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

Gestion forestière et dynamique des populations de Sonneurs à ventre jaune (Bombina variegata): synthèse bibliographique et mesures de conservation: Forest management and population dynamics of the Yellow-bellied Toad (Bombina variegata): bibliographic review and conservation measures

International audienceDuring the 20th century, yellow-bellied toad (Bombina variegata) populations suffered from a strong decline in western Europe, especially in France. The causes of this decline are potentially multiple, including habitat loss and fragmentation, and climate change. To date, production forests host the largest yellow-bellied toad populations in France. Conservation of this species is thus tightly linked to forest management practices. During the last decade, intensification of forest harvesting led to the increasing systematic removal of ruts, the preferential breeding habitat of yellow-bellied toad in production forests. Enstonement of forest paths and timber storage areas, and the rapid filling of ruts after forest harvesting, are potential causes of decline for this species. Here, we synthetize the results of papers focusing on the impact of forest management practices on yellow-bellied toad population dynamics. We started our review paper with a comparative demographic analysis between populations from riverine habitat and production forest. After highlighting the demographic characteristics of forest populations, we documented the influence of path enstonement and road pavement on yellow-bellied toad dispersal. We also reported the effect of rut patch destruction on adult survival and long-term population viability. In the light of scientific evidences gathered in our synthesis, we concluded that these forest management practices pose a major threat for forest populations viability and persistence. We proposed a set of management practices aimed at better alignment of forestry activities and yellow-bellied toad conservation in French production forests.Durant le 20ème siècle, les populations de Sonneurs à ventre jaune (Bombina variegata) ont subi un net déclin en Europe de l’Ouest, et en France tout particulièrement. Les causes de cette régression sont possiblement multiples, incluant la perte et la fragmentation d’habitat, ainsi que les changements climatiques. De nos jours, les forêts de production de bois abritent les plus grandes populations de Sonneurs à ventre jaune du territoire. La conservation de cette espèce apparait donc étroitement dépendante des pratiques de gestion forestière. Depuis une dizaine d’années, l’intensification de l’exploitation forestière favorise l’élimination de plus en plus systématique des ornières, lesquelles constituent l’habitat de reproduction préférentiel du Sonneur à ventre jaune en forêt de production. L’empierrement des chemins forestiers et des places de dépôt de bois, ainsi qu’une tendance au comblement rapide des ornières après l’exploitation des parcelles, constituent des causes potentielles de déclin pour cette espèce. Dans cet article, nous effectuons une synthèse des travaux s’intéressant aux impacts des pratiques de gestion forestière sur la dynamique des populations de Sonneurs à ventre jaune en France. Nous débutons par une analyse de démographie comparée entre les populations d’environnements rivulaires et celles de forêts de production. Après avoir mis en évidence les particularités démographiques des populations forestières, nous rapportons les effets de l’empierrement et du goudronnage des chemins forestiers sur la dispersion. Puis, nous documentons l’effet de la destruction des patchs d’ornières sur la survie des adultes et la viabilité à long terme des populations. Sur la base des faits scientifiques rassemblés dans cette synthèse, il résulte que ces pratiques de gestion font courir un risque majeur pour la viabilité des populations en forêt. Nousproposons une série de préconisations de gestion visant à assurer une meilleure adéquation entre les travaux forestiers et la conservation du Sonneur à ventre jaune dans les forêts de production françaises

Acoustic localization at large scales: a promising method for grey wolf monitoring

Abstract Background The grey wolf (Canis lupus) is naturally recolonizing its former habitats in Europe where it was extirpated during the previous two centuries. The management of this protected species is often controversial and its monitoring is a challenge for conservation purposes. However, this elusive carnivore can disperse over long distances in various natural contexts, making its monitoring difficult. Moreover, methods used for collecting signs of presence are usually time-consuming and/or costly. Currently, new acoustic recording tools are contributing to the development of passive acoustic methods as alternative approaches for detecting, monitoring, or identifying species that produce sounds in nature, such as the grey wolf. In the present study, we conducted field experiments to investigate the possibility of using a low-density microphone array to localize wolves at a large scale in two contrasting natural environments in north-eastern France. For scientific and social reasons, the experiments were based on a synthetic sound with similar acoustic properties to howls. This sound was broadcast at several sites. Then, localization estimates and the accuracy were calculated. Finally, linear mixed-effects models were used to identify the factors that influenced the localization accuracy. Results Among 354 nocturnal broadcasts in total, 269 were recorded by at least one autonomous recorder, thereby demonstrating the potential of this tool. Besides, 59 broadcasts were recorded by at least four microphones and used for acoustic localization. The broadcast sites were localized with an overall mean accuracy of 315 ± 617 (standard deviation) m. After setting a threshold for the temporal error value associated with the estimated coordinates, some unreliable values were excluded and the mean accuracy decreased to 167 ± 308 m. The number of broadcasts recorded was higher in the lowland environment, but the localization accuracy was similar in both environments, although it varied significantly among different nights in each study area. Conclusions Our results confirm the potential of using acoustic methods to localize wolves with high accuracy, in different natural environments and at large spatial scales. Passive acoustic methods are suitable for monitoring the dynamics of grey wolf recolonization and so, will contribute to enhance conservation and management plans

Using acoustic indices to estimate wolf pack size

International audienc

Population position along the fast–slow life‐history continuum predicts intraspecific variation in actuarial senescence

Patterns of actuarial senescence can be highly variable among species. Previous comparative analyses revealed that both age at the onset of senescence and rates of senescence are linked to position of a species along the fast–slow life‐history continuum. As there are few long‐term datasets of wild populations with known‐age individuals, intraspecific (i.e. between‐population) variation in senescence is understudied and limited to comparisons of wild and captive populations of the same species, mostly birds and mammals. In this paper, we examined how population position along the fast–slow life‐history continuum affects intraspecific variation in senescence in an amphibian, Bombina variegata. We used capture–recapture data collected in four populations with contrasting life‐history strategies. Senescence trajectories were analysed using Bayesian capture–recapture models. We show that in populations with fast life histories the onset of actuarial senescence was earlier and individuals aged at a faster rate than individuals in populations with slow life histories. Our study provides one of the few empirical examples of among‐population variation in actuarial senescence patterns in the wild and confirms that the fast–slow life‐history gradient is associated with both macroevolutionary and microevolutionary patterns of actuarial senescence

Data from: Demographic response to patch destruction in a spatially structured amphibian population

1. Economic activities such as logging and mineral extraction can result in the creation of new anthropogenic habitats that host specific biodiversity, including protected species. However, the legislation in many Western European countries requires the rehabilitation of ‘damaged’ areas following logging and mining operations, which can eliminate these early successional habitats. Conservation managers face a dilemma in these situations, but often lack knowledge about the impacts of environmental rehabilitation on the population dynamics of pioneer species and so are unable to take this into account in their actions. 2. We investigated the demography of a spatially structured population of an endangered amphibian (Bombina variegata) that uses waterbodies created by logging activities as breeding sites. Using capture–recapture (CR) data collected during a 9-year study period, we examined how the destruction of breeding patches due to environmental rehabilitation affected adult survival and the long-term population growth rate. For this purpose, we used recently developed capture-recapture multievent models to estimate survival and dispersal rates in the spatially structured population. We then used these estimates to simulate population trajectories and viability depending on differing frequency of breeding patch destruction. 3. The multievent models revealed that dispersal not resulting from patch loss was relatively high and was sex-biased. They also revealed that patch destruction had a negative impact on adult survival. Moreover, simulations showed that the increase of patch destruction frequency had a strong negative influence on the population growth rate, even when the number of patch remained constant over time. This impact was intensified if female fecundity was also affected. 4. Synthesis and applications. Our study quantified for the first time the detrimental effect of habitat rehabilitation on the population dynamics of an endangered, pioneer species. Yet our study also found that this deleterious impact of patch destruction could be reduced by certain management practices, as avoiding the systematic rehabilitation of the breeding patches and compensating for patch destruction by creating substitute breeding patches

Demographic responses to weather fluctuations are context dependent in a long-lived amphibian

International audienceWeather fluctuations have been demonstrated to affect demographic traits in many species. In long-lived organisms, their impact on adult survival might be buffered by the evolution of traits that reduce variation in interannual adult survival. For example, skipping breeding is an effective behavioral mechanism that may limit yearly variation in adult survival when harsh weather conditions occur; however, this in turn would likely lead to strong variation in recruitment. Yet, only a few studies to date have examined the impact of weather variation on survival, recruitment and breeding probability simultaneously in different populations of the same species. To fill this gap, we studied the impact of spring temperatures and spring rainfall on survival, on reproductive skipping behavior and on recruitment in five populations of a long-lived amphibian, the yellow-bellied toad (Bombina variegata). Based on capture–recapture data, our findings demonstrate that survival depends on interactions between age, population and weather variation. Varying weather conditions in the spring result in strong variation in the survival of immature toads, whereas they have little effect on adult toads. Breeding probability depends on both the individual’s previous reproductive status and on the weather conditions during the current breeding season, leading to high interannual variation in recruit- ment. Crucially, we found that the impact of weather variation on demographic traits is largely context dependent and may thus differ sharply between populations. Our results suggest that studies predicting the impact of climate change on population dynamics should be taken with caution when the relationship between climate and demo- graphic traits is established using only one population or few populations. We therefore highly recommend further research that includes surveys replicated in a substantial number of populations to account for context-dependent variation in demographic processes

Life history tactics shape amphibians’ demographic responses to the North Atlantic Oscillation

International audienceOver the last three decades, climate abnormalities have been reported to be involved in biodiversity decline by affecting population dynamics. A growing number of studies have shown that the North Atlantic Oscillation (NAO) influences the demographic parameters of a wide range of plant and animal taxa in different ways. Life history theory could help to understand these different demographic responses to the NAO. Indeed, theory states that the impact of weather variation on a species’ demographic traits should depend on its position along the fast–slow continuum. In particular, it is expected that NAO would have a higher impact on recruitment than on adult survival in slow species, while the opposite pattern is expected occur in fast species. To test these predictions, we used long-term capture–recapture data- sets (more than 15,000 individuals marked from 1965 to 2015) on different sur- veyed populations of three amphibian species in Western Europe: Triturus cristatus, Bombina variegata, and Salamandra salamandra. Despite substantial intraspecific variation, our study revealed that these three species differ in their position on a slow–fast gradient of pace of life. Our results also suggest that the differences in life history tactics influence amphibian responses to NAO fluctuations: Adult survival was most affected by the NAO in the species with the fastest pace of life (T. cristatus), whereas recruitment was most impacted in species with a slower pace of life (B. variegata and S. salamandra). In the context of climate change, our findings suggest that the capacity of organisms to deal with future changes in NAO values could be closely linked to their position on the fast–slow continuum

Life history tactics shape amphibians’ demographic responses to the North Atlantic Oscillation

Over the last three decades, climate abnormalities have been reported to be involved in biodiversity decline by affecting population dynamics. A growing number of studies have shown that the North Atlantic Oscillation (NAO) influences the demographic parameters of a wide range of plant and animal taxa in different ways. Life history theory could help to understand these different demographic responses to the NAO. Indeed, theory states that the impact of weather variation on a species’ demographic traits should depend on its position along the fast–slow continuum. In particular, it is expected that NAO would have a higher impact on recruitment than on adult survival in slow species, while the opposite pattern is expected occur in fast species. To test these predictions, we used long-term capture–recapture datasets (more than 15,000 individuals marked from 1965 to 2015) on different surveyed populations of three amphibian species in Western Europe: Triturus cristatus, Bombina variegata, and Salamandra salamandra. Despite substantial intraspecific variation, our study revealed that these three species differ in their position on a slow–fast gradient of pace of life. Our results also suggest that the differences in life history tactics influence amphibian responses to NAO fluctuations: Adult survival was most affected by the NAO in the species with the fastest pace of life (T. cristatus), whereas recruitment was most impacted in species with a slower pace of life (B. variegata and S. salamandra). In the context of climate change, our findings suggest that the capacity of organisms to deal with future changes in NAO values could be closely linked to their position on the fast–slow continuum

Does habitat unpredictability promote the evolution of a colonizer syndrome in amphibian metapopulations ?

International audienceDispersal is a central component of life history evolution. An increasing number of studies suggest that spatiotemporally variable environments may promote the evolution of “dispersal syndromes,” consisting of covariation patterns between dispersal and morphologi- cal, physiological, behavioral, and life history traits. At the interspecific scale, the “colonizer syndrome” appears to be one of the most frequently recorded associations between dispersal and life history traits, linking a high dispersal rate, high fecundity, and a short lifespan as sys- tematically combined adaptations in spatiotemporally varying environments. However, few studies have highlighted the existence of a “colonizer syndrome” at the intraspecific scale, and none have investigated how different degrees of habitat stochasticity might shape covariation patterns between dispersal and life history traits. In this study, we examined this issue in free- ranging metapopulations of the yellow-bellied toad (Bombina variegata) using capture–recap- ture data. Combining the results of this study with another recent study, we found that a high dispersal rate, high fecundity, and a short lifespan are associated in metapopulations experi- encing unpredictable environments. In contrast, a very low dispersal rate (close to zero), low fecundity and a long lifespan are associated in metapopulations occupying predictable environ- ments. We discuss these results as well as their demographic and evolutionary consequences