Trends in regional occupancy of bird communities and its relationship with land use-cover in Central Argentina

GOIJMAN, A. P.; SOLARI, L. M.; BERNARDOS, J. M.; CALAMARI, N.C.; CANAVELLI, S.B.; DARDANELLI, S.; GAVIER-PIZARRO, G.I.; ZACCAGNINI, M.E.

Puerto Iguazú

Congreso; Ornithological Congress of the Americas; 2017

Asociation of Field Ornithologists; Sociedad Brasilera de Ornitologia & Aves Argentinas

The rapid expansion of agriculture in recent decades in Argentina poses challenges for conservation of bird diversity because many species that provide ecosystem services to agriculture are sensitive to these changes. Several regional drivers, such as climatic conditions or production systems, could affect bird?s persistence and modify distribution patterns. We evaluated relationships between bird occupancy and richness and land use-cover and explored temporal trends in three sub-regions based on predominant agricultural production activities in an area comprising 255,000 km2 of Espinal and Pampas ecoregions, which contains the main agricultural areas in Argentina. Between 2003-2012, we conducted yearly surveys using point counts along secondary roads in two heterogeneous sub-regions, one with native forest, agriculture and cattle activities (?Entre Rios?, n=120 sites) and another with a combination grazing grasslands and crops (?Inland Pampas?, n=168); and an area with a predominance of annual crops(mostly soybean and corn, ?Soybean?,n=192). We accounted for imperfect detection using Bayesian hierarchical, multi-species and multi-season occupancy models. Richness, species occupancy, and temporal trends differed between subregions. A higher number of species were negatively affected by soybean proportion in the Soybean sub-region (Beta community -0.701, CRI95% (-1.39;-0.04)). Landscape heterogeneity in Entre Rios and Inland benefit birds, mitigating agricultural land use effects (Beta community -0.201 (CRI95% -0.75;0.35); -0.24 (CRI95% -0.87;0.39)). Richness was low and stable in Inland, while in Entre Ríos, increased in time. We found no clear trends in richness in the Soybean sub-region. Our results provide baseline information for decision making, to reconcile bird conservation with agriculture at regional scales