We present an updated checklist of native Mexican freshwater gastropods with data on their general distribution, hotspots of endemicity, threats, and for the first time, their estimated conservation status. The list contains 193 species, representing 13 families and 61 genera. Of these, 103 species (53.4%) and 12 genera are endemic to Mexico, and 75 species are considered local endemics because of their restricted distribution to very small areas. Using NatureServe Ranking, 9 species (4.7%) are considered possibly or presumably extinct, 40 (20.7%) are critically imperiled, 30 (15.5%) are imperiled, 15 (7.8%) are vulnerable and only 64 (33.2%) are currently stable. With 61 species in 21 genera, the Cochliopidae are the most diverse family, followed by the Planorbidae (37 species) and Pachychilidae (31). Pachychilus is the most species-rich genus with 30 species. Despite the high number of imperiled species (84), only 7 species (3.6%) are currently listed as endangered by the Mexican Secretariat of Environment and Natural Resources. We identified 3 hotspots and 2 potential centers of gastropod endemicity. Our research serves as a first step for determining priority areas for conservation of imperiled Mexican freshwater gastropods. A. Czaja et al. / Revista Mexicana de Biodiversidad 91 (2020): e912909 2 https://doi.org/10. 22201/ib.20078706e.2020.91.2909 ResumenSe presenta un listado actualizado de gasterópodos dulceacuícolas nativos de México con datos de su distribución general, hotspots de endemicidad, amenazas y, por primera vez, su estado de conservación estimado. La lista contiene 193 especies, 13 familias y 61 géneros. De éstas, 103 especies (53.4%) y 12 géneros son endémicos de México y 75 de estas especies se consideraron endémicas locales debido a su distribución restringida a áreas muy pequeñas. Usando NatureServe Ranking, consideramos 9 especies (4.7%) posiblemente o probablemente extintas, 40 (20.7%) en peligro crítico, 30 (15.5%) en peligro, 15 (7.8%) son vulnerables y solo 64 (33.2%) están estables actualmente. Con 61 especies en 21 géneros, Cochliopidae es la familia más diversa, seguida de Planorbidae (37 especies) y Pachychilidae (31). Pachychilus (Pachychilidae) con 30 especies, es el género más rico en especies de los gasterópodos dulceacuícolas mexicanos. A pesar del alto número de caracoles en peligro (84), solo 7 (3.6%) están actualmente catalogados en peligro por la Secretaría de Medio Ambiente y Recursos Naturales de México. Identificamos 3 hotspots y 2 centros potenciales de endemicidad. Los resultados servirán como un primer paso para determinar las áreas prioritarias para la conservación de los gasterópodos mexicanos amenazados.

Pinus greggii is a species of socioeconomic importance in terms of wood production and environmental services in Mexico, though it is restricted by particular environmental conditions to the Sierra Madre Occidental. Species distribution models are geospatial tools widely used in the identification and delineation of species' distribution areas and zones susceptible to climate change. The objectives of this study were to: (i) model and quantify the environmentally suitable area for Pinus greggii in Mexico, and possible future distributions under four different scenarios of climate change; (ii) identify the most relevant environmental variables that will possibly drive changes in future distribution; and (iii) to propose adequate zones for the species' conservation in Mexico. Some 438 records of Pinus greggii from several national and international databases were obtained, and duplicates were discarded to avoid overestimations in the models. Climatic, edaphic, and topographic variables were used and 100 distribution models for current and future scenarios were generated using the Maxent software. The best model had an area under the curve (AUC) of 0.88 and 0.93 for model training and validation, respectively, a partial ROC of 1.94, and a significant Z test (p<0.01). The current estimated suitable area of Pinus greggii in Mexico was 617,706.04 ha. The most relevant environmental variables for current distribution were annual mean temperature, mean temperature of coldest quarter, and slope. For the 2041-2060 models, annual mean temperature, precipitation of coldest quarter, and slope were the most important drivers. The use of climatic models allowed to predict a future decrease in suitable habitat for the species by 2041-2060, ranging from 48,403.85 (7.8%-HadGEM2-ES RCP 8.5 model) to 134,680.17 ha (21.8%-CNRM-CM5 RCP 4.5). Spatial modeling of current and future ecological niche of Pinus greggii also allowed to delineate two zones for in situ conservation and restoration purpose in northeastern (Nuevo Leon) and central (Hidalgo) Mexico.

Accelerated climate change represents a major threat to the health of the planet's biodiversity. Particularly, lizards of the genus Xenosaurus might be negatively affected by this phenomenon because several of its species have restricted distributions, low vagility, and preference for low temperatures. No study, however, has examined the climatic niche of the species of this genus and how their distribution might be influenced by different climate change scenarios. In this project, we used a maximum entropy approach to model the climatic niche of 10 species of the genus Xenosaurus under present and future suitable habitat, considering a climatic niche conservatism context. Therefore, we performed a similarity analysis of the climatic niche between each species of the genus Xenosaurus. Our results suggest that a substantial decrease in suitable habitat for all species will occur by 2070. Among the most affected species, X. tzacualtipantecus will not have suitable conditions according to its climatic niche requirements and X. phalaroanthereon will lose 85.75% of its current suitable area. On the other hand, we found low values of conservatism of the climatic niche among species. Given the limited capacity of dispersion and the habitat specificity of these lizards, it seems unlikely that fast changes would occur in the distribution of these species facing climate change. The low conservatism in climatic niche we found in Xenosaurus suggests that these species might have the capacity to adapt to the new environmental conditions originated by climate change.

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It has frequently been reported that species with strong niche conservatism will not be able to adapt to new climatic conditions, so they must migrate or go extinct. We have evaluated the shifts in climatic niche occupation of the species Astrophytum coahuilense and its potential distribution in Mexico. We understand niche occupation as the geographic zones with available habitats and with the presence of the species. To assess shifts in climatic niche occupation, we used niche overlap analysis, while potential distribution modeling was performed based on the principle of maximum entropy. The results indicate that this species presents a limited amplitude in its climate niche. This restriction of the climatic niche of A. coahuilense limits its ability to colonize new geographical areas with different climatic environments. On the other hand, the potential distribution models obtained from the present study allow us to identify potential zones based on the climatic requirements of the species. This information is important to identify high priority areas for the conservation of A. coahuilense.