Department of Geography and Environmental Sciences
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Browsing Department of Geography and Environmental Sciences by Author "Burgess, Neil D."
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Item Conservation implications of deforestation across an elevational gradient in the Eastern Arc Mountains, Tanzania(Elsevier, 2009-11) Burgess, Neil D.; Mbilinyi, Boniface; Gereau, Roy E.; Hall, Jaclyn; Lovett, JonDeforestation is a major threat to the conservation of biodiversity, especially within global centers of endemism for plants and animals. Elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species, where some species may exist only in narrow elevational ranges. We use newly compiled datasets to assess the conservation impact of deforestation on threatened trees across an elevational gradient within the Eastern Arc Mountains of Tanzania. The Eastern Arc has suffered an estimated 80% total loss in historical forest area and has lost 25% of forest area since 1955. Forest loss has not been even across all elevations. The upper montane zone (>1800 m) has lost 52% of its paleoecological forest area, 6% since 1955. Conversely, the submontane habitat (800–1200 m) has lost close to 93% of its paleoecological extent, 57% since 1955. A list of 123 narrowly endemic Tanzanian East- ern Arc tree taxa with defined and restricted elevational ranges was compiled and analyzed in regard to mountain block locations, elevational range, and area of forest within each 100 m elevational band. Half of these taxa have lost more than 90% of paleoecological forest habitat in their elevational range. When elevational range is considered, 98 (80%) of these endemic forest trees should have their level of extinc- tion threat elevated on the IUCN Red List. Conservation efforts in montane hotspots need to consider the extent of habitat changes both within and across elevations and target conservation and restoration efforts throughout these ecosystems’ entire elevational ranges.Item Deforestation in an African biodiversity hotspot: extent, variation and the effectiveness of protected areas(Elsevier, 2013-06) Green, Jonathan M.H.; Larrosa, Cecilia; Burgess, Neil D.; Balmford, Andrew; Johnston, Alison; Mbilinyi, Boniface P.; Platts, Philip J.; Coad, LaurenThe Eastern Arc Mountains of Tanzania show exceptional endemism that is threatened by high anthro- pogenic pressure leading to the loss of natural habitat. Using a novel habitat conversion model, we pres- ent a spatially explicit analysis of the predictors of forest and woodland conversion in the Eastern Arc over 25 years. Our results show that 5% (210 km 2 ) of evergreen forest and 43% (2060 km 2 ) of miombo woodland was lost in the Eastern Arc Mountains between 1975 and 2000. Important predictors of habitat conversion included distance to natural habitat edge, topography and measures of remoteness. The main conservation strategy in these mountains for the past 100 years has been to develop a network of pro- tected areas. These appear to have reduced rates of habitat loss and most remaining evergreen forest is now within protected areas. However, the majority of miombo woodland, an important source of eco- system services, lies outside formal protected areas, where additional conservation strategies may be needed.Item Towards regional, error-bounded landscape carbon storage estimates for data-deficient areas of the world(PLOS ONE, 2012-09-14) Willcock, Simon; Phillips, Oliver L.; Platts, Philip J; Balmford, Andrew; Burgess, Neil D.; Lovett, Jon C.; Ahrends, Antje; Mbilinyi, Boniface; Lewis, Simon L.Monitoring landscape carbon storage is critical for supporting and validating climate change mitigation policies. These may be aimed at reducing deforestation and degradation, or increasing terrestrial carbon storage at local, regional and global levels. However, due to data-deficiencies, default global carbon storage values for given land cover types such as ‘lowland tropical forest’ are often used, termed ‘Tier 1 type’ analyses by the Intergovernmental Panel on Climate Change (IPCC). Such estimates may be erroneous when used at regional scales. Furthermore uncertainty assessments are rarely provided leading to estimates of land cover change carbon fluxes of unknown precision which may undermine efforts to properly evaluate land cover policies aimed at altering land cover dynamics. Here, we present a repeatable method to estimate carbon storage values and associated 95% confidence intervals (CI) for all five IPCC carbon pools (aboveground live carbon, litter, coarse woody debris, belowground live carbon and soil carbon) for data-deficient regions, using a combination of existing inventory data and systematic literature searches, weighted to ensure the final values are regionally specific. The method meets the IPCC ‘Tier 2’ reporting standard. We use this method to estimate carbon storage over an area of33.9 million hectares of eastern Tanzania, reporting values for 30 land cover types. We estimate that this area stored 6.33 (5.92–6.74) Pg C in the year 2000. Carbon storage estimates for the same study area extracted from five published Africa-wide or global studies show a mean carbon storage value of ,50% of that reported using our regional values, with four of the five studies reporting lower carbon storage values. This suggests that carbon storage may have been underestimated for this region of Africa. Our study demonstrates the importance of obtaining regionally appropriate carbon storage estimates, and shows how such values can be produced for a relatively low investment.