Jean Secondi

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Verified

Jean verified their affiliation via an institutional email.

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• PhD
• Professor (Assistant) at University of Angers

Context Population expansion into new areas is a common phenomenon resulting from changes in ecological conditions or human-assisted introduction. In the latter case, populations spread into areas where they did not evolve causing various ecological and socio-economic impacts. Spatial sorting (i.e. the enhanced dispersal capacity over time at the p...

Coexistence with related species poses evolutionary challenges to which populations may react in diverse ways. When exposed to similar environments, sympatric populations of two species may adopt similar phenotypic trait values. However, selection may also favor trait divergence as a way to reduce competition for resources or mates. The characteris...

Photoperiod is a major factor regulating biological rhythms in animals and plants. At low latitudes, annual variation in daylength is low and species are expected to strongly rely on photic cues to reset their circadian clocks. A corollary is that individuals should be strongly affected by sudden changes in the photic regime as those generated by a...

Aim Exposure to artificial light at night (ALAN) is a risk factor for organisms. Considering the spread and increasing intensity of night brightness across the globe, and the key role of light at all biological levels, alterations of ecosystems are expected. Yet, we cannot predict the severity of the effects of ALAN in several biomes because little...

MAXENT is now a common species distribution modeling (SDM) tool used by conservation practitioners for predicting the distribution of a species from a set of records and environmental predictors. However, datasets of species occurrence used to train the model are often biased in the geographical space because of unequal sampling effort across the s...

la Stratégie nationale de gestion des amphibiens exotiques envahissants (SNG AEE) dont la rédaction, grâce à l’implication de nombreux experts, et coordonnée par la SHF, se concentre sur des problématiques émergentes connues en France hexagonale et concerne les quatre espèces les plus préoccupantes actuellement présentes sur ce territoire : la Gren...

MtDNA barcoding is regularly applied to determine the provenance of invasive species. Variation in spatial genetic structuring across a species’ range, typically high within glacial refugia and low in postglacially colonized areas, influences the precision of this approach. The palmate newt (Lissotriton helveticus) has been introduced north of its...

Context Functional connectivity models are essential in identifying major dispersal pathways and developing effective management strategies for expanding populations of invasive alien species. However, the extrapolation of models parameterized within current invasive ranges may not be applicable even to neighbouring areas, if the models are not bas...

Conference sesssion: Biodiversity Monitoring in Aquatic Ecosystems to Support a Whole Society Approach to Transformative Change 150004 - Integrating ephemeral wetlands in the sustainable management of boreal forests: an innovative biodiversity assessment of unknown vulnerable ecosystems from space to field supported by art for public involvement...

The conservation of biological diversity has become an important goal of managing forests in an ecologically sustainable way. In the European boreal area, the forest industry has focused on spruce forests where the organic soil layer becomes thick and rich in organic material. When it rains, carbon leaches out into the lakes and streams which is a...

Hybridization between the European smooth and palmate newts has recurrently been mentioned in the literature. The only two studies that attempted to quantify the frequency of hybridization and gene admixture between these two species came to strikingly opposite conclusions. According to Arntzen et al. (1998, 42 allozymes), hybrids are rare in natur...

Der Glatte Krallenfrosch (Xenopus laevis) wurde lange Zeit häufig von Aquarianern, Apothekern und Wissenschaftlern gehalten. Diese Beliebtheit hat allerdings leider dazu geführt, dass der einst nur im südlichen Afrika verbreitete Zungenlose Frosch (Familie Pipidae) nun auf fünf Kontinenten zu finden ist und dort großen Schaden an den heimischen Öko...

Conference session: Nature values: Peatland, Rivers, Coasts Despite the services provided by wetlands, their explicit consideration in watershed management and planning processes is often secondary compared to other aquatic environments. This limitation may partly explain the decline of about 90% of their global coverage. Especially, a loss of 75...

Northern freshwaters have become browner over the last decades. Water browning is especially associated with an increase in the concentration of dissolved organic matter/carbon and iron. Browning has been suspected to be caused by a combination of land use and land cover changes, acid recovery and climate change. However, natural disturbances such...

The worldwide expansion of artificial light at night (ALAN) is acknowledged as a threat to biodiversity through alterations of the natural photoperiod triggering the disruption of physiological functions. In vertebrates, melatonin production during the dark phase can be decreased or suppressed by nocturnal light as shown in many taxa. But the effec...

Hybridization between the European smooth and palmate newts has recurrently been mentioned in the literature. The only two studies that attempted to quantify the frequency of hybridization and gene admixture between these two species came to strikingly opposite conclusions. According to Arntzen et al (1998, 42 allozymes), hybrids are rare in nature...

Aquatic anuran species are difficult to detect and observe and this is a major limit to the study of their behaviour and ecology. This habit limits the direct monitoring of sexual and foraging activity, and the investigation of how environmental factors influence their expression as well as how individuals allocate time between competing activities...

Artificial light at night (ALAN) is expanding worldwide. Many physiological effects have been reported in animals, but we still know little about the consequences for the visual system. The pupil contributes to control incoming light onto the retina. Sudden increases in light intensity evokes the pupil light reflex (PLR). Intrinsically photosensiti...

In the Grinnellian niche concept, the realized niche and potential distribution is characterized as an interplay among the fundamental niche, biotic interactions and geographic accessibility. Climate is one of the main drivers for this concept and is essential to predict a taxon’s distribution. Mechanistic approaches can be useful tools, which use...

Phenotypic variations between populations often correlate with climatic variables. Determining the presence of phenotypic plasticity and local adaptation of a species to different environments over a large spatial scale can provide insight on the persistence of a species across its range. Amphibians, and in particular their larvae, are good models...

Artificial light at night (ALAN) has been massively deployed worldwide and has become a major environmental pressure for biodiversity, especially contributing to habitat loss and landscape fragmentation. To mitigate these latter, green and blue infrastructure policies have been developed throughout the world based on the concept of ecological netwo...

Water browning or brownification refers to increasing water color, often related to increasing dissolved organic matter (DOM) and carbon (DOC) content in freshwaters. Browning has been recognized as a significant physicochemical phenomenon altering boreal lakes, but our understanding of its ecological consequences in different freshwater habitats a...

Artificial light at night (ALAN) affects numerous physiological and behavioural mechanisms in various species by potentially disturbing circadian timekeeping systems and modifying melatonin levels. However, given the multiple direct and indirect effects of ALAN on organisms, large-scale transcriptomic approaches are essential to assess the global e...

• The increasing use of artificial light at night has led to ecosystem exposure to light pollution worldwide. Aquatic ecosystems are particularly exposed, since lit road networks, urban development and industrial infrastructure are frequently located along river, lake, and sea shores. Although the negative effects of night-time lighting on the phys...

Artificial light at night (ALAN) is recognized as one of the major anthropogenic pollutants jeopardizing biodiversity at a global scale. Few studies have focused on the impacts of nocturnal light on freshwater ecosystems despite their increasing exposure to light pollution worldwide due to human activities along rivers or lakes. By modifying metabo...

Artificial light at night (ALAN) affects numerous physiological and behavioural mechanisms in various species by potentially disturbing circadian timekeeping systems. Although gene-specific approaches have already shown the deleterious effect of ALAN on the circadian clock, immunity and reproduction, large-scale transcriptomic approaches with ecolo...

The description of functional connectivity is based on the quantification of landscape resistance, which represents species‐specific movement costs across landscape features. Connectivity models use these costs to identify movement corridors at both individual and population levels and provide management recommendations for populations of conservat...

Given the status of the African clawed frog Xenopus laevis as a global amphibian invader, and the potential spread of its invasive populations in Europe and other continents, it is essential to identify the environmental factors and methods that maximize the trapping output of control actions. Cost-effective methods should maximize the number of tr...

In amphibians, spatial sorting progressively enhances the dispersal capacities of dispersing stages in expanding populations but may enhance or limit the performance of the earlier non-dispersing stages. Phenotypic traits of non-dispersing tadpoles and metamorphs can be coupled, through carry-over effects and trade-offs, or decoupled to dispersal t...

One principle threat prompting the worldwide decline of amphibians is the introduction of nonindigenous amphibians. The African Clawed Frog, Xenopus laevis, is now one of the widest distributed amphibians occurring on four continents with ongoing range expansion including large parts of Europe. Species distribution models (SDMs) are essential tools...

The preservation of genetic diversity is an important aspect of conservation biology. Low genetic diversity within a population can lead to inbreeding depression and a reduction in adaptive potential, which may increase extinction risk. Here we report changes in genetic diversity over 12 years in a declining population of the corncrake Crex crex, a...

Generalist invasive predators consume prey at different trophic levels and generate drastic changes in local communities. However, the long-term effects of predation may be reduced by eco-evolutionary responses of native populations. The capacity of prey species distributed across the trophic network to develop antipredator responses may determine...

• Environmental DNA (eDNA) is becoming an essential tool for detecting aquatic invasive species and investigating their spread. Surprisingly, this technique has been very rarely used to investigate habitat selection, site occupancy, and colonisation despite its higher capacity to detect many species. • The African clawed frog (Xenopus laevis) is a...

In expanding populations, the allocation of resources to life-history traits is expected to change rapidly after the colonization of a new area. Understanding these changes is of crucial importance to predict the future changes in distribution ranges, and the possible impacts of expanding species on the colonized environments. Both theoretical and...

When species are translocated to a novel environment, individuals become exposed to new predators against which they may not express very efficient defences at least at an initial stage. The strength of anti-predator defence is an important parameter that may determine the ability of local communities to control the expansion of invasive population...

The introduction of species to multiple continents creates natural experiments suited to the evaluation of ecological hypotheses. For the Enemy Release Hypothesis (ERH), which postulates that the success of invasive populations hinges upon release from the effects of their natural enemies, assessments of parasite loss during invasion across indepen...

The presence of artificial light at night (ALAN) is currently a global phenomenon. By altering the photoperiod, ALAN may directly affect the physiology and behaviour of many organisms, such as the timing of daily rhythms, hormonal regulation, food intake, metabolism, migration and reproduction. Surprisingly while it is known that ALAN exposure stro...

The conservation of grasslands is a concern worldwide as they are threatened by climate change and the expansion of intensive agricultural practices. The management of these areas must take into account the decisional process of habitat selection by individual organisms to identify potential ecological traps or underused habitats. Organisms that li...

Invasive species are among the most significant threats to biodiversity. They have direct and indirect effects on the colonized environments including the alteration of food web structure by predation. In this study, we focused on the invasive population of the African clawed frog, Xenopus laevis, in France, and compared the composition of the aqua...

As invasive species are one of the principal threats on global biodiversity, assessing their impact is a crucialelement of conservation biology. Quantifying the possible impacts of an invasive population represents the first step in theestablishment of efficient management plans. In this study, we applied a method of site-occupancy modeling to esti...

Aim Species distribution modelling, a family of statistical methods that predicts species distributions from a set of occurrences and environmental predictors, is now routinely applied in many macroecological studies. However, the reliability of evaluation metrics usually employed to validate these models remains questioned. Moreover, the emergence...

Artificial light at night (ALAN) is an increasing phenomenon worldwide. It causes a wealth of biological and ecological effects that may eventually affect populations and ecosystems. Despite the growing concern about ALAN, little is known about the light levels species are exposed to at night, especially for wetlands and underwater habitats. We det...

(a-d) Irradiance spectra measured on all sites under a clear (blue) and an overcast (brown) sky at a night. (PDF)

Nocturnal irradiance spectra measured at 28 sites under a clear and an overcast sky. (XLSX)

Map of irradiance values measured under an overcast sky during a moonless night. The grey areas represent the built areas in and around Angers. The hydrographic network is represented by blue lines. Irradiance values are given in μW/cm2: Dark blue (0–0.025), light blue (0.025-.050), orange (0.050–1), yellow (>1). (PNG)

Map of irradiance values measured under a clear sky during a moonless night. The grey areas represent the built areas in and around Angers. The hydrographic network is represented by blue lines. Irradiance values are given in μW/cm2: Dark blue (0–0.025), light blue (0.025-.050), orange (0.050–1), yellow (>1). (PNG)

Transmission spectra of water for 6 sites representing the range of variation encountered in our study. (EPS)

Database of irradiance measurements. The location of sampling sites, date and time of measurement, and irradiance values under clear and overcast skies during moonless nights are given. (XLSX)

Background Invasive species are among the most significant threats to biodiversity. The diet of invasive animal populations is a crucial factor that must be considered in the context of biological invasions. A broad dietary spectrum is a frequently cited characteristic of invasive species, allowing them to thrive in a wide range of environments. Th...

Individual diet data for the Chilean, French, Portuguese and South African populations of Xenopus laevis

Calculation of the electivity index for the French, South African and Welsh populations of Xenopus laevis Electivity values were calculated following the Vanderploeg and Scavia’s formula (1979) for each prey category detected in the diet of Xenopus laevis and in its environment.

Predicting the magnitude and nature of changes in a species' range is becoming ever more important as an increasing number of species are faced with habitat changes, or are introduced to areas outside of the species’ native range. An organism's investment in life history traits is expected to change during range shifts or range expansion because po...

Although of crucial importance for invasion biology and impact assessments of climate change, it remains widely unknown how species cope to environmental conditions beyond their currently realized climatic niches (i.e., those climatic conditions existing populations are exposed to). The African clawed frog Xenopus laevis, native to southern Africa,...

Plastic phenotypes are expected to be favoured in heterogeneous environments compared with stable environments. Sensory systems are interesting to test this theory because they are costly to produce and support, and strong fitness costs are expected if they are not tuned to the local environment. Consistently, the visual system of several species c...

Forecasting the colonization process is important for wildlife managers who supervise the reintroduction of endangered species or control the spread of invasive species. Patch connectivity is thus critical to predicting the fates of expanding populations. Connectivity in river networks results from river dendritic structure and dispersal modality o...

The concept of umbrella species assumes that concentrating resources on the protection of a single species contributes to the conservation of a suite of species and ecological processes belonging to the same ecosystem. The environmental requirements and geographical distribution of the umbrella species should thus overlap those of the group of targ...

By altering or eliminating delicate ecological relationships, non-indigenous species are considered a major threat to biodiversity, as well as a driver of environmental change. Global climate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus...

Maximum entropy SDM response curves for selected predictor variables displaying relationships between predictor variables and occurrence probability of Xenopus laevis. Model contribution was assessed by building the model using a single corresponding predictor variable. The logistic output (probability of presence) is displayed on the Y axis. Red c...

Response curves for ensemble SDM showing the relationships between environmental predictors and occurrence probability of Xenopus laevis. The logistic output (probability of occurrence) is displayed on the Y axis. (PDF)

Variable contribution for single algorithms of the ensemble SDM. (XLSX)

Predicted area sizes in mio. km² for the ensemble SDM; maximum values for each threshold (mtp, 25%, 50%, 75%) are displayed in bold. (XLSX)

A) Overlap analysis of the ensemble SDM and the maximum entropy SDM, with red highlighting areas where the ensemble SDM yields higher probabilities and blue depicting areas where the maximum entropy SDM yields higher probabilities; B) Overlap analysis of the ensemble SDM and the SDM by Measey et al. (2012), with red indicating higher probability of...

Predicted area sizes in mio. km² for the maximum entropy SDM; maximum values for each threshold (mtp, 25%, 50%, 75%) are displayed in bold. (XLSX)

Understanding patterns of genetic structure, gene flow and diversity across a species range is required to determine the genetic status and viability of small peripheral populations. This is especially crucial in species distributed across a large range where spatial heterogeneity makes it difficult to predict the distribution of genetic diversity....

Ultraviolet (UV) vision exists in several animal groups. Intuitively, one would expect this trait to be favoured in species living in bright environments, where UV light is the most present. However, UV sensitivity, as deduced from sequences of UV photoreceptors and/or ocular media transmittance, is also present in nocturnal species, raising questi...

We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UV) or abs...

Detection is crucial in the study and control of invasive species but it may be limited by methodological issues. In amphibians, classical survey techniques exhibit variable detection probability depending on species and are often constrained by climatic conditions often requiring several site visits. Furthermore, detection may be reduced at low de...

Species distribution modelling is now routinely applied in many macroecologicalstudies. However, the reliability of evaluation metrics used to validate these models remains debated. Moreover, the emergence of online databases of environmental variables with global coverage, especially climatic, has favoured the use of the same set of standard predi...

Edge avoidance is an important feature of habitat selection in grassland birds, as their density is usually reduced close to habitat boundaries. In many extensively managed European grasslands, fragmentation is caused by the presence of wooded hedgerows dividing meadows. Comparing the magnitude of hedgerow avoidance by co-occurring species is essen...

Disentangling the factors shaping species distributions remains a central goal in biogeography, ecology and evolutionary biology. The extrinsic pressures that may facilitate range shifts, such as climatic factors or biotic interactions are well known. However, in contrast, the possible intrinsic factors are manifold and hard to generalize across ta...

Hybridization is known to occur in a wide range of avian species, yet the rate and persistence of hybridization on populations is often hard to assess. Genotyping using variable genetic marker sets has become a common tool to identify hybrid individuals, however assignment outputs can differ depending on the marker set used. Here, we study hybrid a...

Mate selection in heterogeneous sensory environments may be challenging. Assessing the suitability of potential partners may be compromised if individual characteristics cannot be assessed reliably across all encountered conditions. The problem is particularly acute in a species recognition context if matings with heterospecific partners yield lowe...

Despite the expected increase in extreme flood frequency, the manner in which terrestrial arthropods cope with regular submersion of their habitat remains poorly understood in meadows, especially in temperate floodplains. Here, we studied the recolonisation dynamics of arthropods after a severe spring flood in the Loire Valley (France). We carried...

Appendix S1. Phylogenetic analyses of malaria lineages detected in populations of the corncrake. Appendix S2. Method used for the estimation of effective population size by ABC. Table S1. Basic statistics for each microsatellite locus. Table S2. Posterior probability of demographic models inferred by ABC. Table S3. Estimates of effective population...

1. Remotely sensed data are frequently employed for monitoring vegetation and for estimating herbivore diversity. Their use for predicting predator arthropod species abundance and richness has also been investigated with success for ants and beetles in forests using NDVI and for beetles in mountain forests using LiDAR data. 2. We investigated whet...

Pathogen infections can represent a substantial threat to wild populations, especially those already limited in size. To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling...

Pathogens are crucial in the evolution, ecology and demography of wild populations. Inbreeding and reduced genetic diversity are known to affect the capacity of an individual to resist pathogen infection so that a negative relationship between pathogen prevalence and heterozygosity is expected. An expected consequence is that pathogens may shorten...

Microsatellites are a valuable tool in the analysis of population genetic structure. Utilising microsatellite markers that were originally isolated from other species (cross-species amplification) can prove an efficient way, in terms of time and cost, to obtain markers for genetic studies. Here, 55 avian microsatellite primer pairs were tested for...

Whether sexual selection and species recognition involve distinct preferences and signals is still debated. Earlier work showed that traits under sexual selection can reduce the efficiency of species recognition but remains uncertain on how frequently such a conflict occurs. We can, however, hypothesise that overlapping distributions of sexual sign...

Many species breed in heterogeneous environments where conditions affecting signaling fidelity may vary. Species recognition may be impaired under particular environmental conditions enhancing the hybridization risk. We investigated the influence of habitat on species recognition efficiency in two hybridizing newts, Lissotriton vulgaris and L. helv...

The increasing spread of contaminants in the environment affects the behaviour of individuals and can be predicted to modify population characteristics in the long run. It is thus crucial to investigate the effect of contaminants on fitness-related traits. Nitrate is a major pollutant that disrupts oxygen fixation and steroid metabolism and is expe...

The Red List classification of IUCN has become one of the most important evaluations of threats that affect biodiversity at the species level. However, many estimations of species range, one essential factor in the Red List classification, are derived from expert-based assessments that sometimes lack empirical evidence. Our study focused on the cor...

Climate is a major factor delimiting species' distributions. However, biotic interactions may also be prominent in shaping geographical ranges, especially for parapatric species forming hybrid zones. Determining the relative effect of each factor and their interaction of the contact zone location has been difficult due to the lack of broad scale en...

Although species distribution modelling (SDM) has become a common tool to predict potential distributions of birds, several issues have to be addressed to produce reliable outputs. One common and serious challenge is the sampling bias in presence records due to the uneven distribution of the sampling effort across the species’ range. This bias may...

Inbreeding and reduced genetic diversity are known to affect the capacity of an individual to resist pathogen infection so that a negative relationship between pathogen prevalence and heterozygosity is expected. Thus, a high susceptibility to pathogens may contribute to shorten extinction time in populations with low genetic diversity. At the range...

Investigating the extrinsic and intrinsic factors that shape species distributions is one of the central goals of biogeography. For expansive range edges in particular, the extrinsic drivers such as climate of biotic interactions are well mentioned in the literature. However, studies investigating range expansion from an intrinsic perspective on an...

Identifying local adaptation is crucial in conservation biology to define ecotypes and establish management guidelines. Local adaptation is often inferred from the detection of loci showing a high differentiation between populations, the so-called FST outliers. Methods of detection of loci under selection are reputed to be robust in most spatial po...

Aim Selecting informative variables is crucial for species distribution modelling and ecological studies in general. Proxies quantifying water accumulation may have suitable properties because hydromorphy partly determines plant and animal communities. Topographic wetness index (TWI) was developed to locate wetlands but has largely been ignored fro...

Species distribution modelling (SDM) is now a common approach in ecology as well as in many other areas of environmental sciences. SDM techniques have several applications for conservation biology. They estimate the most suitable areas for a species and infer probability of presence in regions where no surveys are available. One recurrent cause of...

Functional communication in the UV range has been reported in Invertebrates and all major groups of Vertebrates but Amphibians. Although perception in this wavelength range has been shown in a few species, UV signalling has not been demonstrated in this group. One reason may be that in lentic freshwater habitats, litter decomposition generates diss...

Effect of filters on irradiance spectra. Irradiance spectra for the UV+ (grey lines) and UV− treatments (black lines). Irradiance is the product of the irradiance produced by the light tube times the transmittance of the filter. (TIF)

Hybridization can drive the convergence of territorial and sexual signals. However, non-genetic processes such as competition, environment matching, or cultural transmission, also generate this pattern. We investigated the effect of hybridization on song convergence between two interspecifically territorial warblers in a moving hybrid zone. We conf...