Potential aboveground biomass increase in Brazilian Atlantic Forest fragments with climate change.

Fragmented tropical forest landscapes preserve much of the remaining biodiversity and carbon stocks. Climate change is expected to intensify droughts and increase fire hazard and fire intensities, thereby causing habitat deterioration, and losses of biodiversity and carbon stock losses. Understanding the trajectories that these landscapes may follow under increased climate pressure is imperative for establishing strategies for conservation of biodiversity and ecosystem services. Here, we used a quantitative predictive modelling approach to project the spatial distribution of the aboveground biomass density (AGB) by the end of the 21st century across the Brazilian Atlantic Forest (AF) domain. To develop the models, we used the maximum entropy method with projected climate data to 2100, based on the Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) 4.5 from the fifth Assessment Report. Our AGB models had a satisfactory performance (area under the curve > 0.75 and p value < .05). The models projected a significant increase of 8.5% in the total carbon stock. Overall, the projections indicated that 76.9% of the AF domain would have suitable climatic conditions for increasing biomass by 2100 considering the RCP 4.5 scenario, in the absence of deforestation. Of the existing forest fragments, 34.7% are projected to increase their AGB, while 2.6% are projected to have their AGB reduced by 2100. The regions likely to lose most AGB-up to 40% compared to the baseline-are found between latitudes 13° and 20° south. Overall, although climate change effects on AGB vary latitudinally for the 2071-2100 period under the RCP 4.5 scenario, our model indicates that AGB stocks can potentially increase across a large fraction of the AF. The patterns found here are recommended to be taken into consideration during the planning of restoration efforts, as part of climate change mitigation strategies in the AF and elsewhere in Brazil.

Random placement models explain species richness and dissimilarity of frog assemblages within Atlantic Forest fragments.

Understanding the effects of random versus niche-based processes on biodiversity patterns is a central theme in ecology, and an important tool for predicting effects of habitat loss and fragmentation on biodiversity. We investigated the predictive power of random processes to explain species richness and species dissimilarity of amphibian assemblages in a fragmented tropical landscape of the Atlantic Forest of South America. We analyzed a large database of amphibian abundance and occupancy, sampled in 21 forest fragments ranging in size from 1.9 to 619 ha. We compared observed species richness and species dissimilarity with the outcomes of two null (random placement) models: 1- the traditional Coleman's area-based model and 2- an abundance-based model (based on the number of individuals observed in each fragment). We applied these models for all species combined, and separately for forest-dependent and habitat-generalist species. The abundance-based model fitted the observed species richness data better than the area-based model for all species, forest-dependent species, and generalist species. The area-based and the abundance-based models were also able to significantly explain species dissimilarity for all species and for generalists, but not for forest dependent species. The traditional area-based model assigned too many individuals to large fragments, thus failing to accurately explain species richness within patches across the landscape. Although niche-based processes may be important to structuring the regional pool of species in fragmented landscapes, our results suggest that part of the variation in species richness and species dissimilarity can be successfully explained by random placement models, especially for generalist species. Evaluating which factors cause variation in the number of individuals among patches should be a focus in future studies aiming to understand biodiversity patterns in fragmented landscapes.

Compreender os efeitos de processos aleatórios versus processos baseados em nicho nos padrões de biodiversidade é um tema central em ecologia e uma ferramenta importante para prever os efeitos da perda e fragmentação de habitat na biodiversidade. Nós investigamos o poder preditivo de processos aleatórios para explicar a riqueza e a dissimilaridade de espécies de assembleias de anfíbios em uma paisagem fragmentada tropical da Mata Atlântica da América do Sul. Analisamos um grande conjunto de dados de abundância e ocupação de anfíbios, amostrados em 21 fragmentos florestais com tamanhos de 1.9 a 619 ha. Comparamos a riqueza e a dissimilaridade de espécies observadas com os resultados de dois modelos nulos (posicionamento aleatório): 1- o modelo tradicional baseado em área de Coleman e 2 - um modelo baseado em abundância (com base no número de indivíduos observados em cada fragmento). Aplicamos esses modelos para todas as espécies combinadas e separadamente para espécies dependentes de floresta e espécies generalistas de habitat. O modelo baseado em abundância ajustou-se melhor aos dados observados de riqueza de espécies do que o modelo baseado em área para todas as espécies, espécies dependentes de floresta e espécies generalistas. Os modelos baseados em área e em abundância também foram capazes de explicar significativamente a dissimilaridade de espécies para todas as espécies e para generalistas, mas não para espécies dependentes de floresta. O modelo tradicional baseado em área atribuiu muitos indivíduos a grandes fragmentos, falhando assim em explicar com precisão a riqueza de espécies dentro de manchas na paisagem. Embora processos baseados em nicho possam ser importantes para estruturar o conjunto regional de espécies em paisagens fragmentadas, nossos resultados sugerem que parte da variação na riqueza e dissimilaridade de espécies pode ser explicada com sucesso por modelos de posicionamento aleatório, especialmente para espécies generalistas. Avaliar quais fatores causam variação no número de indivíduos entre manchas deve ser um foco em estudos futuros que visem compreender os padrões de biodiversidade em paisagens fragmentadas.

Which birds are Brazilians seeing on urban and non‑urban feeders? An analysis based on a collective online birding

Many studies have shown the positive and negative impacts of feeding wild birds using feeders; however, none of them considered case studies in Brazil. In 2020, social isolation measures imposed by COVID-19 boosted Brazilians’ interest in bird feeders, encouraging a group of birders to create an event (called JaneLives) to broadcast simultaneous live images of feeders across the country. Using the structure of JaneLives and relying on volunteers, we investigated which species visit Brazilian bird feeders, and discussed the effectiveness of our opportune citizen science initiative implemented during this event. Forty-eight feeders (19 urban and 29 non-urban) included in six biomes were sampled during nine JaneLives sessions (May–November 2020). The audience watched 133 species, 104 of which were visiting feeders. Non-urban feeders (n = 94) had higher richness than urban feeders (n = 68), but there were shared and unique species in both strata. Thraupidae, Turdidae, small, and medium birds (< 90 g) were the most common at the feeders. Owners of 23 feeders did data sampling at least once, while the other 25 feeders were sampled by 25 online birders (94.8% of their bird records were reliable). The narration that accompanied each JaneLives session enabled the audience to learn about Brazilian birds and increased environmental awareness. Audience numbers declined over the events, but the number of online birders was not affected. Ecolodges and parks that broadcasted their feeders received new clients afterwards. The events generated social interaction and pragmatic discussions about the usage of feeders, indicating that our citizen science initiative has potential for future research.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, southeastern Brazil / Assembleias de aves dispersoras de sementes em ambientes ripários de uma bacia hidrográfica parcialmente urbanizada, no sudoeste brasileiro

Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.(AU)

As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos dágua, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.(AU)

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil / Assembleias de aves dispersoras de sementes em ambientes ripários de uma bacia hidrográfica parcialmente urbanizada, no sudoeste brasileiro

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

Resumo As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos d'água, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.

Morphometric Patterns and Blood Biochemistry of Capybaras (Hydrochoerus hydrochaeris) from Human-Modified Landscapes and Natural Landscapes in Brazil.

The capybara, Hydrochoerus hydrochaeris, is the largest extant rodent of the world. To better understand the correlation between size and body mass, and biochemical parameters of capybaras from areas with different degrees of anthropization (i.e., different food supplies), we sampled free-ranging capybaras from areas of natural landscapes (NLs) and human-modified landscapes (HMLs) in Brazil. Analyses of biometrical and biochemical parameters of capybaras showed that animals from HMLs were heavier (higher body mass) than those from NL, a condition possibly related to fat deposit rather than body length, as indicated by Body Condition Index (BCI) analyses. Biochemical parameters indicated higher serum levels of albumin, creatine kinase, cholesterol, fructosamine and total protein among capybaras from HMLs than from NLs; however, when all adult capybaras were analyzed together only cholesterol and triglycerides were positively correlated with body mass. We propose that the biochemical profile differences between HMLs and NLs are related to the obesity condition of capybaras among HMLs. Considering that heavier animals might live longer and reproduce more often, our results could have important implications in the population dynamics of capybaras among HMLs, where this rodent species is frequently represented by overgrowth populations that generate several levels of conflicts with human beings.

The role of land-use history in driving successional pathways and its implications for the restoration of tropical forests.

Secondary forests are increasingly important components of human-modified landscapes in the tropics. Successional pathways, however, can vary enormously across and within landscapes, with divergent regrowth rates, vegetation structure and species composition. While climatic and edaphic conditions drive variations across regions, land-use history plays a central role in driving alternative successional pathways within human-modified landscapes. How land use affects succession depends on its intensity, spatial extent, frequency, duration and management practices, and is mediated by a complex combination of mechanisms acting on different ecosystem components and at different spatial and temporal scales. We review the literature aiming to provide a comprehensive understanding of the mechanisms underlying the long-lasting effects of land use on tropical forest succession and to discuss its implications for forest restoration. We organize it following a framework based on the hierarchical model of succession and ecological filtering theory. This review shows that our knowledge is mostly derived from studies in Neotropical forests regenerating after abandonment of shifting cultivation or pasture systems. Vegetation is the ecological component assessed most often. Little is known regarding how the recovery of belowground processes and microbiota communities is affected by previous land-use history. In published studies, land-use history has been mostly characterized by type, without discrimination of intensity, extent, duration or frequency. We compile and discuss the metrics used to describe land-use history, aiming to facilitate future studies. The literature shows that (i) species availability to succession is affected by transformations in the landscape that affect dispersal, and by management practices and seed predation, which affect the composition and diversity of propagules on site. Once a species successfully reaches an abandoned field, its establishment and performance are dependent on resistance to management practices, tolerance to (modified) soil conditions, herbivory, competition with weeds and invasive species, and facilitation by remnant trees. (ii) Structural and compositional divergences at early stages of succession remain for decades, suggesting that early communities play an important role in governing further ecosystem functioning and processes during succession. Management interventions at early stages could help enhance recovery rates and manipulate successional pathways. (iii) The combination of local and landscape conditions defines the limitations to succession and therefore the potential for natural regeneration to restore ecosystem properties effectively. The knowledge summarized here could enable the identification of conditions in which natural regeneration could efficiently promote forest restoration, and where specific management practices are required to foster succession. Finally, characterization of the landscape context and previous land-use history is essential to understand the limitations to succession and therefore to define cost-effective restoration strategies. Advancing knowledge on these two aspects is key for finding generalizable relations that will increase the predictability of succession and the efficiency of forest restoration under different landscape contexts.

A meta-analysis contrasting active versus passive restoration practices in dryland agricultural ecosystems.

Restoration of agricultural drylands globally, here farmlands and grazing lands, is a priority for ecosystem function and biodiversity preservation. Natural areas in drylands are recognized as biodiversity hotspots and face continued human impacts. Global water shortages are driving increased agricultural land retirement providing the opportunity to reclaim some of these lands for natural habitat. We used meta-analysis to contrast different classes of dryland restoration practices. All interventions were categorized as active and passive for the analyses of efficacy in dryland agricultural ecosystems. We evaluated the impact of 19 specific restoration practices from 42 studies on soil, plant, animal, and general habitat targets across 16 countries, for a total of 1,427 independent observations. Passive vegetation restoration and grazing exclusion led to net positive restoration outcomes. Passive restoration practices were more variable and less effective than active restoration practices. Furthermore, passive soil restoration led to net negative restoration outcomes. Active restoration practices consistently led to positive outcomes for soil, plant, and habitat targets. Water supplementation was the most effective restoration practice. These findings suggest that active interventions are necessary and critical in most instances for dryland agricultural ecosystems likely because of severe anthropogenic pressures and concurrent environmental stressors-both past and present.

Secondary forests offset less than 10% of deforestation-mediated carbon emissions in the Brazilian Amazon.

Secondary forests are increasing in the Brazilian Amazon and have been cited as an important mechanism for reducing net carbon emissions. However, our understanding of the contribution of secondary forests to the Amazonian carbon balance is incomplete, and it is unclear to what extent emissions from old-growth deforestation have been offset by secondary forest growth. Using MapBiomas 3.1 and recently refined IPCC carbon sequestration estimates, we mapped the age and extent of secondary forests in the Brazilian Amazon and estimated their role in offsetting old-growth deforestation emissions since 1985. We also assessed whether secondary forests in the Brazilian Amazon are growing in conditions favourable for carbon accumulation in relation to a suite of climatic, landscape and local factors. In 2017, the 129,361 km2 of secondary forest in the Brazilian Amazon stored 0.33 ± 0.05 billion Mg of above-ground carbon but had offset just 9.37% of old-growth emissions since 1985. However, we find that the majority of Brazilian secondary forests are situated in contexts that are less favourable for carbon accumulation than the biome average. Our results demonstrate that old-growth forest loss remains the most important factor determining the carbon balance in the Brazilian Amazon. Understanding the implications of these findings will be essential for improving estimates of secondary forest carbon sequestration potential. More accurate quantification of secondary forest carbon stocks will support the production of appropriate management proposals that can efficiently harness the potential of secondary forests as a low-cost, nature-based tool for mitigating climate change.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

Resumo As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos dágua, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.

Large Terrestrial Bird Adapting Behavior in an Urbanized Zone.

Wildlife living within urban ecosystems have to adapt or perish. Red-legged Seriema, a large terrestrial bird, are rare in urban ecosystems, however, they have been reported in a medium-sized Brazilian city. We investigated the reasons for this occurrence as well as their behavior. We assessed the distribution of Seriemas (including fledglings), free-ranging cats, and cat-feeding points provided by humans, and past records of Seriemas in the study area. We discovered that Seriemas are sharing spatial resources with cats without apparent conflicts, and intraspecific competition was important to define the spatial distribution of Seriemas. This species is able to use human-made structures to improve territory defense and opportunistic foraging. Direct and indirect human food provisioning is helping them to survive in the studied area, but is also facilitating the domestication process, which may cause future conflicts with humans and cats. Although Seriemas have inhabited the studied urban area for years, they are still adapting their behaviors for urban life, as they have not yet perceived the dangers of automotive traffic. Our study corroborates that wild species may adapt to urban areas driven by human contact, but it also acts as a trap for the adaptive process.

Is environmental legislation conserving tropical stream faunas? A large-scale assessment of local, riparian and catchment-scale influences on Amazonian fish.

Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human-induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna.To assess the extent to which stream fish are being effectively conserved in agricultural landscapes, we examined the spatial distribution of assemblages in river basins to identify the relative importance of human impacts at instream, riparian and catchment scales, in shaping observed patterns. We used an extensive dataset on the ecological condition of 83 low-order streams distributed in three river basins in the eastern Brazilian Amazon.We collected and identified 24,420 individual fish from 134 species. Multiplicative diversity partitioning revealed high levels of compositional dissimilarity (DS) among stream sites (DS = 0.74 to 0.83) and river basins (DS = 0.82), due mainly to turnover (77.8% to 81.8%) rather than nestedness. The highly heterogeneous fish faunas in small Amazonian streams underscore the vital importance of enacting measures to protect forests on private lands outside of public protected areas.Instream habitat features explained more variability in fish assemblages (15%-19%) than riparian (2%-12%), catchment (4%-13%) or natural covariates (4%-11%). Although grouping species into functional guilds allowed us to explain up to 31% of their abundance (i.e. for nektonic herbivores), individual riparian - and catchment - scale predictor variables that are commonly a focus of environmental legislation explained very little of the observed variation (partial R2 values mostly <5%).Policy implications. Current rates of agricultural intensification and mechanization in tropical landscapes are unprecedented, yet the existing legislative frameworks focusing on protecting riparian vegetation seem insufficient to conserve stream environments and their fish assemblages. To safeguard the species-rich freshwater biota of small Amazonian streams, conservation actions must shift towards managing whole basins and drainage networks, as well as agricultural practices in already-cleared land.

Recovery of Forest and Phylogenetic Structure in Abandoned Cocoa Agroforestry in the Atlantic Forest of Brazil.

Cocoa agroforests like the cabrucas of Brazil's Atlantic forest are among the agro-ecosystems with greatest potential for biodiversity conservation. Despite a global trend for their intensification, cocoa agroforests are also being abandoned for socioeconomic reasons especially on marginal sites, because they are incorporated in public or private protected areas, or are part of mandatory set-asides under Brazilian environmental legislation. However, little is known about phylogenetic structure, the processes of forest regeneration after abandonment and the conservation value of former cabruca sites. Here we compare the vegetation structure and composition of a former cabruca 30-40 years after abandonment with a managed cabruca and mature forest in the Atlantic forest region of Espirito Santo, Brazil. The forest in the abandoned cabruca had recovered a substantial part of its original structure. Abandoned cabruca have a higher density (mean ± CI95 %: 525.0 ± 40.3 stems per ha), basal area (34.0 ± 6.5 m2 per ha) and species richness (148 ± 11.5 species) than managed cabruca (96.0 ± 17.7; 24.15 ± 3.9 and 114.5 ± 16.0, respectively) but no significant differences to mature forest in density (581.0 ± 42.2), basal area (29.9.0 ± 3.3) and species richness (162.6 ± 15.5 species). Thinning (understory removal) changes phylogenetic structure from evenness in mature forest to clustering in managed cabruca, but after 30-40 years abandoned cabruca had a random phylogenetic structure, probably due to a balance between biotic and abiotic filters at this age. We conclude that abandoned cocoa agroforests present highly favorable conditions for the regeneration of Atlantic forest and could contribute to the formation of an interconnected network of forest habitat in this biodiversity hotspot.

Seed-dispersing bird assemblages in riparian environments of a partially urbanized river basin, Southeastern Brazil

Abstract Birds play a key role in ecosystem dynamics, including urban and rural areas, bringing environmental quality improvements and ecological stability. Species contribute directly to natural regeneration of vegetation and succession processes, by offering ecosystem services as seed dispersal, an important role in human-modified areas. We studied the assemblages of fruit-eating birds in riparian environments of Monjolinho basin, central São Paulo state, southeastern Brazil. Birds were recorded in 41 points distributed in riparian ecosystems alongside waterbodies, in landscapes with five types of surrounding matrices: urban, periurban, farmland, and native vegetation. We described how assemblages are structured aiming to evaluate the possible influence of seasonality and landscape type. We recorded 39 bird species that can play a role as seed-dispersers, 32 in wet season and 32 in dry season. There were no significant differences in the diversity and dominance of species between seasons considering the entire area, indicating stability of basic assemblage structure. However, total number of individuals of all species recorded in different landscapes were influenced by seasonality. Also, the composition and abundance of species significantly changed between seasons, leading to a high dissimilarity with almost 50% of the species contributing with almost 90% of the observed variation. A higher taxonomic diversity and distinctness pointed to a wider array of possible seed dispersal services in natural areas, while the lowest values of indexes were found in human-modified areas. The higher number of non-related bird species during dry season contrasted with the higher number of individuals during wet season, indicating that there is more possible ecosystem services offered by frugivorous birds in driest period of the year, while in the rainy period the carrying capacity of the riparian environments was increased.

Resumo As aves desempenham um papel chave na dinâmica dos ecossistemas, incluindo áreas urbanas e rurais, e trazem melhorias na qualidade ambiental e estabilidade ecológica. As espécies contribuem diretamente com a regeneração natural da vegetação e processos de sucessão por oferecerem serviços ecossistêmicos como a dispersão de sementes, um papel fundamental em áreas alteradas. Nós estudamos a assembleia de espécies de aves que se alimentam de frutos em ambientes ripários da bacia do rio Monjolinho, região central do estado de São Paulo, sudeste do Brasil. As aves foram registradas em 41 pontos distribuídos em ecossistemas ripários ao longo dos corpos dágua, em paisagens com quatro tipos de matrizes em seu entorno: urbana, periurbana, rural e vegetação nativa. Nós descrevemos como as assembleias estão estruturadas, objetivando avaliar a possível influência da sazonalidade e do tipo de paisagem do entorno. Foram registradas 39 espécies de aves que podem desempenhar o papel de dispersoras de sementes, sendo 32 espécies no período chuvoso e 32 no período seco. Não foi detectada diferença significativa na diversidade e dominância de espécies entre estações em toda área de estudo, indicando estabilidade da estrutura básica das assembleias. Entretanto, o número total de indivíduos de todas as espécies registrados nas diferentes paisagens foi influenciado pela sazonalidade. Além disso, a composição e abundância de espécies mudou significativamente entre as estações, levando a uma alta dissimilaridade com quase 50% das espécies contribuindo com quase 90% da variação observada. A diversidade e distinção taxonômicas mais altas apontam para maior variedade de serviços ecossistêmicos possíveis relacionados à dispersão de sementes em áreas naturais, enquanto os menores valores desses índices foram encontrados em áreas antropizadas. Um maior número de espécies distintas com menor proximidade taxonômica durante a estação seca, em contraste com um alto número de indivíduos observados na estação chuvosa, indica que existe uma maior gama de possíveis serviços ecossistêmicos oferecidos pelas aves frugívoras no período mais seco do ano, enquanto no período de maior pluviosidade os ecossistemas apresentaram maior capacidade suporte.

Patterns and predictors of ß-diversity in the fragmented Brazilian Atlantic forest: a multiscale analysis of forest specialist and generalist birds.

Biodiversity maintenance in human-altered landscapes (HALs) depends on the species turnover among localities, but the patterns and determinants of ß-diversity in HALs are poorly known. In fact, declines, increases and neutral shifts in ß-diversity have all been documented, depending on the landscape, ecological group and spatial scale of analysis. We shed some light on this controversy by assessing the patterns and predictors of bird ß-diversity across multiple spatial scales considering forest specialist and habitat generalist bird assemblages. We surveyed birds from 144 point counts in 36 different forest sites across two landscapes with different amount of forest cover in the Brazilian Atlantic forest. We analysed ß-diversity among points, among sites and between landscapes with multiplicative diversity partitioning of Hill numbers. We tested whether ß-diversity among points was related to within-site variations in vegetation structure, and whether ß-diversity among sites was related to site location and/or to differences among sites in vegetation structure and landscape composition (i.e. per cent forest and pasture cover surrounding each site). ß-diversity between landscapes was lower than among sites and among points in both bird assemblages. In forest specialist birds, the landscape with less forest cover showed the highest ß-diversity among sites (bird differentiation among sites), but generalist birds showed the opposite pattern. At the local scale, however, the less forested landscape showed the lowest ß-diversity among points (bird homogenization within sites), independently of the bird assemblage. ß-diversity among points was weakly related to vegetation structure, but higher ß-diversity values were recorded among sites that were more isolated from each other, and among sites with higher differences in landscape composition, particularly in the less forested landscape. Our findings indicate that patterns of bird ß-diversity vary across scales and are strongly related to landscape composition. Bird assemblages are shaped by both environmental filtering and dispersal limitation, particularly in less forested landscapes. Conservation and management strategies should therefore prevent deforestation in this biodiversity hotspot.

Role of recent and old riverine barriers in fine-scale population genetic structure of Geoffroy's tamarin (Saguinus geoffroyi) in the Panama Canal watershed.

The role of physical barriers in promoting population divergence and genetic structuring is well known. While it is well established that animals can show genetic structuring at small spatial scales, less well-resolved is how the timing of the appearance of barriers affects population structure. This study uses the Panama Canal watershed as a test of the effects of old and recent riverine barriers in creating population structure in Saguinus geoffroyi, a small cooperatively breeding Neotropical primate. Mitochondrial sequences and microsatellite genotypes from three sampling localities revealed genetic structure across the Chagres River and the Panama Canal, suggesting that both waterways act as barriers to gene flow. F-statistics and exact tests of population differentiation suggest population structure on either side of both riverine barriers. Genetic differentiation across the Canal, however, was less than observed across the Chagres. Accordingly, Bayesian clustering algorithms detected between two and three populations, with localities across the older Chagres River always assigned as distinct populations. While conclusions represent a preliminary assessment of genetic structure of S. geoffroyi, this study adds to the evidence indicating that riverine barriers create genetic structure across a wide variety of taxa in the Panama Canal watershed and highlights the potential of this study area for discerning modern from historical influences on observed patterns of population genetic structure.