Habitat Disturbance Linked with Host Microbiome Dispersion and Bd Dynamics in Temperate Amphibians

Abstract

Anthropogenic habitat disturbances can dramatically alter ecological community interactions, including host-pathogen dynamics. Recent work has highlighted the potential for habitat disturbances to alter hostassociated microbial communities, but the associations between anthropogenic disturbance, host microbiomes, and pathogens are unresolved. Amphibian skin microbial communities are particularly responsive to factors like temperature, physiochemistry, pathogen infection, and environmental microbial reservoirs. Through a eld survey on wild populations of Acris crepitans (Hylidae) and Lithobates catesbeianus (Ranidae), we assessed effects of habitat disturbance on environmental bacterial resevoirs, Batrachochytrium dendrobatidis (Bd) infection, and skin microbiome composition. We found higher measures of microbiome dispersion (a measure of community stability) in A. crepitans from more disturbed ponds, supporting the hypothesis that disturbance increases stochasticity in biological communties. We also found that habitat disturbance limited microbiome similarity between locations for both species, suggesting less bacterial exchange in more disturbed areas. Higher disturbance was associated with lower Bd prevalence for A. crepitans, which could signify suboptimal microclimates for Bd in disturbed habitats. In this system we use microbiome dispersion as a metric of population health. Combined, our ndings show that reduced microbiome stability stemming from habitat disturbance could compromise population health, even in the absence of pathogenic infection.

Environmental and Anthropogenic Factors Shape the Skin Bacterial Communities of a Semi-Arid Amphibian Species

“…This finding is contrary to those of other ranavirus studies, which have found ranavirus spread and prevalence to be coupled with human activity and urban environments [72][73][74]. The limited ranavirus prevalence in disturbed sites observed here is, however, consistent with other amphibian disease systems, such as Bd [33,75]. Given that ranavirus has broad host range in ectothermic vertebrates [76] and its prevalence has been shown to increase with amphibian and fish diversity [74], a potential driver for reduced disease prevalence in disturbed sites may therefore be fewer potential ranavirus carriers (in this case fish owing to already low endemic amphibian diversity).…”

Life stage and proximity to roads shape the skin microbiota of eastern newts (Notophthalmus viridescens)

“…For example, habitat degradation (i.e. fragmentation and deforestation) can alter both skin and gut microbial communities of organisms by altering natural sources of microbial symbionts in the environment (Barelli et al ., 2015 ; Becker et al ., 2017 ; Hughey et al ., 2017 ; Jimenez et al ., 2020 ; Barnes et al ., 2021 ; Neely et al ., 2021 ). Similarly, exposure to human‐made chemicals in the environment has been shown to influence associations between hosts and microbial symbionts, in many cases resulting in negative effects to host health (Redford et al ., 2012 ).…”

Habitat split as a driver of disease in amphibians

“…Recent findings indicate that habitat loss and fragmentation cause shifts in community composition of the amphibian microbiome, such as decreases in skin bacterial diversity (Becker et al ., 2017) and microbiome dysbiosis (Jiménez et al ., 2020; Neely et al ., 2022) in disturbed environments. Using methods to quantify the function (i.e.…”