The role of traditional farming practices in ecosystem conservation: The case of transhumance and vultures

摘要

Transhumance is a traditional livestock practice based on the movement of livestock between winter and summer pastures with importance placed on biodiversity conservation. We analyzed the transhumant activity of sheep and cows in the uplands of the Cantabrian Mountains, NW Spain, and its influence on the ecology and management of the griffon vulture, a scavenger with a relevant ecosystem function. For the first time, we provided strong evidence of the close relationship between vultures and transhumance, which was previously only suggested. Vultures occupied roosting sites very close to the summer pastures and often consumed livestock carcasses. There was a strong spatiotemporal adjustment in the use of these mountain areas by transhumant livestock, especially sheep, and vultures. The number of transhumant sheep and cows within 10-12.5km around the roosts were the best predictors of vulture occurrence and abundance, respectively, in generalized linear mixed models. Our estimates of potentially available food from livestock carcasses for vultures indicated that our study area can maintain important griffon vulture populations through a system based on traditional livestock farming including transhumance. Thus, transhumance is able to influence the top of the ecosystem (scavengers) and could aid in sustainable management of griffon vulture populations. In our study area, transhumant sheep were reduced by 62% in the last 15years and only 20% of summer pastures are now occupied. The potential impact that the ongoing loss of transhumant activity could have on mountain ecosystem conservation should be assessed and taken into account by the new European Common Agricultural Policy.