Differential responses of marsh arthropods to rainfall-induced habitat loss

CANEPUCCIA ALEJANDRO D; CICCHINO ARMANDO C; ESCALANTE ALICIA H; NOVARO ANDRES; ISACCH JUAN P

ZOOLOGICAL STUDIES

ACAD SINICA INST ZOOLOGY

Año: 2009 vol. 48 p. 174 - 183

1021-5506

The rainfall regime of the Pampas region of Argentina has increased over its historical mean during the last several decades. In this paper we used the unusually rainy year of 2002 to explore possible effects on the abundances and diversity of terrestrial arthropods due to reductions in suitable coastal marsh habitats due to flooding in the eastern Pampas. We assessed 1) the effects of changes in monthly cumulative rainfall totals on habitat availability and diversity, 2) the impacts of changes in habitat availability and diversity on ground arthropods, particularly on beetles species, and 3) arthropod responses to changes in habitat availability according to their dispersal ability, and among beetles species, according to their habitat specialization and trophic group. The increase in rain reduced the areal extent of terrestrial habitats through flooding, and as a consequence, reduced habitat diversity. These changes at the landscape level influenced the abundances and diversity of arthropods (assessed by pitfall traps). The most affected species were those with poor dispersal capabilities, which may have been due to their weaker ability to expand their home range. The most affected among beetle species were those that are habitat specialists, which may have been due to shifts in the habitat to which they are adapted, and at higher trophic levels, an indirect effect, in terms of habitat loss, of a reduction in prey availability was added. Moreover, our results exemplify how large-scale processes like changes in rainfall due to global climate change can affect local ecological patterns, such as fluctuations in abundances and diversity of arthropods in wetlands