page_title: Beta diversity
section_title: β-diversity patterns
hierarchical_section_title: Beta diversity / β-diversity patterns
caption_attribution_description: English: Sampling grain size changes the relationship between tree beta-diversity and latitude
context_page_description: In ecology, beta diversity is the ratio between regional and local species diversity. The term was introduced by R. H. Whittaker together with the terms alpha diversity and gamma diversity. The idea was that the total species diversity in a landscape is determined by two different things, the mean species diversity at the habitat level and the differentiation among habitats. Other formulations for beta diversity include "absolute species turnover", "Whittaker's species turnover" and "proportional species turnover".
  Whittaker proposed several ways of quantifying differentiation, and subsequent generations of ecologists have invented more. As a result, there are now many defined types of beta diversity. Some use beta diversity to refer to any of several indices related to compositional heterogeneity. Confusion is avoided by using distinct names for other formulations.
  Beta diversity as a measure of species turnover overemphasizes the role of rare species as the difference in species composition between two sites or communities is likely reflecting the presence and absence of some rare species in the assemblages.
context_section_description: Although understanding the change in species composition from local to regional scales (β-diversity) is a central theme in ecology and biogeography, studies often reached different conclusions as to the fundamental patterns in β-diversity. For example, niche compression hypothesis predicted higher β-diversity at lower latitudes. Studies comparing natural habitats with human-modified habitats are no different. Kitching et al. sampled moths in primary and logged forests of Danum valley, Borneo to show that β-diversity in primary forests was higher than logged forests. Contrastingly, Berry et al. sampled trees in the same study area to show that β-diversity in logged forests was higher than primary forests. The results of these two studies were completely different from the results of a recent quantitative synthesis, which showed that β-diversity in primary forests were similar to β-diversity in all types of human-modified habitats (secondary forests, plantations, pasture and urban). Therefore, there is a clear lack of consensus on β-diversity patterns among studies. Sreekar et al. suggested that most of these inconsistencies were due to the differences in grain size and/or spatial extent among studies. They showed that spatial scale changes the relationship between β-diversity and latitude.
caption: Grain size changes the relationship between tree beta-diversity and latitude. See Sreekar et al.[19]