Forage provision is more affected by droughts in arid and semi-arid than in mesic rangelands

BONDARUK VIVIANA; PASCUAL JESUS

JOURNAL OF APPLIED ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2022

0021-8901

Droughts are projected to increase in magnitude, frequency and duration in the near future. Inrangelands, the provision of valuable ecosystem services (e. g. forage supply for livestockproductivity) is intimately linked to rainfall patterns, which makes it particularly vulnerableto extreme droughts. Nonetheless, rangelands can differ in their sensitivity to droughts asshown by strong differences in the impacts of inter-annual precipitation changes onvegetation productivity in different sites. The aim of this study was to assess the sensitivity toextreme droughts of nine rangelands located across a broad aridity gradient in Argentina,South America. We experimentally imposed comparable extreme droughts (ca. 1/100 yr.occurrence) under field conditions by reducing incoming precipitation during 3 consecutiveyears and assessed changes in forage productivity. We found that arid and semi-aridrangelands were more severely impaired in their forage provision by drought than mesicrangelands, i.e. that sensitivity to drought declined as aridity decreased. The forageproductivity decreased on average by 48.5% and 50%, in arid and semi-arid rangelands,respectively, whereas mesic sites did not exhibit significant changes between droughttreatments and the controls. The negative impact in forage productivity of arid and semi-aridrangelands was mainly driven by the productivity reduction of few key plant species. In seven of the nine rangelands, we found the detrimental effects of drought on forage productivityduring the first drought-experimental year which indicates a serious threat of these extremeevents even in the short-term. Our results highlight the urgent need to implementmanagement efforts to mitigate drought detrimental consequences on rangelands,particularly on arid and semi-arid regions, since they provide essential ecosystem servicesstrongly associated with human well-being.