Wüste geschrumpft: Holzige Vegetation hat in Subsahara-Afrika während der letzten 3 Jahrzehnte zugenommen

Die Webseite CO2 Science bringt fast täglich Berichte zur Auswirkung des Klimawandels auf die Lebewelt. Reinschauen lohnt sich. Vor kurzem brachte die Plattform einen Hinweis auf das folgende Paper in Nature Communications. Anhand von Satellitenbildern fanden Venter et al. 2018 eine achtprozentige Zunahme der holzigen Vegetation in Subsahara Afrika während der letzten drei Jahrzehnte, was den globalen „Ergrünungstrend“ noch einmal unterstreicht. Ursache war ein Rückgang der Vegetationsbrände in einem wärmeren und feuchteren Klima. Abstract:

Drivers of woody plant encroachment over Africa
While global deforestation induced by human land use has been quantified, the drivers and extent of simultaneous woody plant encroachment (WPE) into open areas are only regionally known. WPE has important consequences for ecosystem functioning, global carbon balances and human economies. Here we report, using high-resolution satellite imagery, that woody vegetation cover over sub-Saharan Africa increased by 8% over the past three decades and that a diversity of drivers, other than CO2, were able to explain 78% of the spatial variation in this trend. A decline in burned area along with warmer, wetter climates drove WPE, although this has been mitigated in areas with high population growth rates, and high and low extremes of herbivory, specifically browsers. These results confirm global greening trends, thereby bringing into question widely held theories about declining terrestrial carbon balances and desert expansion. Importantly, while global drivers such as climate and CO2 may enhance the risk of WPE, managing fire and herbivory at the local scale provides tools to mitigate continental WPE.

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