ABSTRACT
This chapter focuses on biodiversity among humans in mountain ecosystems. Because chronic, lifelong hypoxia is a stressor unique to mountain ecosystems, it examines human adaptation to high-altitude hypoxia, rather than other features of mountain ecosystems including cold and ultraviolet radiation. High-altitude hypoxia can significantly affect the success of human populations by influencing health, physical work capacity, and reproductive success. Human population size and density decreases with increasing altitude. A measure of the physiological stress of high-altitude hypoxia is oxygen saturation of haemoglobin, the percent of arterial haemoglobin that carries oxygen. Arterial oxygen content is a function of both oxygen saturation and haemoglobin concentration. One hypothetical way to offset the arterial hypoxia described above is to increase haemoglobin concentration. The functional consequences of variation in traits such as oxygen saturation and haemoglobin concentration have been addressed using physical work capacity.
