Effects of fragmentation and landscape matrix on nesting success of grassland birds in the Pampas grasslands of Argentina

PRETELLI MATIAS GUILLERMO; ISACCH JUAN PABLO; CARDONI DANIEL AUGUSTO

IBIS

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 157 p. 688 - 699

0019-1019

Loss of grasslands in southeastern South America have negatively affected grassland birds leading to marked declines in their populations. However, it is unknown the extent to which habitat transformation impacts on their reproductive performance, and if the magnitude of these effects may be modulated by landscape matrices. We assessed the effect of fragmentation on grassland bird reproduction by comparing the combined influence of fragmentation and landscape matrix on nesting success, brood parasitism and productivity of the Spectacled Tyrant Hymenops perspicillatus and the Brown-and-yellow Marshbird Pseudoleistes virescens. Surveys were performed in small grassland patches embedded within different landscape matrices (urban and agroecosystem) and in a large patch within a reserve. Reproductive performance was adversely affected by fragmentation. However, these effects were conditioned by matrix type, and the response was not the same for the two species. For Brown-and-yellow Marshbirds, fragmentation resulted in higher rates of brood parasitism and lower productivity regardless of the matrix type. However, for the Spectacled Tyrant, we found a negative effect only in an agricultural matrix. The lack of extensive grasslands makes small patches relevant; however, knowing the effects of different matrix types is critical to predict the conservation value of patches, although it should be noted that the response of species is not uniform.