Jason Donaldson

Journal Article Nature Sustainability · March 1, 2025 Adopting early dry season fires in African conservation areas has been proposed as ecologically desired and a means of generating sufficient carbon revenues for their management. We interrogate available peer-reviewed information on the ecology and biogeoc ... Full text Cite

Time since fire interacts with herbivore intake rates to control herbivore habitat occupancy.

Journal Article Ecology · January 2025 Smaller grazers consistently show greater preference for recently burned patches than larger species. Energy optimization theory posits that this pattern is driven by small- versus large-bodied herbivores seeking to maximize energy intake by choosing high- ... Full text Open Access Cite

Open letter: There are more than just trees and forests to be conserved and restored

Journal Article Plants People Planet · January 1, 2025 Full text Cite

Effects of migratory animals on resident parasite dynamics

Journal Article Trends in Ecology & Evolution · July 2024 Full text Cite

Small-scale fires interact with herbivore feedbacks to create persistent grazing lawn environments

Journal Article Journal of Applied Ecology · July 1, 2024 Fire-herbivory feedbacks strongly influence the formation of grazing lawns in savanna ecosystems. Preliminary findings suggest that small-scale (<25 ha) fires can engineer grazing lawns by concentrating herbivores on the post-burn green flush; however, the ... Full text Cite

Interplay of competition and facilitation in grazing succession by migrant Serengeti herbivores.

Journal Article Science (New York, N.Y.) · February 2024 Competition, facilitation, and predation offer alternative explanations for successional patterns of migratory herbivores. However, these interactions are difficult to measure, leaving uncertainty about the mechanisms underlying body-size-dependent grazing ... Full text Cite

Direct and indirect effects of fire on parasites in an African savanna

Journal Article Journal of Animal Ecology · December 1, 2023 Fires in grassy ecosystems consume vegetation and initiate high-quality regrowth, which results in pyric herbivory when mammalian grazers concentrate feeding in recent burns. For environmentally transmitted parasites with transmission mechanisms linked to ... Full text Open Access Cite

Fire, grazers, and browsers interact with grass competition to determine tree establishment in an African savanna.

Journal Article Ecology · August 2022 In savanna ecosystems, fire and herbivory alter the competitive relationship between trees and grasses. Mechanistically, grazing herbivores favor trees by removing grass, which reduces tree-grass competition and limits fire. Conversely, browsing herbivores ... Full text Cite

Sapling growth gradients interact with homogeneous disturbance regimes to explain savanna tree cover discontinuities

Journal Article Ecological Monographs · August 1, 2022 Savanna tree cover often exhibits sudden discontinuities across space. It has been proposed that local spatial processes imposed by variation in tree cover itself (as opposed to by external drivers such as edaphic variation) can reinforce such discontinuit ... Full text Cite

The generality of cryptic dietary niche differences in diverse large-herbivore assemblages.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · August 2022 Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissu ... Full text Cite

Drought and fire determine juvenile and adult woody diversity and dominance in a semi-arid African savanna

Journal Article Biotropica · July 1, 2022 The aim of this study was to understand how communities of adult and juvenile (seedlings and saplings) woody plants were impacted by fire and the 2014–2016 El Niño drought in Kruger National Park, South Africa. We used a landscape-scale fire experiment spa ... Full text Cite

Trophic Interactions Drive Tree Establishment in the Serengeti Ecosystem

Journal Article The Bulletin of the Ecological Society of America · July 2022 Full text Cite

The role of browsers in maintaining the openness of savanna grazing lawns

Journal Article The Journal of ecology · February 2021 In savannas, ruminant herbivores can have divergent impacts on tree recruitment and subsequent woody cover. Whereas heavy grazing by cattle results in woody thickening, intensive grazing by wildlife instead tends to be associated with lower woody cover. To ... Full text Cite

Droughts Decouple African Savanna Grazers from Their Preferred Forage with Consequences for Grassland Productivity

Journal Article Ecosystems. · April 2020 Grazing lawn and flammable-tussock grass communities are contrasting resource pools for mammalian grazers in terms of forage quantity and quality. Drought events fundamentally alter forage availability within these communities and therefore should alter he ... Full text Cite

A handbook for the standardised sampling of plant functional traits in disturbance-prone ecosystems, with a focus on open ecosystems

Journal Article Australian journal of botany. · January 2020 Plant functional traits provide a valuable tool to improve our understanding of ecological processes at a range of scales. Previous handbooks on plant functional traits have highlighted the importance of standardising measurements of traits to improve our ... Full text Cite

Anthropogenic modifications to fire regimes in the wider Serengeti-Mara ecosystem.

Journal Article Global change biology · October 2019 Fire is a key driver in savannah systems and widely used as a land management tool. Intensifying human land uses are leading to rapid changes in the fire regimes, with consequences for ecosystem functioning and composition. We undertake a novel analysis de ... Full text Cite

Alternate Grassy Ecosystem States Are Determined by Palatability-Flammability Trade-Offs.

Journal Article Trends in ecology & evolution · April 2019 Fire and mammalian grazers both consume grasses, and feedbacks between grass species, their functional traits, and consumers have profound effects on grassy ecosystem structure worldwide, such that savanna and grassland states determined by fire or grazing ... Full text Cite

Continent-level drivers of African pyrodiversity

Journal Article Ecography · June 1, 2018 Pyrodiversity, which describes fire variability over space and time, is believed to increase habitat heterogeneity and thereby promote biodiversity. However, to date there is no standardised metric for quantifying pyrodiversity, and so broad geographic pat ... Full text Cite

Pyrodiversity interacts with rainfall to increase bird and mammal richness in African savannas.

Journal Article Ecology letters · April 2018 Fire is a fundamental process in savannas and is widely used for management. Pyrodiversity, variation in local fire characteristics, has been proposed as a driver of biodiversity although empirical evidence is equivocal. Using a new measure of pyrodiversit ... Full text Cite

Ecological engineering through fire‐herbivory feedbacks drives the formation of savanna grazing lawns

Journal Article Journal of applied ecology. · January 2018 Variation in grass height is beneficial to biodiversity conservation in savanna landscapes. Theory predicts that small fires can promote short‐grass areas within savannas. We experimentally assessed the influence of fire season and size on grass height and ... Full text Cite

The ecology of drought - A workshop report

Journal Article South African Journal of Science · January 1, 2018 Full text Cite

The seed ecology of an ornamental wattle in South Africa — Why has Acacia elata not invaded a greater area?

Journal Article South African Journal of Botany. · September 2014 Australian Acacia species introduced to South Africa as ornamentals have notably smaller invasive ranges than those introduced for forestry or dune stabilization. We asked whether the relatively small invasive extent of Acacia elata, a species used widely ... Full text Cite

Invasion trajectory of alien trees: the role of introduction pathway and planting history.

Journal Article Global change biology · May 2014 Global change is driving a massive rearrangement of the world's biota. Trajectories of distributional shifts are shaped by species traits, the recipient environment and driving forces with many of the driving forces directly due to human activities. The re ... Full text Cite

Scale-area curves: a tool for understanding the ecology and distribution of invasive tree species

Journal Article Biological invasions · March 2014 Scale-area curves are increasingly used in ecology to predict population trajectories, based on the assumption that observed patterns are indicative of population dynamics. However, for introduced species, scale-area curves might be strongly influenced by ... Full text Cite