Data/hora: 25/06/2024 13:14:25

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 12/03/1999
Data da última atualização: | 26/09/2013
Autoria: | SORIANO, A.; SALA, O.
Afiliação: | Departamento de Ecologia, Facultad de Agronomia, Universidad de Buenos Aires and PROSAG (CONICET) Argentina.
Título: | Ecological strategies in a Patagonian arid steppe.
Ano de publicação: | 1983
Fonte/Imprenta: | Vegetatio, v.56, n.1, p.9-15, 1983.
Idioma: | Inglês
Conteúdo: | The vegetation in the Coironal arid steppe consists of grasses and shrubs. The objective of this paper was to test Walter's hypothesis that woody vegetation and grasses compete for water in the soil, but woody vegetation has exclusive access to a source of water at deeper levels. Analysis of root profiles and patterns of leaf and soil water potential led us to accept the hypothesis for this arid steppe. Additional information on phenology and on the ability of the major grass species to respond to watering permitted to identify two ecological strategies corresponding to grasses and shrubs. Grasses behave as opportunists having always leaves ready to grow as soon as water becomes available. They have as shallow root system and are able to respond very rapidly to increases in soil water availability. In contrast, woody species have a clear-cut periodic pattern of growth and dormancy. They posses thick horizontal roots running below 35-40 cm and utilized water stored in lower layers of the soil. A diagrammatic model summarizes the role of periodic and opportunistic species upon water circulation in the ecosystem. The effect of changes in the proportion of the two groups upon water dynamics is also discussed.
Palavras-Chave: | Arid steppe; Competicao; Competition; Ecological strategy; Estepe arida; Estrategia ecologica; Forma de vida; Life form; Patagonia; Relacao com agua; Root system; Sistema de raiz; Water relations.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (37241-1) - ADC - SP - -- - SP3957 -  - 3957 - DIS