of the study two main perceptions of the ecotope caíva were found, there is no consensus to the exact definition; perception of caívas is considered a gradient. In general caívas are considered to have the presence of cattle feeding on native pasture, with denser forest area that is managed, and the presence of specific species. Eleven management practices within caívas were found, firewood collection, cattle grazing, trimming of the herbaceous layer, and erva-mate extraction were the most common. Caívas are perceived and defined through the management practices and native plant resources. All participants stated that there have been many changes to the management practices within caívas and to the caíva itself., Conclusions: These areas still remain today due to cultural tradition, use and management of plant resources. Through this cultural tradition of maintaining caívas the vegetation of the Araucaria Forest has been conserved associated to the use of the Araucaria Forests native plant resources.

Studies of genetic diversity in plant species present in the remaining fragments of the Atlantic Forest are very important for understanding their resilience to such a degraded ecosystem. We analyzed the genetic diversity of 3 populations of the high-density understory species Metrodorea nigra St. Hill. (Rutaceae) located in forest remnants in the region of Ribeirão Preto, SP, Brazil (M13-Rib, BSQ-Rib, and FAC-Crav), by using simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) molecular markers for conservation purposes. A total of 133 polymorphic loci were observed in 136 inter-simple sequence repeat loci (average of 17 per primer). The Nei genetic diversity (HE) was relatively high considering all populations (0.31). The BSQ-Rib population exhibited the highest value (0.27), followed by the M13-Rib (0.26) and FAC-Crav (0.24) populations. The simple sequence repeat markers analyzed showed a high number of alleles (K = 104), with an average of 14.85 alleles per locus. The average observed heterozygosity was 0.516 and the average expected heterozygosity was 0.771, ranging from 0.688 (FAC-Crav) to 0.765 (BSQ-Rib). The fixation indexes showed positive and significant differences from zero for all sample sets, indicating inbreeding, which may have resulted from the species' mating patterns and the barochoric seed dispersal system of M. nigra. Both markers indicated differentiation among populations, with higher values observed for inter-simple sequence repeat markers. No significant differences between juvenile and adult generations in any of the fragments were observed, indicating the resilience of M. nigra to the effects of fragmentation and reduced habitat.

Amazonian rainforests sustain some of the richest tree communities on Earth, but their ecological and evolutionary responses to human threats remain poorly known. We used one of the largest experimental datasets currently available on tree dynamics in fragmented tropical forests and a recent phylogeny of angiosperms to test whether tree communities have lost phylogenetic diversity since their isolation about two decades previously. Our findings revealed an overall trend toward phylogenetic impoverishment across the experimentally fragmented landscape, irrespective of whether tree communities were in 1-ha, 10-ha, or 100-ha forest fragments, near forest edges, or in continuous forest. The magnitude of the phylogenetic diversity loss was low (<2% relative to before-fragmentation values) but widespread throughout the study landscape, occurring in 32 of 40 1-ha plots. Consistent with this loss in phylogenetic diversity, we observed a significant decrease of 50% in phylogenetic dispersion since forest isolation, irrespective of plot location. Analyses based on tree genera that have significantly increased (28 genera) or declined (31 genera) in abundance and basal area in the landscape revealed that increasing genera are more phylogenetically related than decreasing ones. Also, the loss of phylogenetic diversity was greater in tree communities where increasing genera proliferated and decreasing genera reduced their importance values, suggesting that this taxonomic replacement is partially underlying the phylogenetic impoverishment at the landscape scale. This finding has clear implications for the current debate about the role human-modified landscapes play in sustaining biodiversity persistence and key ecosystem services, such as carbon storage. Although the generalization of our findings to other fragmented tropical forests is uncertain, it could negatively affect ecosystem productivity and stability and have broader impacts on coevolved organisms.

Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao's H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like Myrtaceae, are also very representative of this forest type. We point out to the need of more attention to Mixed forests as a conservation target within the Brazilian Atlantic Forest given their high phylogenetic uniqueness.

The Brazilian cerrado presents strong climate seasonality. During the dry season, plants may be exposed to stressful situations, such as a soil surface water deficit, that stimulate their chemical defenses. However, the seasonality effect on the production of allelopathic compounds of cerrado plant species is poorly understood. In this study, the phytotoxic activities of common native cerrado plants were evaluated during rainy and dry seasons. Crude leaves extracts (10% concentration: weight/volume, with dry leaves and distilled water) from eleven species were tested on lettuce and sesame germination. The negative effects on germination percentages, rates and informational entropies of the target species were higher when submitted to plant extracts from the dry season, where the germination rate was the most sensible parameter. The higher sensibility of lettuce and the germination rate parameter showed this difference. Only two exceptions had higher effects for rainy season extracts; one species showed higher negative effects on germination informational entropy of lettuce and another species on the germination rate of sesame. Thus, increases in the allelopathic activity were seen in the majority of the studied cerrado plant species during the dry season. These distinct responses to stressful situations in a complex environment such as the Brazilian cerrado may support the establishment and survival of some species.

The main threats to natural populations in terrestrial ecosystems have been widly recognized to be the habitat fragmentation and the exploitation of forest products. In this study, we compared the density of the populations and the structure of three tropical palm species, Astrocaryum aculeatissimum, Euterpe edulis and Geonoma schottiana. For this, we selected five forest fragments of different sizes (3 500ha, 2 400ha, 57ha, 21ha and 19ha) where palms were censused in nine 30 x 30m plots. We tracked the palms survival from 2005 to 2007, and recorded all new individuals encountered. Each individual was assigned in one of the five ontogenetic stages: seedling, infant, juvenile, immature and reproductive. The demographic structure of each palm species was analyzed and compared by a generalized linear model (GLM). The analysis was performed per palm species. The forest fragment area and the year of observation were explanatory variables, and the proportion of individuals in each ontogenetic class and palm density were response variables. The total number of individuals (from seedlings to reproductives, of all species) monitored was 6 450 in 2005, 7 268 in 2006, and 8 664 in 2007. The densities of two palm species were not influenced by the size of the fragment, but the population density of A. aculeatissimum was dependent on the size of the fragment: there were more individuals in the bigger than in the smaller forest fragments. The population structure of A. aculeatissimum, E. edulis, and G. schottiana was not altered in the smaller fragments, except the infants of G. schottiana. The main point to be drawn from the results found in this study is that the responses of density and population structure seem not to be dependent on fragment size, except for one species that resulted more abundant in bigger fragments.

Large areas in the Pantanal wetland are covered by monodominant formations, e.g. typical landscapes with local names such as "paratudal", dominated by T. aurea. Studies on structure of these formations generally include only woody strata, consequently the species richness registered is usually low due to the absence of the 'ground layer' of herbaceous and others low species. We recorded 13 species, 12 genera and 11 families for the arboreal stratum. Considering arboreal flora without the dominant (T. aurea) individuals showed great establishment in relation to the flood level between 35 - 45 cm while the individuals of the dominant species of 30 - 45 cm. The diameter distribution revealed that the population of T. aurea did not show the reverse J curve, the usual pattern for species in constant regeneration, also evidenced in inconstant Licourt quotient, indicating an episodic recruitment that could lead to future changes in structure. In the herbaceous strata we recorded 78 species, included in 62 genera and 27 families. Using plots method we sampled 46 species, 40 genera and 22 families, while in line interception we found 65 species distributed in 57 genera and 26 families. The floristic similarity of Sørensen between both methods was 59.4%, with 33 species in common, and the method of line interception was more efficient in detecting richness, with 35% more species found in the same time. According to the methods of plots and line interception applied on the woody stratum, our results gave similar detailed information on the structure of this type of savanna, and in spite of being monodominant it shows high species richness when the herbaceous stratum is taken into account. Plots and line interception methods showed similar results for the woody stratum and high species richness of the herbaceous stratum.

Currently campo rupestre (CR) is a name accepted and used internationally by botanists, zoologists, and other naturalists, usually applied to a very specific ecosystem, despite the lack of a consensual published circumscription. We present a tentative geographic circumscription of the term, combining data on climate, geology, geomorphology, soil, flora, fauna and vegetation. The circumscription of campo rupestre proposed herein is based on the following premises: (1) the classification of vegetation is not an exact science, and it is difficult to attain a high degree of consensus to the circumscription of vegetation names; (2) despite this, vegetation classification is useful for conservation and management. It is thus desirable to circumscribe vegetation types with the greatest attainable precision; (3) there is a need to preserve all montane and rocky vegetation types, regardless of classification, biome, etc; (4) the CRs are formed by a complex mosaic of vegetation types including rock-dwelling, psammophilous, aquatic, epiphytic, and penumbral plant communities. Campos rupestres stricto sensu are a Neotropical, azonal vegetation complex endemic to Brazil, forming a mosaic of rocky mountaintop "archipelagos" inserted within a matrix of zonal vegetation, mainly in the Cerrado and Caatinga provinces of the Brazilian Shield (southeastern, northeastern and central-western regions), occurring mainly above 900 m asl. up to altitudes exceeding 2000 m, having measured annual precipitation between 800 and 1500 mm, and an arid season of two to five months.

A variety of environmental and biotic factors determine vegetation growth and affect plant biomass accumulation. From temperature to species composition, aboveground biomass storage in forest ecosystems is influenced by a number of variables and usually presents a high spatial variability. With this focus, the aim of the study was to evaluate the variables affecting live aboveground forest biomass (AGB) in Subtropical Moist Forests of Southern Brazil, and to analyze the spatial distribution of biomass estimates. Data from a forest inventory performed in the State of Rio Grande do Sul, Southern Brazil, was used in the present study. Thirty-eight 1-ha plots were sampled and all trees with DBH > or = 9.5cm were included for biomass estimation. Values for aboveground biomass were obtained using published allometric equations. Environmental and biotic variables (elevation, rainfall, temperature, soils, stem density and species diversity) were obtained from the literature or calculated from the dataset. For the total dataset, mean AGB was 195.2 Mg/ha. Estimates differed between Broadleaf and Mixed Coniferous-Broadleaf forests: mean AGB was lower in Broadleaf Forests (AGB(BF)=118.9 Mg/ha) when compared to Mixed Forests (AGB(MF)=250.3 Mg/ha). There was a high spatial and local variability in our dataset, even within forest types. This condition is normal in tropical forests and is usually attributed to the presence of large trees. The explanatory multiple regressions were influenced mainly by elevation and explained 50.7% of the variation in AGB. Stem density, diversity and organic matter also influenced biomass variation. The results from our study showed a positive relationship between aboveground biomass and elevation. Therefore, higher values of AGB are located at higher elevations and subjected to cooler temperatures and wetter climate. There seems to be an important contribution of the coniferous species Araucaria angustifolia in Mixed Forest plots, as it presented significantly higher biomass than angiosperm species. In Brazil, this endangered species is part of a high diversity forest (Araucaria Forest) and has the potential for biomass storage. The results of the present study show the spatial and local variability in aboveground biomass in subtropical forests and highlight the importance of these ecosystems in global carbon stock, stimulating the improvement of future biomass estimates.

Natural rubber latex (NRL) has several features that make it an excellent biomaterial to promote the growth and repair of tissues, skin and bones. Most of the research with NRL membranes uses a mixture of different clones and chemical preservatives in the collection process. In this study, we compared five clones that produce NRL, seeking to identify their differences in biocompatibility. The clones studied were RRIM 600, PB 235, GT1, PR 255 and IAN 873 commonly found in plantations in Brazil. We did also study the effect of ammonia used during latex collection. NRL membranes were prepared aseptically and sterilized. In the in vitro tests, the membranes remained in direct contact with mouse fibroblasts cells for three periods, 24, 48 and 72 h. In the in vivo tests, the membranes were implanted subcutaneously in rabbits. The results indicated the biocompatibility of the membranes obtained from all clones. Membranes from the clones RRIM 600 and IAN 873 induced greater cell proliferation, suggesting greater bioactivity. It was found that the membranes made from latex that was in contact with ammonia during collection, showed cytotoxic and genotoxic effects in cultures, as well as necrosis, and increased inflammatory cells in the rabbit's tissues close to the implant.

Wetland areas in the Brazilian Cerrado, known as "veredas", represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted "veredas". Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

The need for quick identification of priority areas for biodiversity protection makes rapid assessment methods important management tools for defining conservation strategies. An increasingly used rapid assessment method is rapid ecological assessment (REA), a fast and flexible survey directed toward selected indicator species and vegetation forms. The purpose of this study was to propose and test REA based on plant community features of the semideciduous Atlantic forest (SAF). Correlation tests were performed between data collected by REA and plant species diversity, richness, and abundance collected by conventional woody plant inventory methods. The study was conducted in 21 SAF patches in Northern Paraná State, Brazil. The phytosociological inventory was conducted along a single transect and required 2 days to complete (excluding time spent for herbarium identification), whereas REA was conducted along three to four transects per working day. REA results correlated positively with woody plant diversity, proving REA to be an efficient method for defining the conservation status of SAF fragments, but accuracy of evaluations of threats to biological integrity are relatively low. Both the selection of appropriate variables and the skill level of field staff are critical and can strongly influence REA results.

The Deciduous Complex that occurs in northern Minas Gerais State, Brazil, raises questions about the floristic affinities of these formations in relation to neighboring phytogeographical domains. Little is known about the identity of the seasonal forest formations that comprise this complex, or about its relationships to abiotic components, such as soils, topography and climate. This study aimed to recognize the patterns of floristic similarity of all studied fragments of dry forest of northern Minas Gerais with soil and climate attributes, based on the available database. Cluster analysis indicated the existence of two floristic groups that had clear associations with either the Koppen's BSh (semi-arid) or Aw (seasonal tropical) climates. Likewise, the subdivisions of these groups showed clear associations with the dominant soil classes in the region. The Red-Yellow Latosol is the dominant soil classes in the BSh climatic domain, seconded by alluvial areas associated with Fluvic Neosols. The Aw domain comprised a much varied set of soils: Nitosols, Argisols, Cambisols and Litholic Neosols, most derived from the Bambuí limestone/slate formation. The ecotonal nature of northern Minas Gerais State provides a complex interaction between the flora of neighboring phytogeographical domains. This, allied to pedogeomorphological factors, allowed a better understanding of the effects of late Quaternary climate changes for the Deciduous Complex evolution. We conclude that the Latosols under present-day semi-arid climates (BSh) are relicts of former wetter climates, during which humid forest (semideciduous) expansion took place. Later, these semideciduous forests were subjected to a much drier climate, when selection for deciduousness led to the present-days Deciduous Complex scenario.

This paper presents a floristic survey of the wood component of cerrado s.s. (eastern face) and gallery forest (western face) areas carried out in the southern part of the Serra de Maracaju. The dispersal syndromes and floristic relations of this portion of the Serra were compared to those of other formations from different regions of Brazil. Between October 2007 and September 2008, monthly collections identified 144 species. As for dispersal syndromes, zoochory prevails, followed by autochory and anemochory. The gallery forest is a heterogeneous formation that shelters floristic elements shared with the Atlantic rain forest, the Amazonian forest, semi-deciduous seasonal forests and dry forests of the Pantanal. Low similarity between the two areas analyzed makes this region unique and suggests that the Serra de Maracaju is greatly influenced by the semi-deciduous seasonal forests of the southeastern region.

The forest understory is made up of resident and transitory species and can be much richer than the canopy. With the purpose to describe the contribution of these groups to the woody understory, five Atlantic Forest fragments were selected and studied in Northeastern Brazil. In order to analyze the understory's structure, the sample included woody individuals with circumference at breast height (CBH) smaller than 15cm and circumference at ground level (CGL) greater than 3cm, regardless of height. The recorded species were quantified and classified into functional stratification categories (resident and transitory), and the floristic similarity between the understory and the tree stratum was calculated. Species' importance in the understory was analyzed by height and total natural regeneration classes based on a regeneration index. The understory was richer in species (median=63.8, SD=21.72, n=5 fragments) than the tree stratum (43.8, 18.14, 5), and the similarity between these components was relatively high (median=0.54, SD=0.09). The results also showed that the studied understory in the forest fragments was mainly composed by transitory species (median=67.01%, SD=3.76), that were well distributed among height classes and had the highest densities, which may favor their future presence in the canopy's structure and composition. The typical understory species were grouped into two strata: the lower understory, made up of species that generally do not reach more than 4m in height (mostly species from families Piperaceae, Rubiaceae and Melastomataceae); and the upper understory, with intermediate heights between the lower understory and the canopy, but with average heights that were not higher than 10m (mainly of species from families Anonnaceae, Clusiaceae and Myrtaceae). These families' richness was commonly used as an indicator of the vegetation's successional stage; however, such results must be seen with caution as they show that these families co-occurred and were highly important in different strata. Studying the understory is fundamental because it represents a floristically rich stratum with a unique structure, which promotes the natural regeneration of the tree stratum.

This study aims to identify the remnant tree flora in six forest fragments in the metropolitan area of Belém and to analyze these fragments in terms of biological conservation, species richness and diversity in the local urban landscape. The fragments and their respective sampling areas were as follows: Amafrutas reserve (15 ha), Trambioca Is. reserve (2 ha), Bosque Rodrigues Alves city park (15 ha), Combu Is. reserve (10 ha), Gunma Park reserve (10 ha) and Mocambo reserve (5 ha). Inventories were built from lineal plots of 250 m² and included trees with DBH equal to or greater than 10 cm at a height of 1.3 m above ground. Sixty-nine families and 759 species, of which eight were officially listed as endangered (Brazilian National Flora: Ministry of Environment, Normative Instruction of September, 2008; Pará State Flora: Decree Nº. 802 of February 2008) were recorded. These endangered species are: Aspidosperma desmanthum Benth. ex Müll. Arg. (Apocynaceae), Cedrela odorata L. (Meliaceae), Eschweilera piresii S.A Mori (Lecythidaceae), Euxylophora paraensis Huber (Rutaceae), Hymenolobium excelsum Ducke (Leguminosae), Manilkara huberi (Ducke) Chevalier (Sapotaceae), Tabebuia impetiginosa (Mart. ex DC.) Standl. (Bignoniaceae), Mezilaurus itauba (Meisn.) Taub. ex Mez (Lauraceae) and Qualea coerulea Aubl. (Vochysiaceae). Emergency actions such as implementing management plans for already existing Conservation Units, the creation of new such units in areas of primary forest fragments (as in the case of the Amafrutas reserve), as well as the intensification of actions of surveillance and monitoring, should be undertaken by Federal, State, and Municipal environmental agencies so as to ensure the conservation of these last primary forest remnants in the metropolitan area of Belém.

The Amazon region is one of the most diverse areas in the world. Research on high tropical forest diversity brings up relevant contributions to understand the mechanisms that result and support such diversity. In the present study we describe the species composition and diversity of 15 one-ha plots in the Amazonian terra firme dense forest in Brazil, and compare the floristic similarity of these plots with other nine one-ha plots. The 15 plots studied were randomly selected from permanent plots at the Embrapa Experimental site, Amazonas State in 2005. The diversity was analysed by using species richness and Shannon's index, and by applying the Sorensen's index for similarity and unweighted pair-group average (UPGMA) as clustering method. Mantel test was performed to study whether the differences in species composition between sites could be explained by the geographic distance between them. Overall, we identified 8 771 individuals, 264 species and 51 plant families. Most of the species were concentrated in few families and few had large number of individuals. Families presenting the highest species richness were Fabaceae (Faboideae: 22spp., Mimosoideae: 22spp.), Sapotaceae: 22spp., Lecythidaceae: 15 and Lauraceae: 13. Burseraceae had the largest number of individuals with 11.8% of the total. The ten most abundant species were: Protium hebetatum (1 037 individuals), Eschweilera coriacea (471), Licania oblongifolia (310), Pouteria minima (293), Ocotea cernua (258), Scleronema micranthum (197), Eschweilera collina (176), Licania apelata (172), Naucleopsis caloneura (170) and Psidium araca (152), which represented 36.5% of all individuals. Approximately 49% of species had up to ten individuals and 13% appeared only once in all sampled plots, showing a large occurrence of rare species. Our study area is on a forest presenting a high tree species diversity with Shannon's diversity index of 4.49. The dendrogram showed two groups of plots with low similarity between them (less than 0.25), and the closer the plots were one to another, more similar in species composition (Mantel R = 0.3627, p < 0.01). The 15 plots in our study area share more than 50% of their species composition and represent the group of plots that have the shortest distance between each other. Overall, our results highlight the high local and regional heterogeneity of environments in terra firme forests, and the high occurrence of rare species, which should be considered in management and conservation programs in the Amazon rainforest, in order to maintain its structure on the long run.

Premise of the Study: This study was designed to develop and characterize a preliminary set of nuclear microsatellite markers for Aspidosperma polyneuron, an endangered tropical tree species., Methods and Results: Leaf samples were collected from a group of mature A. polyneuron trees in a large area along the Pardo and Mogi-Guaçu river basins in São Paulo State in the southeastern region of Brazil. Twenty-five simple sequence repeat (SSR) markers were developed and 16 of 30 samples had polymorphic loci. The number of alleles per locus ranged from two to 17 (average = 7.06). A high diversity (H(e) = 0.65) and parentage exclusion probability for the first (0.9995) and second (0.9999) parents were measured., Conclusions: These 16 polymorphic markers suggest a high potential for genetic diversity, gene flow, and mating system analyses in A. polyneuron.

This study is part of the Floristic and Forest Inventory of Santa Catarina, conceived to evaluate forest resources, species composition and structure of forest remnants, providing information to update forest conservation and land use policy in Southern Brazilian State of Santa Catarina (95 000 km2). In accordance to the Brazilian National Forest Inventory (IFN-BR), the inventory applies systematic sampling, with 440 clusters containing four crosswise 1 000m2 plots (20 x 50m) each, located on a 10 x 10km grid overlaid to land use map based on classification of SPOT-4 images from 2005. Within the sample units, all woody individuals of the main stratum (DBH > or = 10cm) are measured and collected (fertile and sterile), if not undoubtedly identified in field. Regeneration stratum (height > 1.50m; DBH < 10cm) is registered in 100m2 in each sample unit. Floristic sampling includes collection of all fertile trees, shrubs and herbs within the sample unit and in its surroundings. This study performs analysis based on 92 clusters measured in 2008 within an area of 32320km2 of mixed ombrophyllous forests with Araucaria angustifolia located at the state's high plateau (500m to 1 560m above sea level at 26 degrees 00'-28 degrees 30' S and 49 degrees 13'-51 degrees 23' W). Mean density (DBH > or = 10cm) is 578 individuals/ha (ranging from 85/ha to 1 310/ha), mean species richness in measured remnants is 35 (8 to 62), Shannon and Wiener diversity index (H') varies between 1.05 and 3.48. Despite high total species diversity (364 Magnoliophyta, five Coniferophyta and one tree fern) and relatively high mean basal area (25.75m2/ha, varying from 3.87 to 68.85m2/ha), the overwhelming majority of forest fragments are considered highly impacted and impoverished, mostly by logging, burning and extensive cattle farming, turning necessary more efficient protection measures. Basal area was considered an appropriate indicator for stand quality and conservation status.

The SITE® model was originally developed to study the response of tropical ecosystems to varying environmental conditions. The present study evaluated the applicability of the SITE model to simulation of energy fluxes in a tropical semi-deciduous forest of the southern Amazon Basin. The model was simulated with data representing the wet and dry season, and was calibrated according to each season. The output data of the calibrated model [net radiation (Rn), latent heat flux (LE) and sensible heat flux (H)] were compared with data observed in the field for validation. Considering changes in parameter calibration for a time step simulation of 30 min, the magnitude of variation in temporal flux was satisfactory when compared to observation field data. There was a tendency to underestimate and overestimate LE and H, respectively. Of all the calibration parameters, the soil moisture parameter presented the highest variation over the seasons, thus influencing SITE model performance.

This is a review of current studies in diversity of the flora and main vegetation types in the Brazilian Pantanal. The flora of this wetland, nearly 2,000 species, constitutes a pool of elements of wide distribution and from more or less adjacent phytogeographic provinces, such as Cerrado, dry seasonal forests, Chaco, Amazonia and Atlantic Forest. The most numerous group includes wide-distribution species, mainly herbs, while the second contingent comes from the Cerrado. Endemic plants are rare, numbering only seven. The vegetation of the sedimentary floodplain is a mosaic of aquatics, floodable grasslands, riparian forests, savannas (cerrados), cerrado woodlands, dry forests, and a large area of mono-dominant savannas, and pioneer woodlands. The main vegetation types are briefly described with their characteristic species, and their estimated areas are given according to the latest mapping.

Leaf area index (LAI) is an important ecophysiological variable because leaves are the organs responsible for gas exchange between plants and the atmosphere. This variable can be calculated from primary values of leaf area assessed by destructive or non-destructive methods, which is relatively easy when crop species are investigated, but is not the case when the focus is on natural wood plants communities. In this paper, we analyze the seasonality of LAI estimated by three different methods in the Amazonia-savannah transitional forest, located 50 km north-east of Sinop city, Mato Grosso, Brazil. In the first method, we combine Monsi and Saekis' original method [Monsi M, Saeki T (1953) Jpn J Bot 14:22-52], which measures LAI using the Beer-Lambert extinction law, and the proposition of Goudriaan [Goudriaan J (1988) Agric For Meteorol 43:155-169] to estimate the extinction coefficient from solar height. The second method differed from the first only in the way in which the daily fraction of intercepted photosynthetic active radiation (FPAR) was calculated, as proposed by Charles-Edwards and Lawn (Charles-Edwards DA, Lawn RJ (1984) Plant Cell Environ 7:247-251]. In the third method, we used a remote sensing technique [MOD15&#95;BU-collection 4, produced and distributed by EROS Data Center Distributed Active Archive Center (EDC DAAC)]. We found that the first and the second methods revealed the expected LAI dynamics, which increased during the dry-wet transition and wet season, and decreased during the wet-dry transition and dry season. From 20 randomly distributed sets in a 1.0 ha area, only 3 showed significant differences in LAI estimated from the first two methods; conversely, LAI was overestimated by the third method.

The Brazilian rosewood (Dalbergia nigra) is an endangered tree endemic to the central Brazilian Atlantic Forest, one of the world's most threatened biomes. The population diversity, phylogeographic structure and demographic history of this species were investigated using the variation in the chloroplast DNA (cpDNA) sequences of 185 individuals from 19 populations along the geographical range of the species. Fifteen haplotypes were detected in the analysis of 1297 bp from two non-coding sequences, trnV-trnM and trnL. We identified a strong genetic structure (F(ST)=0.62, P<0.0001), with a latitudinal separation into three phylogeographic groups. The two northernmost groups showed evidence of having maintained historically larger populations than the southernmost group. Estimates of divergence times between these groups pointed to vicariance events in the Middle Pleistocene (ca. 350,000-780,000 years ago). The recurrence of past climatic changes in the central part of the Atlantic forest, with cycles of forest expansion and contraction, may have led to repeated vicariance events, resulting in the genetic differentiation of these groups. Based on comparisons among the populations of large reserves and small, disturbed fragments of the same phylogeographic group, we also found evidence of recent anthropogenic effects on genetic diversity. The results were also analysed with the aim of contributing to the conservation of D. nigra. We suggest that the three phylogeographic groups could be considered as three distinct management units. Based on the genetic diversity and uniqueness of the populations, we also indicate priority areas for conservation.

Despite many studies on fragmentation of tropical forests, the extent to which plant and animal communities are altered in small, isolated forest fragments remains obscure if not controversial. We examined the hypothesis that fragmentation alters the relative abundance of tree species with different vegetative and reproductive traits. In a fragmented landscape (670 km(2) ) of the Atlantic Forest of northeastern Brazil, we categorized 4056 trees of 182 species by leafing pattern, reproductive phenology, and morphology of seeds and fruit. We calculated relative abundance of traits in 50 1-ha plots in three types of forest configurations: forest edges, small forest fragments (3.4-83.6 ha), and interior of the largest forest fragment (3500 ha, old growth). Although evergreen species were the most abundant across all configurations, forest edges and small fragments had more deciduous and semideciduous species than interior forest. Edges lacked supra-annual flowering and fruiting species and had more species and stems with drupes and small seeds than small forest fragments and forest interior areas. In an ordination of species similarity and life-history traits, the three types of configurations formed clearly segregated clusters. Furthermore, the differences in the taxonomic and functional (i.e., trait-based) composition of tree assemblages we documented were driven primarily by the higher abundance of pioneer species in the forest edge and small forest fragments. Our work provides strong evidence that long-term transitions in phenology and seed and fruit morphology of tree functional groups are occurring in fragmented tropical forests. Our results also suggest that edge-induced shifts in tree assemblages of tropical forests can be larger than previously documented., (© 2010 Society for Conservation Biology.)

After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica), considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.

Deforestation and forest fragmentation are known major causes of nonrandom extinction, but there is no information about their impact on the phylogenetic diversity of the remaining species assemblages. Using a large vegetation dataset from an old hyper-fragmented landscape in the Brazilian Atlantic rainforest we assess whether the local extirpation of tree species and functional impoverishment of tree assemblages reduce the phylogenetic diversity of the remaining tree assemblages. We detected a significant loss of tree phylogenetic diversity in forest edges, but not in core areas of small (<80 ha) forest fragments. This was attributed to a reduction of 11% in the average phylogenetic distance between any two randomly chosen individuals from forest edges; an increase of 17% in the average phylogenetic distance to closest non-conspecific relative for each individual in forest edges; and to the potential manifestation of late edge effects in the core areas of small forest remnants. We found no evidence supporting fragmentation-induced phylogenetic clustering or evenness. This could be explained by the low phylogenetic conservatism of key life-history traits corresponding to vulnerable species. Edge effects must be reduced to effectively protect tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

Size structure and spatial arrangement of 13 abundant tree species were determined in a riparian forest fragment in Paraná State, South Brazil (23°16'S and 51°01'W). The studied species were Aspidosperma polyneuron Müll. Arg., Astronium graveolens Jacq. and Gallesia integrifolia (Spreng) Harms (emergent species); Alseis floribunda Schott, Ruprechtia laxiflora Meisn. and Bougainvillea spectabilis Willd. (shade-intolerant canopy species); Machaerium paraguariense Hassl, Myroxylum peruiferum L. and Chrysophyllum gonocarpum (Mart. & Eichler ex Miq.) Engl. (shade-tolerant canopy species); Sorocea bonplandii (Baill.) Bürger, Trichilia casaretti C. Dc, Trichilia catigua A. Juss. and Actinostemon concolor (Spreng.) Müll. Arg. (understory small trees species). Height and diameter structures and basal area of species were analyzed. Spatial patterns and slope correlation were analyzed by Moran's / spatial autocorrelation coefficient and partial Mantel test, respectively. The emergent and small understory species showed the highest and the lowest variations in height, diameter and basal area. Size distribution differed among emergent species and also among canopy shade-intolerant species. The spatial pattern ranged among species in all groups, except in understory small tree species. The slope was correlated with spatial pattern for A. polyneuron, A. graveolens, A. floribunda, R. laxiflora, M. peruiferum and T. casaretti. The results indicated that most species occurred in specific places, suggesting that niche differentiation can be an important factor in structuring the tree community.

A sedimentar core collected at Santo Antônio da Patrulha, Rio Grande do Sul State, southmost Brazil, was submitted to pollen analysis to provide the vegetational history of this region, and the paleoecological and paleoclimatic changes. A total of 98 taxa of palynomorphs was identified from 35 subsamples. Three radiocarbonic datings were obtained along a section of 115 cm depth, including the basal age of 4730 ± 50 yr BP. Pollen diagrams and cluster analysis were performed based on palynomorphs frequencies, demonstrating five distinct phases (SAP-I to SAP-V), which reflected different paleoecological conditions. The predominance of plants associated with grasslands in the phase SAP-I suggests warm and dry climate conditions. A gradual increasing of humidity conditions was observed mainly from the beginning of the phase SAP-III, when the vegetation set a mosaic of grasslands and Atlantic rainforest. Furthermore, the presence of some forest taxa ( Acacia-type, Daphnopsis racemosa, Erythrina-type and Parapiptadenia rigida-type), from the phase SAP-IV, is interpreted as an influence of the seasonal semideciduous forest in the study region. From the phase SAP-V (ca. 4000 yrs BP), the vegetation became similar to the modern one (extant Atlantic rainforest Biome), especially after 2000 yrs BP (calibrated age).

Water availability is a principal factor limiting the distribution of closed-canopy forest in the seasonal tropics, suggesting that forest tree species may not be well adapted to cope with seasonal drought. We studied 11 congeneric species pairs, each containing one forest and one savanna species, to test the hypothesis that forest trees have a lower capacity to maintain seasonal homeostasis in water relations relative to savanna species. To quantify this, we measured sap flow, leaf water potential (Psi(L)), stomatal conductance (g (s)), wood density, and Huber value (sapwood area:leaf area) of the 22 study species. We found significant differences in the water relations of these two species types. Leaf area specific hydraulic conductance of the soil/root/leaf pathway (G (t)) was greater for savanna species than forest species. The lower G (t) of forest trees resulted in significantly lower Psi(L) and g (s) in the late dry season relative to savanna trees. The differences in G (t) can be explained by differences in biomass allocation of savanna and forest trees. Savanna species had higher Huber values relative to forest species, conferring greater transport capacity on a leaf area basis. Forest trees have a lower capacity to maintain homeostasis in Psi(L) due to greater allocation to leaf area relative to savanna species. Despite significant differences in water relations, relationships between traits such as wood density and minimum Psi(L) were indistinguishable for the two species groups, indicating that forest and savanna share a common axis of water-use strategies involving multiple traits.

Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species-Lacistema pubescens and Myrcia sylvatica-in dry-season irrigation, litter-removal and control plots. We then evaluated the effects of altered water and nutrient availability on population demography and dynamics using matrix models and life table response experiments. Our results show that despite prolonged experimental manipulation of water and nutrient availability, there were nearly no consistent and unidirectional treatment effects on the demography of either species. The patterns and significance of observed treatment effects were largely dependent on cross-year variability not related to rainfall patterns, and disappeared once we pooled data across years. Furthermore, most of these transient treatment effects had little effect on population growth rates. Our results suggest that despite major experimental manipulations of water and nutrient availability-factors considered critical to the ecology of tropical pioneer tree species-autogenic light limitation appears to be the primary regulator of tree demography at early/mid successional stages. Indeed, the effects of light availability may completely override those of other factors thought to influence the successional development of Amazonian secondary forests.

The study had the aim of characterizing the geographical distribution of Lutzomyia whitmani s.l. in the state of Maranhão, Northeastern Brazil. Between 1992 and 2005, 9,600 specimens (65.1% males and 34.9% females) were caught in the rural and urban zones of 35 municipalities in regions consisting of forests, savanna and mixed vegetation with coconut plantations, sandbanks and heath. Greater abundance was observed in areas surrounding dwellings (91.6%) than inside the dwellings (8.4%). The presence of the vector in different phytoregions and in rural and urban areas favors the transmission of tegumentary leishmaniasis in these environments. This taxon may constitute a complex of species in Maranhão, which can be confirmed by molecular biology studies.

The study was carried out in a 3,000 m2 area of coastal Atlantic rain forest at Ilha do Mel island (25 degrees 30"S 48 degrees 23'W), on 100 assorted trees separated into 2 meter-high strata starting from the ground. In each stratum all of the occurring epiphytic species were recorded. The sampled species were grouped into three categories: exclusive, preferential, and indifferent, according to their abundance in each strata, and selective, preferential and indifferent, according to abundance on the forophytes. Intermediate strata registered the highest diversity. Six species were considered exclusive to one or two strata, 15 were restricted to some strata and 5 presented a broad distribution. No epiphytic species showed uniform horizontal distribution on the area. The epiphyte richness in a host tree varied from zero to 30. Regarding to fidelity on host tree species, few selective or preferential, and mainly indifferent epiphyte species, were found. A total of 82 epiphyte species were sampled in the surveyed tree, and the Wittaker plot indicate a highly dominant assemblage.

Floristic analyses (Principal Component Analysis and Analysis of Group Indicators) at the genus level were employed to characterize and compare seasonal forest formations in northeastern Brazil. The presence--absence of 248 genera of woody plants occurring in 24 floristic surveys was correlated with geomorphology and climatic variables. The analyses were consistent and point to the existence of two floristic groups of seasonal forests in the region, one more closely related to the Atlantic Coastal Forest (mata atlântica) and the other to the xerophytic formations (caatinga) of the region. The driest seasonal forest group experiences more than 8 dry months per year and/or a total annual rainfall of <1000 mm, and is found on the ancient eroded peaks in the semi-arid core and on the western slopes of the Borborema Plateau.

Dry forests are common, although highly threatened in the Neotropics. Their ecological processes are mostly influenced by rainfall pattern, hence their cycles exhibit contrasting phases. We studied the phenology of canopy trees in a primary dry forest in Western Brazil in the foothills of the Urucum mountain chain, in order to improve our knowledge on the functioning of these poorly-known forests. Leaf shedding started in the early dry season and was massive in the latter part of this period. Most leaf loss occurred in dry hills, while wet valleys remained evergreen. Anemochorich and autochorich species predominated in dry hills, presumably due to their tolerance to dry conditions and enhanced exposition to winds, which favour diaspores removal and dispersal. Conversely, zoochorich species dominated the wet valleys. Flowering was intense in the late dry season, the driest period of the year, while fruiting was massive just after the onset of rains, as well as flushing. Therefore, most flowering was unrelated to wet conditions, although such an abiotic factor, potentially, triggered the major fruiting episode, widely comprised by zoochorich species. Anemochorich and autochorich species flowered and fruited in the course of the long dry season. The contrasting environmental conditions present in the hills and valleys determine the arrangement of a mosaic in which patches of zoochorich and evergreen trees alternate with patches of non zoochorich and highly deciduous species. Consequently, species with such syndromes exhibited marked flowering and fruiting patterns, accordingly to the pronounced seasonality.