Assessing multi-temporal changes of natural vegetation cover between 1987-2018 using serial NDVI: A case study of Tlemcen national park (north-west of Algeria)

Abstract

ABSTRACT Landscape spatial metrics were investigated to assess changes of multi-temporal vegetation cover within the Tlemcen national park (TNP) in north-western Algeria over 31 years. Five landscape metrics, namely number of patches (NP), landscape shape index (LSI), class area (CA), largest patch index (LPI), and percentage of landscape (PLAND) were applied and analysed to assess the fragmentation in the TNP at landscape and class levels. Three Landsat images acquired at three periods of time (1987, 1999 and 2018) with different sensors, namely Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager (OLI) were used. After rigorous pre-processing steps, these images were transformed and thresholded into Normalised Difference Vegetation Index (NDVI) maps that represent the major vegetation cover classes in TNP. The obtained results revealed that during the study period the TNP has undergone a progressive and significant landscape fragmentation.