BIO 3115 Lecture Notes - Lecture 4: Alpha Diversity, Gamma Diversity, Species Richness
17 Feb 2018
School
Department
Course
Professor
Document Summary
Latitudinal variation: over continental and regional scales, species richness is higher in tropical than temperate regions towards the equator (ex. Forest birds of central and south america: bigger diversity and richness across bands of both terrestrial and aquatic taxa, higher latitudes = less species richness because of increase in specific habitat only livable by few. Increasing altitudes = decline of richness of both terrestrial and aquatic taxa, including vascular plants. Structural complexity: alpha diversity of many terrestrial and aquatic taxa increases with structural complexity of habitat. Insular patterns: alpha-richness is usually found (but not always) on smaller islands, primarily because of reduced immigration rates and/or increased extinction rates on islands versus mainland. Increase in distance from immigrant source pool = decline of number of species present (degree of saturation, alpha-diversity) In function of immigration rates, how far the land is from the mainland. Alpha diversity increases with vegetation structure, and decreases with increasing habitat patchiness and isolation.
