Ecological change in Tanzanian montane rainforests: From species to landscap

Deforestation is a major threat to the conservation of global biodiversity, especially within regions that have high numbers of range-restricted species. Species found in tropical forests are typically forest-dependent and strongly tied to the specific environmental conditions associated with intact forest canopies. The Eastern Arc Mountains of Tanzania are one of the world's most important biodiversity hotspots, and is the most important hotspot in terms of density of range restricted species. Conserving the closed-canopy forest in the Eastern Arc is essential for maintaining its function as a biodiversity hotspot for rare species.;Within the past 50 years Eastern Arc has lost 25 % of closed forest area, mostly within the lower elevations. Uneven intensity of deforestation on an elevational gradient can impact the conservation of threatened plants that are restricted to lower elevations. Change in elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species. When elevation range is considered, Eastern Arc endemic species have a smaller area of suitable habitat available than if total area of forest in each mountain range is considered, and 80% endemic species deserve to have their level of extinction threat elevated on the IUCN Red List. Conservation efforts in montane hotspots should consider the extent of habitat changes in all elevations and target conservation and restoration efforts across these ecosystems' entire altitudinal ranges.;Cardamom has been an important part of diversified livelihood strategies with the humid forests of the East Usambara mountains for 50 years. Compared to protected areas, cardamom farms are have fewer trees, lower canopies, and lower species richness, and are dominated by an invasive exotic tree. With increasing population pressure, farmers may be encouraged to move from traditional practices, where agroforests have native tree overstories and are not intensively managed, to intensely managed farms, with non-native single species plantation like overstories. Conservation plans that include encouragement of agroforestry should incorporate incentives which encourage the use of a variety of native tree species. Species and structural diversity in the overstory will increase the potential of agroforests for biodiversity habitat.;Natural resource managers and the conservation community rely on remotely sensed data for identifying aspects of forest stands and forest loss. Estimation of forest canopy variables such as upper canopy height, canopy closure, number of trees, and above-ground biomass has been difficult in humid tropical forests due to a poor understanding of the relationship between satellite data and complexity of the humid forest canopy. Monitoring disturbance in humid tropical forests requires the establishment of new methods and a greater understanding of how different canopy structures affect the spectral signal of a forest.;Due to the high biological importance of humid tropical forests, and the sensitivities of their environments to disturbance, ensuring areas of closed canopy forest are conserved is critical for the conservation of the species that depend on them. Successful conservation efforts must have strong goals that are based on science and focused on the function of the entire ecosystem. Well planned conservation requires investigation of patterns and processes of threats to the closed canopy forest from the local species level and the entire ecosystem.