Format: ORAL

Yessica Rico1, Marisol Zurita Solis1,M. ngel Len-Tapia2, Ara N. Miguel Pealoza1

1 Red de Diversidad Biológica del Occidente Mexicano, Instituto de Ecología A.C. Michoacán, México 2 Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México

Magnolias are representative tree species of the Tropical Montane Cloud Forest (TMCF) in Mexico, which is one of the most endangered ecosystems due to anthropogenic habitat degradation and climate change. Magnolia schiedeana is a vulnerable and restricted endemic TMCF species, occurring in forest fragments in the Sierra Madre Oriental. We sampled remnant populations across the species range to investigate spatial patterns of genetic diversity and gene flow by genotyping polymorphic microsatellite loci. Our data showed a strong spatial structure, which matches the patchy geographic distribution of M. schiedeana. Contemporary migration rates between these genetic clusters are very low. Levels of genetic diversity were low in small populations relative to large populations, and no evidence of inbreeding was found. Landscape genetic analysis revealed that geographic isolation was the main factor shaping genetic differentiation, not slope or environmental variation. Urgent conservation actions are needed as most of the cloud forests in which large and genetically diverse M. schiedeana populations persist are not under federal protection, and which currently experience selective logging. Restoring landscape connectivity should be a priority to reduce risks of inbreeding and genetic drift as populations become smaller and geographically isolated.