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

Abstract

In this paper we summarize for the first time the effects of agriculture expansion and intensification on animal diversity in the Pampas of Argentina and discuss research needs for biodiversity conservation in the area. The Pampas experienced little human intervention until the last decades of the 19th century. Agriculture expanded quickly during the 20th century, transforming grasslands into cropland and pasture lands and converting the landscape into a mosaic of natural fragments, agricultural fields, and linear habitats. In the 1980s, agriculture intensification and replacement of cattle grazingcropping systems by continuous cropping promoted a renewed homogenisation of the most productive areas. Birds and carnivores were more strongly affected than rodents and insects, but responses varied within groups: (a) the geographic ranges and/or abundances of many native species were reduced, including those of carnivores, herbivores, and specialist species (grassland-adapted birds and rodents, and probably specialized pollinators), sometimes leading to regional extinction (birds and large carnivores), (b) other native species were unaffected (birds) or benefited (bird, rodent and possibly generalist pollinator and crop-associated insect species), (c) novel species were introduced, thus increasing species richness of most groups (26% of non-rodent mammals, 11.1% of rodents, 6.2% of birds, 0.8% of pollinators). Much taxonomic and ecological work is still needed to understand Pampean animal biodiversity, to understand how agriculturization is affecting it, and to identify appropriate conservation actions. Networks of Important Bird Areas and Valuable Grassland Areas harbor a balanced representation of Pampean biodiversity and, if adequately protected, may provide valuable research sites, but complementary work should be carried out on agriculturized areas.

Environmental and Human Controls of Ecosystem Functional Diversity in Temperate South America

“…Many studies have also evaluated the positive relationship between stability and species richness (and vice versa); [52][53][54]) and the role that spatial heterogeneity plays in favoring richness [55][56][57]. In addition, human activities have become a major control of the Earth's system [58], affecting both biodiversity patterns and drivers [59][60][61][62][63]. The strength of such effects varies locally depending on the human pressure and the biodiversity component.…”

“…The strength of such effects varies locally depending on the human pressure and the biodiversity component. Responses ranged from increases in species richness due to the introduction of exotics at low human pressure [59], to species loss or displacements at high rates of human intervention [64,65]. However, most of these studies focused at the species level and on the compositional component of biodiversity, but paid little attention to the functional aspects of biodiversity at the ecosystem level [3].…”

Butterflies (Lepidoptera: Papilionoidea) of grassland areas in the Pampa biome, southern Brazil

“…Agricultural activities and the introduction of exotic species are the main threats to the local biodiversity (Martino 2004;Behling et al 2009;Roesch et al 2009;Medan et al 2011).…”

“…Regarding the fauna, the grassland ecosystems are an important habitat for many taxonomic groups, and some studies have been published involving endemic and threatened vertebrate species (Bencke 2009;FZB/ RS 2014;Lipinski and Santos 2014). However, there is still a lack of knowledge in relation to other taxonomic groups, including terrestrial invertebrates, whose functions can be related to herbivory, nutrient cycling, and pollination processes in terrestrial ecosystems, among others (Medan et al 2011). Among the few published studies, we highlight some insect inventories that include butterflies, beetles and heteropterans (Marchiori and Romanowski 2006;Paz et al 2008Paz et al , 2014Bunde et al 2010;Rosa et al 2011, Silva et al 2012.…”

Biodiversity and conservation of insects and other invertebrates

“…For instance, ants have been found to have a role as bioindicators of land-management types (Chen et al 2011); ground beetle assemblages may reflect soil perturbations (Ö dman et al 2011); and dung beetle assemblages can also be linked to human influences (Carpaneto et al 2011). Other papers discuss invertebrate and vertebrate diversity in pampas vegetation (Medan et al 2011); the conservation of the always fascinating trapdoor spiders (Engelbrecht and Prendini 2011); and parasitism in a bog-inhabiting butterfly (Schtickzelle and co-workers 2011).…”