16 Species composition and primary productivity changes after two years of goat grazing exclusion in two Canary Islands pastures

Wednesday, August 5, 2009
Exhibit Hall NE & SE, Albuquerque Convention Center
Silvia Fernández-Lugo , Department of Ecology, Universidad de La Laguna, La Laguna, Spain
Lea de Nascimento , Universidad de La Laguna, La Laguna, Spain
Celia García , Universidad de La Laguna, La Laguna, Spain
Luis Alberto Bermejo , Departamento de Ingeniería, Producción y Economía Agrarias, Universidad de La Laguna, La Laguna, Spain
José Ramón Arévalo , Universidad de La Laguna, La Laguna, Spain
Background/Question/Methods
Extensive goat grazing has played an important role in the configuration of structure and specific composition of the pastures of the Canary Islands. An appropriate grazing management is necessary for maintaining the current species composition and high diversity values of these ecosystems. Due to the steady decline of grazing goats in these Islands, the study of the effect of the abandonment of goat grazing on plant communities is of primary importance, in order to delineate a proper conservation strategy for these ecosystems. We established a net of permanent exclosure and control plots in two Canary Islands’ pastures to analyze the effects of grazing abandonment in these plant communities. We analyzed changes in species composition and primary productivity after two years of goat grazing exclusion.
Results/Conclusions
The DCA analysis revealed some gradients along the plots, but did not reveal significant differences in species composition in response to grazing exclusion. We found a significant increase of productivity in the exclusion plots in one of the studied pastures; this result suggests the effect of grazing abandonment on the fast recovery of net productivity. We related the lack of differences in species composition with the low stocking rate and the productivity of these pastures (less than 200 g/m2), which could imply that species composition requires more time to reveal significant differences. 
Because the pastures of the Canary Islands have an important cultural and socioeconomic value, we consider the monitoring of these areas necessary in order to develop an adequate management for the maintenance and conservation of these ecosystems.
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