Dr Michelle Jackson
Research Interests
My main research interest lies in understanding individual-to-ecosystem level responses to environmental change, including warming, invasion, pollution and habitat loss. I am particularly interested in interactions among these stressors, and how stressor effects cascade through food webs with implications for ecosystem processes and services. I use a combination of field studies across both natural and anthropogenic stressor gradients, manipulative experiments and meta-analyses to seek general predictive rules in multiple stressor effects. Most of my research is in freshwater ecosystems, spanning from the Arctic to the tropics.
Publications
-
Influence of nutrient enrichment on the growth, recruitment and trophic ecology of a highly invasive freshwater fish
September 2020|Journal article|AQUATIC ECOLOGYEstablishment, Eutrophication, Pseudorasbora parva, Stable isotope analysis, 0+fish -
Food web properties vary with climate and land use in South African streams
August 2020|Journal article|Functional Ecology -
Towards a unified study of multiple stressors: divisions and common goals across research disciplines.
May 2020|Journal article|Proc Biol SciAnthropogenic environmental changes, or 'stressors', increasingly threaten biodiversity and ecosystem functioning worldwide. Multiple-stressor research is a rapidly expanding field of science that seeks to understand and ultimately predict the interactions between stressors. Reviews and meta-analyses of the primary scientific literature have largely been specific to either freshwater, marine or terrestrial ecology, or ecotoxicology. In this cross-disciplinary study, we review the state of knowledge within and among these disciplines to highlight commonality and division in multiple-stressor research. Our review goes beyond a description of previous research by using quantitative bibliometric analysis to identify the division between disciplines and link previously disconnected research communities. Towards a unified research framework, we discuss the shared goal of increased realism through both ecological and temporal complexity, with the overarching aim of improving predictive power. In a rapidly changing world, advancing our understanding of the cumulative ecological impacts of multiple stressors is critical for biodiversity conservation and ecosystem management. Identifying and overcoming the barriers to interdisciplinary knowledge exchange is necessary in rising to this challenge. Division between ecosystem types and disciplines is largely a human creation. Species and stressors cross these borders and so should the scientists who study them.antagonism, combined effects, global change factors, multiple drivers, multiple stressors, synergism, Biodiversity, Conservation of Natural Resources, Ecology, Ecosystem, Goals, Humans -
Invasion syndromes: a systematic approach for predicting biological invasions and facilitating effective management
May 2020|Journal article|Biological Invasions© 2020, The Author(s). Our ability to predict invasions has been hindered by the seemingly idiosyncratic context-dependency of individual invasions. However, we argue that robust and useful generalisations in invasion science can be made by considering “invasion syndromes” which we define as “a combination of pathways, alien species traits, and characteristics of the recipient ecosystem which collectively result in predictable dynamics and impacts, and that can be managed effectively using specific policy and management actions”. We describe this approach and outline examples that highlight its utility, including: cacti with clonal fragmentation in arid ecosystems; small aquatic organisms introduced through ballast water in harbours; large ranid frogs with frequent secondary transfers; piscivorous freshwater fishes in connected aquatic ecosystems; plant invasions in high-elevation areas; tall-statured grasses; and tree-feeding insects in forests with suitable hosts. We propose a systematic method for identifying and delimiting invasion syndromes. We argue that invasion syndromes can account for the context-dependency of biological invasions while incorporating insights from comparative studies. Adopting this approach will help to structure thinking, identify transferrable risk assessment and management lessons, and highlight similarities among events that were previously considered disparate invasion phenomena. -
Using stable isotope analysis to answer fundamental questions in invasion ecology: Progress and prospects
February 2020|Journal article|METHODS IN ECOLOGY AND EVOLUTIONadaptation, breath testing, competition, dispersal ecology, ecological physiology, food webs, invasion dynamics, niche overlap -
Bending the rules: exploitation of allochthonous resources by a top-predator modifies size-abundance scaling in stream food webs.
December 2018|Journal article|Ecology lettersBody mass-abundance (M-N) allometries provide a key measure of community structure, and deviations from scaling predictions could reveal how cross-ecosystem subsidies alter food webs. For 31 streams across the UK, we tested the hypothesis that linear log-log M-N scaling is shallower than that predicted by allometric scaling theory when top predators have access to allochthonous prey. These streams all contained a common and widespread top predator (brown trout) that regularly feeds on terrestrial prey and, as hypothesised, deviations from predicted scaling increased with its dominance of the fish assemblage. Our study identifies a key beneficiary of cross-ecosystem subsidies at the top of stream food webs and elucidates how these inputs can reshape the size-structure of these 'open' systems.Animals, Fishes, Ecosystem, Food Chain, Rivers -
Between-lake variation in the trophic ecology of an invasive crayfish
September 2017|Journal article|Freshwater Biology© 2017 John Wiley & Sons Ltd The trophic ecology of invasive species has important implications for their impacts on recipient ecosystems, with omnivorous invaders potentially affecting native species and processes over multiple trophic levels. The trophic ecology of invaders might be affected by both their body size and the characteristics of their habitat due to variation in energy requirements and resource availability. Here, using stable-isotope analysis, we investigated the trophic ecology of the invasive crayfish Procambarus clarkii in 15 populations in southwest France over a gradient of individual (crayfish body size), population (crayfish abundance) and ecosystem (lake size, productivity and predation pressure) characteristics. We predicted that population niche width, level of omnivory and trophic position of individuals would change with abiotic and biotic conditions, but that these relationships would vary with lake size. The trophic position of individual crayfish increased with body size in lakes with low productivity, but decreased with body size in more productive lakes. As crayfish abundance increased (and therefore potential intraspecific competition), individual trophic position and population niche width decreased. This was most apparent in smaller lakes, suggesting it related to an increase in encounter rates with conspecifics. Body size, population abundance, lake size and lake productivity influenced the trophic ecology of invasive crayfish, which can affect their interactions with native species. Our results demonstrated that the trophic ecology of invasive species can be variable across invaded landscapes, with implications for their ecological impacts on native communities. This emphasizes the importance of characterising the diet of invasive species across their non-native range and environmental gradients to better predict and manage their impacts. -
Africa: Brown trout introductions, establishment, current status, impacts and conflicts
August 2017|Chapter|Brown Trout: Life History, Ecology and Management© 2018 John Wiley & Sons Ltd. All rights reserved. Brown trout were imported into Africa between 1890 and 1967 for sport angling. There is evidence for establishment in some high altitude streams in Ethiopia, Kenya, Zimbabwe, Lesotho and South Africa. Available evidence suggests that brown trout populations are declining, partly as a result of changing instream conditions due to human mediated impacts and sport fisheries in the region are often dependent on annual stocking to artificially maintain fisheries in rivers, lakes and impoundments. Their presence has resulted in not only the development of sport fisheries and associated economic activities, but also resulted in negative impacts on native biota. Impacts on aquatic ecosystems, mediated through dietary interactions, have been linked to the decline, and in some cases local extinction, of native invertebrates, frogs and fish which have been shown to result in cascading impacts on leaf litter decomposition rates and ecosystem subsidies. As a result, management is necessary. South Africa for example, has been developing legislation to manage brown trout populations. The process has however been complicated by the conflicting agendas of the development-driven private enterprises vs the conservation driven agendas of local Nature Conservation authorities.
Graduate Students
No items found
Contact Details