ABSTRACT Grasses in the Poaceae family are major components of global ecosystems and agricultural systems, and their adaptive success has enabled some species to become highly competitive weeds. Digitaria insularis (sourgrass), a C4 perennial grass native to the Americas and now widely introduced elsewhere, has evolved herbicide resistance and poses an increasing threat to crop productivity. This study modelled the current and future climatic suitability of D. insularis using ecological niche models under two climate change scenarios (SSP126 and SSP585) for 2030 and 2090. After filtering 1329 occurrence records, 559 high‐confidence records were used for modelling. A total of 19 bioclimatic variables from WorldClim were reduced via Principal Component Analysis, and four algorithms (Bioclim, Maxent, Random Forest, and SVM) were combined into an ensemble approach. Model performance was consistently high across metrics, and MOP analyses indicated limited strict extrapolation, supporting the robustness of projections. Results show extensive suitability across tropical and subtropical regions under current conditions, with substantial retention of suitable areas and progressive gains in future scenarios. Expansion was particularly pronounced under SSP585, with increased suitability in South America, Sub‐Saharan Africa, Southeast Asia, northern Australia, and higher‐latitude agricultural regions, including the U.S. Corn Belt and Mediterranean Europe. These expansions overlap with structurally vulnerable agricultural systems, indicating an elevated risk of invasive spread and potential impacts on food security. The findings highlight the need for proactive, integrated, and cross‐regional management strategies to mitigate future spread and resistance‐related agronomic losses.
Ludwig et al. (Sun,) studied this question.