The spatial and temporal ecology of the large mammal populations and vegetation of Ngorongoro Crater, Tanzania

Ngorongoro Crater in Tanzania is a World Heritage Site and Biosphere Reserve and ishome to tens of thousands of large mammals. This study documents the historical ecology ofthe crater from 1892 to 2012 based on an analysis of the published literature and itinvestigates the potential effects of vegetation change on the dynamics of large mammalpopulations using remote sensing and GIS techniques.Primary drivers of changes in the crater appear to be disease, vegetation change andpoaching. Wildebeest (Connochaetes taurinus) have declined and been replaced by buffalo(Syncerus coffer) as the dominant herbivore in terms of biomass primarily due to vegetationchange, while black rhinoceros (Diceros bicornis) have reduced to population-threateningnumbers due to poaching.Satellite imagery indicates that the woody shrub Gutenbergia cordifolia covered alarge portion of the crater's grasslands in 2001, however by 2008 the species had almostdisappeared. There is no evidence that the distributions of five large herbivore species(wildebeest, zebra (Equus burchellii), Grant's gazelle (Nanger granti), Thomson's gazelle(Eudorcas thomsonii) and warthog (Phacochoerus aethiopicus}} are negatively affected bythe presence of G. cordifolia and the species may therefore not be a significant threat to thelarge mammal community, in spite of anecdotal evidence to the contrary. The Lerai Forest, apreviously important black rhinoceros calving refuge, has declined in area since the 1970s.However, in recent years the loss of trees has slowed and some regeneration appears to beoccurring.In the future the most important driver of change in the crater is likely to be climatechange due to its potential negative effect on the availability of fresh water in the crater