Search Results (6)

The Balsas Basin (BB) is a biogeographic province in south-central Mexico that straddles the Mexican Transition Zone and the Neotropical region. We provide a list of the amphibian and reptile species of the BB based on a detailed review and update of recent species lists of its constituent states. The BB is home to 51 native amphibian and 155 native reptile species, which represent 14.7% of the herpetofauna of Mexico. No amphibian and six reptile species are endemic to the BB. Six species of amphibians and seven of reptiles are categorized as being of conservation concern status (vulnerable, endangered, or critically endangered) on the International Union for Conservation of Nature’s (IUCN) Red List. The main threat these species face is habitat loss due to urbanization, agriculture, and pollution. The herpetofauna of the BB shows significant overlap with neighboring provinces. The composition of amphibian species in the BB is closest to that of the Pacific Lowlands, whereas the composition of reptile species is closest to the Sierra Madre del Sur and the Transvolcanic Belt. These findings suggest that while the BB supports significant amphibian and reptile diversity, its conservation importance may be limited due to the low levels of endemism and the relatively small proportion of species at risk. Full article

Pinus oocarpa Schiede is the most widely distributed conifer in the Americas. In Mexico, it inhabits diverse environments and is the primary pine species utilized for resin production, prompting the establishment of a genetic improvement program (GIP). Preserving a broad genetic diversity is fundamental to the success of the GIP. This study aimed to assess the genetic diversity and structure of trees selected for their high resin yield. A total of 146 trees from 15 provenances within three populations (MX-MIC, MX-MEX, and MX-OAX) constituting the selection population of the GIP were evaluated. Five SSR microsatellite markers (PtTX3013, NZPR1078, PtTX2146, PtTX3107, and PtTX3034) were used to determine key indicators of genetic diversity and structure. All three populations exhibited high genetic diversity; however, the heterozygosity observed was lower than the expected heterozygosity. Genetic structure analysis revealed the presence of two distinct genetic groups: the Transverse Volcanic Axis (MX-MIC and MX-MEX) and the Sierra Madre del Sur (MX-OAX). Most of the genetic diversity (87.42%) was found within provenances. Gene flow was high among provenances within the same genetic group but limited between provenances from different groups. The findings suggest that GIPs should be tailored to each genetic region, with a focus on within-provenance selection to maintain genetic diversity. Full article

This study compiles and updates the checklist of ferns and lycophytes from the Sierra Madre Occidental (SMOc). For this, we revised information on these taxa from regional floristic studies, databases, and herbaria. Our updated list includes 312 species, of which 276 are ferns and 36 are lycophytes integrated into 27 families and 75 genera. The richest families are Pteridaceae (118), Polypodiaceae (31), Selaginellaceae (30), Aspleniaceae (25), and Dryopteridaceae (25). The three most diverse genera were Selaginella (30), Asplenium (25), and Myriopteris (22). The species-rich Mexican states that include the SMOc are Durango (166 species), Chihuahua (149), and Jalisco (146). As in other tropical mountains, species richness in the SMOc is concentrated at the elevation interval of 1500 to 2000 m (236 species). The mid-mountain vegetation forests (Quercus and Pinus-Quercus forests) harbor the most pteridoflora richness (52% of the species). Four species of ferns are listed as threatened in the Mexican Official Norm NOM-059-SEMARNAT-2010, 17 species are listed in the IUCN, and only one tree ferns are in CITES. The SMOc has a Nearctic affinity, and its fern and lycophyte diversity are lower than in other Mexican Transition Zone mountain chains, such as the Sierra Madre del Sur, the Trans-Mexican Volcanic Belt, and the Sierra Madre Oriental. Notwithstanding, its biological composition is unique and distinctive. The species number reported in the SMOc represents 31% of the pteridoflora diversity recorded in Mexico. Full article

Laelia is an endemic genus of the neotropical region, with the greatest richness occurring in Mexico. A recent phylogenetic study transferred some Mexican laelias to the genus Schomburgkia, which has generated debate. The aim of the present study was to analyze the patterns of species richness and endemism and the current and potential geographic distributions of the taxa of Laelia s.l., as well as the putative Laelia s.s., distributed in Mexico as part of an exploratory evaluation of the generic limits to sheds light on the taxonomic debate and generate baselines to guide conservation efforts. A database was generated with information from herbarium specimens and publications. The species richness was estimated by political division, biomes, and elevation. The endemism was analyzed by political division and using the weighted and corrected weighted endemism indices. Geographic data, climatic, and topographic variables were used to predict the distributions with the maximum entropy algorithm. The results supported the proposal to transfer some species to the genus Schomburgkia. Some areas of the Sierra Madre del Sur and Oriental should be included as priority areas in the conservation strategies of Laelia. This study highlights the importance of the taxonomy, distribution, and hotspots in diversity conservation. Full article

A taxonomic and nomenclatural review of the genus Croton (Euphorbiaceae) in the Mexican state of Michoacán is presented. Six sections and 20 species are here reported. The greatest diversity is in the Balsas Depression province, where at least 12 species occur. There is a strong tendency to thrive in tropical deciduous forest. An identification key is provided, and for each species, the following information is included: protologue citation, type information, habit, habitat, and elevation within the state, regional and global distribution, and phenology. Relevant synonyms are listed, as too are herbarium specimens. Lectotypes are designated for Croton draco, C. niveus, and C. calvescens. One species, Croton rojasii, is described as new and illustrated with photos. It is known only from tropical deciduous forest in the Zicuirán-Infiernillo Biosphere Reserve, at elevations from 400 to 700 m. It belongs to sect. Geiseleria and is remarkable because of the strongly unequal pistillate sepals, the larger of which becoming accrescent and exceeding the fruit. Full article

The biotic province of the Sierra Madre del Sur presents a mosaic of woodlands at different successional stages due to frequent modifications in land use. In this study, we analyzed changes in woody flora across three successional stages of pine-oak forest: early, intermediate, and mature. Vegetation composition and diversity were characterized in 10 plots (each 0.28 ha). The mature stage had the highest values for species richness, abundance, and diversity. Pioneer plants were dominant in the early-successional site and may promote the establishment of late-successional species. The vegetation structure was more complex in the mature stage, where members of the Quercus genus were co-dominant with Pinus species. Pine tree richness was highest in the early-successional stage, and its abundance increased at the intermediate-successional site. These results suggest that Pinus species can grow in perturbed and sunny environments but also require favorable edaphic and microclimatic conditions, such as those found in intermediate woodlands. Results of this fieldwork support the initial floristic composition succession model, which suggests that species present at early stages will also occur in subsequent stages. Ecological succession may be considered to be a natural restoration process, and thus, conservation strategies should focus on maintaining distinct successional communities in addition to mature forests in order to preserve a high number of species. Full article