Spatial Distribution and Invasion Potential of the Naturalized Downy Thorn Apple (Datura innoxia): Evidence from Classification and Ordination

Abstract

The present study aimed to assess the spatial distribution and invasion potential of naturalized Datura innoxia Mill., a member of the family Solanaceae, across elevation, edaphic, and climatic gradients in invaded communities of semiarid regions in northern Pakistan. The species’ phytosociological attributes, diversity indices, and biotic and environmental factors were assessed in 21 sites (210 plots) and categorized into three elevation groups separated by Ward’s agglomerative cluster. The vegetation was dominated by annual species, which facilitated the naturalization and invasion of alien species. The groups were dominated by D. innoxia, having different codominant species Parthenium hysterophorus L. in Group I, Medicago denticulata in Group II, and Parthenium hysterophorus in Group III; however, the third codominant species of groups I and III were different. In addition, Canonical correspondence analysis (CCA) unveiled that abiotic factors such as elevation (r = −0.65), mean yearly temperature (r = 0.79), annual yearly humidity (r = 0.76), and day length in hours (r = 0.79) and biotic factors such as cultivated fields (r = −0.83) and traffic density (r = 0.70) were strongly correlated on canonical axes, revealing their vital importance in determining vegetation structure. The study concluded that this naturalized species propagated efficiently in the present environmental conditions and if these conditions prevailed, the species would be established as an invasive species. Therefore, control of this naturalized species is critically important, including their exploitation for medicinal and phytochemical utilization, which will enhance the protection of native populations.