Thirty years of deforestation within the entire ranges of nine endangered lemur species (3 CR, 4 EN, 2 VU) in northwestern Madagascar

Abstract

Forest cover change is of particular concern in tropical regions. In this study, we investigate the degree of deforestation in the entire ranges of nine highly threatened lemur species in northwestern Madagascar. Landsat satellite images were acquired from four different time stages (1990, 2000, 2011, 2020), classified into forest/non-forest, and changes quantified. Forest cover declined from 17.5% to 9.3% within the last 30 years. This decline varied across four protected areas (PAs) investigated: the forest cover of Ankarafantsika National Park (ANP) declined only moderately over time (from 76.3% to 67.4%), while it declined drastically in other PAs (e.g., from 54.9% to 18.9%, Bongolava Forest Corridor). Two lemur taxa are most affected (Lepilemur otto, Microcebus bongolavensis) by having only very few isolated forest patches left within their ranges (approximately 542.7 km{superscript 2}). For two other species (L. ahmansoni, L. aeeclis), most of the remaining forest is concentrated in two coastal PAs (in total 627.2 and 477.9 km{superscript 2}, respectively), while those species occurring inside ANP (5 taxa) experienced rather stable forest coverage until 2020. A reversal of these deforestation trends and active reforestation measures are desperately needed to reduce habitat loss for these nine lemur species. A practical experience-based guideline is therefore provided.