Estimating bird response to field management and pesticide use in Entre Ríos, Argentina: implications for adaptive management

GOIJMAN, A. P., M. J. CONROY, J. J. THOMPSON, V. D. VARNI, M. E. ZACCAGNINI

Snowbird, Utah, Estados Unidos

Conferencia; The Wildlife Society – 17th Anual Conference; 2010

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} span.ecxapple-style-span {mso-style-name:ecxapple-style-span;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The intensification of agriculture generally results in the simplification of landscapes at both spatial and temporal scales, affecting biodiversity and its associated ecosystem services. Agricultural intensification affects many species of birds through the loss of habitat and the effects of pesticides. Spatial heterogeneity, contributed by vegetated borders of cultivated fields, has been shown to benefit insectivorous birds and enhance the ecosystem services they provide. We compare the occupancy of 2 functional groups of potentially beneficial insectivorous birds (insectivorous salliers and aerial foragers) in Entre Ríos, Argentina during the spring and summer, in vegetated field borders with differing vegetative structure and in the interiors of soybean fields. We also explored temporal occupancy patterns in relation to herbicide and insecticide applications and crop stage in field interiors. We surveyed birds in 20 randomly selected soybean fields over two years (October and December 2007-08 and February and March 2008-09) throughout the soybean cycle, conducting line transects in field interiors and borders with different vegetation structure. We estimated occupancy of functional groups, at each soybean field interior (n=20) in the four seasons using occupancy models, evaluating effects of pesticide applications and field characteristics. Occupancy for field borders was inferred at a region level, grouping similar borders as spatial replicates (n = 29), estimating separately for the four seasons, evaluating the effects of borders characteristics on avian occupancy. We used these results in combination to construct a predictive model examining the impacts of various combinations of field management and pesticide use. We used our model, together with an assessment of resource objectives trading off economic gain with ecological loss, to build a prototype of decision model. We use this model to explore implications of alternative management scenarios, and to motivate linkage of our local-scale data with broader monitoring schemes, for support of adaptive decision making.