Niche Modeling Tools Research Articles

Combining phylogeography and ecological niche modeling to infer the evolutionary history of the Cordoba vesper mouse (Calomys venustus).

The evolutionary dynamics of the ecoregions of southern South America and the species that inhabit them have been poorly studied, and few biogeographic hypotheses have been proposed and tested. Quaternary climatic oscillations are among the most important processes that have led to the current distribution of genetic variation in different regions of the world. In this work, we studied the evolutionary history and distribution of the Córdoba vesper mouse (Calomys venustus), a characteristic rodent of the region of which little is known about its natural history. Since the population dynamics of this species are influenced by climatic factors, this rodent is a suitable model to study the effects of Quaternary climatic oscillations in central Argentina. The mitochondrial cytochrome b gene was sequenced to analyze the phylogeography of C. venustus, and ecological niche modeling tools were used to map its potential distributions. The results of these approaches were combined to provide additional spatially explicit information about this species' past. Our results suggest that the Espinal was the area of origin of this species, which expanded demographically and spatially during the last glacial period. A close relationship was found between the Espinal and the Mountain Chaco. These results are consistent with previous studies and emphasize the role of the Espinal in the biogeographic history of southern South America as an area of origin of several species.

Phylogeographical patterns are governed by geography in endemic polymorphic snail Indrella ampulla (Gastropoda: Ariophantidae)

Abstract Genetic diversity within a species can be shaped by abiotic factors, such as climate and geography. We aimed to ascertain the relative importance of these two abiotic factors to Indrella ampulla, a monotypic snail species from the Western Ghats, India, that has three colour morphs with some overlapping distributions. We also wanted to investigate whether these colour morphs represent divergent lineages or incipient species. We sequenced one nuclear and two mitochondrial genes from 32 individuals of I. ampulla. We used phylogenetic, population genetic, and niche modelling tools to address these questions. The results suggested that the colour morphs were not reciprocally monophyletic and exhibited considerable niche overlap, suggesting that they cannot be considered as incipient species. Furthermore, the results showed that the impact of palaeoclimatic oscillations in shaping the genetic diversity of this species cannot be determined conclusively. The Palghat Gap seems to have shaped the genetic diversity in this group to a certain degree. The colour morph distributed south of the Palghat Gap did not show admixture and exhibited the least amount of niche overlap with the other morphs. The geography of the landscape seems to have played a prominent role in shaping genetic diversity in this species.

Ecological niches in the polyploid complex Linum suffruticosum s.l.

The high frequency of polyploidy in the evolutionary history of many plant groups occurring in the Mediterranean region is likely a consequence of its dynamic paleogeographic and climatic history. Polyploids frequently have distinct characteristics that allow them to overcome the minority cytotype exclusion. Such traits may enable polyploid individuals to grow in habitats different from their parentals and/or expand to new areas, leading to spatial segregation. Therefore, the successful establishment of polyploid lineages has long been associated with niche divergence or niche partitioning and the ability of polyploids to cope with different, often more stressful, conditions. In this study, we aimed to explore the role of environmental variables associated with the current distribution patterns of cytotypes within the polyploid complex Linum suffruticosum s.l.. The distribution and environmental niches of the five main cytotypes of Linum suffruticosum s.l. (diploids, tetraploids, hexaploids, octoploids and decaploids) were studied across its distribution range. Realized environmental niche of each cytotype was determined using niche modelling tools, such as maximum entropy modelling and niche equivalency and similarity tests. Differences in the environmental conditions of L. suffruticosum s.l. cytotypes were observed, with polyploids being associated with habitats of increased drought and soil pH, narrower temperature ranges and decreased soil water and cation exchange capacities. Diploids present the widest environmental niche, and polyploids occupy part of the diploid niche. Although some polyploids have equivalent potential ecological niches, cytotypes do not co-occur in nature. Additionally, the ecological niche of this polyploid complex is different between continents, with North African habitats being characterised by differences in soil texture, higher pH, and low cation exchange capacity, precipitation and soil water capacity and higher temperatures than habitats in southwest Europe. The different ecological conditions played a role in the distribution of cytotypes, but the mosaic distribution could not be entirely explained by the environmental variables included in this study. Other factors, such as reproductive isolation and competitive interactions among cytotypes, could further explain the current diversity and distribution patterns in white flax. This study provides relevant data on the niche requirements of each cytotype for further competition and reciprocal transplant experiments. further competition and reciprocal transplant experiments.

Current and Potential Future Global Distribution of the Raisin Moth Cadra figulilella (Lepidoptera: Pyralidae) under Two Different Climate Change Scenarios.

Global trade facilitates the introduction of invasive species that can cause irreversible damage to agriculture and the environment, as well as stored food products. The raisin moth (Cadra figulilella) is an invasive pest that poses a significant threat to fruits and dried foods. Climate change may exacerbate this threat by expanding moth's distribution to new areas. In this study, we used CLIMEX and MaxEnt niche modeling tools to assess the potential global distribution of the raisin moth under current and future climate change scenarios. Our models projected that the area of suitable distribution for the raisin moth could increase by up to 36.37% by the end of this century under high emission scenario. We also found that excessive precipitation decreased the probability of raisin moth establishment and that the optimum temperature range for the species during the wettest quarter of the year was 0-18 °C. These findings highlight the need for future research to utilize a combined modeling approach to predict the distribution of the raisin moth under current and future climate conditions more accurately. Our results could be used for environmental risk assessments, as well as to inform international trade decisions and negotiations on phytosanitary measures with regards to this invasive species.

Cytotype distribution and chloroplast phylogeography of the Actinidia chinensis complex

BackgroundPlant phylogeographic studies of species in subtropical China have mainly focused on rare and endangered species, whereas few studies have been conducted on taxa with relatively wide distribution, especially polyploid species. We investigated the cytotype and haplotype distribution pattern of the Actinidia chinensis complex, a widespread geographically woody liana with variable ploidy in subtropical China comprising two varieties, with three chloroplast fragments DNA (ndhF-rpl132, rps16-trnQ and trnE-trnT). Macroevolutionary, microevolutionary and niche modeling tools were also combined to disentangle the origin and the demographic history of the species or cytotypes.ResultsThe ploidy levels of 3338 individuals from 128 populations sampled throughout the species distribution range were estimated with flow cytometry. The widespread cytotypes were diploids followed by tetraploids and hexaploids, whereas triploids and octoploids occurred in a few populations. Thirty-one chloroplast haplotypes were detected. The genetic diversity and genetic structure were found to be high between varieties (or ploidy races) chinensis and deliciosa. Our results revealed that these two varieties inhabit significantly different climatic niche spaces. Ecological niche models (ENMs) indicate that all varieties’ ranges contracted during the Last Inter Glacial (LIG), and expanded eastward or northward during the Last Glacial Maximum (LGM).ConclusionsPliocene and Plio-Pleistocene climatic fluctuations and vicariance appear to have played key roles in shaping current population structure and historical demography in the A. chinensis complex. The polyploidization process also appears to have played an important role in the historical demography of the complex through improving their adaptability to environmental changes.

Potential impacts of climate change on geographical distribution of three primary vectors of African Trypanosomiasis in Tanzania's Maasai Steppe: G. m. morsitans, G. pallidipes and G. swynnertoni.

In the Maasai Steppe, public health and economy are threatened by African Trypanosomiasis, a debilitating and fatal disease to livestock (African Animal Trypanosomiasis -AAT) and humans (Human African Trypanosomiasis-HAT), if not treated. The tsetse fly is the primary vector for both HAT and AAT and climate is an important predictor of their occurrence and the parasites they carry. While understanding tsetse fly distribution is essential for informing vector and disease control strategies, existing distribution maps are old and were based on coarse spatial resolution data, consequently, inaccurately representing vector and disease dynamics necessary to design and implement fit-for-purpose mitigation strategies. Also, the assertion that climate change is altering tsetse fly distribution in Tanzania lacks empirical evidence. Despite tsetse flies posing public health risks and economic hardship, no study has modelled their distributions at a scale needed for local planning. This study used MaxEnt species distribution modelling (SDM) and ecological niche modeling tools to predict potential distribution of three tsetse fly species in Tanzania's Maasai Steppe from current climate information, and project their distributions to midcentury climatic conditions under representative concentration pathways (RCP) 4.5 scenarios. Current climate results predicted that G. m. morsitans, G. pallidipes and G swynnertoni cover 19,225 km2, 7,113 km2 and 32,335 km2 and future prediction indicated that by the year 2050, the habitable area may decrease by up to 23.13%, 12.9% and 22.8% of current habitable area, respectively. This information can serve as a useful predictor of potential HAT and AAT hotspots and inform surveillance strategies. Distribution maps generated by this study can be useful in guiding tsetse fly control managers, and health, livestock and wildlife officers when setting surveys and surveillance programs. The maps can also inform protected area managers of potential encroachment into the protected areas (PAs) due to shrinkage of tsetse fly habitats outside PAs.

Phylogeographical and cytogeographical history ofArtemisia herba-alba(Asteraceae) in the Iberian Peninsula and North Africa: mirrored intricate patterns on both sides of the Mediterranean Sea

AbstractArtemisia herba-alba is an important component of Mediterranean dry steppe floras, being widely distributed in arid areas of the Iberian Peninsula and North-West Africa. In this study, we use genetic, cytogenetic and niche modelling tools to investigate the natural history of the species, focusing particularly on the role played by polyploidization to explain current diversity patterns throughout the main distribution range of the plant. Our sequencing data indicate a complex phylogeographical structure showing similar haplotype diversity patterns on both sides of the Strait of Gibraltar and no clear signals of genetic refugia. According to our cytogeographical results, we inferred multiple polyploidization events, which probably took place on the Iberian Peninsula and in North Africa independently. Environmental niche modelling suggested stable potential distributions of A. herba-alba on both sides of the Mediterranean Sea under present and past Last Glacial Maximum conditions, which could be related to the intricate spatial genetic and cytogenetic patterns shown by the species. Finally, environmental modelling comparison among cytotypes revealed that the niche of tetraploids is narrower and nested in that of diploids, a result that could indicate environmental specialization and could potentially explain recurrent establishment success of tetraploids.

Current occurrence and potential future climatic niche distribution of the invasive shrub Spiraea tomentosa L. in its native and non-native ranges

The shrub Spiraea tomentosa is native to North America and has been domesticated in Europe, where it is now considered an invasive species. The aim of this study was to determine the locations of current suitable climatic niches for this shrub and to estimate future spatial changes in their locations using ecological niche modelling tools. Model results showed that S. tomentosa has large potential natural and secondary ranges, much larger than the range estimated using presence data only. The potential modelled current distribution of S. tomentosa in North America included areas with a relatively humid climate and corresponded with its climate envelope, but in Eurasia, favourable climatic conditions for the shrub occurred in a much larger area than indicated by its current invasive range, so the shrub has not realised its potential climatic niche. Species distribution in its secondary range seems to be random, which may indicate that its true dispersal capacity in Eurasia has not yet been realised. The models showed that climate changes could alter the distribution of the suitable climatic niches available for S. tomentosa, and favour its continuing spread. The shrub could retain the majority of its currently occupied positions in both natural and secondary ranges and simultaneously extend its latitudinal range towards the west in North America and towards the east in Eurasia. In the case of its longitudinal distribution, there may be a shift in the available climate niches to the north, mainly to Scandinavia, and to the south, pushing the shrubs towards mountainous areas with a colder climate. As both current and forecasted future climate conditions seem to favour the consolidation of S. tomentosa populations as well as the extension of its second range in Eurasia, appropriate management strategies should limit or prevent further invasion. It is crucial to limit the intentional and accidental transfer of the shrub, heighten vigilance to identify and eradicate new invasion foci, identify and implement appropriate control techniques and raise public awareness of the invasion threat posed by the species.

Different Patterns of Ecological Divergence Between Two Tetraploids and Their Diploid Counterpart in a Parapatric Linear Coastal Distribution Polyploid Complex.

Polyploidization is a widespread mechanism of evolutionary divergence in flowering plants. Ecological divergence of polyploid lineages has been proposed as a key process shaping the distribution of cytotypes in nature (niche shift hypothesis); however, evidence for the role of niche separation in replicated diploid-polyploid species pairs is still needed. This study aimed to assess the role of abiotic factors shaping current cytotype distributions. For that, we examined the distribution and environmental niches of two varieties recognized in diploid-tetraploid Jasione maritima across the species range and within a putative contact zone on the Iberian Peninsula. We counted chromosomes, screened for ploidy across Iberian Peninsula and characterized environmental requirements using niche modeling tools. We found that J. maritima var. maritima is composed by diploids with disjunct distribution in the west coast of France and northwest Iberian Peninsula, and by tetraploids in Iberian Peninsula, while var. sabularia is tetraploid. In the Iberian Peninsula, two parapatric contact zones along a linear coastal distribution were detected, one between diploid and tetraploid var. maritima, and the other between tetraploids of the two varieties. Environmental variables of diploid populations from France are distinct from those of southern diploid populations, which are more similar to tetraploids. In general, niche modeling results are congruent with the observed distribution patterns, although the results suggest a wider contact zone between varieties and cytotypes. Tetraploids of both varieties revealed different degrees of environmental divergence in comparison with their diploid counterpart. Tetraploid var. sabularia differed environmentally from diploids suggesting niche divergence. In contrast, tetraploid var. maritima overlapped with diploid environmental niche and currently occupies its entire predicted range, whereas diploids are restricted to northern areas of their suitable environment. Differences in ecological envelopes facilitate the recognition of functional units of biodiversity within polyploid groups, allowing the study of factors related to post-polyploidization divergence. Thus, whereas changes in environmental requirements may have allowed tetraploid var. sabularia to spread in habitats not favorable to diploids, other factors are involved with the distribution of diploid and tetraploid var. maritima.

Collinearity in ecological niche modeling: Confusions and challenges.

Ecological niche models are widely used in ecology and biogeography. Maxent is one of the most frequently used niche modeling tools, and many studies have aimed to optimize its performance. However, scholars have conflicting views on the treatment of predictor collinearity in Maxent modeling. Despite this lack of consensus, quantitative examinations of the effects of collinearity on Maxent modeling, especially in model transfer scenarios, are lacking. To address this knowledge gap, here we quantify the effects of collinearity under different scenarios of Maxent model training and projection. We separately examine the effects of predictor collinearity, collinearity shifts between training and testing data, and environmental novelty on model performance. We demonstrate that excluding highly correlated predictor variables does not significantly influence model performance. However, we find that collinearity shift and environmental novelty have significant negative effects on the performance of model transfer. We thus conclude that (a) Maxent is robust to predictor collinearity in model training; (b) the strategy of excluding highly correlated variables has little impact because Maxent accounts for redundant variables; and (c) collinearity shift and environmental novelty can negatively affect Maxent model transferability. We therefore recommend to quantify and report collinearity shift and environmental novelty to better infer model accuracy when models are spatially and/or temporally transferred.

Mapping parasite transmission risk from white-tailed deer to a declining moose population

White-tailed deer (WTD; Odocoileus virginianus) are the definitive hosts of meningeal worm (Parelaphostrongylus tenuis) and liver fluke (Fascioloides magna); two parasites implicated in the decline of moose populations (Alces alces) in northern USA. Understanding which areas pose transmission risk may contribute to effective mitigation of these parasites in imperiled moose populations. Our objective was to predict areas of potential P. tenuis and F. magna transmission risk in terms of landscape features and deer density. Analyses were based on biogeographic and ecological factors related to both parasites. Using ecological niche modeling tools, remote sensing satellite data, field sampling, and estimated densities of WTD in Minnesota, we characterized current suitable environmental conditions for F. magna and P. tenuis across the historical range of moose in the state and identified potential areas for the occurrence of these parasites in unsampled areas. Our results help elucidate risky landscapes for F. magna and P. tenuis transmission by identifying geographic locations where WTD occur at high densities and with the landscape features suitable for the parasites. High-risk areas identified by our models may guide future surveillance, conservation, and management plans by identifying hotspots of potential infection of these parasites from WTD to moose populations. Our study shows the applicability of ecological niche modeling tools for investigating disease transmission risks of complex parasite systems for conservation purposes.

Unmasking cryptic biodiversity in polyploids: origin and diversification of Aster amellus aggregate.

The origin of different cytotypes by autopolyploidy may be an important mechanism in plant diversification. Although cryptic autopolyploids probably comprise the largest fraction of overlooked plant diversity, our knowledge of their origin and evolution is still rather limited. Here we study the presumed autopolyploid aggregate of Aster amellus, which encompasses diploid and hexaploid cytotypes. Although the cytotypes of A. amellus are not morphologically distinguishable, previous studies showed spatial segregation and limited gene flow between them, which could result in different evolutionary trajectories for each cytotype. We combine macroevolutionary, microevolutionary and niche modelling tools to disentangle the origin and the demographic history of the cytotypes, using chloroplast and nuclear markers in a dense population sampling in central Europe. Our results revealed a segregation between diploid and hexaploid cytotypes in the nuclear genome, where each cytotype represents a monophyletic lineage probably homogenized by concerted evolution. In contrast, the chloroplast genome showed intermixed connections between the cytotypes, which may correspond to shared ancestral relationships. Phylogeny, demographic analyses and ecological niche modelling supported an ongoing differentiation of the cytotypes, where the hexaploid cytotype is experiencing a demographic expansion and niche differentiation with respect to its diploid relative. The two cytotypes may be considered as two different lineages at the onset of their evolutionary diversification. Polyploidization led to the occurrence of hexaploids, which expanded and changed their ecological niche.

Divergence in the ecological niches of the white wagtail (Motacilla alba Linnaeus, 1758) complex using the ecological niche modeling approach

The mtDNA data presently being used for estimating biodiversity is not sufficient for evaluating the Motacilla alba complex species status. Because there is a lack of congruence between morphological and mtDNA data, there are debates about the best approach to use. In this study, we utilize niche modelling to study nine taxa of M. alba complex. Using eight bioclimatic- environmental layers, altitude, and slope MaxEnt modeling was applied to predict distributions. A total of 9087 input points for presence of species were also used. Results showed nine distinct ecological boundaries based on MaxEnt and ecological niche modeling (ENM) tools. The results provide some ecological variables for determining the ecological requirements and distribution patterns of the white wagtail species complex in the Palearctic region.

Assigning conservation value and identifying hotspots of endemic rattan diversity in the Western Ghats, India

Rattans, or canes, are one of the most important non-timber forest products supporting the livelihood of many forest-dwelling communities in South and North-eastern India. Due to increased demand for rattan products, rattans have been extracted indiscriminately from the Western Ghats, a 1600-km mountain chain running parallel to the west coast of India. Extensive harvesting, loss of habitat and poor regeneration has resulted in dwindling rattan populations, necessitating an urgent attempt to conserve existing rattan resources. In this study, using niche-modelling tools, an attempt has been made to identify areas of high species richness of rattans in the Western Ghats, one of the mega-diversity regions of the world. We have also developed conservation values for 21 economically important and endemic rattans of the Western Ghats. We identified at least two to three sites of extremely high species richness outside the existing protected area network that should be prioritized for in situ conservation. This study emphasizes the need to develop strategies for the long-term conservation of rattans in the Western Ghats, India.

Glacial refugia and the prediction of future habitat coverage of the South American lichen species Ochrolechia austroamericana.

The biogeographic history of lichenized fungi remains unrevealed because those organisms rarely fossilize due to their delicate, often tiny and quickly rotting thalli. Also the ecology and factors limiting occurrence of numerous taxa, especially those restricted in their distribution to tropical areas are poorly recognized. The aim of this study was to determine localization of glacial refugia of South American Ochrolechia austroamericana and to estimate the future changes in the coverage of its habitats using ecological niche modeling tools. The general glacial potential range of the studied species was wider than it is nowadays and its niches coverage decreased by almost 25% since last glacial maximum. The refugial areas were covered by cool and dry grasslands and scrubs and suitable niches in South America were located near the glacier limit. According to our analyses the further climate changes will not significantly influence the distribution of the suitable niches of O. austroamericana.

Modeling impacts of future climate on the distribution of Myristicaceae species in the Western Ghats, India

Climate change has the potential to have significant influence on distribution of many species and alter ecosystems. With the current estimates of rate of projected environmental change for the 21st century, urgent adaptation and mitigation measures are required to slow down the impact of climate change on biodiversity. A number of studies have shown that recent human-induced environmental changes have already triggered species range shifts, changes in phenology and species extinctions. However, accurate projections of species responses to future climate change are more difficult to ascertain. In recent years, a number of modeling tools are being used to predict the consequences of climate change on the distribution of species and also identify possible ecological niche of a species under different climate change scenarios.In this paper, using the distribution data of the species, we have attempted to (a) identify the current geographical distribution of five species of the family Myristicaceae and predict the possible sites of occurrence of these species in the Western Ghats, India using the niche modeling tools and (b) predict the impact of climate change on the potential distribution of these species for two scenarios (A1B and A2A). All the five species selected for the study are distributed in the Western Ghats with higher densities in the Central Western Ghats. The model predicted an overall increase in the suitable habitats for the non-swampy species. However, there is a shift in the habitat range of these species in response to climate change. Gymnocranthera canarica and Myristica fatua, which are obligate swampy species, tend to be affected in changing climate. For both these species, the overall habitat is reduced due to climate change. These species already have restricted habitat and therefore climate change could pose a serious threat for their future survival. Predicting how species distribution will change in the wake of future global climate change is important to develop effective conservation strategies for these species, which inhabit fragile ecosystems.

New Distribution Records and Potentially Suitable Areas for the Threatened Snake-Necked TurtleHydromedusa maximiliani(Testudines: Chelidae)

Hydromedusa maximiliani is a freshwater turtle endemic to the Atlantic Forest of eastern and southeastern Brazil and threatened by extinction. Here, we add 15 new locality records for this species based on photographs of specimens encountered in the field and examination of museum collections. We also used ecological niche modeling tools of 3 different algorithms (GARP, SVM, and Maxent) to suggest potential suitable areas for the occurrence of the species. Models predict 53,679–263,844 km2 of suitable habitat for H. maximiliani, with 8396–31,758 km2 inside protected areas. Besides being useful in a reassessment of the species' conservation status, our results contribute to the knowledge of distribution patterns of H. maximiliani and highlight potential areas to drive future field surveys.

Geographic and seasonal distribution of a little-known Brazilian endemic rail (Aramides mangle) inferred from ocurrence records and ecological niche modeling

Regional, intratropical avian migrations have rarely been studied. Here, we employ an occurrence records review and ecological niche modeling tools to test the hypothesis that an understudied Neotropical bird, the Little Wood-Rail (Aramides mangle, Rallidae), seasonally migrates between the humid Atlantic coast and the dry Caatinga biome of interior northeastern Brazil. We divided records geographically between coastal and inland, and temporally between wet/breeding and dry/non-breeding seasons. Coastal records peak when inland records are fewest and vice-versa, and independence between season and region in which records were made was statistically rejected. However, ecological niche modeling shows that coastal regions are suitable habitats for A. mangle year-round, and models built with records from each season were considered statistically equivalent. It seems that this species neither performs erratic, unpredictable movements nor typical avian “to-and-fro” migration. Instead, it undergoes periodical expansion of its range and ecological niche to include the Caatinga, where it breeds, in addition to the coast. It might be counterintuitive that a species can occupy two seemingly so disparate habitats, but rails in general are known to be very adaptable and have wide ecological niches. Further study is needed in order to understand the exact nature of this species' movements and the life-cycle of individual birds. But given that most studies of avian movements have focused on temperate species, it is likely that common models of avian migratory behavior will not easily apply to A. mangle nor to other Neotropical species.

Murciélagos del Ecuador: un análisis de sus patrones de riqueza, distribución y aspectos de conservación

Introduction: The knowledge of the distribution of bat species in Ecuador has changed significantly in recent years, from new records to taxonomic revisions that have shaped distribution maps to a broader biogeographic understanding. A review of the richness patterns and potential distribution of bats in Ecuador is presented, based on the analysis of records published or stored in scientific collections using Ecological Niche Modeling (ENM) tools. Although maps resulting from ENM are limited both because of the lack of equilibrium and limitations on the representativeness of samples, they constitute a better depiction of distribution than minimal convex polygons or altitudinal ranges. According to the Ecuadorian Red List, 19 species of bats are currently threatened, mainly because of habitat conversion as a consequence of recent colonization, so a better understanding of distribution and spatial richness will result in better proposals for research-priority and conservation-priority areas. Methodology: The analysis was based on 21,455 records, corresponding to 162 species. This information was reviewed and validated using Geographic Information Systems. A maximum entropy algorithm implemented in Maxent was used to evaluate and generate potential distribution models of the species. Those species with insufficient data to generate a model or for which the evaluation was unsatisfactory were eliminated from the analysis. The remaining species models were used to create a composite map representing the richness of bat species for Ecuador, which in turn was used to assess the conservation status of bat diversity in the country. Results: Following review and validation of the data, 10,916 records were used to determine the potential distribution of 81 species of bats, based on ENM. A map of potential bat species richness was obtained for the country with the overlap of the models, representing areas that due to climatic conditions, allow a higher or lower species richness of bats living in sympatry. We determined that the central and north-eastern foothills of the Andes are the most suitable areas enclosing the highest richness of bats in Ecuador. Research-priority and conservation-priority areas were identified. Discussion and conclusions: Information on protected areas of Ecuador was overlaid on top of the potential richness map, showing that only 5.6% of the area with the greatest potential bat richness is protected. Accordingly, we determine the existing information gaps and identify priority areas for research and conservation of bats in Ecuador. Three research-priority areas were defined: (1) the Southeastern tropics, between Pastaza and Morona Santiago provinces; (2) the Northern Andes towards the cordillera’s western slopes; and (3) areas of the Western dry tropical forests, between the provinces of Guayas and Manabí. Three conservation priority areas were defined:(1) northwest from the province of Pichincha with patches of forest sufficiently large and connected to be protected; (2) most of the Pastaza province, south of the Yasuní National Park; and (3) from the central region of the Morona Santiago province to the northern half of the province of Zamora, towards the Peruvian border to the east. Key words: Amazonia, deforestation, modeling, priority areas, protected areas, scientific collections.

Hybridization at an ecotone: ecological and genetic barriers between three Iberian vipers

The formation of stable genetic boundaries between emerging species is often diagnosed by reduced hybrid fitness relative to parental taxa. This reduced fitness can arise from endogenous and/or exogenous barriers to gene flow. Although detecting exogenous barriers in nature is difficult, we can estimate the role of ecological divergence in driving species boundaries by integrating molecular and ecological niche modelling tools. Here, we focus on a three-way secondary contact zone between three viper species (Vipera aspis, V.latastei and V.seoanei) to test for the contribution of ecological divergence to the development of reproductive barriers at several species traits (morphology, nuclear DNA and mitochondrial DNA). Both the nuclear and mitochondrial data show that all taxa are genetically distinct and that the sister species V.aspis and V.latastei hybridize frequently and backcross over several generations. We find that the three taxa have diverged ecologically and meet at a hybrid zone coincident with a steep ecotone between the Atlantic and Mediterranean biogeographical provinces. Integrating landscape and genetic approaches, we show that hybridization is spatially restricted to habitats that are suboptimal for parental taxa. Together, these results suggest that niche separation and adaptation to an ecological gradient confer an important barrier to gene flow among taxa that have not achieved complete reproductive isolation.