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Vegetation dynamic trends and the main drivers detected using the ensemble empirical mode decomposition method in East Africa
Author(s) -
Wei Fangli,
Wang Shuai,
Fu Bojie,
Pan Naiqing,
Feng Xiaoming,
Zhao Wenwu,
Wang Cong
Publication year - 2018
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.3017
Subject(s) - greening , normalized difference vegetation index , vegetation (pathology) , environmental science , geography , ecosystem , physical geography , ecology , climate change , medicine , pathology , biology
Understanding vegetation changes and the underlying causes are critical to predict the future ecosystem dynamics. Water‐limited ecosystems in East Africa have been identified as particularly vulnerable to the impacts of increased environmental change, but relatively little is known about the vegetation dynamic trends and the main drivers. Taking the satellite‐derived normalized difference vegetation index (NDVI) as a proxy of vegetation growth, we detected the spatiotemporal evolution of NDVI trends and explored the main drivers based on the ensemble empirical mode decomposition method. Results showed that greening (restoration) and browning (degradation) coexisted in East Africa during 1982–2013. However, the early greening stalled or even reversed as the browning continuously intensified over time. Greening‐to‐browning prevailed in East Africa after 2000. Generally, more than half of the study area (54.77%, 13.77% with a significant decrease) experienced a browning trend during 1982–2013, with an average change rate of (−0.12 ± 1.10) × 10 −3 . We also found that the percentage of greening area in each land cover type overall decreased. Furthermore, the remarkable spatiotemporal correlations between NDVI and soil water suggested that water was a dominant factor governing the vegetation changes in East Africa. The effectiveness of different types of protected areas (PAs) on vegetation change varied, depending to some extent on management policy (legal laws and on‐site patrols). Therefore, a big challenge for sustainable management of protected areas is how to balance conservation and development objectives in East Africa.