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• The distribution and morphology of Rhipicephalus sanguineus sensu lato varies with altitude, this adaptability can encourage the expansion and survival of the species, and consequently, the risk of transmitting infectious agents. • Identifying the tick lineage helps to know the distribution area and supports the geographical limit that is known so far of both lineages. • The ecological niche in which the species lives helps us to know the factors and conditions that favor the presence of this tick and this can be key to better understanding how they are distributed and what environmental variables influence their presence. Studies of morphological and genetic variation in vector populations across environmental gradients can help researchers to estimate species' responses to climate change scenarios and the potential risk of disease-causing pathogen expansion, which impacts negatively on human health. In this study, we analysed the effect of altitudinal gradients on the phenotypic response of the hard tick of medical and veterinary importance, Rhipicephalus sanguineus sensu lato (s.l.). Specimens of R. sanguineus s.l. were collected from host animals in one of Mexico's regions with high climatic heterogeneity (Veracruz), and geometric morphometric theory was employed to assess the response of three morphological characters to the altitudinal gradient. Additionally, genetic similarity data were provided, and ecological niche models were used to project the climatic distribution in the region. Our results demonstrate that the shape and size of ticks respond to altitude. Molecular identification indicate that all analysed samples correspond to the tropical lineage recently named Rhipicephalus linnaei. According to ecological niche models, the mean annual temperature contributes significantly to the spatial distribution of this tick species, with areas of higher suitability in the mountainous region. These changes in morphological structure and the presence of ticks at higher altitudinal gradients suggest that R. linnaei has a high potential for adaptation. Due to the variability of ecosystems in the state of Veracruz, our results could be valuable in assessing the response of this tick in a changing environment, aiding in predicting future scenarios in the distribution and abundance of this species. [Display omitted] [ABSTRACT FROM AUTHOR]

The montane cloud forest (MCF) is one of the most threatened ecosystems, in spite of its high strategic value for sustainable development, the role it plays in the hydrological cycle maintenance, and as reservoir of endemic biodiversity. For Mexico, this forest is considered the most threatened terrestrial ecosystem at national level because of land-use changes and the effects of global climate change. To compare and assess the environmental vulnerability in the MCF we measured two physiological traits (stomatal conductance and leaf water potential), four climate variables (air temperature, photosynthetically active radiation, vapor pressure deficit, water availability) and the potential geographic distribution of eleven tree species from this forest. We evaluated stomatal conductance responses using the envelope function method (EFM), and after analyzing these responses we developed a vulnerability index that allowed us to compare the environmental vulnerability among species. We proposed the EFM as a useful tool to assess regional environmental vulnerability by comparing species. Our results showed differential species responses to all the studied variables; however, the vulnerability index allowed us to conclude that the most vulnerable species was Liquidambar styraciflua , and the least vulnerable Persea longipes . We also found that temperatures above 34 °C, and vapor pressure deficit above 2.9 kPa with relative humidity below 30% jeopardized the stomatal conductance performance of all species. We also found leaf water potential as the most influential variable over the studied species followed by vapor pressure deficit, showing that even in the MCF water is a determinant factor for species’ development. [ABSTRACT FROM AUTHOR]

Abstract: The beaded lizard (Heloderma horridum) is listed as a threatened species in Mexico. Scientific research has been limited to two sites within its range (Chamela and Valle Motagua) outside of these two regions there have not been adequate surveys to define range limits or measure environmental correlates for defining suitable habitat. We constructed an ensemble model (EM) for the distribution of suitable habitat for H. horridum in both Mexico and Guatemala and then used that model to identify potential areas to focus conservation. We used nine presence-only modeling methods, and selected three to generate our EM. We used the EM to evaluate the efficacy of the existing Protected Natural Areas (PNAs) in Mexico and Guatemala for H. horridum. Also we used the best individual predictive model (Maxent) to obtain the most important factors for H. horridum presence and used them to analyse the habitat use; finally we used our predictive model to calculate niche breath for the species. The estimated potential distribution of H. horridum is 370,474km2; within this area we identified nine zones based on continuity and natural barriers. About 1.5% of the species distribution is under protection in the PNAs. The five most important factors for the presence of this species explained 78.2% of the generated model and are related to seasonality and soil cover, and these are used selectively. This species is closely associated with tropical deciduous forests, one of the most threatened ecosystems worldwide and is inadequately protected in both Mexico and Guatemala. Our results clearly show the necessity of a protection plan for this species. [Copyright &y& Elsevier]

Abstract: The bees of the Peponapis genus (Eucerini, Apidae) have a Neotropical distribution with the center of species diversity located in Mexico and are specialized in Cucurbita plants, which have many species of economic importance, such as squashes and pumpkins. Peponapis fervens is the only species of the genus known from southern South America. The Cucurbita species occurring in the same area as P. fervens include four domesticated species (C. ficifolia, C. maxima maxima, C. moschata and C. pepo) and one non-domesticated species (Cucurbita maxima andreana). It was suggested that C. m. andreana was the original pollen source to P. fervens, and this bee expanded its geographical range due to the domestication of Cucurbita. The potential geographical areas of these species were determined and compared using ecological niche modeling that was performed with the computational system openModeller and GARP with best subsets algorithm. The climatic variables obtained through modeling were compared using Cluster Analysis. Results show that the potential areas of domesticated species practically spread all over South America. The potential area of P. fervens includes the areas of C. m. andreana but reaches a larger area, where the domesticated species of Cucurbita also occur. The Cluster Analysis shows a high climatic similarity between P. fervens and C. m. andreana. Nevertheless, P. fervens presents the ability to occupy areas with wider ranges of climatic variables and to exploit resources provided by domesticated species. [Copyright &y& Elsevier]

The anthropogenic introduction of alien species is one of the main causes of biota homogenization worldwide. Part of these introductions provokes biological invasions, which cause serious ecological and economic impacts from local to global scales. In order to prevent this and give proper management to exotic species, it is necessary to use predictive tools to prioritize sites with a higher probability of their establishment, thus preventing impacts in local ecosystems and communities. Here, we used ecological niche and interaction models to estimate the invasive potential of four species of exotic snakes identified as high risk and currently sold as pets in Mexico (Python brongersmai , P. molurus , P. regius , and Malayopython reticulatus), and simulate their impact as top predators (according to the average length of the prey that each snake species consumes) of species of native terrestrial vertebrates to this country. Results indicate that all four exotic snake species could generate severe impact on the community of native vertebrates within the country, while P. molurus could get to cause the largest impact given that it would get to interact and potentially consume a greater number of species. The organisms that would be mostly preyed by these snakes would be birds, followed by mammals, reptiles and finally amphibians. This pattern results from a combination of factors including prey body size preferences for predation in the exotic snakes' native ranges, and the amplitude of the potential distribution areas and the number of species from each vertebrate group in Mexico. This paper shows the utility of combining methodological approaches for risk prevention and risk analysis for invasive alien species. • Exotic pet snakes represent a risk for native vertebrates in Mexico. • Highest negative interactions would be on birds, followed by mammals, reptiles and amphibians. • Risk assessment could improve from combining potential distributions and network analyses. [ABSTRACT FROM AUTHOR]