Anthropogenic stressors and freshwater ecosystems; the impact of plastic pollution, climate change and invasive alien species on invertebrate behaviour and community structure.

Anthropogenic stressors and freshwater ecosystems; the impact of plastic pollution, climate change and invasive alien species on invertebrate behaviour and community structure.

Freshwater makes up less than 2% of water on the planet, but supports a disproportionate amount of biodiversity.  Furthermore, they provide vital ecosystem services.  However, freshwater ecosystems are threatened globally by anthropogenic pressures including pollution, climate change and the spread of Invasive Alien Species. Invasive Alien Species (IAS) can drive biodiversity loss, introduce diseases, and disrupt foodwebs, with climate change predicted to exacerbate the spread and impact of IAS.  Plastic pollution is also of growing concern; for example, one million plastic bottles are purchased every minute with only 10% being recycled. Although recycled and compostable plastics are marketed, they may have long breakdown times. Furthermore, the impact of adding compostable plastic to the food chain is unknown.  This project will explore the combined impacts of plastic pollution, climate change and invasive species on different trophic interactions in freshwater ecosystems.

 

Whilst there is a growing body of evidence of the toxic effects of plastics in freshwater, less well studied are the non-lethal effects on animal behaviour and how these may interact with other stressors and ramify through the community. Invasive alien species not only reach high densities but are often stronger competitors and predators, causing extinction of native species, with warming temperatures found to exacerbate their spread.  This project will investigate how these different stressors affect key trophic interactions in freshwaters, as well as how these effects are felt throughout the ecological community. Shredding. Leaf fall is a main resource input to temperate freshwaters and leaf shredding by invertebrates such as amphipods provides resources higher up the food chain. However, the availability of such organic detritus may be affected by anthropogenic processes including the introduction of plastic debris, and the differential shredding of native vs invasive species. Conversely, shredding invertebrates may, in fact, facilitate plastic breakdown.  Filter feeding by invasive species such as zebra mussels can reduce nutrients available to native species. Plastics can be accumulated by both native and invasive species, perhaps helping clean up rivers, but also with the potential for transmission of plastics up the food chain. Novel invasive predators impact native prey populations, whilst microplastics may affect both predator behaviour and the anti-predator defences of their prey.

 

Aims. To explore the effects of these different stressors on animal behaviour and on aquatic communities, the student will;

– Use laboratory experiments to investigate key trophic behaviours (shredding, filter feeding, predator-prey interactions) under the influence of single and multiple stressors (plastic pollution, climate change and Invasive Alien Species).

– Compare the rates of plastic breakdown by native and invasive species under different climate scenarios (laboratory)

– Explore the impact of native and invasive species and of plastics on invertebrate colonisation, resource consumption and community structure in natural field settings.

 

Training. The project crosses the disciplines of behavioural ecology, ecotoxicology, Invasive Alien Species and conservation and will provide the student with the interdisicplinary training in academic and applied skills whilst developing our understanding of the impact of  multiple anthropogenic stressors. The student will be jointly supervised by AD and PK. With AD’s research group, they will receive training in behavioural ecology, field and lab work, Invasive Alien Species biology and  biosecurity. With PK’s  research group they will receive training in ecotoxicology and microplastics. In addition to leading to peer-reviewed academic papers, the project will have future impact through developing our understanding of the ecosystem level effects of these stressors.

Following induction, the student will undertake the Leeds NERC-DTP skills training programme and the Faculty of Biological Sciences post graduate training which includes courses in statistics, R and GIS,  and will join the water@leeds Graduate School and the Ecology and Evolution research group.

WNW Fincham et al. 2023 Freshwater Biology 68, 915-925

DA Warren et al 2021. Scientific Reports 11, 4570

TM Doherty‐Bone et al 2018 Ecology and Evolution 8, 10049-10056

Pramanik, et al. 2024 Marine Environmental Research 106810.

Pramanik, et al 2023  Marine Pollution Bulletin 190: 114828.