An analysis of long-term trends in the abundance of domestic livestock and free-roaming dogs in the Bale Mountains National Park, Ethiopia

摘要

Livestock inside the Bale Mountains National Park poses a threat to the persistence of the Ethiopian wolf (Canis simensis) through grazing-induced habitat degradation and the transmission of diseases from the domestic dogs kept alongside the herds. We used a 21-?year time series to explore long-term trends in the numbers of cattle, caprines and free-roaming domestic dogs in two core Ethiopian wolf areas (the Web valley and the Sanetti plateau) and to test whether seasonal variations in primary productivity underlies the current livestock production system. No trends in livestock numbers were detected in the Web valley, where livestock are most abundant and graze seasonally. Livestock numbers have increased significantly on most of the Sanetti plateau, grazing all year-round albeit at a lower intensity. Livestock use of the Web valley was positively correlated with vegetation productivity as derived from remotely sensed data, the Normalized Difference Vegetation Index (NDVI). On the Sanetti plateau, neither primary productivity nor livestock numbers showed signs of strong seasonality. The current livestock production system has the potential to degrade the vegetation that sustains the wolves’ rodent prey while an increase in free-roaming domestic dogs in parts of their range may heighten the risk of disease transmission.