Patrones de distribución y áreas prioritarias para la conservación de las orquídeas en riesgo de Oaxaca

Abstract

Oaxaca has 700 of orchid species, more than half of the richness recorded for the country, but only 6% of its surface is under protection within the National System of Protected Natural Areas (PNA). The loss of habitat, removal for illegal trade, and effects from climate change are risk factors for orchids and in Oaxaca are particularly serious for the endemic and those included in the NOM-059-ECOL-2001, which are consider here as orchids at risk. To evaluate the status of knowledge, diversity and distribution patterns for these orchids there was built a geographic information system, georeferencing all their Oaxacan localities obtained from literature reviews and scientific collections. The localities were superimposed using themes of political division, vegetation, elevation model, PNA, Terrestrial Priority Regions (TPR) and Terrestrial Priority Sites (TPS). Oaxacan orchids at risk include 137 species from 1,066 collected records. The Sierra Norte region house 63 species, while Ixtlán and Juchitán districts present 43 and 38 species, respectively. The cloud forest (CF) hosted more species (70) than other habitat. The greatest diversity of orchids at risk was found between 1801 and 2000 m elevation. Of the 137 orchids at risk, only 40 of them are known within some PNA, which represents only 29% of that richness. Benito Juarez National Park was the PNA with more orchids at risk (12). In the (TPR) and (TPS) are present 88.3% of the species and 87.6% of records for orchids at risk; unfortunately these are not areas for conservation. There are considered as priority for conservation of Oaxacan orchids at risk the Sierra Norte, Cañada and Istmo regions, since they present habitat favorable for these plants (CF). This study also shows that PNA does not guarantee the effective protection of orchids at risk, nor the habitats that house the greatest richness and endemism for orchids at risk in Oaxaca.