As environmental conditions change over time, some species can follow the spatial footprint of their ecological niches or can adapt physiologically to the new conditions; modifying behavior can offer an alternative means of adapting to novel environments. The burrowing habit allows organisms to avoid adverse climatic conditions during part of the year by remaining inside burrows. Smilisca fodiens and S. dentata are two burrowing hylid frogs that inhabit areas beyond the northernmost distributional limits of the other six arboreal species of their genus, and indeed beyond of most American hylids. In this study, we tested whether burrowing habit allows these species to adapt to drier conditions while conserving the climatic niche of the arboreal species. We compared the annual niches of the arboreal species to those of the burrowing species under two assumptions: true seasonal niches and full annual niches. Through ecological niche similarity tests, we performed 24 comparisons in both geographic and environmental spaces. In geographic space, when considering burrowing annual niches, only five of 24 tests indicated similarity, yet as regards seasonal niche, 18 of 24 tests indicated similarity. In environmental space, all tests failed to reject null hypotheses. The analyses showed clearly that burrowing and arboreal species were closer in environmental space when seasonal niches of the burrowing species were used, rather than annual niches. That is, climatic conditions in seasonal niches of burrowing species resemble the annual niches of arboreal species, supporting the proposition that reduction of activity to certain periods of the year is a strategy in burrowing species to conserve their tropical niches while living in dry regions.

Megaloprepus caerulatus is a Neotropical species with a highly specialised niche, found from Mexico to Bolivia, primarily in mature tropical forests lower than 1500 masl. It is also the damselfly with the largest wingspan in the world. Recent studies found strong genetic isolation among populations of M. caerulatus. Further studies found genetic and morphological divergence, but ecological divergence was not tested. Here, we test for ecological divergence by evaluating niche differences among populations of M. caerulatus in Los Tuxtlas (Mexico), Corcovado (Costa Rica), Barro Colorado (Panama), and La Selva (Costa Rica). We used Ecological Niche Modelling (ENM) to compare potential distribution ranges, and we estimated the breadth and overlap of the ecological niche using equivalence and similarity tests. The potential distributions estimated with ENM were heavily fragmented and we found no geographic overlap of potential distributions among populations. However, we found geographic correspondence between populations with a close phylogenetic relationship. Even though all similarity tests were non-significant, the results of the equivalence tests suggest niche divergence between Corcovado and the other three populations, but also between Barro Colorado (Panama) and La Selva. These results show evidence of strong ecological divergence in Corcovado and Barro Colorado populations.

Measuring the potential effects of future climate changes on the spatio-temporal variance of optimal conditions for seasonal species is a key conservation issue. This study assesses the impact of climate change on the spatial and temporal patterns of optimal conditions for activity in two burrowing frogs, Smilisca fodiens and S. dentata. Ecological Niche Modeling was used to implement niche seasonality models, with calibration performed during the peak activity (July). These models were then transferred to current and future conditions for the remainder of the year, predicting future scenarios up to 2070 with an intermediate trajectory greenhouse gas concentration of 4.5 W/m2. Climate change transferability was assessed for four potential scenarios: 1) high precipitation and low temperature, 2) high precipitation and high temperature, 3) low precipitation and low temperature, and 4) low precipitation and high temperature. We examined the impact across future projected areas and analyzed geographic change trends based on latitude, longitude, and elevation. For both species, the best scenario would involve increased precipitation in the future. However, the worst-case would be a combination of reduced precipitation and higher temperatures. Due to large area loss, northern populations of S. fodiens may be highly vulnerable. Concerning S. dentata, the outlook is worrisome, with all known populations experiencing losses in most months. Area gains may not help either species since they tend to occur at elevations above their known ranges. Using a seasonal approach in spatio-temporal analysis enhances comprehension of the behavioral adaptations of seasonal species and their vulnerability to current and future climatic variations.

Zacatecas is in the north-central region of Mexico. Its territorial extension, as well as the unique combination of climatic and physiographic characteristics, favor high biological diversity. However, until now, it has been considered one of the states with lowest herpetofaunal diversity, mainly due to low sampling effort. We provide an updated checklist of the herpetofauna of Zacatecas, including the physiographic provinces and ecoregions where they occur, a summary of their conservation status, and a comparison with neighboring states. Zacatecas has 25 species of native amphibians and 119 native reptiles, with five introduced species (1 frog, 2 lizards, 1 snake and 1 turtle). Of 149 species, four have their type locality in Zacatecas, 16 represent new state records, and 232 records from 79 species are new municipal contributions. More than half of the native herpetofauna (53.5%) of Zacatecas is endemic to Mexico. However, it does not have state endemics, but harbors populations of regional endemics that only inhabit north-central Mexico. Of the native amphibian and reptile species in Zacatecas, 2.8% are listed by IUCN in threatened categories (i.e., Vulnerable, Endangered, Critically Endangered), 13.9% are placed in a protected category by SEMARNAT (i.e., Threatened and in Danger of Extinction), and 33.3% are categorized as high vulnerability by the EVS criteria. Among adjacent states with which it shares a border, Zacatecas is the fourth with the largest territorial extension, the fifth in herpetofauna diversity, and the third with the highest number of country endemic species. Large areas of the state remain underexplored, suggesting that the herpetofauna richness of Zacatecas may increase in the future.