Effects of agriculture expansion and intensification on the vertebrate and invertebrate diversity in the Pampas of Argentina

MEDAN, D., J. P. TORRETTA, K. HODARA, E. DE LA FUENTE N. MONTALDO

BIODIVERSITY AND CONSERVATION

SPRINGER

Año: 2011 vol. 20 p. 3077 - 3100

0960-3115

In this paper we summarize for the first time the effects of agricultureexpansion and intensification on animal diversity in the Pampas of Argentina and discussresearch needs for biodiversity conservation in the area. The Pampas experienced littlehuman intervention until the last decades of the 19th century. Agriculture expandedquickly during the 20th century, transforming grasslands into cropland and pasture landsand converting the landscape into a mosaic of natural fragments, agricultural fields, andlinear habitats. In the 1980s, agriculture intensification and replacement of cattle grazingcroppingsystems by continuous cropping promoted a renewed homogenisation of the mostproductive areas. Birds and carnivores were more strongly affected than rodents andinsects, but responses varied within groups: (a) the geographic ranges and/or abundances ofmany native species were reduced, including those of carnivores, herbivores, and specialistspecies (grassland-adapted birds and rodents, and probably specialized pollinators),sometimes leading to regional extinction (birds and large carnivores), (b) other nativespecies were unaffected (birds) or benefited (bird, rodent and possibly generalist pollinatorand crop-associated insect species), (c) novel species were introduced, thus increasingspecies richness of most groups (26% of non-rodent mammals, 11.1% of rodents, 6.2% ofbirds, 0.8% of pollinators). Much taxonomic and ecological work is still needed tounderstand Pampean animal biodiversity, to understand how agriculturization is affectingit, and to identify appropriate conservation actions. Networks of Important Bird Areas andValuable Grassland Areas harbor a balanced representation of Pampean biodiversity and, ifadequately protected, may provide valuable research sites, but complementary work shouldbe carried out on agriculturized areas.