Invasion alert: Lindenleaf sage (Salvia tiliifolia) in the Tigray highlands

Abstract

Lindenleaf sage (Salvia tiliifolia Vahl) is an annual plant native to Mesoamerica that thrives in tropical, seasonally dry environments. It was introduced to Ethiopia in the late 20th century and made its way to the Tembien highlands in Tigray in 2018. With its many branching stems and profusion of seeds, this upright pioneer plant becomes dominant in the herbaceous layer of intensively used rangeland and roadsides before spreading to areas with other land uses, including agricultural land. Visual observations show that in areas with less grazing pressure, S. tiliifolia is not prevalent. Farmers uproot S. tiliifolia from their crops, which is rather simple because this species is easily recognized, and its roots do not withstand much force. On rangeland, weeding is labor-intensive. As an alternative, we recommend converting rangelands into managed exclosures to maximize grass production, with initial S. tiliifolia removal. Natural vegetation regrowth on infested places would keep the most significant S. tiliifolia seed supply under control and reduce the species’ invasion of farmlands.