Michelle A Louw

• MSc Plant Science
• PhD candidate at Utrecht University

Increases in the abundance of woody species have been reported to affect the provisioning of ecosystem services in drylands worldwide. However, it is virtually unknown how multiple biotic and abiotic drivers, such as climate, grazing, and fire, interact to determine woody dominance across global drylands. We conducted a standardized field survey in...

Earth harbours an extraordinary plant phenotypic diversity¹ that is at risk from ongoing global changes2,3. However, it remains unknown how increasing aridity and livestock grazing pressure—two major drivers of global change4–6—shape the trait covariation that underlies plant phenotypic diversity1,7. Here we assessed how covariation among 20 chemic...

Mineral-associated organic carbon (MAOC) constitutes a major fraction of global soil carbon and is assumed less sensitive to climate than particulate organic carbon (POC) due to protection by minerals. Despite its importance for long-term carbon storage, the response of MAOC to changing climates in drylands, which cover more than 40% of the global...

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in dryla...

Biomes are regional to global vegetation formations characterised by their structure and functioning. These formations are thus valuable for both quantifying ecological status at sub-regional spatial scales and defining broad adaptive management strategies. Global changes are altering both the structure and the functioning of biomes globally, and w...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that in...

Biotic modifiers are species that strongly alter environmental conditions, and that often shape local communities. When more than one biotic modifier co-occurs, the potential for interactive effects exists, where the effects of one species may negate or enhance the impacts of a second biotic modifier. Here we test for an interactive effect of aardv...

The impacts of ecosystem engineers may be expected to vary along environmental gradients. Due to some resources being more limited in arid than in mesic environments, disturbances created by burrowing mammals are expected to have a greater ameliorating effect in arid environments, with larger differences in microhabitat conditions expected between...

Burrowing mammals are often considered to be ecosystem engineers as burrowing disturbs the soil, thereby potentially changing resource availability and affecting habitat conditions for other species. After their excavation, burrows may strongly impact local plant communities through several mechanisms, including resource trapping, altered chemical...

Burrowing mammal disturbances often create heterogeneity within landscapes. Aardvark (Orycteropus afer) are extensive burrowers in sub-Saharan ecosystems and play an important role in structuring communities in arid environments. The burrowing activities of aardvark are often associated with heuweltjies (nutrient-rich mounds differing in soil and v...

Studies on the effects of off-road driving on soils were conducted in the Makuleke Contractual Park of the Kruger National Park. The studies were conducted on three different soils with different textures and soil compactibilities. Traffic pressure was applied with a game drive vehicle loaded with 10 sand bags, each weighing 70 kg, plus the driver....