How vegetation cover characteristics response to the spread of Prosopis juliflora: a time-series remote sensing analysis in southern Iran.

Abstract

Plant invasion is recognized as the second most severe threat to biodiversity, following habitat loss. As one of the world's worst invasive alien plant species, Prosopis juliflora (Mesquite) has severely affected the majority of the Earth's dry ecosystems. Hence, this study attempted to identify the distribution, dominance, and changes in the vegetation characteristics of Mesquite-invaded regions along a series of coastal ecosystems in Southern Iran. Mesquite and other tree/shrub types were successfully classified using a temporarily-median-filtered Landsat 8-OLI image with acceptable kappa coefficient and overall accuracy values of 80.66 and 84.75, respectively. The multi-resolution segmentation was used to divide the region into spectrally homogenous parcels, then calculating the percentage cover (dominance) of Mesquite relative to other tree/shrub types. Analysis of MODIS NDVI products in highly invaded parcels showed a steady increase in NDVI values from 0.27 to 0.53 during 2000-2020 with a significant difference (z = -3.12, 0.183, sig ≤ .05, 2-tailed) from that of the low-invaded regions whose NDVI values oscillated constantly in a range between 0.15 and 0.28. Mesquite distribution also showed a local invasion pattern from areas with a steady or saturated status to neighboring parcels. In regions susceptible to Mesquite invasion, constant investigation of uncommon changes in NDVI whose vegetation characteristics differ significantly from that expected in poor dry vegetation covers of southern Iran can be considered as a conservation tool to identify and manage areas with early Mesquite establishment.