Favourable areas for co‐occurrence of parapatric species: niche conservatism and niche divergence in Iberian tree frogs and midwife toads

Abstract

Aim The study of areas of sympatry of species with predominantly parapatric distributions can provide valuable insights into their evolutionary history and the factors shaping patterns of species co‐occurrence. This information is key in biogeography, evolutionary biology and conservation planning. In this study we analyse the distributions of two pairs of partially co‐occurring congeneric amphibian species: tree frogs (Hyla molleri and H. meridionalis) and midwife toads (Alytes obstetricans and A. cisternasii). Location Iberian Peninsula (SW Europe). Methods We obtained distribution data from the herpetological atlases of Portugal and Spain, consisting of presences and absences on UTM 10 × 10 km grid cells. We built an environmental favourability model for each species, using 24 potential predictor variables representative of physiography, climate and human activity. Variables were selected for each model using both information and significance criteria. Models were evaluated using both calibration and discrimination measures. Models were then combined using fuzzy intersection, and compared using correlation analysis (accounting for spatial autocorrelation), niche comparison metrics and fuzzy similarity indices. Results We found significant dissimilarity between the favourability patterns for A. obstetricans and A. cisternasii, indicating environmental segregation of these two midwife toad species. In tree frogs, we found significant similarity between favourability for H. meridionalis and for its co‐occurrence with H. molleri – that is, sympatry occurs mainly in areas that are favourable for H. meridionalis. Main conclusions These results provide clues to understand the evolutionary history of these four species, including the evolution of reproductive isolation, and suggest that conservation efforts for tree frogs may be focused on the areas that are favourable for both species, whereas midwife toads will require specific measures tailored for each species.

Mountains as barriers to gene flow in amphibians: Quantifying the differential effect of a major mountain ridge on the genetic structure of four sympatric species with different life history traits

“…Among these, the Central System mountains are thought to represent a historical barrier to gene flow across diverse taxonomic groups. The ranges of several amphibian species find their distributional limit in the Iberian Central System (Arntzen & Espregueira Themudo, ; Reino et al., ), and these mountains separate well‐differentiated intraspecific clades in other species (Gutiérrez‐Rodríguez, Barbosa, & Martínez‐Solano, ).…”

“…Among these, the Central System mountains are thought to represent a historical barrier to gene flow across diverse taxonomic groups. The ranges of several amphibian species find their distributional limit in the Iberian Central System (Arntzen & Espregueira Themudo, 2008;Reino et al, 2017), and these mountains separate well-differentiated intraspecific clades in other species (Guti errez-Rodr ıguez, Barbosa, & Mart ınez- . Explicitly testing the differential role of a putative barrier in shaping genetic structure across taxa requires assessing: (1) whether the putative barrier acts as such in the present, disrupting patterns of population connectivity and (2) the consistency of the barrier effect across species with different life history traits (e.g.…”

Unraveling climate influences on the distribution of the parapatric newts Lissotriton vulgaris meridionalis and L. italicus

“…The presence of certain species in a territory can be read as the result of many factors interacting in space and time, such as historical distributions, paleoclimatic events, large and fine-scale fragmentation, biotic interactions, niche width and dispersal ability (e.g., [ 7 – 10 ]). Thus, modelling the distribution of species within discrete biogeographical units, especially when dealing with low-dispersal ability species [ 11 , 12 ], requires a proper implementation of both Species Distribution Models (SDMs) and phylogeographic analyses based on genetic evidence [ 13 – 15 ]. Species’ distribution is usually constrained by biotic interactions, dispersal capability and geographic accessibility (the “B” and “M” of a BAM diagram [ 16 ]) or by abiotic factors (the “A” part).…”

Research Article Parapatric speciation found in Limnonectes (Dicroglossidae) species in Thailand

“…The study of species co-occurrence and parapatric distributions can provide an evolutionary history of amphibian species, for example, in tree frogs (Hyla molleri and H. meridionalis) and midwife toads (Alytes obstericans and A. cisternasii). Their combined fuzzy intersection and niche comparison metrics showed the effect of the environment or niche on the survival until segregation (Reino et al, 2017). Similarly, Posso-Terranova and Andrés (2016) showed the relative contribution of geographical and environmental factors to the diversification of poison frogs (Oophaga) using gene genealogies and the phylogenetic method.…”