Mountain biodiversity patterns at low and high latitudes

• Published in: Ambio Vol. Spec No 13; p. 24
• Main Author: Molau, Ulf
• Format: Journal Article
• Language: English
• Published: Sweden 01.11.2004
• Subjects: Altitude; Biodiversity; Cold Climate; Ecosystem; Genetic Variation; Plants - genetics; Snow; South America; Species Specificity; Tropical Climate; South America
• ISSN: 0044-7447
• DOI: 10.1007/0044-7447-33.sp13.24

This paper presents an overview of mountain biodiversity at a multitude of scales in space, time, and function. Even though species richness is usually the focal component in nature conservation, genetic diversity within species is equally important. The small-scale distribution of species in the tropical Andes, as exemplified by the plant genera Calceolaria and Bartsia, contrasts against the situation in high-latitude mountains, e.g., the Scandes, where species have wide ranges and many are circumpolar. Recent studies on alpine plants based on molecular methods show that the intraspecific genetic diversity tends to increase with latitude, a situation brought about by the glaciation history with repeated contraction-expansion episodes of species' distributions. In tropical mountains, species distributions are geographically much narrower, often as a result of relatively recent, local speciation. Thus, whereas species richness in mountains decreases from the Equator towards the poles, genetic diversity shows the opposite trend. Finally, a comparison of ecosystem diversity in low- and high-latitude mountain ranges (tropical Andes vs. Scandes) shows that the landscapes differ profoundly with regard to timberline ecotones, snow distribution, and climate variables, and are subject to widely different impacts of global change