Avalição Intermédia do Impacte do Plano Zonal de Castro Verde na Avifauna.

Abstract

The intermediate impact of the Zonal Plan of Castro Verde (ZP) on bird diversity and abundance was evaluated using data from seventy-one 250-m transect counts performed in April 1995, just before the implementation of the ZP, and repeated in April 1997, two years after its implementation. Parametric and non-parametric ANOVAs were used to test the null hypothesis that there were no differences in the variation of Shannon's diversity index, total species richness, total relative abundance, richness of threatened Portuguese species and their abundance, richness of SPEC species and their abundance, between transects located: (1) within the ZP area in sites where agri-environmental measures were applied, (2) within the ZP in sites where no measures were applied, and (3) outside the ZP. Significantly higher (positive) variations of diversity and richness of both threatened and non-threatened species, and of abundance of Portuguese threatened species, where detected within the ZP where the measures were implemented comparatively to the remaining cases, whereas no differences were ever detected between the other two classes of transects, indicating that the agri-environmental measures had a positive effect on bird diversity.