Wide-area mapping of invasive species propagation and containment zones in somaliland using phenometric trends and generalized linear modelling

Spatial information on the occurrence and propagation of invasive species is imperative in order to manage their risk and spread. In this contribution we used phenology and vegetation productivity trends (2001 to 2014) from 250-meter MODIS (Moderate Resolution Imaging Spectroradiometer) EVI (Enhanced Vegetation Index) time-series data to map propagation and possible containment areas for Prosopis juliflora and Parthenium hysterophorus in western Somaliland (eastern Africa). Generalized Linear Modeling (GLM) with a binomial logistics function was used to link available reference data (Landsat-based) on both invasive species to the MODIS-based vegetation trends. Spread corridors and containment zones were, furthermore, identified for both species. Variable relevance in GLM showed that the variables `EVI trend' and `peak value' were highly relevant for P juliflora (log odds ratio >200, p<;0.001 and regression estimate >|5|). Riverside and peri-urban areas were identified as important propagation and risk zones.