A5052160143- Ecology and Vegetation Dynamics Studies
- Wildlife Ecology and Conservation
- Rangeland Management and Livestock Ecology
- Rangeland and Wildlife Management
- Fire effects on ecosystems
- Species Distribution and Climate Change
- Plant Parasitism and Resistance
- Animal Ecology and Behavior Studies
- Conservation, Biodiversity, and Resource Management
- Plant and animal studies
- Plant Taxonomy and Phylogenetics
- Forest ecology and management
- Bioenergy crop production and management
- Agriculture and Rural Development Research
- Ecology and biodiversity studies
- Disaster Management and Resilience
- Forest Management and Policy
- African Botany and Ecology Studies
- Agroforestry and silvopastoral systems
- Radiomics and Machine Learning in Medical Imaging
- Aeolian processes and effects
- Insect and Arachnid Ecology and Behavior
- Animal Diversity and Health Studies
- Sustainability and Climate Change Governance
- Statistical Methods and Bayesian Inference
University of Glasgow
2022-2025
University of the Witwatersrand
2015-2024
Organization for Tropical Studies
2022-2023
South African Environmental Observation Network
2017-2022
Sapienza University of Rome
2021
University of Cape Town
2007-2015
University of Edinburgh
2015
How herbivores affect ecosystems Abiotic forces, such as fire and water, have powerful effects on ecosystem structure function. Animals that eat plants also strong in natural systems, but their impacts are harder to assess. Hempson et al. measured how vegetation across Africa (see the Perspective by Gill). Four distinct herbivory regimes emerge from analysis, characterized forest antelopes, arid-region gazelles, high-diversity savannah fauna, bulk feeders (such elephants), which had...
ABSTRACT Grazing lawns are a distinct grassland community type, characterised by short‐stature and with their persistence spread promoted grazing. In Africa, they reveal long co‐evolutionary history of grasses large mammal grazers. The attractiveness to grazers low‐biomass sward lies in the relatively high quality forage, largely due low proportion stem material sward; this encourages repeat grazing that concomitantly suppresses tall‐grass growth forms would otherwise outcompete lawn species...
Fire and herbivory both remove aboveground biomass. Environmental factors determine the type intensity of these consumers globally, but traits plants can also alter their propensity to burn degree which they are eaten. To understand plant life-history strategies associated with fire we need describe response effect functional traits, how sort within communities, along resource gradients, across evolutionary timescales. herbivore generally considered separately, there advances made in...
Significance Africa hosts contrasting communities of mammal browsers and is, thus, the ideal background for testing their effect on plant evolution. In this study at continental scale, we reveal which are most closely associated with spiny trees. We then show a remarkable convergence between evolutionary histories these (the bovids) plants. Over last 16 My, plants from unrelated lineages developed spines 55 times. These convergent patterns evolution suggest that arrival diversification...
The extirpation of native wildlife species and widespread establishment livestock farming has dramatically distorted large mammal herbivore communities across the globe. Ecological theory suggests that these shifts in form intensity herbivory have had substantial impacts on a range ecosystem processes, but for most ecosystems it is impossible to quantify changes accurately. We address challenges using species-level biomass data from sub-Saharan Africa both present day reconstructed...
Abstract Herbivory is a key process structuring vegetation in savannas, especially Africa where large mammal herbivore communities remain intact. Exclusion experiments consistently show that herbivores impact savanna vegetation, but effect size variation has resisted explanation, limiting our understanding of the past, present and future roles herbivory ecosystems. Synthesis responses to exclusion shows decreased grass abundance by 57.0% tree 30.6% across African savannas. The magnitude...
Significance We develop a biogeographic approach to analyzing the presence of alternative stable states in tropical biomes. Whilst forest–savanna bistability has been widely hypothesized and modeled, empirical evidence remained scarce controversial, here, applying our method Africa, we provide large-scale that there are tree species composition vegetation. Furthermore, results have produced more accurate maps forest savanna distributions which take into account differences composition,...
The ecology of Madagascar's grasslands is under-investigated and the dearth ecological understanding how disturbance by fire grazing shapes these stems from a perception that shaped Malagasy only after human arrival. However, worldwide, shape tropical over evolutionary timescales, it curious Madagascar should be global anomaly. We examined functional community across 71 communities in Central Highlands. Combining multivariate abundance models composition clustering grass traits, we...
Climate models predict increases in drought frequency and severity worldwide, with potential impacts on diverse systems, including African savannas. These droughts pose a concern for the conservation of savanna mammal communities, such that understanding how different species respond to is vital.Because grass decreases so consistently during droughts, we grass-dependent (grazers mixed feeders) will strongly drought, whether by changing diets, seeking refugia, or suffering mortality.A recent...
Fire is a fundamental process in savannas and widely used for management. Pyrodiversity, variation local fire characteristics, has been proposed as driver of biodiversity although empirical evidence equivocal. Using new measure pyrodiversity (Hempson et al.), we undertook the first continent-wide assessment how affects protected areas across African savannas. The influence on bird mammal species richness varied with rainfall: strongest support positive effect occurred wet (> 650 mm/year),...
Plant functional traits provide a valuable tool to improve our understanding of ecological processes at range scales. Previous handbooks on plant have highlighted the importance standardising measurements and evolutionary processes. In open ecosystems (i.e. grasslands, savannas, woodlands shrublands), related disturbance (e.g. herbivory, drought, fire) play central role in explaining species performance distributions are focus this handbook. We brief descriptions 34 list important...
Fire is a key driver in savannah systems and widely used as land management tool. Intensifying human uses are leading to rapid changes the fire regimes, with consequences for ecosystem functioning composition. We undertake novel analysis describing spatial patterns regime of Serengeti-Mara ecosystem, document multidecadal temporal investigate factors underlying these patterns. MODIS active burned area products from 2001 2014 identify individual fires; summarizing four characteristics each...
Abstract Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing recent advances expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process estimate ‘intactness scores’: remaining proportion an ‘intact’ reference species group particular use, scale from 0 (no individuals) 1 (same abundance as reference) and, rare cases, 2 (populations that...
Fire and herbivory interact to alter ecosystems carbon cycling. In savannas, herbivores can reduce fire activity by removing grass biomass, but the size of these effects what regulates them remain uncertain. To examine grazing on fuels regimes across African we combined data from herbivore exclosure experiments with remotely sensed density. We show that, broadly substantially both herbaceous biomass activity. The was strongly associated densities, surprisingly, mostly consistent different...
Large-mammal herbivore populations are subject to the interaction of internal density-dependent processes and external environmental stochasticity. We disentangle these by linking consumer population dynamics, in a highly stochastic environment, availability their key forage resource via effects on body condition subsequent fecundity mortality rates. Body demographic rate data were obtained monitoring 500 tagged female goats Richtersveld National Park, South Africa, over three-year period....
Abstract Aims Bark thickness–stem diameter relationships are non‐linear above a stem threshold in many woody species, which makes relative bark thickness measures dependent on the range of diameters that sampled. This influences appropriateness different methods for comparing fire responses plants across studies. Here we develop framework comparisons by evaluating estimates and predictions obtained from linear curved models fitted to raw log‐transformed bark–stem data. We use this contrast...
Abstract Ideas on hominin evolution have long invoked the emergence from forests into open habitats as generating selection for traits such bipedalism and dietary shifts. Though controversial, savanna hypothesis continues to motivate research palaeo-environments of Africa. Reconstruction these ancient environments has depended heavily carbon isotopic analysis fossil bones palaeosols. The sparsity record, however, imposes a limit strength inference that can be drawn data. Time-calibrated...
Pyrodiversity, which describes fire variability over space and time, is believed to increase habitat heterogeneity thereby promote biodiversity. However, date there no standardised metric for quantifying pyrodiversity, so broad geographic patterns drivers of pyrodiversity remain unexplored. We present the first generalizable method quantify use it address fundamental questions what drives attributes constrain under different conditions, whether spatial grain‐dependent. linked MODIS burned...