Woody Vegetation Die off and Regeneration in Response to Rainfall Variability in the West African Sahel
| Autor: | Gora Beye, Rasmus Fensholt, Martin Brandt, Abdoul Aziz Diouf, Cheikh Mbow, G. Gray Tappan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010504 meteorology & atmospheric sciences
Science 0211 other engineering and technologies 02 engineering and technology drought shrub encroachment 01 natural sciences Population density Greening Combretaceae Sahel Dominance (ecology) resilience 021101 geological & geomatics engineering 0105 earth and related environmental sciences environmental monitoring 2. Zero hunger biology Ecology Species diversity Primary production 15. Life on land biology.organism_classification Guiera senegalensis Senegal Ferlo high resolution imagery tree mortality Geography 13. Climate action General Earth and Planetary Sciences Balanites aegyptiaca Woody plant |
| Zdroj: | Remote Sensing Remote Sensing, Vol 9, Iss 1, p 39 (2017) Brandt, M S, Tappan, G, Diouf, A, Beye, G, Mbow, C & Fensholt, R 2017, ' Woody vegetation die off and regeneration in response to rainfall variability in the West African Sahel ', Remote Sensing, vol. 9, no. 1 . https://doi.org/10.3390/rs9010039 Remote Sensing; Volume 9; Issue 1; Pages: 39 |
| ISSN: | 2072-4292 |
| DOI: | 10.3390/rs9010039 |
| Popis: | The greening in the Senegalese Sahel has been linked to an increase in net primary productivity, with significant long-term trends being closely related to the woody strata. This study investigates woody plant growth and mortality within greening areas in the pastoral areas of Senegal, and how these dynamics are linked to species diversity, climate, soil and human management. We analyse woody cover dynamics by means of multi-temporal and multi-scale Earth Observation, satellite based rainfall and in situ data sets covering the period 1994 to 2015. We find that favourable conditions (forest reserves, low human population density, sufficient rainfall) led to a rapid growth of Combretaceae and Balanites aegyptiaca between 2000 and 2013 with an average increase of 4% woody cover. However, the increasing dominance and low drought resistance of drought prone species bears the risk of substantial woody cover losses following drought years. This was observed in 2014–2015, with a die off of Guiera senegalensis in most places of the study area. We show that woody cover and woody cover trends are closely related to mean annual rainfall, but no clear relationship with rainfall trends was found over the entire study period. The observed spatial and temporal variation contrasts with the simplified labels of “greening” or “degradation”. While in principal a low woody plant diversity negatively impacts regional resilience, the Sahelian system is showing signs of resilience at decadal time scales through widespread increases in woody cover and high regeneration rates after periodic droughts. We have reaffirmed that the woody cover in Sahel responds to its inherent climatic variability and does not follow a linear trend. |
| Databáze: | OpenAIRE |
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