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Context: The Dry Chaco spans more than 87 million hectares across Argentina, Bolivia, and Paraguay. This unique forest system has experienced extensive loss and fragmentation due to land-use change, with different land-use histories in the three countries. This forest loss has altered landscape connectivity for the Dry Chaco's associated biota. Objectives: We compared patterns of deforestation-induced fragmentation and concomitant changes in structural landscape connectivity between 2000 and 2019 in the three countries to identify consistent patterns that might facilitate biome-wide conservation. Methods: We quantified forest cover in the Dry Chaco of Argentina, Bolivia, and Paraguay for the years 2000 and 2019 at 30 m resolution. We analyzed structural connectivity at three scales. Then, we identified and visualized the most important stepping stones per country per year. Results: Between 2000 and 2019, the overall extent of Dry Chaco forest cover decreased by 20.2% (9.5 million ha). All three counties experienced substantial reductions, with Paraguay undergoing the greatest loss and fragmentation relative to 2000. Most of the overall network metrics decreased from 2000 to 2019 for Paraguay and Bolivia, but Argentina experienced increased coalescence distance and average nodal connectance. Dispersal-level metrics showed clustering threshold distances between 1000 and 2000 m for each country in both years. Conclusions: The large number of forest fragments and distances between them suggest that some mammals characteristic of the biome may be experiencing negative impacts from this fragmentation. Contemporary and future challenges of uncoordinated national conservation and management policies, land speculation, and increased human infrastructure will accelerate the rate of deforestation. [ABSTRACT FROM AUTHOR]

Aim: Spatial patterns of local species composition are shaped by dispersal ability. Here we examine the effects of dispersal ability on metacommunity structure of bats throughout the Atlantic Forest of South America considering differences among communities, functional groups and species regarding environmental, spatial and connectivity‐related drivers of composition. We also examined phylogenetic and ecological correlates, such as incidence (i.e. frequency of occurrence across sites) and wing morphology, of the degree to which species respond to spatial and environmental drivers. Location: Atlantic Forest of Argentina, Brazil and Paraguay. Taxon: Phyllostomid bats. Methods: Data from the Atlantic Bats dataset were compiled for 39 species at 120 sites. Variation was partitioned into pure environmental, pure space, pure connectivity, joint and unaccounted variation fractions. Redundancy analyses or linear regression determined amount of variation in variation fractions that was accounted for by phylogeny or ecological characteristics of species. Results: The metacommunity of Atlantic Forest phyllostomid bats was significantly structured by environmental, space and connectivity characteristics. Animalivore, nectarivores and sanguinivore species composition was significantly related only to connectivity. Frugivores exhibited structure that was significantly related to all three kinds of characteristics (pure environmental, pure spatial and pure connectivity) and similar to that of the overall metacommunity. Species‐specific responses to environmental, spatial and connectivity drivers were variable but exhibited strong affinities related to phylogeny and functional group. As incidence of a species increased, variation in distribution and abundance was more related to environmental characteristics. There was no significant relationship between forearm length and magnitude of the connectivity variation partition. Main Conclusions: Metacommunity structure of bats in the Atlantic Forest is complex and includes variation across multiple scales of ecological organization. Structure is strongly associated with phylogenetic, functional and distributional characteristics of species, with these, in turn, related to responses to spatial and environmental gradients in the Atlantic Forest. [ABSTRACT FROM AUTHOR]

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., (© 2013 John Wiley & Sons Ltd.)