Impact of droughts and El Niño Costero on dry forest and white-tailed deer in the Coto de Caza El Angolo - Perú

Abstract

Dry forests have a great environmental, social and economic value due to the ecosystem services they provide and the biodiversity they contain, and are being affected by the strong atmospheric fluctuations generated by the increasing climate variability of the last decades, endangering species of flora and fauna as representative as the white-tailed deer (Odocoileus virginianus peruvianus) in the tropical premontane zones of the western slope of the Andes, Therefore, we sought to analyze the relationship between the vigor of the vegetation cover and the historical fluctuations of the population density of white-tailed deer, with climatic variations and the incidence of El Niño Costero in the Coto de Caza El Angolo and its buffer zone in the period 1984-2023. For this purpose, statistical data of white-tailed deer in the study area and vegetation vigorousness levels determined with the normalized difference vegetation index (NDVI) calculated by processing Landsat scenes with meteorological data and the occurrence of El Niño Southern Oscillation events were analyzed and correlated. As a result, it was found that the vigorousness of the vegetation fluctuated strongly until 2002, when it showed a more regulated behavior, but in frank ascent, a phenomenon that coincides with the increase in the recurrence of El Niño events, which would have generated a continuous and sustained increase in the area with dense and sparse leaf cover since 2005, These changes are affecting white-tailed deer populations, which, despite showing increasing values (in density and harvested individuals) between 2004 and 2010, have shown a marked decline since 2011, with a negative trend in both indicators. It is concluded that the greater frequency of ENSO in the last 15 years has been generating changes in the vegetation, increasing its leaf area, due to the reduction of dry periods, a factor that paradoxically would be negatively affecting white-tailed deer populations.