Identifying habitats and corridors of an invasive plant, Ageratina altissima, in an urban forest

Abstract

The spread of invasive plants in urban forests is of great concern to land managers and ecologists. Here, we analyse the distribution pattern and potential occurrence of a problematic invasive plant, Ageratina altissima, on Mt. Umyeon, in the Seoul metropolitan area of South Korea, using multiple species distribution modelling with geographic information system layers and a time series of Landsat 8 satellite imagery data. Also, we identify this species' potential dispersal corridors using a network-based landscape lattice approach. All five species distribution models performed well with a range of test area under the receiver operating characteristic curve values of 0.843-0.899 with an average of 0.876. Distance from trails had the greatest effect on its occurrence probability, and generally exerted a negative influence within ca. 20m of trails, indicating that urban forest trails facilitate the spread of invasive plants. Of the remote sensing-based predictors used, 7 August 2016 tasselled cap brightness index was an important variable having a negative effect on the presence of A. altissima. Elevation generally had a positive effect on its presence, although it was less important than tasselled cap brightness index. We explicitly detected the distribution pattern of high invasion risk corridors, mostly located on or around trails, which follow the central ridgeline of the study area. The results and approaches employed here can be useful for understanding, monitoring, and predicting invasive plant distribution and spread for the management of urban natural resources and biodiversity conservation.