
Frédéric SantoulUniversité Toulouse III - Paul Sabatier | UPS Toulouse · Laboratoire Evolution et Diversité Biologiques (EDB)
Frédéric Santoul
PhD, Assistant professor
About
110
Publications
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Introduction
My research theme aims at determining how species introduction can influence the functioning of aquatic communities. I assess the trophic interactions between top-indigenous and exotic predators, and their impact on the structure of aquatic food webs. I seek to identify sources of carbon (13C) and trophic levels (15N) involved in the biological interactions, in order to identify the influence of introductions of exotic species.
Skills and Expertise
Publications
Publications (110)
We studied variations in the size of breeding colonies and in breeding performance of White Storks Ciconia ciconia in 2006–2008 in north-east Algeria. Each colony site was characterized using 12 environmental variables describing the physical environment, land-cover categories, and human activities, and by three demographic parameters: the number o...
This study aims to identify large-scale environmental variables that explain the distribution of continental exotic fish across five bioclimatic regions in east Algeria (160,000 km²), North Africa. Fish communities were sampled at 39 sites from 2007 to 2010. Seven environmental variables were investigated: habitat type, altitude, latitude, longitud...
We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural
wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five
were regionally rare. We used the Self-Organizing Map algorithm to calculate the probabilities of pres...
Digital droplet PCR (ddPCR) is an emerging and affordable method already applied to different fields and can now be used to enhance the detection of new species using DNA samples. It could be particularly useful for detecting prey DNA in stomach content or faeces of predators, which is often challenging using traditional methods. Here, we develop a...
Effective (Ne) and census (Nc) population sizes are key eco-evolutionary parameters. Jointly estimating them have an important practical value for efficient conservation and wildlife monitoring and management. Assessing Ne and Nc remains however challenging for elusive, rare species or species inhabiting in complex habitats like large rivers. Genet...
Angling plays a crucial role in promoting freshwater fish introductions in several regions of the globe, particularly for apex predators like the European catfish (Silurus glanis). To optimize the management strategy to avoid the spread and environmental impacts of invasive species is fundamental to understand major trends on sport-recreational fis...
Invasive species can affect food web structure possibly modifying the transfer of pollutants in ecosystems but this facet of biological invasion remains largely unexplored. We examined how trophic and ontogenetic characteristics of the invasive European catfish could differ from its native counterpart, the Northern pike, possibly resulting in the a...
Biological invasions are a major component of global change worldwide. But paradoxically, an invasive species might also have threatened populations within its native range. Designing efficient management policies is needed to prevent and mitigate range expansions of invasive alien species (IAS) in non-native areas, while protecting them within the...
Animal aggregation, particularly in large-bodied species, is both a fascinating and intriguing phenomenon. Here we analyzed the overwintering behavior of the European catfish, Silurus glanis Linnaeus, 1758, the largest freshwater fish in Europe. By tracking 47 subadults and adults in a shallow lake in southeastern France, we reported a consistent a...
Climate change is altering the multifunctionality of ecosystems worldwide and is often associated with changes in biodiversity that can modulate the impacts of climate change on ecosystems through interactive effects. Genetic and phenotypic variation within species are particularly influenced by climatic conditions, and can mediate several ecosyste...
1. Predatory fish species play a key role in aquatic ecosystems by exerting top-down control on the food web. Also, their intra-guild trophic interactions (i.e. competition) are crucial for the stability of the community. However, most studies focus on adult stages, while juveniles remain poorly studied, although their recruitment is the basis for...
Animal aggregation, particularly in large-bodied species, is both a fascinating and intriguing phenomenon. Here we analyzed the overwintering behavior of the European catfish, Silurus glanis Linnaeus, 1758, the largest freshwater fish in Europe. By tracking 47 subadults and adults in a shallow lake in southeastern France, we reported a consistent a...
Collecting quantitative data on insect species occurrence and abundance is a major concern to document population trends. This is especially the case to assess the conservation status of species listed in the European Habitats Directive and to assess the efficiency of mitigation measures with a view to achieve the “no net loss of biodiversity” goal...
Collection of quantitative data regarding the presence and abundance of insect species is essential to document population trends and promote action in favor of their conservation. It is particularly true for species with an unfavorable conservation status, listed on the annexes of the Habitats Directive and/or protected. Among the European Union c...
Hypoxic events have always naturally occurred in freshwater ecosystems but are worsening due to anthropogenic activities. Hypoxia tolerance greatly varies among fish species and is difficult to quantify in nature in large fish species. We analysed the movements of 40 subadult and adult European catfish Silurus glanis [(727; 2150) mm] exposed to a n...
We analyzed the influence of land use and water physical-chemical characteristics on the trait composition of benthic macroinvertebrates in arid-land streams of North-East Algeria. Macroinvertebrates were sampled in the spring season of 2015, 2017 and 2018 at 36 sampling sites distributed along 5 streams of the Belezma biosphere reserve. Samples we...
We analyzed the influence of land use and water physical-chemical characteristics on the trait composition of benthic macroinvertebrates in arid-land streams of North-East Algeria. Macroinvertebrates were sampled in the spring season of 2015, 2017 and 2018 at 36 sampling sites distributed along 5 streams of the Belezma biosphere reserve. Samples we...
The diversity of predatory species plays a key role in ecosystem functioning but our understanding of the mechanisms underlying their coexistence is limited, particularly in freshwater ecosystems. Northern pike Esox lucius, European perch Perca fluviatilis and pikeperch Sander lucioperca are three widespread predatory species in European lakes, whe...
Stocking and electrofishing occurrence and abundance data for northern pike Esox lucius L. in >3800 km of French rivers across 7 years were compared to assess the effect of recreational fisheries stocking programmes on wild pike populations. A positive relationship was found between the additive effect of stocking and the size of the stocked pike....
Loss in intraspecific diversity can alter ecosystem functions, but the underlying mechanisms are still elusive, and intraspecific biodiversity–ecosystem function (iBEF) relationships have been restrained to primary producers. Here, we manipulated genetic and functional richness of a fish consumer (Phoxinus phoxinus) to test whether iBEF relationshi...
European catfish Silurus glanis is a large non-native opportunistic predator able to develop hunting strategy in response to newly available prey where it has been introduced. Migrating spawning anadromous prey such as allis shad Alosa alosa could represent this available and energy-rich food resource. Here, we report an impressive catfish hunting...
Although freshwater fish stocking is widely used by managers, quantitative assessments of stocking practices are lacking in many countries. The general objective of the present study was to determine the quantity and characteristics of fish stocking in metropolitan France. Using a survey‐based approach, stocking practices for 2013 by recreational a...
Encouraging pro-environmental behavior is an urgent global challenge. An interdisciplinary framework covering governance, economic, social, ecological, and psychological dimensions is required to understand the salient features that encourage pro-environmental outcomes within and across contexts. We apply the Ostrom social-ecological systems framew...
A bstract
Loss in intraspecific diversity can alter ecosystem functions, but the underlying mechanisms are still elusive, and intraspecific biodiversity-ecosystem function relationships (iBEF) have been restrained to primary producers. Here, we manipulated genetic and functional richness of a fish consumer ( Phoxinus phoxinus ), to test whether iBE...
1. Intraspecific trophic variability has important ecological and evolutionary implications, and is driven by multiple interacting factors. Functional traits and environmental conditions are important in mediating the trophic niche of individuals because they determine their ability to consume certain prey, their energetic requirements, and resourc...
Niche divergence resulting from coevolution is commonly believed to favour coexistence among competing species; however, recent investigations have demonstrated that an unexpected niche convergence can occur when native and non-native species coexist. Yet, our understanding of the ontogenetic characteristics of this niche convergence remains limite...
Sea lamprey (Petromyzon marinus) is a unique jawless vertebrate among the most primitive of all living vertebrates. This migratory fish is endangered in much of its native area due to dams, overfishing, pollution, and habitat loss. An introduced predator, the European catfish (Silurus glanis), is now widespread in Western and Southern European fres...
Intraspecific trait variability (ITV) maintains functional diversity in populations and communities, and plays a crucial role in ecological and evolutionary processes such as trophic cascades or speciation. Furthermore, functional variation within a species and its populations can help buffer against harmful environmental changes. Trait variability...
Phenotypic or genotypic variation within species affects ecological processes, from populations to ecosystems. However, whether the ecological imprint of intraspecific variation is substantial compared to key environmental drivers, and persistent enough to carry over to next generations is still questioned. Here, we experimentally showed that intra...
This study was carried out to evaluate the variation of diversity and composition of benthic insects in streams, along an altitudinal gradient in an arid area of Belezma National Park, Northern East of Algeria. Benthic entomofauna was sampled in the spring season of 2015, 2017 and 2018 at 28 sampling sites distributed along 4 streams unaffected by...
Teleost fishes interact with diverse microbial communities, playing crucial functions for host fitness. While gut microbiome has been extensively studied, skin microbiome has been overlooked. Specifically, there is no assessment of the relative impact of host and environmental factors on microbiome variability as well as neutral processes shaping f...
Functional traits can covary to form “functional syndromes.” Describing and understanding functional syndromes is an important prerequisite for predicting the effects of organisms on ecosystem functioning. At the intraspecific level, functional syndromes have recently been described, but very little is known about their variability among population...
The European catfish (Silurus glanis) is the largest freshwater fish in Europe. In France, where the catfish has been widely introduced, it reaches more than twice the size of native predators such as pike, which has the effect of increasing the maximum size at which preys are no longer predated. Fish species (e.g. migratory species) that previousl...
Genetic introgression from stocked adult northern pike Esox lucius to a wild self-recruiting population was detected in a large river system and some stocked E. lucius survived up to two spawning seasons and dispersed over several kilometres in the river. Moreover, the catch rate of stocked E. lucius by anglers was low (9.6%), hence suggesting that...
Understanding the relationships between biodiversity and ecosystem functioning has major implications. Biodiversity–ecosystem functioning relationships are generally investigated at the interspecific level, although intraspecific diversity (i.e. within‐species diversity) is increasingly perceived as an important ecological facet of biodiversity. He...
Changes in phenology and in body size are two of the three main consequences of global warming on organisms. We investigated whether living in a warm artificial habitat would induce changes in the phenology and body size of dragonflies. We monitored in natura the emergence pattern of three protected and red-listed dragonfly species in three geograp...
Management actions aimed at eradicating exotic fish species from riverine ecosystems can be better informed by forecasting abilities of mechanistic models. We illustrate this point with an example of the Logan River, Utah, originally populated with endemic cutthroat trout (Oncorhynchus clarkii utah), which compete with exotic brown trout (Salmo tru...
Understanding the relationships between biodiversity and ecosystem functioning has major implications. Biodiversity-function relationships are generally investigated at the interspecific level, although intraspecific diversity is increasingly perceived as an important ecological facet of biodiversity. Here, we provide a quantitative synthesis testi...
The Atlantic salmon (Salmo salar) is one of the world’s most emblematic freshwater fish. Despite conservation and rehabilitation plans, populations of this species are dramatically declining due to human impacts such as habitat fragmentation, overfishing and water pollution. Owing to their large body size, anadromous adults were historically invuln...
Adult Atlantic salmon have a new freshwater predator.
(MP4)
The extreme body sizes of megafishes associated with their high commercial values and recreational interests have made them highly threatened in their native range worldwide by human-induced impacts such as overexploitation. Meanwhile, some megafishes have been introduced outside of their native range. A notable example is the European catfish (Sil...
Increases in both food availability and intraspecific competition downstream of dams have the potential to trigger the emergence of trophic specialisation among fish predators, with considerable implications for prey species populations. The aim of this study was to assess whether the presence of a dam located on the River Garonne (France) affected...
Arid regions lack models predicting shifts in biological and environmental conditions, thus precluding the implementation of efficient water policies. The aim of this study was to evaluate how macroinvertebrate communities respond to habitat and chemical conditions in arid-land streams of North Eastern Algeria, and how these communities are affecte...
The non-native rainbow trout (Oncorhynchus mykiss) has been introduced worldwide for angling purposes and has established self-reproducing populations in many parts of the world. Introduced rainbow trout often have negative effects on the native salmonid species, ranging from decrease abundance, growth and survival, to their local extinction. Asses...
Angling clubs in central Europe regularly use fish stocking to maintain or enhance stocks. Our objective was to understand the behavioral intention of club decision makers to alter stocking practices. To that end, we conducted a survey among a random sample of fisheries managers in angling clubs in Germany (n = 1222) and France (n = 587). We report...
La présence du silure glane (Silurus glanis) dans les rivières françaises est l’objet d’une importante couverture médiatique. Ces articles de presse portent en partie sur l’aspect indésirable de l’espèce : elle serait invasive et perturberait l’équilibre des écosystèmes aquatiques. Cependant, les premières recherches scientifiques sur la question (...
In this study, the results of conventional stomach-content analysis are compared with the recent DNA metabarcoding approach on faeces to identify fish species consumed by non-native European catfish Silurus glanis in the Garonne River (south-western France), with a special emphasis on anadromous prey. Fourteen prey species were identified in the st...
The European catfish Silurus glanis is the largest freshwater fish (excluding anadromous species) in Europe. Its measurements raise many concerns about its potential impact on recipient ecosystems and fish communities and also feed many rumors and fantasies. It is largely accepted that the largest individual ever caught was 5 m long and weighed 306...
Niche-based hypotheses have been proposed to explain processes and mechanisms of success in the establishment of non-native species into native communities. Competition due to niche overlap may lead to native species niche shift and to native species replacement. To understand the ecological consequences of trophic interactions between non-native r...
We filmed and analysed, in natural and field conditions, behaviours of large-bodied European catfish (Silurus glanis) individuals (body size ranging from 80 to 220 cm) exposed to a hook baited with 20 cm-long Carassius spp. Among a total of 95 individuals observed, 80 % of the catfish clearly demonstrated interest in the bait but attacks were perfo...
Dietary plasticity of populations can be associated to ontogenetic diet preferences and
depends on the size-structure of populations. Dietary niche characterizes the functional role of organisms
in a food web, as it reflects both resources’ diversity used by a consumer and trophic interactions in the
system. Dietary niches are controlled both by bi...
Originating in eastern Europe and western Asia, the European catfish (Silurus glanis) was introduced to France and has now established self-sustaining populations in many French rivers. This species, twice as large as the native piscivore Northern pike (Esox lucius), raises deep concerns about its foraging behaviour and impact on freshwater biota....
Multiple anthropogenic pressures including the widespread introductions of non-native species threaten biodiversity and ecosystem functioning notably by modifying the trophic structure of communities. Here, we provided a global evaluation of the impacts of non-native species on the isotopic structure (δ13C and δ15N) of freshwater fish communities....
The European catfish, Silurus glanis , was widely introduced in western Europe, and it has now established self‐sustaining populations in numerous large rivers of western France. Using data collected from surveys conducted by the French National Agency for Water and Aquatic Environment (Onema) from 1989 to 2010 in more than 500 sites throughout the...
Invasive species may have strong negative impacts on ecosystems. Invasive crayfish are well known to cause ecological imbalances in freshwater systems and have become targets in eradication programmes.
The red swamp crayfish ( Procambarus clarkii ) is vulnerable to predation by several fish species. The European eel ( Anguilla anguilla ) appears to...
Coexistence between the marble trout (native) and the rainbow trout trout (exotic): trophic approach
The live capture of coastal marine fish larvae is a critical step for studying the early life stages of fish and to better understand populations and community dynamics. Although a variety of methods have been used to capture live fish larvae in marine environments, very few innovative techniques have been deployed, tested and validated in freshwat...
In southwest France, the increasing abundance of gravel pits has allowed several bird species to colonize the region. These wetlands have become substitutes for the natural habitats of waterbirds. Little grebe Tachybaptus ruficollis have colonized southwest France since availability of gravel pits expanded and began to be exploited by the species i...
Counts of Coots (Fulica atra), an herbivorous bird species, and Pochards (Aythya ferina), an invertebrate feeder species, were realised during two years in two adjoining gravel pits, presenting the same physical factors, of the Garonne river floodplain (South-West France). At the same time, we analysed in each gravel pit, the composition and densit...
Le régime alimentaire de Grands Cormorans Phalacrocorax carbo hivernant dans le sud-ouest de la France. — L’étude du régime alimentaire du Grand Cormoran Phalacrocorax carbo
dans le sud-ouest de la France a été réalisée grâce à l’analyse de 385 contenus stomacaux issus d’oiseaux prélevés dans le cadre du plan de régulation national de cette espèce....
The behavioral strategies developed by predators to capture and kill their prey are fascinating, notably for predators that forage for prey at, or beyond, the boundaries of their ecosystem. We report here the occurrence of a beaching behavior used by an alien and large-bodied freshwater predatory fish (Silurus glanis) to capture birds on land (i.e....
Stable isotope values of the three potential prey sources (fish, crayfish and pigeon) used in the mixing models. Reported values are the number of sampled individuals (n) and mean (± SD) δ13C and δ15N (in ‰).
(DOC)
Movie showing European catfish displaying beaching behavior to capture land birds, with two successful and two unsuccessful attacks.
(WMV)
Abstract Freshwater fish ecology has greatly benefited from the use of innovative tools such as stable isotope analysis to determine the ecological effects of non-native fishes. Stable isotope analyses are based on the predictable relationship between the isotope composition of a consumer and its prey, and have become increasingly popular amongst...