TITLE:
NDVI-Derived Vegetation Trends and Driving Factors in West African Sudanian Savanna
AUTHORS:
Benewindé J.-B. Zoungrana, Kangbeni Dimobé
KEYWORDS:
Vegetation Trends, NDVI, Sudanian Savanna, Burkina Faso, West Africa
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.14 No.10,
October
26,
2023
ABSTRACT: The Sudanian savanna is a key vegetation biome in West Africa providing
food and vital ecosystem services. Recently, it has been reported alarming
vegetation loss in this biome, calling for more investigation, relevant to
tackle land degradation and ensure food security. However, vegetation dynamics
in this area remains a matter of debate, and one of the main challenges is to
document consistently the underlying driving factors. This study aimed at
assessing vegetation trends and driving factors from 2000 to 2022. NDVI trend,
detected using the Mann-Kendall’s monotonic trend test, was used as proxy to
express vegetation dynamics. In addition to the non-parametric Spearman correlation
analysis, variables importance scores, derived from Random Forest (RF)
classifications, were used to determine key driving factors among climatic,
topographic, edaphic, accessibility and demographic factors. During 2000-2022,
no significant trends largely characterised the vegetation cover of the study
area. However, patterns of strong (weak) browning and strong (weak) greening
affected 7.1% (10.6%) and 12.8% (19.1%) of the study area respectively.
According to the driving factors analysis, the observed vegetation trends were
mainly driven by rainfall dynamics (trend and mean annual), population growth
and anthropogenic activities. The results of this study can support the
development of efficient strategies for safeguarding vegetation cover in the
Sudanian savanna of Burkina Faso.