Habitat amount drives the functional diversity and nestedness of anuran communities in an Atlantic Forest fragmented landscape

Natural environments disturbed by human activities can suffer from species extinctions, but some can still harbor high taxonomic diversity. However, disturbances may have impacts beyond the species level, if the species lost represent unique functions in the ecosystem. In this study, we evaluated to what extent the amount of habitat can determine the functional diversity and nestedness of amphibian communities in an Atlantic Forest fragmented landscape in Brazil, and if there is a threshold of habitat amount beyond which there is severe loss of functional diversity. As species responses may depend on their habitat type, we performed the analyses for three different sets of species: all species, forest‐dependent species, and generalist species. We also evaluated the relative importance of turnover and nestedness components to total functional dissimilarity among sites. Habitat amount affected functional diversity of frogs, especially for forest‐dependent species where a linear reduction was detected. The functional dissimilarity among sites was mostly explained by the nestedness component. The reduction of functional diversity was mediated by an ordered loss of traits, leading to a functionally nested metacommunity. These sensitive traits were closely related to habits and reproductive modes that depend on rivers and streams. The maintenance of functional diversity of frogs in fragmented landscapes must rely on the conservation of both terrestrial and aquatic environments, as some species and their traits can disappear from remnants of native vegetation lacking some specific habitats (e.g. streams). Abstract in Portuguese is available with online material.     

The matrix-tolerance hypothesis: an empirical test with frogs in the Atlantic Forest

The matrix-tolerance hypothesis suggests that the most abundant species in the inter-habitat matrix would be less vulnerable to their habitat fragmentation. This model was tested with leaf-litter frogs in the Atlantic Forest where the fragmentation process is older and more severe than in the Amazon, where the model was first developed. Frog abundance data from the agricultural matrix, forest fragments and continuous forest localities were used. We found an expected negative correlation between the abundance of frogs in the matrix and their vulnerability to fragmentation, however, results varied with fragment size and species traits. Smaller fragments exhibited stronger matrix-vulnerability correlation than intermediate fragments, while no significant relation was observed for large fragments. Moreover, some species that avoid the matrix were not sensitive to a decrease in the patch size, and the opposite was also true, indicating significant differences with that expected from the model. Most of the species that use the matrix were forest species with aquatic larvae development, but those species do not necessarily respond to fragmentation or fragment size, and thus affect more intensively the strengthen of the expected relationship. Therefore, the main relationship expected by the matrix-tolerance hypothesis was observed in the Atlantic Forest; however we noted that the prediction of this hypothesis can be substantially affected by the size of the fragments, and by species traits. We propose that matrix-tolerance model should be broadened to become a more effective model, including other patch characteristics, particularly fragment size, and individual species traits (e.g., reproductive mode and habitat preference).     

Functional composition and phenology of fruit-feeding butterflies in a fragmented landscape: variation of seasonality between habitat specialists

For butterflies, tolerance to the matrix may be an important criterion of habitat occurrence in fragmented landscapes. Here we examine the relative effects of habitat fragmentation and the surrounding agricultural matrix on the functional composition of fruit-feeding butterflies of the Atlantic rain forest in southeastern Brazil. Generalized linear models were used to detect the effects of landscape metrics on butterfly richness and abundance of the total assemblage and functional groups. Circular statistics were used to analyze the patterns of monthly abundance of the total assemblage and functional groups in the forest remnants and the surrounding matrices. In total, 650 butterflies representing 57 species were captured; species composition differed significantly between the forest fragments and the surrounding matrices. We recorded 22 forest specialists, 18 matrix specialists, 11 common species with matrix preference and six common species with forest preference. Forest connectivity favored the richness of forest specialists, while habitat fragmentation enhances the richness and abundance of matrix-tolerant species. Circular analysis revealed that forest specialists were more abundant in the rainy season while matrix-tolerant species proliferated in the dry season. Although maintaining connectivity of forest fragments may increase the mobility and dispersion of forest species, our results showed that landscape fragmentation modify butterfly assemblage by promoting an increase of matrix tolerant species with detriment of forest specialists.     

Habitat fragmentation rather than habitat amount or habitat split reduces the diversity and abundance of ground-dwelling anurans within forest remnants of the Brazilian Cerrado

Rampant deforestation has caused the loss and fragmentation of natural habitats, which has precipitated a global biodiversity crisis. Research on how land-use change contributes to a loss of biodiversity is urgently needed, especially in ecosystems that have undergone rapid anthropogenic changes. We sought to investigate the extent to which habitat loss, fragmentation, and habitat split (the separation of forest and aquatic habitats) negatively influenced taxonomic diversity, functional diversity, total abundance, and the individual abundances of five anuran species in the Brazilian Cerrado. We sampled anurans between December 2017 and March 2018 using pitfall traps at sites distributed along a gradient of habitat fragmentation/habitat split: unfragmented forest, forest fragments without habitat split, and forest fragments with habitat split. Forest cover was measured within a 1-km radius of each site. Sites within unfragmented forests had higher taxonomic and functional diversities than either fragment type. Taxonomic diversity was highly correlated with functional diversity, but we did not find a pattern to the loss of functional traits. Total anuran abundance and the abundances of Chiasmocleis albopunctata, Physalaemus cuvieri, and Rhinella diptycha were higher in unfragmented forests compared to forest fragments. No species was more abundant in fragments than in unfragmented forests. Our results indicate that the fragmentation of forests by agricultural land use is directly and indirectly responsible for the loss of taxonomic and functional diversity, as well as for reducing population sizes of ground-dwelling anurans. Although we did not find a distinct effect of habitat split on ground-dwelling anurans, our study underscores the importance of preserving continuous forest habitats for the maintenance of anuran diversity in the Cerrado.     

Landscape context of plantation forests in the conservation of tropical mammals

Plantation forests have been expanding in many tropical and subtropical environments. Howerver, even when they replace less wildlife friendly land uses such as pastures and annual crops, the biodiversity levels of pristine natural habitats often have not been recovered. Here we addressed how the landscape context of plantation forests located in South-eastern Brazil affects species richness and community resilience of medium and large size mammals. The area covered by native habitat fragments surrounding plantation forests is positively related to functional richness, including the presence of species more vulnerable to extinction in fragmented landscapes. In addition, the degree of aggregation of plantation forest stands is negatively related to more vulnerable species. No primates were recorded in our seven plantation forest sites (ranging from 272 to 24,921 ha), even when they were seen in native habitat fragments adjacent to commercial tree stands. Two invasive species (Sus scrofa and Lepus capensis) were recorded in four plantation forest sites. The impoverishment of fauna in plantation forests is due to two factors. First, plantation forests generally are structurally simplified habitats when compared to highly diverse tropical forests. Secondly, the isolation from habitat fragments which act as source of individuals in the landscape precludes the establishment of individual in plantation forest. We also highlighted the management practices to improve the complexity of vegetation in commercial tree stands should be taken cautiously, insofar as reduced productivity per area entails a greater demand for land. Thus, an alternative would be intensify the management of the commercial tree stands for wood production together with the restoration of adjacent areas set aside to conservation and native habitat fragments protection.     

Species richness, composition and abundance of fruit-feeding butterflies in the Brazilian Atlantic Forest: comparison between a fragmented and a continuous landscape

Aim  To evaluate frugivorous butterflies as indicators of forest disturbance in the Brazilian Atlantic Forest.
Location  The study area is located in the municipality of Cotia, São Paulo State, south-eastern Brazil (23°35'−23°50' S, 46°45'−47°15' W).
Methods  Sampling was done at four sites inside a large forest block, the Morro Grande State Reserve, and in five forest fragments in an adjacent fragmented landscape. Butterflies were sampled with portable traps, baited with a fermented mixture of banana and sugar cane juice. Sampling was carried out during the period most favourable for the capture of frugivorous butterflies in south-eastern Brazil.
Results  All richness-related results indicated no effect of forest fragmentation on the frugivorous butterfly guild, concurring with the suggestion of appreciable resistance of Atlantic Forest butterflies to habitat modification. However, species composition discriminated between the two landscapes, indicating that fragmentation may have effects beyond simple species richness. When species were analysed individually, clear patterns of distribution emerged, with some species that were very abundant in the fragmented landscape being practically absent in the continuous landscape, and vice versa. This pattern seems consistent even for some subfamilies.
Main conclusion  Our findings support the usefulness of the frugivorous butterfly guild as a biological indicator of forest disturbance effects in one of the world's most threatened ecosystems.     

Vanishing bird species in the Atlantic Forest: relative importance of landscape configuration, forest structure and species characteristics

Patch size, isolation, and vegetation structure are expected to strongly affect species persistence in fragmented landscapes, particularly for those with <30% of native habitat remaining. Those influences should be modulated by species characteristics, resulting in complex relationships. In order to investigate how species, habitat structure and landscape factors are related and how they affected species persistence, we studied bird communities in a fragmented Atlantic Forest region. Patch size strongly affected species richness and population abundances. However, some functional groups were more affected than others, particularly endemic and understory insectivores, species that are near the limits of their geographical distribution, those using few forest types, and those with their center of abundance in high altitude tropical forests. The effect of vegetation structure was mainly at the species level, reflecting specific responses to habitat quality. The importance of landscape variables varies according to the species group. For the most affected ones, which usually have low dispersal capacity, patch size and quality were the most relevant factors, whereas patch isolation was associated with the richness of groups with more generalist species. This pattern is due to the limited structural connectivity in the study region, composed of low matrix permeability (e.g. pastures and sugar cane), which isolate the most affected species, making them more dependent on local factors. In such a fragmented landscape, the largest patches should be prioritized for conservation purposes, as they aggregate the most vulnerable species and present the highest alpha diversity. Landscape management, as such, should also reconnect large fragments through corridors or matrix improvements, promoting better conditions for long-term persistence of the most affected species.     

Isolation determines patterns of species presence in highly fragmented landscapes

In fragmented landscapes, changes in habitat availability, patch size, shape and isolation may affect survival of local populations. Proposing efficient conservation strategies for such species relies initially on distinguishing the particular effects of those factors. To address these issues, we investigated the occurrence of 3 bird species in fragmented Brazilian Atlantic Forest landscapes. Playback techniques were used to collect presence/absence data of these species inside 80 forest patches, and incidence models were used to infer their occupancy pattern from landscape spatial structure. The relative importance of patch size, shape and surrounding forest cover and isolation was assessed using a model selection approach based on maximum likelihood estimation. The presence of all species was in general positively affected by the amount of surrounding habitat and negatively affected by inter‐patch distances. The joint effects of patch size and the surrounding landscape characteristics were important determinants of occupancy for two species. The third species was affected only by forest cover and mean patch isolation. Our results suggest that local species presence is in general more influenced by the isolation from surrounding forests than by patch size alone. We found evidence that, in highly fragmented landscapes, birds that can not find patches large enough to settle may be able to overcome short distances through the matrix and include several nearby patches within their home‐ranges to complement their resource needs. In these cases, patches must be defined as functionally connected habitat networks rather than mere continuous forest segments. Bird conservation strategies in the Atlantic forest should focus on increasing patch density and connectivity, in order to implement forest networks that reduce the functional isolation between large remnants with remaining core habitat.     

Effects of forest fragmentation on the lekking behavior of White-throated Manakins in Central Amazonia

Forest fragmentation can affect various aspects of population dynamics, but few investigators have assessed possible effects on the behavior of a species. Loss of habitat may limit population recruitment and abundance, which may alter breeding dynamics in forest remnants. We examined the lekking behavior of White-throated Manakins (Corapipo gutturalis) in a fragmented landscape to determine if forest fragmentation affected the spatial distribution of display courts and male behavior at courts. We captured and observed males at 19 courts located in 11 primary forests of different sizes in forest habitats of the Biological Dynamics of Forest Fragments Project area, an experimentally fragmented landscape located in the central Brazilian Amazon, and estimated their spatial distribution as the distance to the nearest court in the landscape. We quantified habitat loss using the proportion of forest cover surrounding courts and their distances to forest edges. No courts were detected in 1-ha forest fragments, suggesting direct effects from habitat loss following fragmentation that affected connectivity and thus recruitment and persistence of courts in the smallest fragments. The spatial distribution of display courts in forests larger than 10 ha remained unaltered, compared to display courts in continuous forests, but adult males were less numerous on courts with a higher percentage of forest cover and they displayed less on courts closer to forest edges. The spatial distribution of courts also contributed to variation in male social behavior, with more juvenile males present and adult males displaying at lower rates at more isolated courts. Although White-throated Manakins are locally common, the observed behavioral changes in response to habitat loss may affect their population dynamics. Our results show the importance of assessing behavioral changes in conservation programs and, in particular, of including biologically relevant measures of habitat loss in addressing its possible effects on species persistence in fragmented landscapes.     

Lizard assemblages in a fragmented landscape of central Chile

We studied lizard assemblages assessing abundance, richness, and nestedness in a fragmented landscape of central Chile including native temperate forest, forest fragments, and commercial pine plantations. Fragmentation and plantations increase the availability of edge habitats triggering both the support of additional lizard species, absent at the continuous forest, and the nestedness of lizard assemblages, where interior habitats of forest and plantations are nested subsets of habitat edges. A vulnerable lizard (Liolaemus tenuis) thrives at fragments in abundance similar to the continuous forest. Therefore, remnants ought to be considered in the conservation of lizard assemblages.     

Changes in tree reproductive traits reduce functional diversity in a fragmented Atlantic forest landscape

Functional diversity has been postulated to be critical for the maintenance of ecosystem functioning, but the way it can be disrupted by human-related disturbances remains poorly investigated. Here we test the hypothesis that habitat fragmentation changes the relative contribution of tree species within categories of reproductive traits (frequency of traits) and reduces the functional diversity of tree assemblages. The study was carried out in an old and severely fragmented landscape of the Brazilian Atlantic forest. We used published information and field observations to obtain the frequency of tree species and individuals within 50 categories of reproductive traits (distributed in four major classes: pollination systems, floral biology, sexual systems, and reproductive systems) in 10 fragments and 10 tracts of forest interior (control plots). As hypothesized, populations in fragments and control plots differed substantially in the representation of the four major classes of reproductive traits (more than 50% of the categories investigated). The most conspicuous differences were the lack of three pollination systems in fragments--pollination by birds, flies and non-flying mammals--and that fragments had a higher frequency of both species and individuals pollinated by generalist vectors. Hermaphroditic species predominate in both habitats, although their relative abundances were higher in fragments. On the contrary, self-incompatible species were underrepresented in fragments. Moreover, fragments showed lower functional diversity (H' scores) for pollination systems (-30.3%), floral types (-23.6%), and floral sizes (-20.8%) in comparison to control plots. In contrast to the overwhelming effect of fragmentation, patch and landscape metrics such as patch size and forest cover played a minor role on the frequency of traits. Our results suggest that habitat fragmentation promotes a marked shift in the relative abundance of tree reproductive traits and greatly reduces the functional diversity of tree assemblages in fragmented landscapes.     

Fragmentation of Atlantic Forest has not affected gene flow of a widespread seed‐dispersing bat

Habitat loss and resultant fragmentation are major threats to biodiversity, particularly in tropical and subtropical ecosystems. It is increasingly urgent to understand fragmentation effects, which are often complex and vary across taxa, time and space. We determined whether recent fragmentation of Atlantic forest is causing population subdivision in a widespread and important Neotropical seed disperser: Artibeus lituratus (Chiroptera: Phyllostomidae). Genetic structure within highly fragmented forest in Paraguay was compared to that in mostly contiguous forest in neighbouring Misiones, Argentina. Further, observed genetic structure across the fragmented landscape was compared with expected levels of structure for similar time spans in realistic simulated landscapes under different degrees of reduction in gene flow. If fragmentation significantly reduced successful dispersal, greater population differentiation and stronger isolation by distance would be expected in the fragmented than in the continuous landscape, and genetic structure in the fragmented landscape should be similar to structure for simulated landscapes where dispersal had been substantially reduced. Instead, little genetic differentiation was observed, and no significant correlation was found between genetic and geographic distance in fragmented or continuous landscapes. Furthermore, comparison of empirical and simulated landscapes indicated empirical results were consistent with regular long‐distance dispersal and high migration rates. Our results suggest maintenance of high gene flow for this relatively mobile and generalist species, which could be preventing or significantly delaying reduction in population connectivity in fragmented habitat. Our conclusions apply to A. lituratus in Interior Atlantic Forest, and do not contradict broad evidence that habitat fragmentation is contributing to extinction of populations and species, and poses a threat to biodiversity worldwide.     

Long-term effects of forest fragmentation on Amazonian ant communities

Aim To analyse the effects of forest fragmentation on ant communities in an Amazonian landscape that has been fragmented for over a century. Location The region surrounding the village of Alter do Chão in the Brazilian Amazonian state of Pará (2°30′ S, 54°57′ W). Methods Collection of ants and measurements of tree density were performed along transects established in eight sites in continuous forest and in 24 forest fragments surrounded by savanna vegetation. Data on size, perimeter, and degree of isolation (distance to continuous forest and distance to nearest area of forest > 5 ha) of each fragment were obtained from a georeferenced Landsat image of the study area. Results There were significant differences in species richness and composition between fragments and continuous forest, and these differences were not related to intersite variation in vegetation structure (tree density). Fragments supported fewer ant species per plot, and these species tended to represent a nested subset of those found in continuous forests. Fragments had significantly fewer rare species and fewer ant genera. However, fragments and continuous forest had similar numbers of species that also occur in the savanna matrix (i.e. that are not forest specialists). Multiple linear regression analyses indicated that species richness and composition in the fragments are significantly affected by fragment area, but not by fragment shape and degree of isolation. More species were found in larger fragments. Main conclusions Forest fragmentation influences the organization of ant communities in Amazonian savanna/forest landscapes. Forest fragments harboured, on average, 85% of the species found in continuous forest. That these fragments, despite their long history of isolation, support a relatively large complement of the species found in continuous forest is surprising, especially given that in some recently fragmented landscapes the proportion of species surviving in the fragments is lower. Differences in inter‐fragment distance and type of matrix between Alter do Chão and these other landscapes may be involved. The fact that fragments at Alter do Chão are surrounded by a natural (rather than an anthropogenic) habitat, and that most of them are less than 300 m from another forest area, may have helped to ameliorate the adverse effects of forest fragmentation.     

Fruit‐feeding Butterfly Communities are Influenced by Restoration Age in Tropical Forests

Currently, a large‐scale restoration project aims to restore around 15 million hectares of Atlantic Forest in Brazil. This will increase forest cover and connectivity among remnant sites as well as restore environmental services. Currently, studies on recovery of fauna in restored areas of the Atlantic Forest are practically nonexistent. To address this knowledge vacuum, our study compares diversity patterns of fruit‐feeding butterflies in three forest areas with different restoration ages (11, 22, and 54 years), and uses a native forest area as reference. Results showed butterfly communities in maturing restored areas becoming more similar to the ones found in the native forest, with an increase in the proportional abundance of forest species, and a decrease of edge and grassland species. Moreover, we found a higher diversity among sites at the intermediate restoration age, with a community composed of both grassland and forest species. Butterfly species composition differed significantly among sites, showing interesting patterns of potential species replacement over time. Our results indicate that, although restored sites were located in a fragmented landscape, they provide suitable habitats for recolonization by fruit‐feeding butterfly assemblages. Hence, restored areas can be considered important habitat for forest animal species, increasing local biodiversity and, possibly, restoring some of the ecosystem services provided by them.     

Traits reveal how habitat‐quality gradients structure small mammal communities in a fragmented tropical landscape

Understanding the relationships among community structure, vegetation structure and availability of food resources are a key to unravelling the ecological processes that structure biological communities. In this study, we tested (i) whether the composition of small mammal communities changed across gradients in habitat quality in tropical forest fragments, and (ii) whether any observed change could be explained by the functional traits of species. We sampled 24 trapping grids in fragments of semi‐deciduous forest, in each of two 6‐month periods. We considered each trapping grid as a sampling unit, for which we collected three datasets: an environmental matrix (vegetation structure and food resource availability), the abundance of small mammal species (community structure) and a matrix of functional traits (ecological and morphological traits which express tolerance to habitat disturbance and trophic guild). We used an RLQ approach to evaluate the association between traits and environmental gradients. Forest‐specialist and scansorial–arboreal species were associated with more complex habitat that had greater litter and canopy cover and more fallen logs. In relation to trophic guilds, granivore (fruit seeds), insectivorous and omnivorous species were also associated with higher complexity habitat, while frugivores were associated with shrub cover and availability of fruits. We conclude that functional traits (habitat use, use of vertical strata and diet) provide valuable insights into the distribution of small mammals along gradients of habitat quality in tropical forest fragments. We highlight that communities studies in fragmented landscapes should investigate the different components of biodiversity not only in landscape‐scale but also in habitat scale. Abstract in Portuguese is available with online material.     

Forest Fragment and Breeding Habitat Characteristics Explain Frog Diversity and Abundance in Singapore

Habitat loss and fragmentation can have severe negative and irreversible effects on biodiversity. We investigated the effects of forest fragmentation on frog diversity in Singapore because of its high rates of deforestation and the demonstration that frogs are some of the most sensitive species to habitat degradation. We surveyed frog species in 12 forest fragments varying from 11 to 935 ha. We compared differences in species richness, abundance, and Shannon's index in relation to forest fragment size, connectivity (distance between fragments), and breeding habitat heterogeneity. A total of 20 species from 12 genera and five families were encountered in 12 fragments. Larger fragments and those closer to larger fragments had higher species richness. Abundance, however, was not correlated with forest area or connectivity, but we found fewer individual frogs in the larger fragments. We also found that breeding habitat heterogeneity best explained frog species diversity and abundance in forest fragments. Fragments with a high diversity of breeding habitats had more species. We found no evidence to suggest that abundance and diversity are strongly correlated, particularly in disturbed areas, but that breeding habitat heterogeneity is an under-appreciated factor that should be considered when prioritizing areas for anuran conservation. Enriching breeding habitat heterogeneity, creating corridors between fragments, and reforesting degraded areas are some of the most beneficial strategies for preserving urban frog biodiversity.     

Habitat fragmentation,EFN‐bearing trees and ant communities: Ecological cascades in Atlantic Forest of northeastern Brazil

Habitat fragmentation has a marked impact on the functional composition of tropical forest tree assemblages, and such change is likely to cascade through other trophic levels. Here, we investigate how habitat fragmentation affects extrafloral nectary (EFN)‐bearing plants and ant functional groups known to attend EFNs in a fragmented landscape of the Atlantic Forest. Extrafloral nectary‐bearing trees were identified in 50 0.1‐ha plots located in forest fragments, edge and interior patches. Ants were surveyed in 30 1‐m² litter samples in each of 17 forest fragments and in forest interior. Extrafloral nectary‐bearing plants accounted for 19.9% of individuals and 10.5% of species and included both pioneer and shade‐tolerant species similarly rich in the three habitat types. However, shade‐tolerant individuals accounted for >80% of EFN‐bearing plants in forest interior, compared with 2% in forest edge and 29% in fragments. Forest edge and fragment plots had a third fewer EFN‐bearing individuals and species compared with forest interior. This appeared to have important implications for local ant communities as the density of EFN‐bearing trees was the most important variable explaining the species richness of arboreal dominant ants. Our results show that plant loser–winner replacements promoted by forest fragmentation can cascade through higher trophic levels, with implications for forest dynamics and biodiversity conservation.     

Effects of forest fragmentation on small mammals in an Atlantic Forest landscape

Recent studies on the effects of tropical forest fragmentation indicate that fragmented landscapes are complex and heterogeneous systems influenced by factors other than the size or degree of isolation of forest remnants: of particular importance are the quality of the matrix and the edge-induced habitat changes. In order to investigate the influence of these factors, small mammals were surveyed in 36 sites in the landscape of Una, a region that encompasses some of the last and largest Atlantic Forest remnants in northeastern Brazil. Six sites were distributed on each of six landscape components – the interiors and edges of small remnants, the interiors and edges of large remnants, and the most common forested habitats found in the matrix. The survey comprised 46,656 trap-nights and yielded 1725 individuals of 20 species of rodents and marsupials. Results revealed: an increase in beta-diversity caused by fragmentation; the contrasting effects of the altered forested habitats of the matrix, which harbor both forest and disturbance-adapted species; a greater importance of edge effect than of patch size to the observed changes in small mammal community in remnants; an association among terrestrial forest species and among arboreal forest species in terms of the distribution and abundance in the Una mosaic; and a distinctive vulnerability of these two groups of species to fragmentation. Results emphasize the biological importance and conservation value of both fragmented landscapes and small remnants in the Atlantic Forest, as well as the importance of management techniques to control and attenuate edge effects.     

Sugarcane and Eucalyptus plantation equally limit the movement of two forest‐dependent understory bird species

Habitat fragmentation results in landscape configuration, which affects the species that inhabit it. As a consequence, natural habitat is replaced by different anthropogenic plantation types (e.g. pasture, agriculture, forestry plantations and urban areas). Anthropogenic plantations are important for biodiversity maintenance because some species or functional groups can use it as a complementary habitat. However, depending on plantation permeability, it can act as a barrier to the movement of organisms between habitat patches, such as forest fragments, reducing functional connectivity for many species. Anthropogenic plantations are becoming the most common land use and cover type in the Anthropocene and biodiversity conservation in fragmented landscapes requires information on how different plantation types affect the capacity of the species to move through the landscape. In this study, we evaluated the influence of the type and structure of plantations on the movement of two forest‐dependent understory bird species – plain antvireo (Dysithamnus mentalis) and flavescent warbler (Myiothlyps flaveola) – within a highly fragmented landscape of Atlantic Forest hotspot. Knowing that forestry plantation is assumed to be more permeable to dependent forest bird species than open ones, we selected six study areas containing a forest fragment and surrounding plantation: three with sugarcane plantation and three with Eucalyptus sp. plantation. We used playback calls to stimulate the birds to leave forest fragments and traverse the plantations. Control trials were also carried out inside the forest fragments to compare the distances crossed. We observed that individuals moved longer distances inside forest than between plantation types, which demonstrate that plantations do constrict the movements of both species. The two plantation types equally impeded the movements of the species, suggesting the opposite of the general assumption that forestry plantations are more permeable. Our results indicate that, for generalist species, plantation type does not matter, but its presence negatively impacts movement of these bird species. We highlight that plantations have negative influences on the movements of common bird species, and discuss why this is important when setting conservation priorities.     

Enhanced seed dispersal of Prunus africana in fragmented and disturbed forests?

Forest destruction and disturbance can have long-term consequences for species diversity and ecosystem processes such as seed dispersal. Understanding these consequences is a crucial component of conserving vulnerable ecosystems. In the heavily fragmented and disturbed Kakamega Forest, western Kenya, we studied seed dispersal of Prunus africana (Rosaceae). In the main forest, five forest fragments, and differently disturbed sites, we quantified the overall frugivore community as an indicator for species diversity. Furthermore, we determined the frugivores on 28 fruiting P. africana trees, estimated seed dispersal, crop size and the general fruit availability of surrounding trees. During the overall frugivore census we recorded 49 frugivorous species; 36 of them were observed visiting P. africana trees and feeding on their fruits. Although overall frugivore species richness was 1.1 times lower in fragments than in main forest sites and 1.02 times higher in highly disturbed than in less disturbed sites, P. africana experienced 1.1 times higher numbers of frugivores in fragments than in main forest sites and 1.5 times higher numbers of frugivores in highly disturbed than in less disturbed sites. Correspondingly, seed dispersal was 1.5 times higher in fragments than in main forest sites and 1.5 times higher in more disturbed than less disturbed sites. Fruit availability of surrounding trees and crop size influenced the number of visitors to some degree. Thus, the number of dispersed seeds seemed to be slightly higher in fragmented and highly disturbed sites. This indicates that loss of single species does not necessarily lead to a decrease of ecosystem services. However, loss of diversity could be a problem in the long term, as a multitude of species might act as buffer against future environmental change.