Conservation of vegetation coverage in Maderas del Carmen, Coahuila, multitemporal analysis using SAVI index

Abstract

Evidences of vegetation coverage management were analyzed according to Soil Adjusted Vegetation Index (SAVI) values in private and communal lands of the Maderas del Carmen and Ocampo Natural Protected Areas; the index values were generated from three Landsat satellite images of 1985, 2001 and 2019. The data index values were acquired from forests, scrublands, and grasslands from supervised classified maps generated with training areas, from Inegi vegetation and land use map series II, IV and VI, adding resources management intensity as a factor derived from property maps. A shapefile point network of the study area, with 500 m of separation, was created in order to capture the values of presence of forest, scrubland, or grassland ecosystems; the management intensity (Private lands with conservation, private lands with management, and communal lands with management) and the SAVI values from the three dates generated a database used to analyze the index values (vegetation coverage) through time. Normality tests were made in the database; no normal distribution was detected on them. The variance of the index was calculated by ecosystem and management factor (intensive, moderate and conservation). The results of the non-parametric H Kruskal Wallis tests indicated significant differences (α>0.95, Z = 2.394 critical value) on the three dates for all the ecosystems and management intensities. In the forests and grasslands, the private lands under conservation management exhibited the highest vegetation index values, while in the scrublands, the highest values corresponded to lands with a moderate management.