Introduced species as a disturbance symptom

Abstract

Introduced exotic species are often considered opportunistic, having arrived in their host habitats due to errors or simply by chance. However, the vulnerability of an ecosystem can be assessed based on a series of exotic species it may harbor. In this study, a dozen invasive exotic species from the Canary Islands ("dirty dozen," selected from Royal Decree 216/2019) have been chosen, and a survey has been conducted from coastal to summit roads (4), traversing all major zonal ecosystems of the island. Four roads were selected, ranging from nearly 0 meters above sea level to the highest point at 2450 meters. The most widely distributed species we have found are Pennisetum setaceum, Nicotiana glauca, and Agave americana, highly associated with environmental degradation or agriculture. Ecosystems more closely linked to agriculture are the most vulnerable to the infiltration of exotic species, a result that holds true for both windward and leeward areas. This coincides with the thermophilic zone, where agriculture was initially established in the Canary Islands. It has also been determined that altitudes, especially above 2000 meters, would be practically impossible to colonize by invasive species since the preferred environmental conditions of these species are in the mid-altitude zones, which coincide with the establishment of agriculture.