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Species diversity patterns in Mediterranean grasslands
Author(s) -
Montalvo J.,
Casado M. A.,
Levassor C.,
Pineda F. D.
Publication year - 1993
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3236107
Subject(s) - herbivore , ecology , grassland , mediterranean climate , altitude (triangle) , biology , intermediate disturbance hypothesis , grazing , old field , species diversity , disturbance (geology) , biomass (ecology) , paleontology , geometry , mathematics
. A field experiment involving herbivore exclusion, ploughing, and the combination of both was carried out over a period of 4 ‐ 5 yr in Mediterranean grasslands located along an elevational gradient. The empirical results provide a general hierarchical framework for understanding patterns of plant species diversity in thesegrasslands. In grazed grasslands, plant species density decreased as altitude increased, and this pattern was maintained through time. The reduced seasonality along the climatic gradient is suggested as the extrinsic, indirect control factor. Ploughing caused species loss, but after 4 yr the original diversity was recovered in most grasslands. Our hypothesis is that a negative feedback mechanism regulates species increase towards a characteristic level. A trend of species density reduction was observed in ungrazed grasslands. Plant‐herbivore interaction is considered to be essential for maintaining species diversity in grazed grasslands and for the recovery of diversity in mechanically disturbed grasslands.