Floristic variation across 600 km of inundation forests (Igapó) along the Negro River,Central Amazonia

We inventoried 10 ha of late-successional and seasonally inundated black-water floodplain (igapó) forest along four river sections of the Negro River, Central Amazonia, Brazil. The aim of the study was to test if tree species composition and diversity changes along the river course, and whether these changes reflect the different geological formations of the Negro River. On a continental-wide scale, we assessed alpha-diversity patterns of black-water flooded forests across the Amazon and Orinoco basins. Phytosociological analyses include family and species importance, species similarity, and Fisher’s alpha-diversity, as well as Detrended Correspondence Analysis. A total of 6.126 individuals were recorded, belonging to 243 tree species. Only few tree species occurred in more than one river section, and floristic composition changed abruptly from one section to the other. Tree species richness ranged from 57 to 79 species ha^?1, and alpha-diversity was highest (27.24) in the lower river section upon sediments of Pliocene–Pleistocene origin. We found a gradual decrease in species diversity with increasing age of the geological formations. The igapó forest is relatively species-poor, which we interpret to be the result of general low nutrient availability in alluvial substrates of the Negro River.     

Patterns of ant species diversity and turnover across 2000 km of Amazonian floodplain forest

Aim To determine the effect and relative importance of geographic and local environmental factors on species richness and turnover of ant assemblages in floodplain forests across the Amazon basin. Location Twenty‐six mature forest sites scattered along the entire extension of the Amazon River in Brazil. The study area encompassed nearly 18° of longitude and 3.5° of latitude. Methods Systematic collections of ants were performed at each site during the low‐water season (i.e. when forests are not inundated) using three complementary sampling methods. We used variance partitioning techniques to assess the relative effects of the spatial (latitude and longitude) and environmental (rainfall, length of the dry season and flood height) variables on ant species richness and composition. Results There was a twofold variation in the number of species per site, which was largely explained by inter‐site variations in rainfall seasonality and flooding intensity. In general, there were more species at sites located in the western part of the basin, where the dry season is less severe, or near the river estuary, where precipitation is also high and flooding is less intense. Ant community composition was also affected by environmental heterogeneity. For instance, some species only occurred at those sites less affected by the river’s seasonal flooding, whereas others were mostly associated with the drier or wetter regions of the basin. In addition, the turnover of species increased significantly as geographic distances increased. Nevertheless, the rate of change was small given that many species had a broad distribution across the study area. Main conclusions Ant distribution patterns along the floodplain forests of the Amazon appear to be controlled to a relatively large extent by the current gradient in flooding intensity and – most importantly – in precipitation. Altered rainfall regimes resulting from global warming and land‐use change thus have the potential to influence these patterns.     

Ethnobotanical ground‐truthing: indigenous knowledge,floristic inventories and satellite imagery in the upper Rio Negro,Brazil

Aim To assess the utility of indigenous habitat knowledge in studies of habitat diversity in Amazonia. Location Baniwa indigenous communities in Rio Içana, upper Rio Negro, Brazil. Methods Six campinarana vegetation types, recognized and named by a consensus of Baniwa indigenous informants according to salient indicator species, were studied in 15 widely distributed plots. Floristic composition (using Baniwa plant nomenclature only, after frustrated attempts to obtain botanical collection permits), quantitative measures of forest structure and GPS waypoints of the 4‐ha composite plot contours were registered, permitting their location on Landsat satellite images. Non‐metric multidimensional scaling (NMDS) ordination was carried out using pc‐ord software. Results The NMDS ordinations of the plot data revealed a clear gradient of floristic composition that was highly correlated with three quantitative measures of forest structure: basal area, canopy height and satellite reflectance. Main conclusions Baniwa‐defined forest types are excellent predictors of habitat diversity along the structural gradient comprising distinctive white‐sand campinarana vegetation types. Indigenous ecological knowledge, as revealed by satellite imagery and floristic analyses, proves to be a powerful and efficient shortcut to assessing habitat diversity, promoting dialogue between scientific and indigenous worldviews, and promoting joint study and conservation of biodiversity.     

Floodplain lake fish assemblages in the Amazon River: directions in conservation biology

The Neotropical region is renowned for its high biodiversity, and the Amazon River basin contains the highest number of fish species of any river system in the world. In recent years, habitat fragmentation and exploitation of biotic resources have threatened biological integrity and provoked to need for sustainable management and conservation of the Amazon River system. We studied 36 floodplain lakes along 2000 km of the Amazon River. The fish assemblages associated with flood forests are moderately diverse, with low species dominance and reduced populations. To detect nestedness of fish assemblage composition in floodplain lakes, a nested subset analysis was performed on species presence–absence. The incidence matrix (species × lakes) was maximally packed using the Nestedness Temperature Calculator software. The results of ranking lakes and species allow us to establish targets for conservation. Such strategy for sustainable management should be focused on maintaining the Amazonian biodiversity.     

Using river color to predict Amazonian floodplain forest avifaunas in the world's largest blackwater river basin

Despite the importance of rivers in Amazonian biogeography, avian distribution patterns in river‐created habitats (i.e., floodplain forests) have been sparsely addressed. Here, we explore geographic variation in floodplain forest avifaunas, specifically regarding one of the most striking aspects of the Amazon: the diversity of river “colors” (i.e., types, based on the color of the water). We sampled the avifauna at 30 sites, located in 17 different rivers (nine black‐ and eight whitewater), in the Rio Negro basin, northwestern Brazil. Our sampling comprised ten 15‐min point‐counts per site, distributed every 500–1000 m along the river. We recorded a total of 352 bird species, many of which occurred in both river types. Although bird species richness was similar among rivers, we found significant differences in species composition. Nearly 14 percent of the species were significantly associated with one or the other river type. Most floodplain forest specialists occurred predominantly in whitewater rivers, whereas species that are typically associated with white‐sand habitats occurred in blackwater. Despite significant distinctions between river types, occurrence patterns and levels of habitat association differed among indicator species and may vary in the same species throughout its global distribution. There were also “intermediate” avifauna in some of our sites, suggesting that continuous parameters characterizing river types structure species turnover. The water color‐based classification of Amazonian rivers represents a simple and powerful predictor of the floodplain forest avifauna, offering a stimulating starting point for understanding patterns of floodplain bird distributions and for prioritizing conservation efforts in these overlooked habitats. Abstract in Portuguese is available with online material.     

Plant composition associated with environmental gradients in tropical montane forests (Cueva de Los Guacharos National Park,Huila, Colombia)

Niche differentiation among tropical forest plants can generate species turnover along gradients of soil, topography, climate, and land use history. In this study we explore the relative importance of these variables as drivers of floristic composition in Cueva de Los Guacharos National Park. We established twenty 0.1‐ha plots, within which trees, lianas, and shrubs (diameter ≥ 2.5 cm) were censused. We selected plot locations in primary and disturbed forests, and we measured topography and soil variables. Despite their structural similarity, primary and disturbed forests differed floristically, and also differed in environmental variables measured. A NMDS ordination showed that variation in the floristic composition across plots is highly correlated to the exchangeable acidity, elevation, temperature, and magnesium availability. Variance partitioning analysis shows that together spatial and environmental variables explain 24.2 percent of the variation in species composition. ‘Pure environmental’ variables were more important in explaining compositional variability than ‘pure spatial’ processes (9.8% and 1.4%, respectively). Residual variance may be attributed to stochastic process or non‐measured biotic effects.     

Assessing the relationship between forest types and canopy tree beta diversity in Amazonia

Planning of conservation priorities has often taken mapped forest types as surrogates for biological complementarity. In the Brazilian Amazon, these exercises have given equal weight to each forest type as if they were all equally distinct. Here, we examine floristic similarity between forest types to assess the reliability of vegetation maps as a surrogate for canopy tree‐community composition. We analyzed floristic differences at the genus level between twelve Amazonian forest types using 1184 one‐hectare inventories of large trees with three complementary approaches. First, we compared a map of floristic composition, from a uni‐dimensional NMDS ordination of the inventories, with a map of coarser‐level forest types commonly recognized as distinct by classification systems across Amazonia. Using Mantel and means‐difference tests, we next examined the distance‐decay of floristic similarity for all paired samples and for the pairs drawn from within and between twelve more finely divided forest types. Finally, we examined the degree of floristic separation of each pair of the twelve forest types using non‐parametric analysis of variance. Maps of floristic composition and coarse‐level forest types were highly congruent. At the finer level of classification, similarity was only slightly higher when pairs were drawn from the same versus from different forest types. This was true for all geographic distances. Nonetheless, eighty percent of the 66 paired combinations of forest types were significantly different in the unreduced genus‐space and nearly half showed little or no overlap in a two‐dimensional ordination. Three types were most distinct from all others: white sand, seasonally dry, and bamboo‐dominated forests. Here, we show that forest types exhibit variable degrees of separation. For this reason, treating all fine‐level forest types as equally distinct results in poor representation of canopy tree beta diversity. We recommend explicitly considering the degree of floristic separation between all forest types – as presented here for Amazonian flora – as a way to improve the use of this biodiversity surrogate.     

Environmental drivers of tree community turnover in western Amazonian forests

A more comprehensive understanding of the factors governing tropical tree community turnover at different spatial scales is needed to support land‐management and biodiversity conservation. We used new forest inventory data from 263 permanent plots in the Carnegie Biodiversity‐Biomass Forest Plot Network spanning the eastern Andes to the western Amazonian lowlands of Peru to examine environmental factors driving genus‐level canopy tree compositional variation at regional and landscape scales. Across the full plot network, constrained ordination analysis indicated that all environmental variables together explained 23.8% of the variation in community composition, while soil, topographic, and climatic variables each explained 15.2, 10.9, and 17.0%, respectively. A satellite‐derived metric of cloudiness was the single strongest predictor of community turnover, and constrained ordination revealed a primary gradient of environmentally‐driven community turnover spanning from cloudy, high elevation sites to warm, wet, lowland sites. For three focal landscapes within the region, local environmental variation explained 13.4–30.8% of compositional variation. Community turnover at the landscape scale was strongly driven by topo‐edaphic factors in the two lowland landscapes examined and strongly driven by potential insolation and topography in the montane landscape. At the regional scale, we found that the portion of compositional variation that was uniquely explained by spatial variation was relatively small (2.7%), and was effectively zero within the three focal landscapes. Overall, our results show strong canopy tree compositional turnover in response to environmental gradients at both regional and landscape scales, though the most important environmental drivers differed between scales and among landscapes. Our results also highlight the usefulness of key satellite‐derived environmental covariates that should be considered when conducting biodiversity analyses in tropical forests.     

Using generalized dissimilarity modelling to analyse and predict patterns of beta diversity in regional biodiversity assessment

Generalized dissimilarity modelling (GDM) is a statistical technique for analysing and predicting spatial patterns of turnover in community composition (beta diversity) across large regions. The approach is an extension of matrix regression, designed specifically to accommodate two types of nonlinearity commonly encountered in large-scaled ecological data sets: (1) the curvilinear relationship between increasing ecological distance, and observed compositional dissimilarity, between sites; and (2) the variation in the rate of compositional turnover at different positions along environmental gradients. GDM can be further adapted to accommodate special types of biological and environmental data including, for example, information on phylogenetic relationships between species and information on barriers to dispersal between geographical locations. The approach can be applied to a wide range of assessment activities including visualization of spatial patterns in community composition, constrained environmental classification, distributional modelling of species or community types, survey gap analysis, conservation assessment, and climate-change impact assessment.     

Habitat specifity,endemism and the neotropical distribution of Amazonian white‐water floodplain trees

.The Amazon basin is covered by the most species‐rich forests in the world and is considered to house many endemic tree species. Yet, most Amazonian ecosystems lack reliable estimates of their degree of endemism, and causes of tree diversity and endemism are intense matters of debate. We reviewed the spatial distribution of 658 of the most important flood‐tolerant Amazonian white‐water (várzea) tree species across the entire Neotropics by using data from herbaria, floras, inventories and checklists. Our results show that 90% of the várzea tree species are partially or widely distributed across neotropical macro‐regions and biomes. Chi‐square analyses indicated that várzea species richness in non‐várzea macro‐regions was dependent on the flooding gradient and the longitudinal position. Cluster analysis combined with association tests indicated four significant patterns of várzea species distributions depending on species flood‐tolerance (low vs high) and spatial distribution (restricted vs widespread). We predict that the predominance of Andean substrates is the most important factor that determines the distribution of várzea tree species within and beyond the Amazon basin and explains the high floristic similarity to the Orinoco floodplains. Distribution patterns in other extra‐Amazonian macro‐regions are more likely linked to climatic factors, with rainforest climates housing more várzea species than savanna climates. 130 tree species were restricted to South‐American freshwater floodplains, and 68 (> 10%) were endemic to Amazonian várzea. We detected two centers of endemism, one in the western Amazon characterized by low and brief floods, and one in the central Amazon, characterized by high and prolonged floods. Differences in taxonomic composition of endemic centers in the western and central Amazon are the result of different abiotic factors (i.e. flood regimes), as well as the regional species pools from where the species are recruited from. We hypothesize that numerous morphological, physiological and biochemical adaptations permit survival of trees in flooded environments. Furthermore, these adaptations are independently derived across many taxa and result in a highly specialized flora. We attribute higher than expected levels of endemism to the great spatial extent and age of floodplain ecosystems in the Amazon basin, and highlight the role of Amazonian várzea as an potential driver in speciation and diversification processes.     

Environment versus dispersal in the assembly of western Amazonian palm communities

Aim It is a central issue in ecology and biogeography to understand what governs community assembly and the maintenance of biodiversity in tropical rain forest ecosystems. A key question is the relative importance of environmental species sorting (niche assembly) and dispersal limitation (dispersal assembly), which we investigate using a large dataset from diverse palm communities. Location Lowland rain forest, western Amazon River Basin, Peru. Methods We inventoried palm communities, registering all palm individuals and recording environmental conditions in 149 transects of 5 m × 500 m. We used ordination, Mantel tests and indicator species analysis (ISA) to assess compositional patterns, species responses to geographical location and environmental factors. Mantel tests were used to assess the relative importance of geographical distance (as a proxy for dispersal limitation) and environmental differences as possible drivers of dissimilarity in palm species composition. We repeated the Mantel tests for subsets of species that differ in traits of likely importance for habitat specialization and dispersal (height and range size). Results We found a strong relationship between compositional dissimilarity and environmental distance and a weaker but also significant relationship between compositional dissimilarity and geographical distance. Consistent with expectations, relationships with environmental and geographical distance were stronger for understorey species than for canopy species. Geographical distance had a higher correlation with compositional dissimilarity for small‐ranged species compared with large‐ranged species, whereas the opposite was true for environmental distance. The main environmental correlates were inundation and soil nutrient levels. Main conclusions The assembly of palm communities in the western Amazon appears to be driven primarily by species sorting according to hydrology and soil, but with dispersal limitation also playing an important role. The importance of environmental characteristics and geographical distance varies depending on plant height and geographical range size in agreement with functional predictions, increasing our confidence in the inferred assembly mechanisms.     

Mountain passes are higher at low latitudes for madicolous insect communities of the Neotropical region

Aim

To test whether spatial turnover patterns of mountain madicolous insect communities in the Southern Hemisphere support the ‘mountain passes are higher in the Tropic’ hypothesis (MPHT). To do this, we compared madicolous communities in the Amazon Mountains (equator) and the Atlantic Forest Mountains (23°S).

Location

Brazil.

Methods

We characterized madicolous insect communities in two elevational gradients between 90 to 3000 m a.s.l. separated by 23° of latitude, totalling 108 sampling sites. Since the MPHT predicts a more intense turnover along elevational gradients at lower latitudes than at higher latitudes, we evaluated beta diversity in the Amazon mountains, at the equator, and in the Atlantic Forest mountains, in the subtropical region. We quantified multiple-site abundance-based dissimilarity to assess whether beta diversity was different between both regions. We also performed constrained ordination (db-RDA) analyses to assess whether community dissimilarity (balanced variation in abundances) was uniquely or jointly explained by environmental, spatial and/or elevational predictors. Additionally, we independently assessed the relationship between community dissimilarity and altitudinal difference in each region and tested for differences in model parameters between regions.

Results

Although we found high species turnover in both regions, the community variation explained by environmental factors and altitude was higher in the Amazon than in the Atlantic Forest, as evidenced by db-RDA and altitudinal difference models. In general, communities were remarkably constrained by spatial predictors, which result from low dispersion capacity of most madicolous insects and low connectivity of madicolous systems. Consequently, the composition of madicolous insects notably diverged between regions, highlighting the complementarity and high conservation value of both systems.

Main Conclusions

Our results indicate that the MPHT explains, at the community level, the differences between low- and high-latitude mountain systems in community turnover along elevational gradients, even within a relatively short latitudinal distance in the Southern Hemisphere.     

Forest fragmentation drives Atlantic forest of northeastern Brazil to biotic homogenization

Aim To examine whether the tree flora of the Atlantic forest of northeastern Brazil has experienced detectable taxonomic homogenization via the proliferation of native pioneer species in response to habitat loss and fragmentation. Location Biotic homogenization (BH) was examined across the Atlantic forest of northeast Brazil, i.e. a 56,000 km² piece of tropical forest and a distinct centre of species endemism in South America. Methods We assessed a dataset consisting of 5122 tree records and compared the similarity of tree floras from 12 semi‐natural sub‐regions of the Atlantic forest between two time periods: pre‐1980 (plant records between 1902 and 1980), and post‐1980 (between 1981 and 2006). To understand the mechanisms leading to BH (1) tree floras were ordered (via non‐metric multidimensional scaling – NMDS) by date (pre/post 1980) based on species occurrence and frequency, (2) NMDS axes were regressed against the proportion of those species that increased their occurrence post‐1980 (i.e. the winner species), and (3) patterns of geographic distribution and frequency of particular life‐history traits were examined across winner species and a control group. Results Tree floras across the Atlantic forest became c. 20–40% more similar to each other post‐1980, but patterns of species similarity were also influenced by between‐plot geographical distance. NMDS ordination clearly segregated pre‐ and post‐1980 floras with a clear signal of floristic convergence. Furthermore, winner tree species were largely composed of short‐lived and small‐seeded pioneer species that exhibit wide geographic distributions. Main conclusions Our results suggest that tropical forest biotas are susceptible to taxonomic homogenization (i.e. increasing levels of similarity) in the context of severe human‐disturbance via the proliferation of particular groups of native species comprised mainly by ecologically‐plastic, generalist species. We are thus extending the concept of homogenization to address and highlight a pervasive biological shift in the structure of tropical forest communities currently taking place across hyper‐fragmented landscapes.     

Order and disorder in the river continuum: the contribution of continuity and connectivity to floodplain meadow biodiversity

Aim Aspects of connectivity and continuity operating in the River Meuse were analysed for their contribution to the biodiversity of the floodplain. From this analysis of the diversity and composition of the meadow communities, we aimed to derive effective biodiversity conservation strategies. Location The River Meuse is one of the larger rivers in the European Western Plains ecoregion. The alluvial plains of the river have a long history of cultivation, and for these plains the floodplain meadow vegetation is a highly appreciated and valuable nature conservation asset. Method We sampled floodplain meadows from 400 km of the six geomorphic reaches of the middle to lower course of the River Meuse. For each, 50 vascular plant relevés were recorded, representing the spectrum of floodplain meadow communities of that reach. Beta diversity was calculated to quantify similarity in species pools between the reaches. A dissimilarity formula was used to determine the turnover between the reaches, and these dissimilarities were compared with a Mantel test to detect whether species composition of the floodplain meadows exhibited connectivity and continuity between the reaches. Species richness for the floodplain vegetation data of the reaches was compared with data for riparian invertebrate communities. The vegetation data sets were ordinated using detrended correspondence analysis (DCA) to reveal patterns in the floodplain meadow species composition, and the DCA axes were related to plant functional groups and population strategies. The axis scores of the species and plots were linked to river and plant species traits. Results We did not observe an overall continuity trend in similarity, nor one in diversity in a downstream direction. Lateral connectivity was highlighted by the dissimilarity between the reaches and in the influxes of species from adjacent ecoregions. The DCA ordination showed statistically significant separations between reaches and between the plant functional groups. The second DCA axis related to the longitudinal gradient of the river, whereas the first axis showed stronger correlations with river and plant species traits. We termed this axis the ‘disorder axis’. Plant invaders and avoiders are located at the left side of the disorder axis, whereas the true river‐adapted categories of resisters and endurers are at the right extremity. Contributions to the disorder were identified in terms of connectivity with adjacent ecoregions and the physical disturbance regime of natural and anthropogenic perturbations, resulting in community changes between the reaches. Main conclusions We concluded that a single overall strategy for biodiversity conservation of the river or its floodplains is not feasible. Strategies can, however, be derived for separate river reaches based on functional groups in the communities, the disorder characteristics of the reach, and the influence of surrounding ecoregions.     

Gallery forest types and their environmental correlates in a Colombian savanna landscape

Savanna regions may contain significant areas of forest, usually in riparian environments. We described forest composition and quantified environmental variables for 80 plots in the watershed of the Yucao River (2550 km²), a tributary to the Meta River (Orinoco basin) in the eastern plains of Colombia. The total sampled area of 3.2 ha contained 147 tree species (110 genera and 45 families) with diameter at breast height >5 cm. The families represented by most species were Leguminosae (15 species), Arecaceae (11 species), Rubiaceae (9), Chrysobalanaceae (7), Euphorbiaceae (7), Melastomataceae (7) and Myrtaceae (7). Although most of the tree species have wide distribution ranges in humid neotropical forests, and few are endemic to the region, comparison with other neotropical forests suggests that the combination of taxa is characteristic for neotropical gallery forests. Cluster analysis allowed the definition of five forest types. They show important differences in a number of environmental variables, especially those related to inundation regimes and soil properties. Canonical correspondence analysis indicates good correlation of the first ordination axis with the size of the stream with which the forest is associated, the height to which the water rises during floods and variables related to soil fertility. The second ordination axis differentiates between soils with high or low water content in the dry season, high or low organic matter content and low or high bulk density. The results demonstrate the role of spatial variability and interactions of floodplain morphology, hydrological regime, and soil properties in structuring this important riparian community.     

The relative role of rivers,environmental heterogeneity and species traits in driving compositional changes in southeastern Amazonian bird assemblages

Amazonian rivers have been proposed to act as geographic barriers to species dispersal, either driving allopatric speciation or defining current distribution limits. The strength of the barrier varies according to the species’ ecological characteristics and the river's physical properties. Environmental heterogeneity may also drive compositional changes but has not been well assessed in Amazonia. Aiming to understand the contributions of riverine barriers and environmental heterogeneity in shaping compositional changes in Amazonian forest bird assemblages, we focus on the Tapajós River. We investigate how spatial variation in species composition is related to physical barriers (Tapajós and Jamanxim rivers), species’ ecological characteristics (distinct guilds), and environmental heterogeneity (canopy reflectance, soils, and elevation). We sampled birds through point-counts and mist nets on both banks of the Tapajós and Jamanxim rivers. To test for relationships between bird composition and environmental data, we used Mantel and partial Mantel tests, NMDS, and ANOVA + Tukey HSD. The Mantel tests showed that the clearest compositional changes occurred across the Tapajós River, which seems to act unequally as a significant barrier to the bird guilds. The Jamanxim River was not associated with differences in bird communities. Our results reinforce that the Tapajós River is a biogeographical boundary for birds, while environmental heterogeneity influences compositional variation within interfluves. We discuss the combined influence of geographical barriers, environmental heterogeneity, and ecological characteristics of species in shaping species distributions and community composition and the complexity of extrapolating the patterns found for birds to other Amazonian organisms. Abstract in Portuguese is available with online material.     

Within Flood Season Variation in Fruit Consumption and Seed Dispersal by Two Characin Fishes of the Amazon

Many Amazon River fishes consume fruits and seeds from floodplain forests during the annual flood season, potentially serving as important seed dispersers and predators. Using a participatory approach, this study investigated how within-season variation in flood level relates to fruit consumption and seed dispersal by two important frugivorous fish, Colossoma macropomum and Piaractus brachypomus , in two Lower Amazon River fishing communities in Brazil. Diets of both fish species were comprised of 78–98 percent fruits, largely dominated by a few species. Diets included fruits of 27 woody angiosperms and four herbaceous species from 26 families, indicating the importance of forest and Montrichardia arborescens habitat during peak flood. A correspondence between peak fruit species richness and peak flood level was observed in one of two communities, which may reflect higher forest diversity and/or differences in selection of fishing habitat. Both fishes are seed dispersers and predators, the relative role of which did not vary by flood level, seed size, or fish size, but may vary with seed hardness. Interspecific differences in diet volume and intact seeds suggest P. brachypomus are more effective seed dispersers than C. macropomum . Overall, the spatial and temporal variation in fruit species composition and richness demonstrate plasticity in fruit consumption in relation to flood level and locally available fruits. While such diets are adaptive to the dynamic changes of Amazon floodplain habitats, the high consumption of forest fruits and seeds from mid- and late-successional species suggests that floodplain forest degradation could disrupt seed dispersal and threaten local and regional fisheries.     

Morphobiological aspects of Rhodnius brethesi Matta, 1919 (Hemiptera:Reduviidae) from the Upper and Middle Negro River, Amazon region of Brazil: I - scanning electron microscopy

The occurrence of autochthonous cases of Chagas disease in the Amazon region of Brazil over recent decades has motivated an intensification of studies in this area. Different species of triatomines have been identified, and ten of these have be proven to be carriers of the parasite Trypanosoma cruzi or " cruzi-like " parasites. Studies conducted in the municipalities of Santa Isabel do Rio Negro and Barcelos, located on the Upper and Middle of the Negro River, microregion of Negro River, state of Amazonas have confirmed not only that Rhodnius brethesi is present in the palm tree Leopoldinia piassaba, but also that this insect was recognized by palm fiber collectors. A morphological study of eyes, inter-ocular and inter-ocellar regions, antennae, buccula, labrum, rostrum, stridulatory sulcus and feet, including the apex of the tibia, spongy fossette and ctenidium was conducted by scanning electron microscopy. The buccula and the stridulatory sulcus presented notable differences in specimens of different genera and also of different species. These data make it possible to suggest that the details presented in these structures can be included as diagnostic characteristics to be used in new dichotomous keys, thereby contributing towards studies of taxonomy and systematics and furnishing backing for comparative analysis of specimens collected from different localities.     

Landscape patterns of species-level association between ground-beetles and overstory trees in boreal forests of western Canada (Coleoptera, Carabidae)

Spatial associations between species of trees and ground-beetles (Coleoptera: Carabidae) involve many indirect ecological processes, likely reflecting the function of numerous forest ecosystem components. Describing and quantifying these associations at the landscape scale is basic to the development of a surrogate-based framework for biodiversity monitoring and conservation. In this study, we used a systematic sampling grid covering 84 km(2) of boreal mixedwood forest to characterize the ground-beetle assemblage associated with each tree species occurring on this landscape. Projecting the distribution of relative basal area of each tree species on the beetle ordination diagram suggests that the carabid community is structured by the same environmental factors that affects the distribution of trees, or perhaps even by trees per se. Interestingly beetle species are associated with tree species of the same rank order of abundance on this landscape, suggesting that conservation of less abundant trees will concomitantly foster conservation of less abundant beetle species. Landscape patterns of association described here are based on characteristics that can be directly linked to provincial forest inventories, providing a basis that is already available for use of tree species as biodiversity surrogates in boreal forest land management.