EL ELEMENTO ALPINO EN LA VEGETACIÓN DE CIMAS DE LA SIERRA MADRE OCCIDENTAL

Abstract

The Sierra Madre Occidental (SMO) is a mountainous province ecologically and economically important in Mexico which acts as a natural biological corridor and provides multiple and valuable environmental services. However, it is one of the least studied areas of this country as far as flora is concerned. The information generated through the study of the components on the vegetation contributes to environmental management as a fundamental tool to build new environmental policies and improve current management plans. Having a better knowledge of mountain biomes is very useful nowadays, as because their extreme environmental conditions they are highly sensitive to temperature disturbance and they are among the first terrestrial areas where the effects of climatic change can be detected. The aim of this thesis is to contribute to the knowledge of the SMO flora and vegetation, providing information about the structure and composition of summit vegetation in three of the highest peaks of this sierra: Cerro Gordo (3 347 m asl), Huehuento (3 262 m asl) and Las Antenas (3 224 m asl). The samplings were based on the methodology proposed by the GLORIA project. Additionally, monitoring points for future research about climate change effects on vegetation were established. A Canonical Correspondence Analysis (CCA) was performed, which showed a close relationship between environmental variables and species distribution in these peaks. There were a total of 174 plants species. We found that the alpine element is poorly represented in SMO and the main floristic affinities are toward the north