Keywords: isotopic niche, osmolality, Pelobates cultripes, δ 15 N, δ 13 C, δ 34 S

Coastal ecosystems are among the most diverse and productive systems on earth, but they are threatened by various anthropogenic pressures. To understand the magnitude of these constraints on biodiversity, it is essential to assess habitat use of coastal species, which can be challenging in the complex matrix of habitats in coastal environments. The stable isotope method is a powerful tool to assess foraging habitat, as marine influences on the trophic web should decrease with increasing distance from the ocean. In this study, we evaluated whether isotopic values (δ 15 N, δ 13 C and δ 34 S) can be useful to assess habitat use in a coastal amphibian, the western spadefoot toad (Pelobates cultripes). In two coastal wetlands of the French Atlantic coast, we captured individuals from 20 to 1300 m from the seashore in order to assess whether isotopic values were related to the distance to the coastline, and we combined this dataset with data on osmolality that correlate to distance to the ocean in this species. We found divergent site-specific responses, presumably linked to the site-specific extent of a recent marine submersion, highlighting the long-lasting effects of such extreme weather event on trophic webs. In both sites however, we found a larger isotopic niche closer to the seashore suggesting wider diet or prey depending on wider resources near the sea. Overall, our results suggest that isotopic values can provide insights on habitat use depending on site-specific characteristics. Combining isotopic values with other metrics (e.g., osmolality) allows to better understand isoscapes in a site-specific context.

Can stable isotopes assess habitat use in complex coastal wetlands? A case study in an amphibian species

Léa Lorrain-Soligon a , Frédéric Robin b,c,d , Vincent Lelong c , Marko Jankovic d , Paco Bustamante e,f , Yves Cherel a , François Brischoux a a. Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS -La Rochelle Université, 79360 Villiers-en-Bois, France b. LPO France, Fonderies Royales, 17300 Rochefort, France c. Réserve naturelle de Moëze-Oléron, LPO, Plaisance, 17780 Saint-Froult, France d. Réserve naturelle du marais d'Yves LPO, Ferme de la belle espérance, 17340 Yves, France e. Littoral Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France f. Institut Universitaire de France (IUF), 1 rue Descartes 75005 Paris, France Correspondence: lea.lorrain-soligon@cebc.cnrs.fr ID ORCID: 0000-0002-8723-7478 Full postal address : Centre d'Etudes Biologiques de Chizé (CEBC), 405 route de Prissé la Charrière, 79360 Villiers-en-Bois, France ORCIDs LLS: 0000-0002-8723-7478 FR : 0000-0003-0232-1142 PB : 0000-0003-3877-9390 YC : 0000-0001-9469-9489 FB : 0000-0002-5788-1326

Introduction

Terrestrial coastal ecosystems are located at the boundary between oceanic and terrestrial ecosystems. They are one of the most dynamic interfaces among biomes [START_REF] Sheaves | Consequences of ecological connectivity: the coastal ecosystem mosaic[END_REF] and are subject to complex interactions between marine and terrestrial influences [START_REF] Mclean | Coastal zones and marine ecosystems[END_REF]. As a consequence, coastal ecosystems are among the most diverse and productive systems on earth [START_REF] Hobohm | Coastal habitats, shallow seas and inland saline steppes: Ecology, distribution, threats and challenges[END_REF][START_REF] Sheaves | Consequences of ecological connectivity: the coastal ecosystem mosaic[END_REF].

They are recognized as hotspots of biodiversity providing resources for a large number of species [START_REF] Hobohm | Coastal habitats, shallow seas and inland saline steppes: Ecology, distribution, threats and challenges[END_REF]. In addition, they contribute to a large panel of ecosystem services [START_REF] Barbier | Valuing the storm protection service of estuarine and coastal ecosystems[END_REF][START_REF] Spalding | Coastal ecosystems: A critical element of risk reduction[END_REF]). Yet, they are threatened by various anthropogenic activities such as urbanization, agriculture, environmental contamination, tourism and overexploitation [START_REF] Hobohm | Coastal habitats, shallow seas and inland saline steppes: Ecology, distribution, threats and challenges[END_REF]. In addition to these spatially restricted threats, coastal areas are also predicted to be impacted by climate change through two main processes: the progressive rise of sea level [START_REF] Kulp | New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding[END_REF] and the increase in frequency and intensity of storms and associated marine submersions (i.e., causing ocean water to temporary cover coastal areas, [START_REF] Dettinger | Climate change, atmospheric rivers, and floods in California -A multimodel analysis of storm frequency and magnitude changes[END_REF][START_REF] Mclean | Coastal zones and marine ecosystems[END_REF]. All of these threats are expected to affect coastal biodiversity, but it remains essential to assess habitat use of coastal species to better understand how increasing environmental changes affect coastal ecosystems and their biodiversity.

Coastal wetlands are composed of a complex matrix of habitat types distributed across very short spatial scales (e.g., few hundred meters, [START_REF] Mclean | Coastal zones and marine ecosystems[END_REF]. These habitats cover a continuum between intertidal sandy area, mudflats and seagrass beds; through salt and freshwater marshes or swamps; up to sand dunes, grasslands and forests; along with increasing distance from the seashore [START_REF] Maynard | Coastal Wetlands[END_REF][START_REF] Mclean | Coastal zones and marine ecosystems[END_REF]. In most cases, a given species will use each of these habitat types differentially according to its life-history stage [START_REF] Arthur | Ontogenetic changes in diet and habitat use in green sea turtle (Chelonia mydas) life history[END_REF][START_REF] Rathbun | Terrestrial habitat use by pacific pond turtles in a mediterranean climate[END_REF], its physiological state [START_REF] Brischoux | Behavioral and physiological correlates of the geographic distributions of amphibious sea kraits (Laticauda spp.)[END_REF] and its energetic requirements [START_REF] Schwemmer | Regular habitat switch as an important feeding strategy of an opportunistic seabird species at the interface between land and sea[END_REF]. Foraging habitat is thus a central feature of overall habitat use as it will determine the quality and the quantity of resources available to an organism, which will be selected according to life stage of an individual (growth, reproduction, migration); or individual strategies and dietary specialization [START_REF] Robinson | Optimal foraging, specialization, and a solution to Liem's paradox[END_REF]. In addition, foraging is often associated with risk-taking behaviours [START_REF] Verdolin | Meta-analysis of foraging and predation risk trade-offs in terrestrial systems[END_REF]. These elements suggest that precise selection of a suitable foraging habitat will ultimately influence fitness through increased energetic incomes and reduced predation risks. Importantly, in coastal ecosystems, the use of habitats situated close to the seashore is also expected to reflect an individual's vulnerability to extreme weather events (e.g. marine submersions, [START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF]) and thus the persistence of coastal populations. Yet, assessing the habitat use of individuals within the complex matrix of habitats highlighted above is a challenging task that may reveal logistically prohibitive (e.g., fine scale tracking of individual movements, [START_REF] Ponchon | Tracking prospecting movements involved in breeding habitat selection: insights, pitfalls and perspectives[END_REF]. The use of stable isotopes analyses can offer a powerful alternative to identify hard-to-measure variables, such as foraging habitats [START_REF] Bearhop | A forensic approach to understanding diet and habitat use from stable isotope analysis of (avian) claw material[END_REF][START_REF] Choy | Isotopic shift for defining habitat exploitation by the Antarctic limpet Nacella concinna from rocky coastal habitats (Marian Cove, King George Island)[END_REF][START_REF] Monti | Using GPS tracking and stable multi-isotopes for estimating habitat use and winter range in Palearctic ospreys[END_REF].

The concept of the isotopic niche is based on the fact that an individual's chemical composition is influenced by what it consumes and assimilates [START_REF] Brüssow | You are what you eat[END_REF][START_REF] Kohn | You are what you eat[END_REF], which can be characterized by analyzing stable isotopes [START_REF] Kudman | A comparison of the diets of three Diamondback Terrapin populations using fecal analysis and stable isotope analysis[END_REF][START_REF] Layman | Applying stable isotopes to examine food-web structure: an overview of analytical tools[END_REF][START_REF] Mccue | Using stable isotope analysis to answer fundamental questions in invasion ecology: Progress and prospects[END_REF]. Stable nitrogen isotope values (δ 15 N) are mostly used as a surrogate of trophic position, but can be also a relevant proxy of consumers' foraging habitat [START_REF] Minagawa | Stepwise enrichment of 15N along food chains: Further evidence and the relation between δ 15 N and animal age[END_REF][START_REF] Peterson | Stable isotopes in ecosystem studies[END_REF][START_REF] Vander Zanden | Primary consumer δ 13 C and δ 15 N and the trophic position of aquatic consumers[END_REF]. In our context, δ 15 N is thought to increase with increasing salinity [START_REF] Fry | Conservative mixing of stable isotopes across estuarine salinity gradients: A conceptual framework for monitoring watershed influences on downstream fisheries production[END_REF][START_REF] Hussain | Effect of salinity stress on phenotypic plasticity, yield stability, and signature of stable isotopes of carbon and nitrogen in safflower[END_REF], and may thus increase in marine compartments compared to terrestrial ones. Complementarily, stable carbon values (δ 13 C) vary among specific primary producers and this parameter can be used to examine differences in trophic support and thus presumably habitats [START_REF] Minagawa | Stepwise enrichment of 15N along food chains: Further evidence and the relation between δ 15 N and animal age[END_REF][START_REF] Peterson | Stable isotopes in ecosystem studies[END_REF][START_REF] Vander Zanden | Primary consumer δ 13 C and δ 15 N and the trophic position of aquatic consumers[END_REF]. Similarly to δ 15 N, δ 13 C is thought to increase with salinity [START_REF] Fry | Conservative mixing of stable isotopes across estuarine salinity gradients: A conceptual framework for monitoring watershed influences on downstream fisheries production[END_REF], and thus values for oceanic carbon should be higher than for terrestrial one. Finally, stable sulfur values (δ 34 S) allow discriminating between marine or terrestrial food webs since values for marine sulfate are generally higher [START_REF] Leyden | A simple and rapid ICP-MS/MS determination of sulfur isotope ratios (34S/32S) in complex natural waters: A new tool for tracing seawater intrusion in coastal systems[END_REF][START_REF] Lott | Estimating the latitudinal origins of migratory birds using hydrogen and sulfur stable isotopes in feathers: Influence of marine prey base[END_REF][START_REF] Michener | Stable isotope ratios as tracers in marine aquatic food webs[END_REF]. As such, like for δ 15 N and δ 13 C values, δ 34 S is thought to decrease when salinity decreases and distance from the coastline increases [START_REF] Fry | Sulfur stable isotope indicators of residency in estuarine fish[END_REF].

Isotopic values of all three elements are expected to vary across coastal habitats, especially according to increasing distance from the ocean. Indeed, coastal winds cause landward transport of matter such as sediment [START_REF] Ridderinkhof | Sediment transport in intertidal areas, in: Intertidal Deposits[END_REF][START_REF] Zhang | Determining the drivers of suspended sediment dynamics in tidal marsh-influenced estuaries using high-resolution ocean color remote sensing[END_REF], organic matter [START_REF] Pelegrí | Coupling between the open ocean and the coastal upwelling region off northwest Africa: water recirculation and offshore pumping of organic matter[END_REF] and salts [START_REF] Demoisson | A model for the atmospheric transport of sea-salt particles in coastal areas[END_REF]; and their deposition is expected to progressively decrease with increasing distance from the shore [START_REF] Meira | Modelling sea-salt transport and deposition in marine atmosphere zone -A tool for corrosion studies[END_REF][START_REF] Mustafa | Atmospheric chloride penetration into concrete in semitropical marine environment[END_REF]. Accordingly, the influence of such deposition of matter of marine origin on the trophic web -and thus on stable isotope values -should progressively decreases with increasing distance from seawater. It is therefore expected that isotopic values will be enriched close to the seashore, and that they will decrease with increasing distance from the ocean. Indeed, an individual foraging closer to the seashore should display δ 15 N, δ 13 C and δ 34 S values close to those from marine systems, while individuals foraging further inland should display δ 15 N, δ 13 C and δ 34 S values indicative of terrestrial ecosystems.

In this study, we tested this hypothesis and evaluated whether δ 15 N, δ 13 C and δ 34 S values can be useful to assess habitat use (proximity to the seashore) in the terrestrial coastal amphibian Pelabates cultripes captured along a continuum of distance from the seashore (from 20 to 1300 m). Because landward transport of sediments and organic matters occurs primarily at a very short spatial scale [START_REF] Bainbridge | Fine sediment and particulate organic matter: A review and case study on ridge-to-reef transport, transformations, fates, and impacts on marine ecosystems[END_REF][START_REF] Ridderinkhof | Sediment transport in intertidal areas, in: Intertidal Deposits[END_REF], we also investigated these variations at a smaller extend, within 200 m from the seashore. Such decrease in marine influence on isotopic values has already been suggested with a similar variation of osmolality of toad blood according to distance to seawater [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF], because osmolality is related to salt exposure through sea-spray [START_REF] Benassai | Sea-spray deposition in Antarctic coastal and plateau areas from ITASE traverses[END_REF][START_REF] Mclean | Coastal zones and marine ecosystems[END_REF]. As a consequence, we complemented our isotopic analyses with osmolality measurements [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF] as an independent marker of marine influence and we predicted that individual's plasma osmolality should correlate with δ 15 N, δ 13 C and δ 34 S values.

MATERIALS AND METHODS

Study species

The western spadefoot toad, Pelobates cultripes, is an amphibian relatively tolerant to salinity [START_REF] Stănescu | Salinity tolerance in Pelobates fuscus (Laurenti, 1768) tadpoles (Amphibia: Pelobatidae)[END_REF][START_REF] Thirion | Salinity of the reproduction habitats of the western spadefoot toad Pelobates cultripes (cuvier, 1829), along the atlantic coast of France[END_REF]. This species is mostly distributed in the region of the Iberian Peninsula and along the French Mediterranean and Atlantic coasts [START_REF] Lizana | Reproductive biology of Pelobates cultripes in Central Spain[END_REF][START_REF] Leclair | Application of skeletochronology to a population of Pelobates cultripes (Anura: Pelobatidae) from Portugal[END_REF][START_REF] Thirion | Salinity of the reproduction habitats of the western spadefoot toad Pelobates cultripes (cuvier, 1829), along the atlantic coast of France[END_REF]). As most amphibians, western spadefoot toads have a biphasic lifestyle. Eggs and larvae develop in fresh and brackish water bodies [START_REF] Stănescu | Salinity tolerance in Pelobates fuscus (Laurenti, 1768) tadpoles (Amphibia: Pelobatidae)[END_REF], while terrestrial juveniles and adults are distributed from very close to the seashore up to 5 km inland, where they shelter in sandy soils during the day and forage for invertebrates at night [START_REF] Speybroeck | Guide Delachaux des amphibiens & reptiles de France et d'Europe[END_REF].

Study sites

The These two sites are composed of a matrix of habitats typical of coastal wetlands: salt marsh, meadows, and freshwater ponds. In MO, pond salinity decreases with increasing distance from the shore, while in MY, pond salinity remains constant [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF]. Both sites are exposed to an oceanic climate (Cfb according to Köppen classification), and to the same regime of winds.

Field procedures

On each site, three areas were prospected according to their distance to the seashore:

close (<200 m from the ocean), intermediate (between 200 and 600 m to the ocean), and distant (>600 m from the ocean) (see Figure 1), all characterized by the presence of sandy soil. All field surveys were carried out at night, between 9 p.m and 4 a.m. Sixtyseven adults were captured (35 in MO, 28 females and 7 males, and 32 in MY, 24 females and 8 males). Each individual toad was measured (Snout-to-Vent Length

[SVL]) using a caliper [±1 mm]), weighed (pesola spring scale [±0.5 g]), and sexed using secondary sexual characters [START_REF] Speybroeck | Guide Delachaux des amphibiens & reptiles de France et d'Europe[END_REF]. Characteristics of body mass and size of the individuals are given in Table S1. Precise locations of capture were recorded with a GPS (Garmin GLO) to assess the exact position of individuals, and thus its distance to the ocean at high tide, using the NNJoin extension on Qgis 3.10.

All blood sampled individuals weighted >15 g. Blood was collected by cardiocentesis, and blood volume was ≤150 μl, thus representing <1% of toad body mass [START_REF] Diehl | A good practice guide to the administration of substances and removal of blood, including routes and volumes[END_REF][START_REF] Soulsbury | The welfare and ethics of research involving wild animals: A primer[END_REF]. Blood was centrifuged for 7 min at 2000 G to separate plasma from blood cells. Both fractions were stored frozen at -20°C until analyses.

Plasma osmolality (mOsmol.kg -1 ) were re-analyzed from Lorrain-Soligon et al., (2022) and red blood cells (hereafter blood) were used for isotopic analyses (see below).

Isotopic analyses

Isotopic analyses were carried out on freeze-dried blood at the LIENSs (La Rochelle, France). Aliquots of ~0.3 mg (for δ 13 C and δ 15 N) and ~0.8 mg (for δ 34 S) dry mass were analyzed with a continuous flow mass spectrometer (Thermo Scientific Delta V Advantage) coupled to an elemental analyzer (Thermo Scientific Flash EA 1112).

Results are presented as standard delta (δ) notation as parts per mil (‰) deviation relative to Vienna Pee Dee Belemnite, atmospheric N2 and Vienna-Canyon Diablo Troilite for S) for δ 13 C, δ 15 N and δ 34 S, respectively. Internal laboratory standards USGS-61 (Caffeine) and USGS-62 (Caffeine) for both C and N, and USGS-42 (human hair)

and IAEA-S2 (silver sulfide) for S were used to check accuracy. Measurement errors were <0.15 ‰ for both δ 13 C and δ 15 N values, and < 0.20 ‰ for δ 34 S values.

Statistical analyses

The effects of the distance to the shore on variables were tested across the whole spatial scale of our study, and also within the closest area (<200 m) to investigate localized effects at small scale (see results).

To test for the effect of distance to the ocean on blood isotopic values, simple linear models (lms) were computed, and we further tested if individual traits (sex and body size) were significant covariates by using lms with size, sex and their interaction with distance to the ocean. A backward model selection using F tests [START_REF] Bolker | Generalized linear mixed models: a practical guide for ecology and evolution[END_REF][START_REF] Zuur | Mixed effects models and extensions in ecology with R, Statistics for Biology and Health[END_REF] was carried out, and only the retained variables are represented (e.g.

sex was never a significant predictor). A dataset of plasma osmolality values [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF] was also re-analyzed, with a focus on small scale localized effects within the sites situated close to the seashore. The relationships between isotopic values were analyzed, as were those between isotopic values and osmolality, using lms with osmolality or isotopic values as a covariate. Package SIBER: Stable Isotope Bayesian Ellipses in R [START_REF] Jackson | Comparing isotopic niche widths among and within communities: SIBER -Stable Isotope Bayesian Ellipses in R[END_REF]. These Bayesian models can be applied for populations if n>10 [START_REF] Jackson | Comparing isotopic niche widths among and within communities: SIBER -Stable Isotope Bayesian Ellipses in R[END_REF] as it is the case in our populations. This approach computes the total area of the convex hull encompassing the data points (TA), representing the total extent of trophic diversity and niche width [START_REF] Jackson | Comparing isotopic niche widths among and within communities: SIBER -Stable Isotope Bayesian Ellipses in R[END_REF][START_REF] Layman | Can stable isotope ratios provide for community-wide measures of trophic structure?[END_REF], and the Standard Ellipse Area (SEA) or the corrected Standard Ellipse Area (SEAc) [START_REF] Jackson | Comparing isotopic niche widths among and within communities: SIBER -Stable Isotope Bayesian Ellipses in R[END_REF], allowing to compare subpopulations. Overlap of SEAC among areas (close, intermediate, distant) was calculated for each population. Additionally, we compared populations using the range of δ 15 N values illustrating trophic diversity, the range of δ 13 C and δ 34 S values illustrating the diversity of basal resources, the mean distance to centroid (CCD) providing information on niche width as well as individual spacing, the mean nearest neighbour distance (MNND) illustrating density of individuals in the populations, and the standard deviation of the nearest neighbour distance (SDNND), a measure of evenness of spatial density and packing [START_REF] Jackson | Comparing isotopic niche widths among and within communities: SIBER -Stable Isotope Bayesian Ellipses in R[END_REF][START_REF] Layman | Can stable isotope ratios provide for community-wide measures of trophic structure?[END_REF].

All data analysis were performed using R 3.6.3 (R Core Team, 2020) and Rstudio v1.1.419.

RESULTS

Variations with distance to the ocean

In MO (« Réserve Naturelle Nationale de Moëze-Oléron ») when the whole spatial scale (close, intermediate and distant area) was considered, blood δ 13 C, δ 15 N and δ 34 S values, as well as plasma osmolality, decreased with distance from the ocean (Table 1; Fig. 2 ACEG). This decrease was sharper for δ 13 C, δ 15 N and osmolality when considering only the closest area (<200 m from the ocean, Table 1, Fig. 2 BDH), but this was not the case for δ 34 S for which, in the closest area, the isotopic value was not influenced by distance to the ocean (Table 1, Fig. 2F).

In MY (« Réserve Naturelle Nationale du marais d'Yves »), when the whole spatial scale was considered, plasma osmolality decreased significantly when distance to the ocean increased (Table 1, Fig. 2G). Blood δ 34 S values increased with distance from the ocean (Table 1, Fig. 2E), while δ 15 N and δ 13 C did not vary according to the distance to the ocean (Fig. 2 AC). Distance to coastline did not influence δ 15 N, δ 13 C, δ 34 S or osmolality on the small spatial scale (i.e. on the closest area only, <200 m from the ocean, Fig. 2 BDFH).

Effects of individual traits

In interaction with distance to the coast, a negative effect of body size on δ 15 N and δ 13 C values was found only in MO, and when considering the closest area only (<200 m, Table 1, Fig. S1). For all other isotopic values and osmolality, and for all sites and areas, there were no effects of size, sex, and of their interaction with distance to the coast (Table 1).

Correlations between isotopic values

In MO, across the whole spatial scale, δ 15 N and δ 13 C values were correlated (R 2 = 0.615, p-value<0.001), as well as δ 15 N and δ 34 S values (R 2 = 0.140, p-value=0.015), but not δ 13 C and δ 34 S (R 2 = 0.006, p-value=0.279). When restricting our analyses to the closest area (<200 m from the ocean), δ 15 N and δ 13 C values were correlated (R 2 = 0.986, p-value<0.001), but no correlation with δ 34 S values was significant (all R 2 <-0.064, all p-value>0.545).

In MY across the whole spatial scale, none of the isotopic values was correlated (all R 2 <0.057, all p-value>0.100). When restricting our analyses to the closest area (<200 m from the ocean), δ 15 N and δ 13 C values were correlated (R 2 = 0.617, p-value=0.001), but no correlation with δ 34 S values was significant (all R 2 <-0.064, all p-value>0.545).

Correlations between isotopic values and osmolality

In MO, both across the whole spatial scale and when restricting our analyses to the closest area (<200 m from the ocean), blood δ 15 N and δ 13 C values were correlated with plasma osmolality (all R 2 >0.607, all p-value<0.001, Fig. 3 ABCD), but this was not the case for δ 34 S values (whole spatial scale, R 2 =-0.011, p-value=0.428, Fig. 3E; closest area, R 2 =-0.085, p-value=0.655, Fig. 3F).

In MY, δ 15 N, δ 13 C and δ 34 S values were not correlated to osmolality (all R 2 <0.191, all p-value>0.087, Fig. 3 ABCDEF).

Comparisons of isotopic niches

Western spadefoot toads from the two sites differed in their isotopic niche. In particular the δ 13 C-δ 15 N niche (TA) was larger in MO compared to MY, with wider δ 13 C and δ 15 N ranges, more dispersion in δ 13 C and δ 15 N values, more trophic diversity (CCD) and trophic evenness (SDNND) for the δ 13 C-δ 15 N range (Table 2). By contrast, the δ 13 C-δ 34 S niche (TA) was larger in MY compared to MO, with a wider δ 34 S range, and more dispersion in δ 34 S values (Table 2). Individuals from MY also expressed more trophic diversity (CCD) and trophic evenness (SDNND) for the δ 13 C-δ 34 S range (Table 2).

When considering isotopic niches with δ 13 C and δ 15 N values, we found that the trophic niche (TA and SEA) was larger closer to the ocean (in the closest area, <200 m from the ocean) in both sites (Fig. 4AB, Table 3).

Concerning isotopic niches with δ 13 C and δ 34 S values, we also found that the trophic niches (TA and SEA) were larger closer to the ocean (in the closest area, <200 m from the ocean) in both sites (Fig. 4CD, Table 3).

Overlaps between the close, intermediate and distant areas were smaller in MO than in MY (Table S2).

DISCUSSION

In this study, we tested whether blood stable isotope values are useful to assess habitat use (distance to the shoreline) across terrestrial coastal wetlands in an amphibian, the western spadefoot toad Pelobates cultripes. Because coastal winds cause landward transport of matter, marine influence was expected to progressively decrease with increasing distance from the ocean [START_REF] Meira | Modelling sea-salt transport and deposition in marine atmosphere zone -A tool for corrosion studies[END_REF][START_REF] Mustafa | Atmospheric chloride penetration into concrete in semitropical marine environment[END_REF].

Overall, our results highlighted divergent site-specific responses [START_REF] Denton | Stable Isotope Analysis Enhances Our Understanding of Diamondback Terrapin (Malaclemys terrapin) Foraging Ecology[END_REF].

In one of our study sites (MO), as predicted, all three elements investigated (blood δ 15 N, δ 13 C and δ 34 S values) decreased with increasing distance from the ocean.

However, in the other study site (MY), two of the isotopic values (δ 15 N and δ 13 C) did not vary with distance to the shoreline and δ 34 S values showed a trend opposite to our prediction. Nevertheless, individual osmolality (related to landward transport of seaspray and salt intake, [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF] showed a decrease according to distance to the ocean at both sites.

In MO, we found that all three isotopic values decreased with increasing distance from the shoreline as expected from a progressive decline in marine matter deposition with increasing distance from the ocean. This trend was also detectable at a smaller spatial scale (<200 m from the coastline) for both δ 15 N and δ 13 C values. Such a pattern suggests that the deposited marine matter is integrated within the trophic web, from primary producers up to meso-predators such as the western spadefoot toad. All three isotopic values were related to one another when considering the whole spatial scale, which strengthens this hypothesis. The strong effect close to the shoreline (see slopes in Fig. 2AC versus Fig. 2BD, Table 1) suggests that this process occurs primarily at a very short spatial scale, as expected from the spatial extent of the windward transport of relatively heavy particles such as sediment and organic matter [START_REF] Bainbridge | Fine sediment and particulate organic matter: A review and case study on ridge-to-reef transport, transformations, fates, and impacts on marine ecosystems[END_REF][START_REF] Ridderinkhof | Sediment transport in intertidal areas, in: Intertidal Deposits[END_REF]. Interestingly, δ 34 S variation showed a similar trend across the whole spatial scale of our study, but no significant trend when restricting our analyses to the close study area (<200 m). These results suggest that δ 34 S values does not vary on such a restricted spatial scale, as shown in other studies [START_REF] Nehlich | The application of sulfur isotope analyses in archaeological research: a review[END_REF][START_REF] Novák | Sulfur isotope inventories of atmospheric deposition, spruce forest floor and living Sphagnum along a NW-SE transect across Europe[END_REF]. Blood δ 34 S values could thus decrease on a larger spatial scale, only a small part of which being covered by our sampling [START_REF] Nehlich | The application of sulfur isotope analyses in archaeological research: a review[END_REF][START_REF] Novák | Sulfur isotope inventories of atmospheric deposition, spruce forest floor and living Sphagnum along a NW-SE transect across Europe[END_REF]. In line with these results, we found that individual osmolality (related to salt intake and linked to landward transport of sea-spray, [START_REF] Lorrain-Soligon | Distance to coastline modulates morphology and population structure in a coastal amphibian[END_REF] dovetails remarkably well with the isotopic trends. Plasma osmolality was strongly linked to both blood δ 15 N and δ 13 C values either at the global scale, or when restricted to the closest study area. It is noteworthy that both sets of markers provide information at different temporal scale. Blood isotopic values provide information according to the life of erythrocytes that lasts several months in amphibians [START_REF] Altland | Red cell life span in the turtle and toad[END_REF][START_REF] Cloyed | Trophic discrimination factors and incorporation rates of carbon-and nitrogen-stable isotopes in adult green frogs, Lithobates clamitans[END_REF]. Plasma osmolality is much more dynamic (e.g., days or weeks) and varies according to freshwater intake (e.g., during rainfall) that allows equilibrating an individual's hydric state [START_REF] Hillyard | The water absorption response: a behavioral assay for physiological processes in terrestrial amphibians[END_REF][START_REF] Park | Physiological response of Pelophylax nigromaculatus adults to salinity exposure[END_REF].

Such similar trends for markers that integrate different temporal scales suggest individual specialization in habitat use. Future studies combining mark-recapture studies and repeated measures of isotopic values (on plasma and red blood cells, see [START_REF] Denton | Stable Isotope Analysis Enhances Our Understanding of Diamondback Terrapin (Malaclemys terrapin) Foraging Ecology[END_REF] and plasma osmolality should usefully test for this hypothesis.

In strong contrast with the results from MO, none of the isotopic values displayed the expected trends at the MY site. Neither δ 15 N nor δ 13 C values were related to distance to the shoreline, either at the whole spatial scale or when restricting our analyses to the closest area solely. This divergence was even stronger for δ 34 S values, which increased with increasing distance from the shoreline. Similarly to MO, osmolality of individuals from MY decreased with increasing distance from the ocean (Lorrain-Soligon et al., 2022), but, unlike MO, osmolality was not related to any isotopic value.

Although such contrast between close and structurally similar study sites can appear puzzling, we believe the underlying reason is related to the recent history of these sites.

Indeed, both sites were hit by storm Xynthia in 2010, but the spatial extent of the associated marine submersion was strongly different between the two sites, due to their slightly different topography (i.e., additional sand dune in MO compared to MY; [START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF]. MY was entirely submerged and seawater have been retained several weeks, especially in lowland areas. The resulting salinization was still detectable seven years after the submersion [START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF]. By contrast, owing to its topography [START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF], coastal wetlands of MO were spared from the marine submersion induced by storm Xynthia [START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF]. This suggests that the effects of a marine submersion and the resulting deposition of marine elements (salt, sediments, and organic matter) can disrupt isotopic signatures of coastal areas, a process that appears to be long-lasting as our isotopic sampling occurred 11 years post-submersion. If such hypothesis holds true, it is a major element to take into account when integrating isotopic analyses to habitat use and individual movements in coastal ecosystems, as it seems necessary to take into account the history of marine intrusions to understand the spatio-temporal dynamics of isotopic values [START_REF] Baumann | Contrasting sediment records of marine submersion events related to wave exposure, Southwest France[END_REF][START_REF] Raji | Extreme sea events during the last millennium in the northeast of Morocco[END_REF]. However, this hypothesis cannot fully explain the δ 34 S variation at MY, as well as the strong contrast of δ 34 S values close to seashore between MO and MY. Such contrasts between close and structurally similar study sites remain puzzling and clearly deserve future investigations. Overall, δ 34 S isoscapes are known to be highly variable [START_REF] Nehlich | The application of sulfur isotope analyses in archaeological research: a review[END_REF], and such variation may explain the trends we found. Future studies are required to decipher the bases for such divergences between close and structurally similar coastal wetlands. Extending our investigations to other coastal taxa may also provide critical insights on the variation of δ 34 S values.

As a consequence of these divergent spatial dynamics of isotopic values, trophic niches of western spadefoot toads were also different between our study sites. Blood δ 34 S range was higher in MY, suggesting more marine-derived nutrients in the habitat [START_REF] Hesslein | Stable Isotopes of Sulfur, Carbon, and Nitrogen as Indicators of Trophic Level and Fish Migration in the Lower Mackenzie River Basin, Canada[END_REF][START_REF] Macavoy | Marine nutrient contributions to freshwater apex predators[END_REF]. However, δ 13 C and δ 15 N ranges were higher in MO, suggesting wider food resources, as these elements reflect the variability of basal food resources [START_REF] Potapov | Uncovering trophic positions and food resources of soil animals using bulk natural stable isotope composition[END_REF]. Interestingly, in both study sites, we found a larger isotopic niche closer to the seashore, both considering the δ 13 C-δ 15 N or δ 13 C-δ 34 S niches. Such results suggests that, at both sites, individuals that live close to the seashore have access to a wider spectrum of food resources [START_REF] Carmo | Eat on the beach: diet composition of an endemic miniature frog from sandy coastal environments of southeastern Brazil[END_REF].

Indeed, anecdotal observations of prey regurgitation during sampling showed that individuals captured further from the seashore feed on insects (rove beetles) and terrestrial gastropods (slugs and snails), while individuals captured near the seashore incorporate marine prey (sand hoppers) as well as terrestrial prey in their diet, indicating trophic adaptability [START_REF] Andolina | Trophic adaptability shapes isotopic niche of the resident fish Aphanius fasciatus across lagoon habitats[END_REF], or an opportunistic feeding behavior [START_REF] Shaiek | Étude du régime alimentaire de l'ichtyofaune du lac ichkeul (Tunisie), Study of the ichthyofauna diet in the Ichkeul Lake (Tunisia)[END_REF]. Additionally, the larger isotopic niche close to the seashore could be due to a greater range in isotopic values of the potential preys, and thus more variation at the base of the food web. Measurements of isotope values of preys are required to test for these hypotheses. Despite divergence in overall isotopic values, such dietary variation according to the distance to the ocean seems similar between the two study sites.

Conclusions

Taken together these results suggest that blood δ 15 N, δ 13 C and δ 34 S values can provide insight on habitat use, but their usefulness is site-specific. Indeed, one needs to be cautious with the recent history (e.g., marine submersion) of a site before applying this technique. Moreover, δ 34 S values may be suitable to discriminate marine habitats from terrestrial ones, but less useful to infer habitat use at a smaller spatial scale, such as those characterizing coastal wetlands. As such, we recommend using δ 34 S values as a tool to understand habitat use in coastal environments, assuming that history of recent marine intrusions, topological profiles of the sites, and land cover are well known.

Indeed, coastal habitats are complex environmental matrix with multiple influences, resulting in many different types of habitats spread over a restricted spatial scale.

Combining the stable isotope method with other habitat use metrics (e.g., osmolality in the collection, analysis and interpretation of data; in the writing of the report; nor in the decision to submit the article for publication.

  study was carried out from 7/10/2020 to 23/10/2020 on two natural reserves located on the Atlantic coast of France (Département de la Charente-Maritime), and separated by ~15 km straight line: the « Réserve Naturelle Nationale de Moëze-Oléron » (45°54'20.4"N, 1°04'19.9"W, hereafter MO), and the « Réserve Naturelle Nationale du marais d'Yves » (46°2'40.735"N, 1°3'16.906"W, hereafter MY) (see Figure1). The two sites have been thoroughly described in[START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF], including their topographic profiles. Both sites are low coastal wetlands (mean elevation: MY = 2.64 m ± 0.02 SE; MO = 2.90 m ± 0.01 SE), with sand dunes near the seashore (~100 m from the seashore; 3.30 m high for both sites). Additionally, MO displays an additional dune situated ~500 m inland. These slightly different topographies have led to different consequences of marine submersions. Indeed, both sites were hit by storm Xynthia in 2010, during which MY was completely submerged, while the extent of the submersion was minor in MO (see[START_REF] Lorrain-Soligon | Slight variations in coastal topography mitigate the consequence of storm-induced marine submersion on amphibian communities[END_REF].

Finally, categories of

  distance to the seashore (close [<200 m], intermediate [between 200 and 600 m], and distant [>600 m]) were used to investigate the trophic niches of populations living closer to or further from the shore using Bayesian statistics with the

Figure 1 :

 1 Figure 1: Map of Western France including the two study sites and the position of the

Figure 2 :

 2 Figure 2: Blood δ 13 C, δ 15 N, δ 34 S values, and plasma osmolality in relation to distance to the ocean across the whole study sites (left column) and restricted to the closest area (right column). Regression lines are used for significant relationships solely. MO: Réserve Naturelle Nationale de Moëze-Oléron and MY: Réserve Naturelle Nationale du marais d'Yves. Panel G is redrawn from Lorrain-Soligon et al. (2022).

Figure 3 :

 3 Figure 3: Correlations between blood δ 13 C, δ 15 N, δ 34 S values, and plasma osmolality

Figure 4 :

 4 Figure 4: Blood isotopic niches for δ 13 C and δ 15 N (upper panels) and δ 13 C and δ 34 S

Table 2 :

 2 Isotopic site metrics for blood δ 13 C and δ 15 N values (upper line), and blood δ 13 C and δ 34 S values (lower line), computed from SIBER for MO (Réserve Naturelle Nationale de Moëze-Oléron) and MY (Réserve Naturelle Nationale du marais d'Yves): δ 13 C (δ 13 C range), δ 15 N (δ 15 N range) and δ 34 S ( δ 34 S range), Total Area of the convex hull encompassing the data points (TA), mean Distance to Centroid (CCD), Mean Nearest Neighbour Distance (MNND), and Standard Deviation of the Nearest Neighbour Distance (SDNND).

		MO	MY
	δ 15 N range 2.086	0.990
	δ 13 C range	1.632	0.666
	Blood
	TA	1.640	0.028
	δ 13 C and
	CCD	1.190	0.423
	δ 15 N
	MNND	1.746	0.564
	SDNND	0.295	0.119
	δ 34 S range	1.205	5.182
	δ 13 C range	1.632	0.666
	Blood
	TA	0.967	1.472
	δ 13 C and
	CCD	0.894	2.013
	δ 34 S
	MNND	1.372	2.311
	SDNND	0.286	1.246

Table 3 :

 3 Subpopulations metrics computed from SIBER for blood δ 13 C and δ 15 N values (upper line), and blood δ 13 C and δ 34 S values (lower line). Total Area of the convex hull encompassing the data points (TA), Standard Ellipse Area (SEA) and corrected Standard Ellipse Area (SEAc) in the close, intermediate and distant areas in MO and MY. MO: Réserve Naturelle Nationale de Moëze-Oléron and MY: Réserve Naturelle Nationale du marais d'Yves.

				MO		MY
		Areas Close Intermediate Distant Close Intermediate Distant
	Blood	TA	2.961	0.855	0.847 4.863	1.350	1.062
	δ 13 C	SEA	1.693	0.416	0.386 2.010	0.627	0.491
	and
	δ 15 N	SEAc 1.881	0.454	0.428 2.210	0.705	0.552
	Blood	TA	16.788	0.980	0.765 7.323	4.338	2.196
	δ 13 C	SEA	9.195	0.421	0.390 2.978	2.307	1.195
	and
	δ 34 S	SEAc 10.216	0.460	0.433 3.276	2.595	1.345

Table S2 .

 S2 Overlaps between ellipses of subpopulations, computed using SIBER for blood δ 13 C and δ 15 N values (upper line), and blood δ 13 C and δ 34 S values (lower line), between the close, intermediate and distant areas in MO and MY. MO: Réserve Naturelle Nationale de Moëze-Oléron and MY: Réserve Naturelle Nationale du marais d'Yves.

		Overlap	MO	MY
	Blood	Close-Intermediate	<0.001	0.134
	δ 13 C and	Close-Distant	0.146	0.174
	δ 15 N	Intermediate-Distant	<0.001	0.449
	Blood	Close-Intermediate	0.045	0.298
	δ 13 C and	Close-Distant	0.042	0.036
	δ 34 S	Intermediate-Distant	0.075	0.292

Acknowledgements. The authors would like to thank Philippe Delaporte, Pierre Rousseau, Loïc Jomat, Nathalie Bourret, Julia Guerra Carande, Flavie Rouet, Guillaume Seglen, Bernard Queval, Christophe Dufour, Claude Champarnaud, Thomas Herault, Karine Vennel, Ludovic Pépin, Camille Pereira, Nathan Chouteau, François Villain, Yakov Uzan and all volunteers for their help during field work. We are also thankful to Gaël Guillou from the "Plateforme analyses isotopiques" of LIENSs (La Rochelle Université) for computing isotopic analyses. Thanks are due to the Contrat de Projet Etat-Région (CPER) and the Fonds Européen de Développement Régional (FEDER) for funding the isotope-ratio mass spectrometers of LIENSs laboratory. The Institut Universitaire de France (IUF) is acknowledged for its support to Paco Bustamante as a Senior Member.

Funding statement

Funding was provided by the CNRS, La Rochelle Université, the LPO, the Agence de l'Eau Adour-Garonne, the Conseil Départemental de la Charente-Maritime, the ANR PAMPAS (ANR-18-CE32-0006), the Contrat de plan Etat-Région Econat and the Fonds Européen de Développement Régional (FEDER). Funders had no role in study design;

Data availability statement

Data will be made available on the corresponding author upon reasonable request.

in the current study) seems to be relevant to comprehensively understand isoscapes in a site-specific context.

Declarations Declaration of competing interest

The authors declare that they have no conflict of interest.

Ethics statement

This work was approved by the French authorities under permits R-45GRETA-F1-10 and 135-2020 DBEC.


Christian Piedallu

Nancy Agroparistech

La Avec

A Contribution D'

D Taccoen

C Dallery

M Bresson

J C Legay

R Gégout

I Pierrat

V Seynave

A Perez

L M Gégout-Petit

JD Nageleisen

N Bontemps

L Bréda

Ingénieurs Saint-André

Agroparistech

Détermination et cartographie de la vulnérabilité des essences au changement climatique récent

• La mortalité d'arbres est un phénomène naturel (Charru et al 2012) • De nombreuses crises se sont déjà succédées (1916-1925, 1943-1951, 1973-1981, …) • Sécheresses, pollution, … (Bonneau, 1985) • De nombreuses causes possibles qui interagissent (Sinclair, 1965) La spirale du déclin, Manion 1991

Merci pour votre attention … Colloque SANTECOFOR

Santé des écosystèmes forestiers : enjeux de société

  et al 2018) En France (réseau systématique, DSF) Constat : • Préservation d'une forêt fonctionnelle : un enjeu majeur /services écosystémiques dont stockage de carbone … (Brockerhoff et al. 2017 ) • Difficile de : i) quantifier les tendances de fond, ii) démêler les différentes causes (vieillissement, capitalisation, changement climatique, biotiques …), iii) anticiper les problèmes sanitaires. => Acteurs ont besoin d'outils pour adapter les forêts Dans quelle mesure les forêts sont-elles mises à mal par le changement climatique ? Objectifs : • Evaluer l'impact du changement climatique • Identifier les différents facteurs de risque • Cartographier la vulnérabilité des peuplements • France: 43 à 8 espèces d'arbres, 373000 à 207000 placettes IGN Une approche de modélisation/différentes échelles

•••••

  France: 43 espèces, 373000 arbres, 29 prédicteurs, 2009-2015 • Performance modèles AUC = 0,78 ± 0,06 (Taccoen et al, 2019) Une surmortalité climatique ± moitié des espèces Anomalies de température (°C) /1961-1987 Anomalies de précipitations (mm) /1961-1987 • Changement climatique/mortalité d'arbres, à paramètres constants (Taccoen et al, 2019) des variables liées au changement de température ou de régimes de précipitations (Taccoen et al, 2021) France: 12 espèces, 265000 arbres (Taccoen et al, 2022) Occurrence des variables liées au changement climatique seule (hypothèse 1, à gauche) ou en interaction avec le climat moyen (hypothèse 2, à droite) (Piedallu et al, 2022) • Massif Vosgien : dépérissements liés à la dynamique d'augmentation du stress hydrique estival des sols (1986Plus faible mortalité dans les zones habituées au stress hydrique => prendre en compte la dynamique d'évolution Arbres dominés ou de faible circonférence • Arbres âgés • Importance et nature du mélange, selon l'espèce, par ex. effet positif d'un fort mélange avec feuillus pour sapin/épicéa • Forte surface terrière et fort recouvrement de la canopée • Structure régulière • Présence de lisières (particulièrement orientées sud) => microclimat défavorable Que faut-il en retenir ? 13 13 Augmentation de la mortalité liée dynamique du climat, bien intégrer les caractéristiques peuplement, détection seuils climatiques critique • Sous estimation de la mortalité /BD => séries temporelles d'images satellitales • Les facteurs biotiques indirectement intégrés dans les modèles • Des effets différents selon l'échelle : décalage aires de distribution, adaptation, topographie … • Des enseignements sur les peuplements plus résistants : nécessaire d'approfondir (structure, mélange …) • Importance des variables liées au bilan en eau : forte variabilité locale des évolutions du stress hydrique/sols, difficile à prédire à court terme, augmentation du stress à long terme (GIEC, 2022).

 (Piedallu et al, 2022)Cartographie des zones vulnérables


domain: sdv shs

text:
Anne Aupiais

Elsa Delanoue

Agathe Cheype

Denis Gautier

Marie-Madeleine Mialon

Noémie Devriendt

Stella Delaunay

Louis Ferran

Xavier Boivin

la diffusion de documents scientifiques de niveau

recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

  Indicateur d'évaluation du bien-être des ovins évoqués par les acteurs de terrain au cours d'enquêtes et de focus groupes Indicateurs d'évaluation du bien-être des ovins évoqués par les acteurs de terrain au cours d'enquêtes et de focus groups Projets MOUBIENE et MOUBIENELait LOGOS LOGOS CONTEXTE MATÉRIEL ET MÉTHODES Le respect du bien-être des animaux d'élevage est une préoccupation importante pour un grand nombre de citoyens et de professionnels. Dans leur « Plan de filière » commun, les filières ovines prévoient la mise en place d'une grille objective pour « mesurer » le bien-être animal en élevage. Dans le cadre des projets MOUBIENE (agneaux en engraissement issus des troupeaux laitiers et allaitants) et MOUBIENELait (brebis laitières), financés respectivement par INTERBEV OVINS et FBL (France Brebis Laitières), des focus groups et enquêtes ont été menées auprès d'acteurs de terrain afin de recenser les indicateurs qu'ils jugent d'intérêt pour évaluer le bien-être des agneaux et brebis. RÉSULTATS (PROVISOIRES) CONCLUSION cités par les éleveurs (a) et les techniciens (b) au cours des enquêtes A l'issue de cette partie sociologique, nous avons donc pu disposer d'une liste d'indicateurs d'évaluation du bienêtre des ovins jugée d'intérêt par les acteurs de terrain. Elle est en cours de validation scientifique et reste à valider par la profession. Cette étape de concertation et de co-construction des indicateurs de bien-être est cruciale pour que les acteurs de terrain puissent ensuite s'approprier l'outil d'évaluation et de gestion du bien-être des ovins qui leur sera proposé. AUTEURS : Aupiais Anne 1 , Delanoue Elsa 2 , Cheype Agathe 3 , Gautier Denis 4 , Mialon Marie-Madeleine 5 , Devriendt Noémie 1 , Ferran Louis 1 , Delaunay Stella 1 et Boivin Xavier 5 . (1) Institut de l'Elevage, Monvoisin, 35650 Le Rheu, (2) Institut de l'Elevage, 149 rue de Bercy, 75595 Paris Cedex 12, (3) Institut de l'Elevage, Maison Régionale de l'Agriculture du Limousin, Boulevard des Arcades, 87060 Limoges (4) Ferme Expérimentale ovine du Mourier, 87800 St Priest Ligoure, (5) INRAE, UMR Herbivores, F-63122 Saint-Genès-Champanelle cités par les techniciens et les éleveurs au cours des focus groups Agneaux issus du troupeau allaitant Indicateurs de bien-être Agneaux issus du troupeau laitier Brebis laitières Tous les éleveurs citent en premier lieu des indicateurs liés au comportement des animaux. Etant au contact de leurs animaux tous les jours et détectent rapidement un changement de comportement et/ou un comportement anormal chez leurs animaux qui peut être indicateur d'un problème de santé. Ils citent par contre moins d'indicateurs des principes de bonne alimentation et logement correct, considérant qu'ils nourrissent et logent correctement leurs animaux. Les indicateurs cités par les techniciens sont mieux répartis dans les quatre principes du BEA.