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Phenotypic variability is ubiquitous. This is especially true in bats, where families such as Phyllostomidae encompass as much phenotypic variability as some entire orders of mammals. Typically, phenotypic variability is characterized based on cranial morphology, with studies of other functionally important aspects of the phenotype, such as legs, feet and wings, being less frequent. We examined patterns of secondary sexual dimorphism and allometry of wing elements of the fringed fruit-eating bat (Artibeus fimbriatus) and examined, for the first time, the modularity of bat wings. Patterns were based on 13 wing measurements taken from 21 females and 15 males from eastern Paraguay. From a multivariate perspective, A. fimbriatus exhibited significant secondary sexual dimorphism. Females were larger than males for all 13 wing characteristics, with significant differences involving the last phalanx of the fourth and fifth digits. Female wings were also relatively larger than male wings from a multivariate perspective, as was the last phalanx of the fourth and fifth digits, after adjusting for wing size based on forearm length. Wing elements were highly variable regarding allometric relationships, with some exhibiting no allometric patterns and others exhibiting isometry or hyperallometry, depending on the element. Wings exhibited significant modularity, with metacarpals, proximal phalanges and distal phalanges each representing a discrete module. The wings of A. fimbriatus exhibit substantive patterns of dimorphism, allometry and modularity. Although the big mother hypothesis is a strong theoretical construct to explain wing dimorphism, there is not yet any sound theoretical basis for the patterns of allometry and modularity of the wing. Further investigation is required to understand the determinants of variation in wing morphology. [ABSTRACT FROM AUTHOR]

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]

We examined patterns of dietary overlap of phyllostomid bats in interior Atlantic Forest of Paraguay. In addition, we examined microgeographic, seasonal, and species-specific, differences in dietary patterns. We obtained 4,519 dietary records for bats from two sites in eastern Paraguay representing 26 different kinds of resources. The three most abundant resources made up 85% of all dietary records. No significant difference in diets of phyllostomid bats existed between sites. Overlap was high and significantly greater than random. Overlap at both sites was higher in winter than in summer. Consumption of dietary items was different between seasons and reflected changes in consumption primarily of the three most consumed items. Resource breadth was narrower in winter than summer. Sites, season, and species together accounted for 71% of the variation in dietary items. Unique effects, after controlling for variation shared with other factors, of species and season were significant, whereas that of site was not. While much dietary variation in interior Atlantic Forest falls along phylogenetic lines, such patterns are weak and resource utilization appears to be substantively influenced by generalist ecology of bats and seasonal nature of the environment in this system. [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]

Despite extensive focus on numerous mechanisms that potentially structure Neotropical bat communities, understanding of the relative importance of any is still illusive. Recently, it has been demonstrated that all mechanisms used to explain community organization can be conceptualized as one or a combination of the few higher-level processes of dispersal, drift, selection and speciation. These four higher-level processes have not been addressed equally by Neotropical bat community ecologists. In particular, predictions formulated from a hypothesis of ecological drift have not been tested for any Neotropical bat community. Herein we contrast efficacy of predictions based on the higher-level processes of drift and selection in describing community structure of bats in the Atlantic Forest of eastern Paraguay. Predictions apply to species-environment interactions, patterns of trait variation and beta-diversity, predictability of dominant competitors and responses to seasonality. At best, there was inconsistent support for the operation of either drift or selection within this bat community. Selection, however, had more various forms of support including strong species-environment relationships, predictable patterns of dominant competitors and strong responses to seasonality. Despite stronger support for selection, a number of predictions of drift were supported as well. It is likely that a combination of both of these processes operates across the variable environments experienced in Atlantic Forest. Predictions of both processes are difficult to make operational. Support for drift often comes from failure to demonstrate a significant pattern and should not be considered strong support of a prediction. Similarly, many predictions of selection predict phenotypic patterns among species without specifying a particular trait. This is problematic because the phenotype is multifaceted and a lack of pattern in one measured trait might mask a strong pattern in some other unmeasured trait. Distilling mechanisms of community organization into four higher level processes is a substantial innovation in community ecology. Nonetheless, efforts need to be made to develop a suite of mutually exclusive and falsifiable predictions to facilitate future and more rapid understanding of community organization. [ABSTRACT FROM AUTHOR]

• Great fruit-eating bats select tree and stand characteristics when choosing roosts. • Tree and vine species differed in composition and structure between two landscapes. • Selected roost trees differed compared to those chosen by other tree-roosting bats. • Findings highlight the critical need for a holistic understanding of bat roosting. 1. Species that range across heterogeneous environments should optimally modify their behavior to local conditions. We explored this adaptive habitat-use concept by examining a primary resource: bat roosts. If landscape types differ in roosting characteristics, changes in roost use should manifest. 2. We tested this relationship between bats and landscape by contrasting bat roost use between contiguous forest and fragmented matrix. We posited that if forest structure is different and roosts are limited, fragmentation may affect roost use and selection. 3. The neotropical great fruit-eating bat (Artibeus lituratus) is a common bat species in Alto Paraná Atlantic Forests of eastern Paraguay. We collected habitat use data by following 39 telemetered bats, and compared tree and stand characteristics from roost trees and random trees in both contiguous and matrix landscapes. 4. Diameter at breast height (DBH) of trees used as roosts was greater than the DBH of random trees, but only in the contiguous landscape. Tree height and crown cover density decreased in tandem and sequentially: contiguous landscape (roost trees taller with denser crowns than random trees), then matrix landscape (random trees taller with denser crowns than roost trees). 5. Across both landscapes, roost trees had greater vine species richness, and more vine knots and surrounding vines than random trees. Also, the nearest taller tree occurred closer to random trees than roost trees. Furthermore, canopy height around random trees was taller than around roost trees, and random trees tended to have more surrounding basal area than roost trees. 6. When A. lituratus roost selection in the Atlantic Forest is considered across disparate landscapes, a tall, large-boled tree is not the most important predictor. The strongest indicators of an A. lituratus roost were a vine-covered tree, in an uncluttered stand of smaller trees. While roost selection by A. lituratus also differed between contiguous and matrix landscapes, the aforementioned indicators remained consistent. Ergo, behavioral differences between these two A. lituratus groups cannot be explained through roost-use alone. Further exploration of tropical bat roosting is needed if a true comprehensive and holistic synthesis of bat roosting ecology is to be achieved. [ABSTRACT FROM AUTHOR]

This study reports the occurrence of Myotis levis in Paraguay and compares phenotypic and morphometric data for southern South American Myotis. Principal components analysis on cranial measurements reveals that the Paraguayan specimen is larger, has short and wooly hair, dark brown dorsal discoloration and bicolored individual dorsal hairs with dark brown bases and lighter brown tips. Observation shows that its ventral pelage is lighter brown while white-tipped ventral hairs become denser towards the posterior end. Plagiopatagium is inserted at the toes and the skull appears robust with a long restrum, narrow interorbital constriction, wide braincase and its sagittal crest is not developed. These components differentiate M. levis from M. simus, M. ruber, M. chiloensis and M. albescens.

Based on more than a year and a half of intensive fieldwork, we document the community structure of bats at 2 sites (Reserva Natural del Bosque Mbaracayú and Yaguareté Forests) in eastern Paraguay. Twenty-nine species from 17 genera and 3 families were documented based on more than 7,000 captures. In general, these communities share greatest affinities with either Atlantic rainforest or savanna-grassland sites of South America. Significant differences exist between these communities in terms of structure based on rank-abundance distributions and species composition. Moreover, Yaguareté exhibits significantly more species than does Mbaracayú even after removing the effects of differences due to high-flying insectivores. No significant differences existed between communities regarding other aspects or taxonomic diversity (e.g., evenness, diversity, or dominance of species) or any aspect of functional diversity. A higher degree of habitat heterogeneity at Yaguareté likely underlies these differences in community structure. [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.)

Techniques to evaluate elements of metacommunity structure (EMS; coherence, species turnover and range boundary clumping) have been available for several years. Such approaches are capable of determining which idealized pattern of species distribution best describes distributions in a metacommunity. Nonetheless, this approach rarely is employed and such aspects of metacommunity structure remain poorly understood. We expanded an extant method to better investigate metacommunity structure for systems that respond to multiple environmental gradients. We used data obtained from 26 sites throughout Paraguay as a model system to demonstrate application of this methodology. Using presence-absence data for bats, we evaluated coherence, species turnover and boundary clumping to distinguish among six idealized patterns of species distribution. Analyses were conducted for all bats as well as for each of three feeding ensembles (aerial insectivores, frugivores and molossid insectivores). For each group of bats, analyses were conducted separately for primary and secondary axes of ordination as defined by reciprocal averaging. The Paraguayan bat metacommunity evinced Clementsian distributions for primary and secondary ordination axes. Patterns of species distribution for aerial insectivores were dependent on ordination axis, showing Gleasonian distributions when ordinated according to the primary axis and Clementsian distributions when ordinated according to the secondary axis. Distribution patterns for frugivores and molossid insectivores were best described as random. Analysis of metacommunities using multiple ordination axes can provide a more complete picture of environmental variables that mold patterns of species distribution. Moreover, analysis of EMS along defined gradients (e.g., latitude, elevation and depth) or based on alternative ordination techniques may complement insights based on reciprocal averaging because the fundamental questions addressed in analyses are contingent on the ordination technique that is employed.

We examined the relative contributions of regional spatial characteristics and local environmental conditions in determining Paraguayan bat species composition. We used a suite of full and partial redundancy analyses to estimate four additive partitions of variance in bat species composition: (a) unexplained variation, (b) that explained purely by spatial characteristics, (c) that explained purely by local environmental conditions and (d) that explained jointly by space and environment. The spatial component to bat species composition was greater than the environmental component and both pure spatial and pure environmental characteristics accounted for significant amounts of variation in bat species composition. Results from variance decomposition suggest that the mass effects model describes metacommunity structure of Paraguayan bats better than species sorting or neutral models. Such mass effects may potentially be general for bats and could explain the inability of purely local factors to fully account for bat community organization. Mass effects also have substantial conservation implications because rescue effects may enhance the persistence of mobile species in fragmented landscapes with relatively few protected sites.