Most Mexican hummingbirds lose under climate and land-use change: Long-term conservation implications

Abstract

Hummingbirds are one of the most threatened bird groups in the world. However, the extent to which global climate change (GCC) and habitat loss compromise their conservation status remains unclear. Herein, we proposed to: (1) assess how predicted GCC impacts the distribution of non-migrant hummingbirds according to their conservation status, degree of restriction and habitat specificity; and (2) delineate priority conservation areas where species could persist in the face of both threats. We estimated the potential distributions of 49 species under current and future climates (year 2040, 2060, and 2080), analyzing the effects of current habitat loss and the importance of existing Protected Areas (PAs) on the species’ ranges and hummingbird hotspot areas in Mexico. Our projections were consistent in the identity of the species that are most vulnerable to GCC: while 10.2% of species will have potentially habitat gains/stability (“winners”), the remaining 89.8% of species (“losers”) will face habitat reductions under new climate conditions. These changes were mostly related to temperature increases (>2 °C) and rainfall decreases (<50 mm). The combined impacts of GCC and habitat loss may represent a higher risk, leading to an average reduction of ~26-59% in species’ ranges. Already-established Mexican PAs cover ~12% of the hummingbirds’ current ranges, but showed an important reduction of surface across the species distribution (on average >15%) and hotspot areas (>60%) for future. We identified highly resilient priority areas across southern Mexico, in Oaxaca and Guerrero. Ambitious conservation actions by decision-makers are now crucial to avoid losing these highly-vulnerable taxa.