Spatial heterogeneity and habitat configuration overcome habitat composition influences on alpha and beta mammal diversity

The effects of habitat fragmentation on different taxa and ecosystems are subject to intense debate, and disentangling them is of utmost importance to support conservation and management strategies. We evaluated the importance of landscape composition and configuration, and spatial heterogeneity to explain α‐ and β‐diversity of mammals across a gradient of percent woody cover and land use diversity. We expected species richness to be positively related to all predictive variables, with the strongest relationship with landscape composition and configuration, and spatial heterogeneity respectively. We also expected landscape to influence β‐diversity in the same order of importance expected for species richness, with a stronger influence on nestedness due to deterministic loss of species more sensitive to habitat disturbance. We analyzed landscape structure using: (a) landscape metrics based on thematic maps and (b) image texture of a vegetation index. We compared a set of univariate explanatory models of species richness using AIC, and evaluated how dissimilarities in landscape composition and configuration and spatial heterogeneity affect β‐diversity components using a Multiple Regression on distance Matrix. Contrary with our expectations, landscape configuration was the main driver of species richness, followed by spatial heterogeneity and last by landscape composition. Nestedness was explained, in order of importance, by spatial heterogeneity, landscape configuration, and landscape composition. Although conservation policies tend to focus mainly on habitat amount, we advocate that landscape management must include strategies to preserve and improve habitat quality and complexity in natural patches and the surrounding matrix, enabling landscapes to harbor high species diversity

Which Factors Determine Spatial Segregation in the South American Opossums (Didelphis aurita and D. albiventris)? An Ecological Niche Modelling and Geometric Morphometrics Approach

Didelphis albiventris and D. aurita are Neotropical marsupials that share a unique evolutionary history and both are largely distributed throughout South America, being primarily allopatric throughout their ranges. In the Araucaria moist forest of Southern Brazil these species are sympatric and they might potentially compete having similar ecology. For this reason, they are ideal biological models to address questions about ecological character displacement and how closely related species might share their geographic space. Little is known about how two morphologically similar species of marsupials may affect each other through competition, if by competitive exclusion and competitive release. We combined ecological niche modeling and geometric morphometrics to explore the possible effects of competition on their distributional ranges and skull morphology. Ecological niche modeling was used to predict their potential distribution and this method enabled us to identify a case of biotic exclusion where the habit generalist D. albiventris is excluded by the presence of the specialist D. aurita. The morphometric analyses show that a degree of shape discrimination occurs between the species, strengthened by allometric differences, which possibly allowed them to occupy marginally different feeding niches supplemented by behavioral shift in contact areas. Overlap in skull morphology is shown between sympatric and allopatric specimens and a significant, but weak, shift in shape occurs only in D. aurita in sympatric areas. This could be a residual evidence of a higher past competition between both species, when contact zones were possibly larger than today. Therefore, the specialist D. aurita acts a biotic barrier to D. albiventris when niche diversity is not available for coexistence. On the other hand, when there is niche diversification (e.g. habitat mosaic), both species are capable to coexist with a minimal competitive effect on the morphology of D. aurita

The taxonomic status of Myotis levis levis and Myotis levis dinellii (Mammalia: Chiroptera: Vespertilionidae)

Investigating the Myotis levis complex is important for understanding the taxonomic status of the two subspecies currently recognized in it: Myotis levis levis (I. Geoffroy, 1824) and M. levis dinellii Thomas, 1902. Both M. levis levis and M. levis dinellii have been recently observed in sympatry in Argentina. This finding suggests that these populations might in fact correspond to distinct species rather than subspecies, as they have traditionally been designated. By using a multivariate morphometric approach, we demonstrate that M. l. levis has secondary sexual dimorphism in several measurements, with females being larger than males; sexual dimorphism was not detected in M. levis dinellii. However, we found morphometric differences between the two taxa. These differences exceeded those documented for other Neotropical Myotis. Based on their sympatry, morphological, and morphometrical differences, we propose a change in the status of both subspecies to M. levis and M. dinellii

The taxonomic status of Myotis levis levis and Myotis levis dinellii (Mammalia: Chiroptera: Vespertilionidae)

Investigating the Myotis levis complex is important for understanding the taxonomic status of the two subspecies currently recognized in it: Myotis levis levis (I. Geoffroy, 1824) and M. levis dinellii Thomas, 1902. Both M. levis levis and M. levis dinellii have been recently observed in sympatry in Argentina. This finding suggests that these populations might in fact correspond to distinct species rather than subspecies, as they have traditionally been designated. By using a multivariate morphometric approach, we demonstrate that M. l. levis has secondary sexual dimorphism in several measurements, with females being larger than males; sexual dimorphism was not detected in M. levis dinellii. However, we found morphometric differences between the two taxa. These differences exceeded those documented for other Neotropical Myotis. Based on their sympatry, morphological, and morphometrical differences, we propose a change in the status of both subspecies to M. levis and M. dinellii

143_Primates_Phylo

Phylogenetic tree in nexus format suitable for Mesquite describing evolutionary relationship for 143 primates. The topology and branch lenghts are based on on Springer et al 2012, PLoS One, 7:e49521

Testing the habitat amount hypothesis for South American small mammals

According to the habitat amount hypothesis the species richness in a sample site should increase with the habitat amount in the local landscape around the sample site. On the other hand, size and isolation of the patch containing the sample site should have no effect on species richness if the habitat amount in the local landscape remains constant. We tested these predictions using a small mammal dataset recorded in 100 transects in a savanna region of Brazil. We used generalized linear models considering the predictors - habitat amount, patch size, and patch isolation - together and singly, using subsets of data to control for correlations between them. We measured the habitat amount in 10 nested circles ranging in radius from 250 m to 6000 m around each transect. The scale of effect was the radius with the strongest estimated correlation between habitat amount and species richness. Our results indicate that habitat amount is the most important single predictor of species richness. The habitat amount effect was always positive and large. In general, patch size and patch isolation had no effect on species richness after controlling for the effect of habitat amount. The results are consistent with the habitat amount hypothesis, and suggest that habitat amount can be used in place of patch size and isolation in predicting small mammal species richness. This simplifies information needs by landscape managers as it replaces two predictors with one. Our results also support the use of estimated dispersal distance as a way of determining the appropriate landscape scale of effect

Meloro-et-al_Form_143Primates

2D landmark Procustes coordinates and PC scores of primate mandibles belonging to 143 species. The procustes coordinates can be manipulated to make ".NTS" files suitable for tps series and for the R package geomorph