Data/hora: 19/06/2024 04:26:38

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 22/01/1997
Data da última atualização: | 22/01/1997
Autoria: | TERBORGH, J.
Afiliação: | Department of Biology, Princeton University, Princeton, New Jersey.
Título: | On the notion of favorableness in plant ecology.
Ano de publicação: | 1973
Fonte/Imprenta: | American Naturalist, v.107, n.956, p.481-501, July/Aug.1973.
Idioma: | Inglês
Conteúdo: | For many years ecologists have espoused the notion that habitats differ in an intrinsic quality that has been called favorableness. Here I point out that the concept of favourableness is circular and counterproductive. I develop the thesis that species diversity is determined by the balance of several dynamics processes: speciation, competition, immigration, adaptation, and extinction. A simple kinetic model places each of these processes in a definite perspective. My arguments are based on the observation that widespread mesic environments commonly support vegetation containing greater species diversity than enviroments of more unusual character such as sand dunes, inundated depression, bogs, mountain tops, saline soils, etc. Habitats such as these, that incorporate uncommon features and are often patchy and of small total area, are called peripheral habitats. Empirical and theoretical considerations both lead to the opinion that the pressure of competition in the species-rich communities of mesic habitats impels and adaptive outflow of species down gradient toward relatively impoverished peripheral habitats. Evolutionary difficulties involved in adapting up a competition gradient argue that the species flow from core to peripheral habitats is virtually uniderectional. Application of the kinetic model to some elementary features of the earth's geography provides a quantitative result that predicts a large and universal tropical-temperate diversity gradient. The mechanims is founded on an area-dependent model of specification coupled to the estimated rate of environmental change with latitude. It requires no assumptions about stability, food webs, or niche packing. The last section addresses the problem of how the dimensions of plant niche space could vary between different vegetation mformation and briefly discusses components of rainforest diversity.
Thesagro: | Ecologia; Habitat; Planta.
Thesaurus Nal: | plant ecology.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (33528-1) - ADD - SP - -- - SP3390 -  - 3390 - DIS