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Climate changes during the Pleistocene produced shifts, reductions, and expansions of biomes that, in turn, have been hypothesized to have driven speciation and extinction and shaped patterns of biodiversity. Here, we explore effects of Late Pleistocene climatic changes on environmentally and geographically cohesive areas mimicking species' distributions. We analyzed persistence of these 'species' over the transition from the warm Last Interglacial period to the cool Last Glacial Maximum period to warm present-day conditions, for four levels of environmental restriction (5, 10, 15 and 20% of overall variation; akin to niche breadths). African environments were overall much less conserved over these periods than those of South America, matching diversity contrasts between the two continents. Results thus indicate that biodiversity patterns relate closely to historical patterns of environmental grain and their stability through time; this view is a step toward an integral understanding of the role of environmental and geographic factors in the process of biological diversification. [ABSTRACT FROM AUTHOR]

Geographic and ecological distributions of three Lutzomyia sand flies that are cutaneous leishmaniasis vectors in South America were analysed using ecological niche modelling. This new tool provides a large-scale perspective on species’ geographic distributions, ecological and historical factors determining them, and their potential for change with expected environmental changes. As a first step, the ability of this technique to predict geographic distributions of the three species was tested statistically using two subsampling techniques: a random-selection technique that simulates 50% data density, and a quadrant-based technique that challenges the method to predict into broad unsampled regions. Predictivity under both test schemes was highly statistically significant. Visualisation of ecological niches provided insights into the ecological basis for distributional differences among species. Projections of potential geographic distributions across scenarios of global climate change suggested that only Lutzomyia whitmani is likely to be experiencing dramatic improvements in conditions in south-eastern Brazil, where cutaneous leishmaniasis appears to be re-emerging; Lutzomyia intermedia and Lutzomyia migonei may be seeing more subtle improvements in climatic conditions, but the implications are not straightforward. More generally, this technique offers the possibility of new views into the distributional ecology of disease, vector, and reservoir species. [Copyright &y& Elsevier]

Geographic studies addressing the role of competition in determining species' macro-distributions have been limited by only simple or subjective means of identifying regions of suitable habitat. Now, ecological-niche models of species' potential distributions present a possible approach to testing for the geographic patterns predicted under competitive exclusion and competitive release. Previously, we modeled the potential distributions of two spiny pocket mice (Heteromys australis and H. anomalus) in northwestern South America using specimen localities, environmental data, and the Genetic Algorithm for Rule-Set Prediction (GARP). Here we superimpose the models to examine known distributional records in areas of potential sympatry between the two species, thus testing the geographic predictions of competitive exclusion. In addition, we examine environmental characteristics of known localities, testing for data consistent with competitive release. Areas of potential sympatry are minimal, lying in regions of intermediate water balance. Only records of H. australis are known from areas of potential sympatry in regions where the species' ranges meet, consistent with exclusion of H. anomalus by H. australis. Heteromys anomalus inhabits areas ecologically suitable for both species only in the isolated Sierra Nevada de Santa Marta, in which H. australis is not present (most likely for historical reasons). Furthermore, environmental characteristics of localities of H. anomalus in biogeographic regions where H. australis is absent fit the pattern predicted under competitive release. In contrast, localities of H. australis show no indication of competitive release. Although the results of present analyses do not conclusively demonstrate competitive exclusion or release, they provide directional hypotheses that can now be tested in experimental field and laboratory studies. [ABSTRACT FROM AUTHOR]

Abstract Aim Predictive models of species’ distributions use occurrence records and environmental data to produce a model of the species’ requirements and a map of its potential distribution. To determine regions of suitable environmental conditions and assess biogeographical questions regarding their ranges, we modelled the potential geographical distributions of two spiny pocket mice (Rodentia: Heteromyidae) in north-western South America. Location North-western South America. Methods We used the Genetic Algorithm for Rule-Set Prediction (GARP), environmental data from GIS maps and georeferenced collection localities from a recent systematic review of Heteromys australis and H. anomalus to produce the models. Results GARP models indicate the potential presence of H. australis throughout mesic montane regions of north-western South America, as well as in some lowland regions of moderately high precipitation. In contrast, H. anomalus is predicted to occur primarily in drier areas of the Caribbean coast and rain-shadowed valleys of the Andes. Conclusions The models support the disjunct status of the population of H. australis in the Cordillera de Mérida, but predict a continuous distribution between known populations of H. anomalus in the upper Magdalena Valley and the Caribbean coast. Regions of suitable environmental conditions exist disjunct from known distributional areas for both species, suggesting possible historical restrictions to their ranges. This technique holds wide application to other study systems. [ABSTRACT FROM AUTHOR]

The role of Pleistocene climate changes in promoting evolutionary diversification in global biota is well documented, but the great majority of data regarding this subject come from North America and Europe, which were greatly affected by glaciation. The effects of Pleistocene changes on cold- and/or dry-adapted species in tropical areas where glaciers were not present remain sparsely investigated. Many such species are restricted to small areas surrounded by unfavourable habitats, which may represent potential interglacial microrefugia. Here, we analysed the phylogeographic structure and diversification history of seven cactus species in the Pilosocereus aurisetus complex that are restricted to rocky areas with high diversity and endemism within the Neotropical savannas of eastern South America. We combined palaeodistributional estimates with standard phylogeographic approaches based on two chloroplast DNA regions (trnT-trnL and trnS-trnG), exon 1 of the nuclear gene PhyC and 10 nuclear microsatellite loci. Our analyses revealed a phylogeographic history marked by multiple levels of distributional fragmentation, isolation leading to allopatric differentiation and secondary contact among divergent lineages within the complex. Diversification and demographic events appear to have been affected by the Quaternary climatic cycles as a result of isolation in multiple patches of xerophytic vegetation. These small patches presently harbouring P. aurisetus populations seem to operate as microrefugia, both at present and during Pleistocene interglacial periods; the role of such microrefugia should be explored and analysed in greater detail., (© 2014 John Wiley & Sons Ltd.)

Rabies was known to humans as a disease thousands of years ago. In America, insectivorous bats are natural reservoirs of rabies virus. The bat species Tadarida brasiliensis and Lasiurus cinereus, with their respective, host-specific rabies virus variants AgV4 and AgV6, are the principal rabies reservoirs in Chile. However, little is known about the roles of bat species in the ecology and geographic distribution of the virus. This contribution aims to address a series of questions regarding the ecology of rabies transmission in Chile. Analyzing records from 1985-2011 at the Instituto de Salud Pública de Chile (ISP) and using ecological niche modeling, we address these questions to help in understanding rabies-bat ecological dynamics in South America. We found ecological niche identity between both hosts and both viral variants, indicating that niches of all actors in the system are undifferentiated, although the viruses do not necessarily occupy the full geographic distributions of their hosts. Bat species and rabies viruses share similar niches, and our models had significant predictive power even across unsampled regions; results thus suggest that outbreaks may occur under consistent, stable, and predictable circumstances.

Recent studies have increasingly implicated deep (pre-Pleistocene) events as key in the vertebrate speciation, downplaying the importance of more recent (Pleistocene) climatic shifts. This work, however, has been based almost exclusively on evidence from molecular clock inferences of splitting dates. We present an independent perspective on this question, using ecological niche model reconstructions of Pleistocene Last Glacial Maximum (LGM) potential distributions for the Thrush-like Mourner (Schiffornis turdina) complex in the neotropics. LGM distributional patterns reconstructed from the niche models relate significantly to phylogroups identified in previous molecular systematic analyses. As such, patterns of differentiation and speciation in this complex are consistent with Pleistocene climate and geography, although further testing will be necessary to establish dates of origin firmly and unambiguously.

Modeling ecological niches of species is a promising approach for predicting the geographic potential of invasive species in new environments. Argentine ants (Linepithema humile) rank among the most successful invasive species: native to South America, they have invaded broad areas worldwide. Despite their widespread success, little is known about what makes an area susceptible--or not--to invasion. Here, we use a genetic algorithm approach to ecological niche modeling based on high-resolution remote-sensing data to examine the roles of niche similarity and difference in predicting invasions by this species. Our comparisons support a picture of general conservatism of the species' ecological characteristics, in spite of distinct geographic and community contexts.

The distribution of the Anopheles gambiae complex of malaria vectors in Africa is uncertain due to under-sampling of vast regions. We use ecologic niche modeling to predict the potential distribution of three members of the complex (A. gambiae, A. arabiensis, and A. quadriannulatus) and demonstrate the statistical significance of the models. Predictions correspond well to previous estimates, but provide detail regarding spatial discontinuities in the distribution of A. gambiae s.s. that are consistent with population genetic studies. Our predictions also identify large areas of Africa where the presence of A. arabiensis is predicted, but few specimens have been obtained, suggesting under-sampling of the species. Finally, we project models developed from African distribution data for the late 1900s into the past and to South America to determine retrospectively whether the deadly 1929 introduction of A. gambiae sensu lato into Brazil was more likely that of A. gambiae sensu stricto or A. arabiensis.