Elevational and seasonal changes in a bird assemblage within a mountain system in central Mexico

Abstract Mountain systems around the world represent very important research models because they are hot spots for biological diversity. Understanding how animals communities change across environmental variation (e.g., elevational gradients) is central. Currently, the knowledge of the Mexican avian diversity is incomplete due to the absence of detailed studies and inventories in regions such as the mountainous systems of central Mexico. These surveys represent a simple and effective measure to estimate the diversity and perform as a basis for ecological research, as well as to determine priority areas for biological conservation. Here, we sampled 113 points divided into seven elevational segments ranging from 1000 to 3100 to assess differences along elevation and between seasons. We expected to find a gradual turnover of species, as well as a monotonic decrease in richness with respect to altitude. We obtained a total of 100 bird species representing 23% of the species registered for the state and 30% of the species registered for the Reserva de la Biosfera Sierra Gorda. We observed differences in species composition only in the extremes of the gradient. We recorded highest richness values towards the middle part of the gradient decreasing with elevation in winter. The results of this work contribute to increase the knowledge about bird diversity in the state of Querétaro, and highlights the importance of diversity analysis at different levels, such α and β diversity, through altitudinal clines.