Gamma diversity

About: Gamma diversity is a research topic. Over the lifetime, 1012 publications have been published within this topic receiving 80814 citations.

Measuring Biological Diversity

Abstract: Summary As prehistoric cave paintings illustrate, our species has had an enduring appreciation of the variety and abundance of life on Earth. Today, however, concern is focused on the pressure humanity is placing on the natural world, and on the continued ability of ecosystems to deliver the services on which we all depend. To understand the extent of this ‘biodiversity crisis’ and develop strategies to ameliorate its impact, it is essential to be able to accurately measure biological diversity (a term often contracted to biodiversity) and make informed predictions about how and why this diversity varies over space and time.

Diversity and Evenness: A Unifying Notation and Its Consequences

Abstract: Three commonly used measures of diversity, Simpson's index, Shannon's entropy, and the total number of species, are related to Renyi's definition of a generalized entropy. A unified concept of diversity is presented, according to which there is a continuum of possible diversity measures. In a sense which becomes apparent, these measures provide estimates of the effective number of species present, and differ only in their tendency to include or to ignore the relatively rarer species. The notion of the diversity of a community as opposed to that of a sample is examined, and is related to the asymptotic form of the species—abundance curve. A new and plausible definition of evenness is derived.

The Measurement of Species Diversity

Abstract: Inspired significantly by the provocative papers of MacArthur (34, 35, 38) and Hutchinson (22), ecologists over the past twenty years have devoted considerable energy to the explanation of patterns of diversity in ecologic systems Despite considerable interest, however, no generally accepted definition of diversity has emerged "Diversity per se does not exist," was the contention of Hurlbert (20), who suggested abandoning the term because of the multiplicity of meanings and interpre­ tations attached to it MacArthur (37) also considered the term had outlived its usefulness, and Eberhardt (10), Austin (2), and McIntosh (40) all complained of the lack of a definition Eberhardt considered that diversity "mostly suggests a consider­ able confusion of concepts, definitions, models, and measures (or indices)" If diver­ sity is to continue to play a productive role in ecological investigations, agreement is needed on the definitions of the many constituent concepts included in its current application At the community level of synthesis many phenomena are complex and open to multiple interpretation Consequently, many authors have suggested diversity in­ dices appropriate for their own studies, no one of which can be considered a priori correct for general application (12, 19,20,32,40) Diversity, in essence, has always been defined by the indices used to measure it, and this has not fostered the sort of uniformity which allows the clear statement of ideas and hypotheses Progress in ecology, as in all science, depends upon precise and unambiguous definition of terms and concepts (2, 40, 44) The present contribution attempts to define in a precise, but still generalized I1\anner, what is or should be meant by the many terms sur­ rounding the concept-cluster diversity Guidelines are also suggested for the applica­ tion of the many ayailable diversity indices