Table 1 Description of the predictive variables used in modelling and mapping the current distribution of invasive Prosopis. The variables were categorized under vegetation indices, soil indices, water radiometric indices, and biophysical variables

Brightness Index (BI)

BI is a soil radiometric index that represents the mean of the brightness of satellite images. It is highly associated with soil brightness (Escadafal 1989).

Colour Index (CI)

CI is a soil radiometric index that helps to differentiate soils and their development. Higher CI values representing crusted soils and sands while lower CI values indicating a high concentration of carbonates or sulfates (Escadafal 1989).

Canopy Water Content (CWC)

CWC is a biophysical variable that quantifies the amount of water in the given area. It is also an essential predictor in the areas of agriculture and forestry (Cernicharo et al. 2013).

Fraction of Absorbed Photosynthetically Active Radiation (FAPAR)

FAPAR is an important biophysical variable that indicates the capacity of the vegetation canopy to absorb Photosynthetically Active Radiation (Fensholt et al. 2004).

Leaf Area Index (LAI)

LAI is a key biophysical variable that quantifies the amount of leaf area per unit ground surface (Zhang et al. 2003).

Modified Chlorophyll Absorption Ratio Index (MCARI)

MCARI is a vegetation radiometric index, responsive to chlorophyll variations (Daughtry et al. 2000).

Modified Normalized Difference Water Index (MNDWI)

MNDWI is a water radiometric index promoted to enhance open water features by minimizing the effect of vegetation, soil, and built-up land noises (Xu 2006).

Meris Terrestrial Chlorophyll Index (MTCI)

MTCI is a water radiometric index that estimates the amount of chlorophyll (Dash and Curran 2004).

RI is a soil radiometric index that gives information about soil color variation in a given area. It is an important index to measure soil redness in the arid environment (Mathieu et al. 1998).

Sentinel-2 Red-Edge Position Index (S2REP)

S2REP is a vegetation radiometric index that provides information on chlorophyll content and the growth status of vegetation.

Transformed Normalized Difference Vegetation Index (TNDVI)

TNDVI is a vegetation radiometric index that shows the amount of green biomass in a pixel. It has a high coefficient of determination and excellent linearity to vegetation cover (Bannari et al. 2002).

Transformed Soil Adjusted Vegetation Index (TSAVI)

TSAVI is a soil radiometric index developed to minimize the influence of soil brightness (Baret and Guyot 1991).