Showing papers by "An Martel published in 2022"

Tree Species Diversity and Forest Edge Density Jointly Shape the Gut Microbiota Composition in Juvenile Great Tits (Parus major)

Abstract: Despite the microbiome’s key role in health and fitness, little is known about the environmental factors shaping the gut microbiome of wild birds. With habitat fragmentation being recognised as a major threat to biological diversity, we here determined how forest structure influences the bacterial species richness and diversity of wild great tit nestlings (Parus major). Using an Illumina metabarcoding approach which amplifies the 16S bacterial ribosomal RNA gene, we measured gut microbiota diversity and composition from 49 great tit nestlings, originating from 23 different nests that were located in 22 different study plots across a gradient of forest fragmentation and tree species diversity. Per nest, an average microbiome was determined on which the influence of tree species (composition and richness) and forest fragmentation (fragment area and edge density) was examined and whether this was linked to host characteristics (body condition and fledging success). We found an interaction effect of edge density with tree species richness or composition on both the microbial richness (alpha diversity: Chao1 and Shannon) and community structure (beta diversity: weighted and unweighted UniFrac). No significant short-term impact was observed of the overall faecal microbiome on host characteristics, but rather an adverse effect of specific bacterial genera on fledging success. These results highlight the influence of environmental factors on the microbial richness as well as the phylogenetic diversity during a life stage where the birds’ microbiota is shaped, which could lead to long-term consequences for host fitness.

Tourism may threaten wildlife disease refugia

Abstract: The remoteness and isolation of South American tabletop mountain (tepui) summits may protect against infections that underpin global amphibian declines. Increases in recreational pressure in such unspoiled destinations, and in isolated ecosystems globally, pose a poorly understood risk of wildlife disease introduction, especially in supposedly immunologically naïve communities. We here report the first observed chytrid infections in the Pantepui biogeographical region. Infections significantly correlate with proximity to the nearest basic tourist infrastructure in four endemic amphibians occurring on tepui summits and their slopes. Phylogenetic relationships and environmental context suggest a high risk of severe and irreversible population declines in unique, early branching amphibians. These findings advocate for an urgent control of recreational pressure in isolated, highly vulnerable ecosystems.

Zoonotic pathogens linked with hedgehog diphtheric disease.

Abstract: Hedgehog diphtheric disease (HDD), an ulcerative skin disease with a high fatality rate is an emerging threat to European hedgehogs (Erinaceus europaeus). We explored the potential role of a panel of zoonotic pathogens in the presumed multifactorial nature of HDD in 188 hedgehogs from three wildlife rescue centers in Belgium. As expected, and with a prevalence of 67% in 57 hedgehogs with skin lesions, characteristic of HDD, the occurrence of Corynebacterium ulcerans was strongly associated with the disease. Remarkably, with a prevalence of 42% in affected animals, infections with Borrelia burgdorferi sensu latu were 3.92 times more likely to be detected in HDD (95% confidence interval: 1.650 - 9.880; p = 0.0024). Overall, 40 hedgehogs tested positive for the Borrelia burgdorferi sensu latu complex, including B. afzelii (n = 30), B. bavariensis (n = 7) and B. spielmanii (n = 7). Other widely occurring pathogens included Salmonella (prevalence of 19%, with three PFGE profiles) and Leptospira sp. (prevalence of 11%, including L. interrogans and L borgpetersenii) but these were not associated with occurrence of HDD. These findings show that hedgehogs in Belgium represent a significant reservoir of multiple zoonotic bacteria, of which toxigenic C. ulcerans and Borrelia burgdorferi sensu latu are associated with widespread hedgehog skin pathology and mortality. This article is protected by copyright. All rights reserved.