Thomas A.J. Janssen, George K.D. Ametsitsi, Murray Collins, Stephen Adu-Bredu, Imma Oliveras, Edward T.A. Mitchard, Elmar M. Veenendaal
1School of GeoSciences, University of Edinburgh, Crew Building, The King's Buildings, EH9 3JN Edinburgh, United Kingdom
2Plant Ecology and Nature Conservation Group, Wageningen University, Droevendaalsesteeg 3a, 6708 PB, Wageningen, The Netherlands
3Department of Earth Sciences, VU Amsterdam, Boelelaan 1085,, 1081 HV Amsterdam, The Netherlands
4Forestry Research Institute of Ghana, UPO 63, KNUST, Kumasi, Ghana
5Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, OX1 3QY Oxford, United Kingdom
||Biological Conservation, 2018, Vol.218 , pp.163-172
Abstract(#br)Tropical dry forests experience the highest deforestation rates on Earth, with major implications for the biodiversity of these ecosystems, as well as for its human occupants. Global remote sensing based forest cover data (2000−2012) point to the rapid loss of tropical dry forest in South America and Africa, also, if not foremost, inside formally protected areas. Here, we significantly extend the baseline of tropical dry forest loss inside a protected area in Ghana using a generalizable change detection technique. The forest cover change detection is based on the normalized difference vegetation index (NDVI) derived from historical Landsat data (1984–2015). Field measurements were carried out in dry semi-deciduous forest and in the... adjacent savanna and woodland. Estimates of the canopy area index and above ground woody biomass were related to NDVI derived from Landsat 8 data. The change detection indicated significant NDVI decrease in a large area initially covered by tropical dry forest, associated with deforestation. The peak in deforestation was found to have occurred between 1990 and 2002, hereafter, the conservation status of the area was improved. A combination of remote sensing data corroborated by secondary data sources provides evidence for the almost complete clearance of a tropical dry forest inside a strictly protected area, attributable to logging and land clearing for arable farming. The NDVI change detection also revealed NDVI increase in the adjacent woodlands from 2002 to 2015, demonstrating woody encroachment. Historical fire data from the MODIS burned area product indicate that the deforested area experienced a high frequency of anthropogenic burning since 2004, which may have caused further degradation and largely prevents forest regeneration. The results show the ongoing destruction of tropical ecosystems even within ostensibly protected areas and ask for the revision of protection and management strategies of such areas.