Environmentally mediated reproductive success predicts breeding dispersal decisions in an early successional amphibian

Dispersal is a central mechanism in ecology and evolution. Dispersal evolution is driven by a trade-off between costs and benefits, which is influenced by interindividual variability and local environmental conditions (context-dependent dispersal). Many studies have investigated how dispersal decisions may be influenced by environmental factors, including density, predation and interspecific competition. Yet few have attempted to examine how habitat disturbance may affect the dispersal process in spatially structured populations. In early successional species, one might expect individuals to adjust their dispersal decisions based on two main factors that potentially have an influence on reproductive success: patch size and the level of patch disturbance. In this study, we examined how these two factors affect breeding success and dispersal decisions in an early successional amphibian, the yellow- bellied toad, Bombina variegata. To this end, we used capture–recapture data collected on a spatially structured population occupying 28 breeding patches. We took advantage of recent developments in multievent capture–recapture models to detect signs of context-dependent dispersal. The results revealed that the probability of successful reproduction and the number of newly metamorphosed individuals increased with both the size and the proportion of disturbance of a patch. In addition, our results showed that the factors affecting breeding success also influenced breeding dispersal probability. Large patch size negatively influenced emigration probability; in contrast, it positively influenced immigration probability. Equally, higher disturbance had a strong negative influence on emigration probability and slightly positively affected immigration probability. These findings strongly suggest that individuals make context-dependent dispersal decisions, adjusted to maximize future fitness prospects in a patch, allowing them to better cope with rapid changes in environmental conditions resulting from the ecological succession process. This opens new areas of potential research into the role of dispersal in organism specialization along an ecological succession gradient

Movement patterns, habitat selection, and corridor use of a typical woodland-dweller species, the European pine marten (Martes martes), in fragmented landscape

International audienceWoodland fragmentation through land consolidation practices (the merging of small fields by the removal of separating structures like hedgerows) is recognised as a major threat to biodiversity in Europe. While its impact on the occurrence of species has frequently been the object of focus, its impact on the movements of individuals has rarely been studied. We used paths of radio-tracked European pine martens (Martes martes (L., 1758)), a forest-dwelling species, with fixes taken at 3 min intervals to determine their habitat use in fragmented landscape. Our results differ from those generally reported in the literature. Monitored individuals were not confined to large forests, and made additional use of small wood plots and hedgerows. Indeed, individuals moved faster in forests than in all other habitat types, which suggests that martens preferentially foraged in small woods, edges, and hedgerows. Roads and buildings were not avoided; fields, however, were avoided, although they did not act as barriers. Martens stayed close to forest cover when venturing into open ground, which suggests that although not restricted to forests, pine martens exhibit a certain dependence on the presence of trees in the vicinity.La fragmentation du milieu forestier par le remembrement des terres agricoles (le fusionnement des petits champs par le retrait des barrières telles que les haies) est considérée comme une menace majeure pour la biodiversité en Europe. L’impact de cette fragmentation sur la présence des espèces a souvent été évalué, mais son effet sur les déplacements des individus a rarement été étudié. Notre étude avait pour but d’examiner l’utilisation des différents types d’habitats en paysage fragmenté par une espèce forestière, la martre d’Europe (Martes martes (L., 1758)). Pour ce faire, nous avons relevé les parcours d’individus équipés de colliers émetteurs sur la base de localisations effectuées toutes les 3 minutes. Nos résultats diffèrent de ceux généralement rapportés dans la littérature. Les martres suivies n’étaient pas confinées aux grands massifs forestiers, mais fréquentaient également les bosquets et les haies. Les martres se déplaçaient même plus rapidement dans les grands massifs que dans n’importe quel autre habitat, suggérant qu’elles chassaient préférentiellement dans les bosquets, les lisières et les haies. Les routes et les bâtiments n’étaient pas évités. Seul le milieu ouvert l’était, sans pour autant constituer une barrière. Les martres restaient à proximité du couvert forestier lorsqu’elles s’aventuraient en milieu ouvert. Soulignant ainsi leur attachement a la proximité du couvert forestier

Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

Studying dental ontogeny in mammals can provide valuable insight on the evolution of their masticatory apparatus and their related adaptations. The multiple acquisitions of a prolonged to continuous growth of teeth in herbivorous mammals in response to high abrasion represent an intensively investigated issue. However, the ontogenetic and architectural patterns associated with these repeated dental innovations remain poorly known. Here, we focused on two case studies corresponding to distant mammalian clades, the extinct Mesotheriidae (Notoungulata), which shared some striking dental features with the extant Ctenodactylidae (Rodentia). We studied the impact of prolonged to continuous growth of molars on their occlusal complexity, their relative size and their dynamics in the jaw. We found that variations of occlusal complexity patterns are the result of paedomorphic or peramorphic heterochronic processes impacting dental crown. We showed that variations in both upper and lower molar proportions generally follow the inhibitory developmental cascade model. In that context, prolonged dental growth implies transitory adjustments due to wear, and also involves dental migration and loss when combined with molar lengthening. Interestingly, these features may be present in many mammals having prolonged dental growth, and emphasize the crucial need of considering these aspects in future evolutionary and developmental studies.Fil: Rodrigues, Helder Gomes. Centre National de la Recherche Scientifique; Francia. Universite de Paris VI; FranciaFil: Lefebvre, Rémi. Centre National de la Recherche Scientifique; Francia. Universite de Paris VI; FranciaFil: Fernández García, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Quispe Colquehuanca, Wilmer Edy. Museo Nacional de Historia Natural; BoliviaFil: Billet, Guillaume. Centre National de la Recherche Scientifique; Francia. Universite de Paris VI; Franci

Identifying environmental drivers of spatial genetic structure of the European pine marten (Martes martes)

International audienceIn a global context of erosion of biodiversity, the current environmental policy in Europe is oriented towards the creation and the preservation of ecological networks for wildlife. However, most of the management guidelines arose from a structural landscape diagnostic without truly taking into consideration species' needs. We tested whether and how landscape elements influence the functional connectivity of landscapes for a forest specialist species, the European pine marten (Martes martes), in Northeastern France. We collected pine marten scats and tissues from 13 evenly distributed study sites across the whole study area in order to test several types of barriers such as highways, waterways, and open agricultural fields. We crossed the results of several methods: spatial autocorrelation analysis, causal modelling framework, and clustering methods. The study indicates significant genetic differentiation among the sampling sites. A signal of isolation by distance was detected but disappeared after partialling out landscape or barrier resistance. The only model that was fully supported by causal modelling was the one identifying waterways as the main driver of genetic differentiation. Moreover, clustering analyses indicated the presence of genetic clusters, suggesting that pine marten spatial genetic pattern could be explained by the presence of waterways but also by their reluctance to cross open fields. The current ecological network could thus be improved by increasing permeability of waterways, in particular navigation canals, and by maintaining and restoring forested corridors in agricultural plains

The project of a LTSER site Driven by civil society in the Argonne

International audienc

Supp. Tab. 2 from Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

Test of correlation between dental area and occlusal complexity

Supp. Tab.1 from Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

Dental measurements in Mesotheriidae and Ctenodactylida

Effect of forest fragmentation on space-use patterns in the European pine marten (Martes martes)

International audienceThe cffcct:\ of forest fragmentation on individual space-use patterns were investigated in the European pine marten (Martes martes), considered as a forest-dependent species. The study was done in Ârdennes, France, with the landscape consisting of both cominuous ÎoresI and fragmented habiiai, poor-quality habiiat for pim: marLens. In Lois lanùsr.:ape cOnLexl 3 preûictions were tested: ùue to inuaspeclflc competition, subadults should be overrepresented in fragmented habitat; according to the landscape supplementation theory, home ranges should be larger in fragmented habitat; and over seasons, home ranges should be more stable in forest than in fragmented habitat. Thirty-six individuals were trapped in both habitats, and 23 were radiotrackcd during 3-5 consecutive se.asons. Confirming our 1st prediction, v,le found Lhat the ratio of subadu1ts to adults in fragmente.d habitat was higher Lhan in forest. On the contrary; annu~J home ranges were larger in forest than in fragmented habitat, and temporal stability of home ranges was not significantly different between habitats. Therefore, our results indicate that the pine marten can persist in fragmented habitat and could rathee be defined as a treedependent species