Research lines

General research context

Human activities have significantly altered the wetted areas of freshwater ecosystems and their riparian areas, posing ecological and health risks. Terrestrial landscapes are increasingly drained by human-modified waterways, such as urban rivers, agricultural ponds, and wetland-based wastewater-treatment systems. While some animal species can thrive in these often polluted waters, they may facilitate the spread of harmful chemicals and pathogens to other wildlife, livestock, and ultimately, humans. Furthermore, the extirpation of sensitive species due to pollution disrupts food webs and potentially leads to the proliferation of habitat generalist animals of low conservation value such as many nuisance insects and invasive species.

Nature-based Solutions (NbS) are emerging as a cost-effective and increasingly popular approach to restoring freshwater environments. NbS enhance water and habitat quality promoting natural ecosystem processes through planting vegetation or boosting populations of filter-feeding organisms. Compared to conventional wastewater-treatment systems, NbS offer a more affordable and sustainable alternative for many small and medium-sized communities lacking adequate sanitation. NbS also provide crucial ecological benefits, including the creation of permanent aquatic habitats for wildlife in semi-arid regions. For all these reasons, a key topic of our research is understanding the effects of NbS on species, habitats, and ecological processes.

We evaluate the ecological benefits and public health risks of implementing NbS through a One Health lens, utilizing various animal groups as sentinels. Our research, initially focused on fish, now has a broader food-web approach, including microeukaryotes, crustaceans, and medically relevant insects. We employ an individual-scale assessment to detect sublethal effects arising from altered water properties or vegetation structure due to NbS implementation. We also conduct a community-scale assessment to evaluate the effects on the recipient ecosystem more widely and better inform potential public health risks.

The pollutants of primary interest to us are microbial contamination (e.g., Escherichia coli and amoeba), excessive nutrient levels (e.g., nitrogen and phosphorus), and metals (e.g., mercury, lead, and arsenic). These pollutants, often concentrated in urban and agricultural wastewaters, pose significant threats to aquatic life and are still the most prevalent drivers of water degradation. We also investigate the impacts of emerging contaminants and the intricate interactions within this 'cocktail' of pollutants, which is key in the management of NbS under global change effects.

Specific research interests

1. Biology of tolerant animals. We investigate the biology of native generalist and invasive species, primarily fish, that thrive in altered freshwater environments. Through the analysis of biomarkers in these animals (e.g. blood parameters, parasite load, and tissue pollutant levels), we aim to elucidate the mechanisms underlying their tolerance to pollution and the ecological and public health risks associated with the presence of these species in human-altered ecosystems.

2. Trophic cascades. We investigate the multitrophic impacts of altered basal resources (bottom-up control) and apex predators (top-down control) within both the aquatic and terrestrial components of freshwater ecosystems. We focus on understanding the taxonomic and functional shifts in animal communities driven by invasive plants, invasive fish, and inputs of agricultural and urban wastewaters.

3. Restoration and naturalization. We use our knowledge of animal biology, and of the trophic cascades driven by habitat-forming organisms like vegetation, to guide the naturalization of urban ponds, agricultural streams, and urban rivers. We focus on evaluating the success of restoration efforts by monitoring biodiversity patterns, pollutant pathways, and energy flow from basal resources to apex consumers .

4. New bioassays and biomarkers. We are exploring a multitrophic bioassay that more accurately reflects real-world ecological interactions compared to traditional single-species toxicity tests, and non-destructive sampling methods for assessing fish health, with the potential for application to other animal groups.

5. Aquarium hobby and trade. We evaluate the role of the pet trade as the primary source of invasive species in naturalised urban habitats. We also use knowledge gained from our background in the aquarium hobby to refine the use of fish and other aquatic animals as both bioindicators and key components of NbS.