Land cover change and carbon emissions over 100 years in an African biodiversity hotspot

Autor: Elmer Topp-Jørgensen, Kathryn Doody, Jaclyn Hall, Philip J. Platts, Jonathan Green, Nisha Owen, Neil D. Burgess, Eibleis Fanning, Simon Willcock, Boniface Mbilinyi, Andrew R. Marshall, Nike Doggart, Pantaleon K T Munishi, Antje Ahrends, Andrew Balmford, Ruth D. Swetnam, Rob Marchant, Oliver L. Phillips, Julian Bayliss, Simon L. Lewis, Kim L. Howell, Jon C. Lovett
Rok vydání: 2016
Předmět:
Zdroj: Willcock, S, Phillips, O L, Platts, P J, Swetnam, R D, Balmford, A, Burgess, N D, Ahrends, A, Bayliss, J, Doggart, N, Doody, K, Fanning, E, Green, J M H, Hall, J, Howell, K L, Lovett, J C, Marchant, R, Marshall, A R, Mbilinyi, B, Munishi, P K T, Owen, N, Topp-Jørgensen, E & Lewis, S L 2016, ' Land cover change and carbon emissions over 100years in an African biodiversity hotspot ', Global Change Biology, vol. 22, no. 8, pp. 2787-2800 . https://doi.org/10.1111/gcb.13218
ISSN: 1354-1013
1365-2486
DOI: 10.1111/gcb.13218
Popis: This article is protected by copyright. All rights reserved.\ud ABSTRACT\ud Agricultural expansion has resulted in both land use and land cover change (LULCC) across the tropics. However, the spatial and temporal patterns of such change and their resulting impacts are poorly understood, particularly for the pre-satellite era. Here we quantify the LULCC history across the 33.9 million ha watershed of Tanzania’s Eastern Arc Mountains, using geo-referenced and digitised historical land cover maps (dated 1908, 1923, 1949 and 2000). Our time series from this biodiversity hotspot shows that forest and savanna area both declined, by 74% (2.8 million ha) and 10% (2.9 million ha), respectively, between 1908 and 2000. This vegetation was replaced by a five-fold increase in cropland, from 1.2 million ha to 6.7 million ha. This LULCC implies a committed release of 0.9 Pg C (95% CI: 0.4-1.5) across the watershed for the same period, equivalent to 0.3 Mg C ha-1 yr-1. This is at least three-fold higher than previous estimates from global models for the same study area. We then used the LULCC data from before and after protected area creation, as well as from areas where no protection was established, to analyse the effectiveness of legal protection on land cover change despite the underlying spatial variation in protected areas. We found that, between 1949 and 2000, forest expanded within legally protected areas, resulting in carbon uptake of 4.8 (3.8-5.7) Mg C ha-1, compared to a committed loss of 11.9 (7.2-16.6) Mg C ha-1 within areas lacking such protection. Furthermore, for nine protected areas where LULCC data is available prior to and following establishment, we show that protection reduces deforestation rates by 150% relative to unprotected portions of the watershed. Our results highlight that considerable LULCC occurred prior to the satellite era, thus other data sources are required to better understand long-term land cover trends in the tropics.
Databáze: OpenAIRE
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