Patterns of Bird Diversity and Endemism Along an Elevational Gradient in the Southern Mexican Highlands.

Knowledge of bird species diversity along elevational gradients is key for understanding the distributional limits of species and, ultimately, for promoting measures that conserve biodiversity. In the present study, we evaluated changes in bird species richness, diversity, and endemism along an elevational gradient in the Sierra Madre del Sur in southern Mexico -a globally recognized biodiversity hotspot. Monthly bird surveys were carried out at localities with elevations of 1600, 1800, 2000, and 2200 m over the course of one year (2014-2015) covering an area of 2000 km (10 circular plots with a radius of 25 m per elevation site).