CR 68:39-48 (2016)  -  DOI: https://doi.org/10.3354/cr01372

ABSTRACT: As shown by recent studies, the population dynamics of many avian species have been affected by global climatic processes. Nevertheless, the number of studies on the effects of multivariate climatic predictors is still rather low. Using a long-term dataset of 19 species breeding in the Hortobágy (Hungary), considered the largest unbroken alkaline steppe in Europe, we estimated the effects of global and local climatic variables on avian population trends. Our results indicate that the population dynamics of several species might be driven by multivariate climatic effects. Specifically, the population trends of long-distance migratory species increasing in the Hortobágy were affected by both the NAO inducing milder climatic conditions in the southern part of Europe and increasing trends in Sahel rainfall. In turn, short-distance migrants reacted to warming winters through population growth. Additionally, negative population trends correlated with climatic parameters in several species of key conservation importance, with unknown causes of decline. In sum, we suggest that a sound understanding of multivariate climatic effects on avian populations is needed to outline more effective management plans that help avoid the erroneous attribution of causes of failure and success in practical conservation.

KEY WORDS: Climatic change · NAO · Sahel rainfall index · Population dynamics · Alkaline steppe · Hortobágy