CR 60:163-174 (2014)  -  DOI: https://doi.org/10.3354/cr01231

ABSTRACT: We define vulnerability here as the extent to which climate change may damage or harm a system, depending not only on a system’s sensitivity, but also on its ability to adapt to new climatic conditions. Current climate change has already affected the Earth’s biodiversity, and the rate of change is likely to accelerate in the future. It is expected that climate change will affect the performance, structure and distribution of ecosystems, species and genetic constituents. Changes in temperature and precipitation, and in the frequency and intensity of extreme events, can directly influence ecosystem functioning. To determine the vulnerability or fragility of different species to climate change, we used the envelope function method, because of its capacity to analyze the variables that directly affect different species; by measuring the effect of climate variables on stomatal conductance, this provided an effective analysis of the diversity of eco-physiological responses. Using this method to assess vulnerability helped us predict the extreme values that the species could tolerate; and also gave information about the species’ sensitivity. We analyzed the effects of air temperature, photosynthetically active radiation, vapor pressure deficit and leaf water potential on the stomatal conductance in 4 tree species (Alnus acuminata, Quercus xalapensis, Liquidambar styraciflua and Pinus ayacahuite) from different altitudinal ranges in the central region of Veracruz, Mexico, in Las Grandes Montañas. Knowing how vulnerability affects the species and ecosystems is a key element of maintaining regional biodiversity.

KEY WORDS: Vulnerability · Climate change · Stomatal conductance · Air temperature · Photosynthetically active radiation · Vapor pressure deficit · Leaf water potential