Landscape epidemiology of Batrachochytrium salamandrivorans : reconciling data limitations and conservation urgency

Starting in 2010, rapid-fire salamander (Salamandra salamandra) population declines in northwestern Europe heralded the emergence of Batrachochytrium salamandrivorans (Bsal), a salamander-pathogenic chytrid fungus. Bsal poses an imminent threat to global salamander diversity owing to its wide host range, high pathogenicity, and long-term persistence in ecosystems. While there is a pressing need to develop further research and conservation actions, data limitations inherent to recent pathogen emergence obscure necessary insights into Bsal disease ecology. Here, we use a hierarchical modeling framework to describe Bsal landscape epidemiology of outbreak sites in light of these methodological challenges. Using model selection and machine learning, we find that Bsal presence is associated with humid and relatively cool, stable climates. Outbreaks are generally located in areas characterized by low landscape heterogeneity and low steepness of slope. We further find an association between Bsal presence and high trail density, suggesting that human-mediated spread may increase risk for spillover between populations. We then use distribution modeling to show that favorable conditions occur in lowlands influenced by the North Sea, where increased survey effort is needed to determine how Bsal impacts local newt populations, but also in hill- and mountain ranges in northeastern France and the lower half of Germany. Finally, connectivity analyses suggest that these hill- and mountain ranges may act as stepping stones for further spread southward. Our results provide initial insight into regional environmental conditions underlying Bsal epizootics, present updated invasibility predictions for northwestern Europe, and lead us to discuss a wide variety of potential survey and research actions needed to advance future conservation and mitigation efforts

Expanding distribution of lethal amphibian fungus Batrachochytrium salamandrivorans in Europe

Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity

Rapport sur les espèces macro-indicatrices de la qualité des cours d’eau. Répartition, Habitat, Mesures de protection et de restauration des populations

The Direction of the non-navigable watercourses of the Ministry of the Walloon Region commited the realisation of a study on some flagship riverine or aquatic animal species to the zoogeographical research unit’s care. The species were selected owing to their aquatic or semi-aquatic life history traits and to their interest as bio-indicators of the quality of the riverine habitats. Their patrimonial interest was also taken into account, some of them are indeed concerned either by the Bird or by the Habitat directives (CE 79/409 and CE 92/43). The next species were considered in this report: European otter (Lutra lutra), Dipper (Cinclus cinclus), Kingfisher (Alcedo atthis) unionid mussels (Unio crassus and Margararitifera margaritifera), water shrews (Neomys anomalus and Neomys fodiens), Sand martin (Riparia riparia), bats (Chiroptera) and four species of damselflies :Onychogomphus forcipatus, Oxygastra curtisi, Gomphus vulgatissimus, Cordulegaster boltonii. The main life history traits of every species was reminded and their main habitat requirements were presented. The available distributional data were reviewed and proposals made to complete the surveys and to implement the conservation needs, especially the ones relevant to the watercourses management office. In the northern part of the region, most of the rivers and streams are heavily polluted and their banks damaged. Most of the species concerned by the present report are therefore absent or scarce. In this region, the priority is a significant reduction of the pollution level. In the south, water quality is better and the hydraulic works were less strong, except in some limited parts. Formerly distributed throughout the Ardenne, the pearl mussel is now limited to very few rivers (Ourthe, Sûre, Semois and Our catchments). Its conservation status is of great concern since its populations are tiny and made up of old individuals only. The situation of Unio crassus is better as far as its ecological requirements are less specialised. Some young individuals were found, indicating that this mussel is still reproducing in several rivers. The water shrew is present throughout the region whereas the Miller’s water shrew is restricted to the Ardenne, east of the river Meuse. Their precise habitat requirements are not well known and it should be interesting to start up a new survey of both species including the study of their ecology. The few otters still surviving in the south of the region must benefit from habitat preservation measures. Suitable structures for holts, couches or resting places must be located (GIS) and protected. The main conservation problem for the kingfisher and for the sand martin is the protection of banks suitable for nest-building. These structures ought to be mapped and strictly protected. As far as the dipper and the bats are concerned, some attention is needed when bridges need maintenance repairs. Small cavities or even nestboxes must be fit up to allow these animals to breed or to rest

Ségregation alimentaire entre deux martins-pêcheurs: Alcedo cristata et Ceryle rudis dans le lac Nokoué (Bénin)

Several species of kingfisher occur on Lake Nokoué, southern Bénin, including Malachite (Alcedo cristata) and Pied Kingfishers (Ceryle rudis). Here, we compare their diet and estimate the degree of overlap in food niche by analysing contents of regurgitated pellets collected near nesting sites of Pied Kingfishers or inside the nest chambers of Malachite Kingfishers. Characteristic fish skull bones were identified using a reference collection of local fish skeletons. Malachite Kingfishers feed most frequently on fish that occur around floating vegetation, mainly Kribia sp. (56%), Hemichromis fasciatus (28%) and Sarotherodon melanotheron (8%). Important differences were found between different pairs, and between adults and nestlings, the latter being fed almost exclusively on Kribia sp. Larger fish are fed to nestlings than are eaten by the adults. Pied Kingfishers prey upon 14 different fish species, some of them being caught in the pelagic region of the lake, particularly clupeids taken by hovering. By comparison with Malachite Kingfishers, Pied Kingfishers feed on a wider diversity of prey, and take larger fish, so that the dietary overlap between the species is relatively low (O = 0.181)

On the feeding ecology of the pied kingfisher, Ceryle rudis at Lake Nokoué, Benin. Is there competition with fishermen ?

Lake Noukoué in southern Benin, is heavily exploited fishery, but it is also inhabited by numerous piscivorous birds, escpecially kingfishers. This study considers the similarity between the diet of kingfishers and fish available on the local market between mid-February to mi-May 1999, durng a low water level preriod. Excretory pellets were collected on the top of breeding banks and inside brood chambers. The diet was determined by comparing the bones recovered from the pellets with a reference collection. Eighteen prey categories were recognised in the 1099 diagnostic items. Kingfishers preyed mostly on cichlids (Sarotherodon melanotheron Rüppell and Hemichromis fasciatus Peters), clupeids (Ethmalosa fimbria (Bowdich)), eleotrids (Kribia sp.) and Hyporhamphus picarti (Val.). Prey size of H. fasciatus ranged from 22 to 73 mm (46.4 +/- 11.6 mm) and S. melanotheron from 24 to 65 mm (44 +/- 9.2 mm). The compositionof the diet varied depending on time and location. Overlap with marketed fish is limitid to S. melanotheron

Food niche segregation between the Malachite Kingfisher, Alcedo cristata, and the Pied Kingfisher, Ceryle rudis, at Lake Nokoué, Bénin

Several species of kingfisher occur on Lake Nokoué, southern Bénin, including Malachite (Alcedo cristata) and Pied Kingfishers (Ceryle rudis). Here, we compare their diet and estimate the degree of overlap in food niche by analysing contents of regurgitated pellets collected near nesting sites of Pied Kingfishers or inside the nest chambers of Malachite Kingfishers. Characteristic fish skull bones were identified using a reference collection of local fish skeletons. Malachite Kingfishers feed most frequently on fish that occur around floating vegetation, mainly Kribia sp. (56%), Hemichromis fasciatus (28%) and Sarotherodon melanotheron (8%). Important differences were found between different pairs, and between adults and nestlings, the latter being fed almost exclusively on Kribia sp. Larger fish are fed to nestlings than are eaten by the adults. Pied Kingfishers prey upon 14 different fish species, some of them being caught in the pelagic region of the lake, particularly clupeids taken by hovering. By comparison with Malachite Kingfishers, Pied Kingfishers feed on a wider diversity of prey, and take larger fish, so that the dietary overlap between the species is relatively low (O = 0.181).Ostrich 2004, 75(1&2): 32–3

Adaptation de l'entretien des ripisylves au patrimoine naturel

Sectorisation des cours d'eau de première catégorie de la Région wallonne et conception d'un plan d'entretien des ripisylve

Divergent population responses following salamander mass mortalities and declines driven by the emerging pathogen Batrachochytrium salamandrivorans

Understanding wildlife responses to novel threats is vital in counteracting biodiversity loss. The emerging pathogen Batrachochytrium salamandrivorans (Bsal) causes dramatic declines in European salamander populations, and is considered an imminent threat to global amphibian biodiversity. However, real-life disease outcomes remain largely uncharacterized. We performed a multidisciplinary assessment of the longer-term impacts of Bsal on highly susceptible fire salamander (Salamandra salamandra) populations, by comparing four of the earliest known outbreak sites to uninfected sites. Based on large-scale monitoring efforts, we found population persistence in strongly reduced abundances to over a decade after Bsal invasion, but also the extinction of an initially small-sized population. In turn, we found that host responses varied, and Bsal detection remained low, within surviving populations. Demographic analyses indicated an ongoing scarcity of large reproductive adults with potential for recruitment failure, while spatial comparisons indicated a population remnant persisting within aberrant habitat. Additionally, we detected no early signs of severe genetic deterioration, yet nor of increased host resistance. Beyond offering additional context to Bsal-driven salamander declines, results highlight how the impacts of emerging hypervirulent pathogens can be unpredictable and vary across different levels of biological complexity, and how limited pathogen detectability after population declines may complicate surveillance efforts