Pumping stations negatively affect the distribution of critically endangered European eel (Anguilla anguilla); a landscape-scale study using environmental DNA metabarcoding

Monaghan, A. I. T.; Griffiths, N. P.; Sellers, G. S.; Lawson Handley, L.; Nunn, A. D.; Hänfling, B.; Macarthur, J. A.; Wright, R. M.; Cattaneo, M.; Bolland, J. D.

doi:10.64898/2026.08.28.746846

bioRxiv · 10.64898/2026.08.28.746846

Pumping stations negatively affect the distribution of critically endangered European eel (Anguilla anguilla); a landscape-scale study using environmental DNA metabarcoding

Monaghan, A. I. T.·Griffiths, N. P.·Sellers, G. S.·Lawson Handley, L.·Nunn, A. D.·Hänfling, B.·Macarthur, J. A.·Wright, R. M.·Cattaneo, M.·Bolland, J. D.

View original source ↗Export metadata ↓

Abstract

Context Pumping stations pose a threat to fish globally through land use change, habitat fragmentation and entrainment risk, with the catadromous and critically endangered European eel particularly impacted. Objectives/methods Establish, model, assess and understand the present-day distribution of European eel and resident fishes in 152 pumping station catchments in a once extensive wetland (The Fens) using eDNA metabarcoding (855 samples over two and half years), with specific focus on anthropogenic influences on hydrological connectivity and habitat quality. A removal survey design maximised confidence in negative results while minimising time and consumable costs. Results Eel occurrence upstream of pumping stations was low (occupancy = 28.3%) and positively associated with catchment area, fish species richness and natural hydrological connectivity (gravity drainage or flooding) and negatively associated with distance from the tidal limit. Fish species richness replaced catchment area and improved model performance, potentially acting as a biotic indicator of habitat quality and connectivity. Pumped catchments with manually operated upstream water transfers had reduced eel presence, potentially linked to the direction of water flow or the timing of operation. By contrast, fish species richness increased in these catchments during summer, suggesting displacement into unsuitable long-term habitats. Physical habitat maintenance had no detectable effect on eel occurrence or fish species richness. Conclusions This study provides the first landscape-scale assessment of European eel distribution and drivers of occurrence in pumped river catchments. The highly novel and comprehensive insights have implications for European eel conservation as well as infrastructure and catchment management, including compliance with legislation (EC Regulation No. 1100/2007).

Explore related subjects

ecology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Monaghan, A. I. T., Griffiths, N. P., Sellers, G. S., Lawson Handley, L., Nunn, A. D., Hänfling, B., Macarthur, J. A., Wright, R. M., Cattaneo, M., Bolland, J. D.. 2026-09-01. Pumping stations negatively affect the distribution of critically endangered European eel (Anguilla anguilla); a landscape-scale study using environmental DNA metabarcoding. https://doi.org/10.64898/2026.08.28.746846

Cite the original work for its findings. Save a collection to share your selection of sources.

Discover connections

Preprint resource Preprint subject ecology subject

Connections use source metadata and explicit phrase matches, not verified experimental comparisons.

KEEP EXPLORING

Related preprints

bioRxiv2026

Forest fragmentation, anthropogenic land use, and climate shape sand fly community composition in central Panama.

Background: American cutaneous leishmaniasis (ACL) is endemic in central Panama, where rapid land use change is transforming tropical landscapes and potentially altering the ecology of sand fly vectors. Although researchers have widely studied environmental determinants of individual vector species, community-level responses of sand fly assemblages to landscape modification remain poorly understood. We evaluated how landscape composition, fragmentation, climate, and topography influence sand fly community structure in a rural landscape of central Panama. Methodology/Principal Findings: We combined metacommunity analyses with joint species distribution models (JSDMs) to quantify species-specific and community-level responses to climatic variables, land-cover composition, and forest configuration. We collected 1,692 individuals representing 30 species, including nine anthropportunist taxa of epidemiological importance. Sand fly assemblages had strong nestedness, low species turnover, and predominantly positive residual associations. Several anthropportunist sand fly species occurred across heterogeneous landscapes, although their responses to environmental conditions differed among taxa. Land-cover composition, forest fragmentation metrics, and elevation together explained about half of the variance in species occurrence and abundance, with the remainder attributed to climate and spatial, temporal, and community-level random effects. Grassland cover contributed most strongly to sand fly occurrence and abundance, whereas artificial surfaces consistently reduced both metrics. Fragmentation effects varied by species: edge density often increased occurrence and abundance, whereas more forest patches generally suppressed populations. Increased precipitation broadly enhanced occurrence and abundance, whereas higher temperatures negatively affected several taxa. Conclusions/significance: Landscape heterogeneity predictably structures sand fly communities, and different forms of anthropogenic disturbance exert non-uniform effects on vector assemblages. The nested organization of these assemblages and the co-occurrence of several anthropophilic species suggest that multiple potential vector species may be present across heterogeneous landscapes. These findings highlight the need for landscape-informed surveillance and control strategies that prioritize grassland-forest interfaces and other disturbed ecotones where sand fly species of epidemiological importance frequently co-occur.

ecology↗

bioRxiv2026

Climate change and extreme weather events to intensify West Nile virus activity

Vector-borne zoonotic diseases pose a substantive risk to public health worldwide, yet predicting outbreaks at scales useful for public health response remains a critical challenge. Transmitted by Culex mosquitoes, West Nile virus is the leading cause of arboviral disease in the United States, progressing to neuroinvasive disease in approximately 1% of infections. Arizona's record-breaking 2021 outbreak, with 1,715 reported human cases and 127 deaths exemplifies this growing burden. Using a decade of mosquito surveillance data coupled with time-lagged weather patterns in a random forest framework, we developed spatial models predicting Culex abundance and West Nile virus occurrence across Arizona at weekly temporal and fine spatial resolution. Our weighted models classified viral occurrence with 98.9% accuracy and explained 65.3% of weekly variation in county-level human cases, with human cases lagging modeled activity by one week. Neither mosquito abundance nor viral occurrence declined at the extreme temperatures characteristic of Arizona summers, suggesting that thermal refugia sustain transmission. Drought-monsoon cycling, rather than temperature alone, emerged as the primary driver of West Nile activity, and projections through 2100 indicate intensifying activity under all climate change scenarios.

ecology↗

bioRxiv2026

Differing patterns in community composition and diversity of biofilm-forming bacteria and fungi along a large salinity gradient

Aim: Biofilms are complex ecosystems formed by phototrophic and heterotrophic organisms, such as bacteria and fungi. Biofilms are hotspots for microbial activity and crucial for the functioning of all aquatic ecosystems, but they are overlooked and poorly studied, especially along large environmental gradients. We aimed at resolving the responses of bacterial and fungal communities to environmental variation along a gradient with strong variation in environmental factors, especially salinity. We also investigated whether the diversity of biofilm-forming bacteria and fungi follows the pattern predicted by the Remane curve, which posits that species diversity is lowest at intermediate salinity. Location: 2300-km-long spatial gradient in the Baltic Sea, Northern Europe Time period: August 2018 Major taxa studied: Biofilm-forming bacteria and fungi Methods: We investigated the composition and diversity of bacteria and fungi by collecting biofilm samples from 42 shallow benthic ecosystems. We also characterized key environmental variables, such as salinity, nutrient concentrations, wind exposure, and climatic conditions. Bacterial and fungal communities in biofilm samples were identified using Illumina MiSeq sequencing. Results: We found that bacteria and fungi responded differently to environmental variation. Bacterial communities were mainly controlled by salinity, and their diversity was lowest in the intermediate salinity. Bacterial communities were also dominated by different bacterial orders in high, intermediate, and low salinity. Fungal communities, instead, were jointly controlled by several environmental variables, i.e., salinity, water temperature, wind exposure, and nutrients, and their diversity or composition did not show a clear pattern along the salinity gradient. Main conclusions: To our knowledge, this is one of the first studies to investigate the biofilm-forming communities, especially fungal communities, along large environmental gradients. Our results highlight the role of biofilms as complex ecosystems where organisms ecological requirements are unique and variable.

ecology↗