Predictable waves of sequential forest degradation and biodiversity loss spreading from an African city
- 2 August 2010
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (33), 14556-14561
- https://doi.org/10.1073/pnas.0914471107
Abstract
Tropical forest degradation emits carbon at a rate of similar to 0.5 Pg.y(-1), reduces biodiversity, and facilitates forest clearance. Understanding degradation drivers and patterns is therefore crucial to managing forests to mitigate climate change and reduce biodiversity loss. Putative patterns of degradation affecting forest stocks, carbon, and biodiversity have variously been described previously, but these have not been quantitatively assessed together or tested systematically. Economic theory predicts a systematic allocation of land to its highest use value in response to distance from centers of demand. We tested this theory to see if forest exploitation would expand through time and space as concentric waves, with each wave targeting lower value products. We used forest data along a transect from 10 to 220 km from Dar es Salaam (DES), Tanzania, collected at two points in time (1991 and 2005). Our predictions were confirmed: high-value logging expanded 9 km.y(-1), and an inner wave of lower value charcoal production 2 km.y(-1). This resource utilization is shown to reduce the public goods of carbon storage and species richness, which significantly increased with each kilometer from DES [carbon, 0.2 Mg.ha(-1); 0.1 species per sample area (0.4 ha)]. Our study suggests that tropical forest degradation can be modeled and predicted, with its attendant loss of some public goods. In sub-Saharan Africa, an area experiencing the highest rate of urban migration worldwide, coupled with a high dependence on forest based resources, predicting the spatiotemporal patterns of degradation can inform policies designed to extract resources without unsustainably reducing carbon storage and biodiversity.This publication has 41 references indexed in Scilit:
- Effects of roads, topography, and land use on forest cover dynamics in the Brazilian Atlantic ForestForest Ecology and Management, 2010
- The high value of logged tropical forests: lessons from northern BorneoBiodiversity and Conservation, 2010
- Towards a worldwide wood economics spectrumEcology Letters, 2009
- Where does biodiversity go from here? A grim business-as-usual forecast and a hopeful portfolio of partial solutionsProceedings of the National Academy of Sciences of the United States of America, 2008
- Improved Tropical Forest Management for Carbon RetentionPLoS Biology, 2008
- Climate change impacts on forestryProceedings of the National Academy of Sciences of the United States of America, 2007
- Tree allometry and improved estimation of carbon stocks and balance in tropical forestsOecologia, 2005
- Quantifying biodiversity: procedures and pitfalls in the measurement and comparison of species richnessEcology Letters, 2001
- Economics of charcoal production in miombo woodlands of eastern Tanzania: some hidden costs associated with commercialization of the resourcesEcological Economics, 2000
- Fishing Down Marine Food WebsScience, 1998