Effects of agricultural management policies on the exposure of black-winged stilts (Himantopus himantopus) chicks to cholinesterase-inhibiting pesticides in rice fields

Levels of exposure to pesticides in rice fields can be significant depending on the environmental policies practiced. The aim of European Union integrated management policy is to reduce pesticide use and impact on environment. Rice fields provide an alternative breeding habitat for many waterbirds that are exposed to the pesticides used and therefore can be valuable indicators of their risk for wildlife. To evaluate integrated management success we examined exposure of Black-winged Stilts (Himantopus himantopus) to cholinesterase-inhibiting pesticides in rice fields under different types of management by measuring plasma cholinesterase activity. Cholinesterase activity was lower in birds sampled in (a) 2008 after a period of intense pesticide application, than in (b) 2005-2007 and 2011 in rice fields subject to integrated management in Doñana (SW Spain) and (c) in control natural wetlands in Spain and Morocco. During 2009 and 2010, cholinesterase activity was lower in rice fields in Doñana than in rice fields in Larache and Sidi Allal Tazi (NW Morocco). Our results suggest that integrated management successfully reduced the exposure of Black-winged Stilts to pesticides in most of the years. Care should be taken to implement mosquito and pest crop controls on time and with environmentally friendly products in order to reduce its impact on wildlife.The Junta de Andalucía funded this study through the project “Las aves acuáticas de Doñana y el cultivo del arroz: la interacción entre la agricultura y la conservación de las zonas húmedas”. This study was possible thanks to the INRA administration and CNRST-CSIC collaboration program (P2007MA01 and P2009MA01). GMT was funded by an I3P-CSIC grant for the formation of Researchers. MMH is supported by a Marie Curie Intra-European Fellowship for Career Development (PIEF-GA-2011-299747) within the 7th Framework Programme (FP7 2007-2013) of the European Commission.Peer Reviewe