Environmental differences in the microbiome and exposure to the emerging fungal pathogen, Emydomyces testavorans, in conservation rearing and release programs for the western pond turtle (Actinemys marmorata)

Hazemi, Monique S.

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Description

Title

Environmental differences in the microbiome and exposure to the emerging fungal pathogen, Emydomyces testavorans, in conservation rearing and release programs for the western pond turtle (Actinemys marmorata)

Author(s)

Hazemi, Monique S.

Issue Date

2020-04-16

Director of Research (if dissertation) or Advisor (if thesis)

Kent, Angela D

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• western pond turtle
• emydomyces testavorans
• microbiome
• health
• conservation
• headstart program
• managed care
• disinfection
• shell disease

Abstract

Artificial animal environments, such as human-managed conservation rearing programs, represent an extreme change in lifestyle for many animal species that may be accompanied by unintended alterations to host microbiota and immune function. It is unknown if the management practices of built environments (e.g., disinfection, simplified substrates, full water changes) induce shifts to dysbiotic environmental and host-associated microbiomes that are susceptible to infection. We investigated the effect of the microbial rearing environment on shaping the microbiome structure, hematology, and shell health of free-ranging and managed-care Western Pond Turtle (Actinemys marmorata) populations. This (critically) imperiled turtle species participates in conservation rearing and release, or “headstart” (HS), programs to help mitigate population threats. Despite decades of successful recovery efforts, an apparently severe shell disease associated with a newly described fungus (Emydomyces testavorans) has been discovered and may be threatening the conservation gains of this species. Habitat and host-associated turtle microbiomes were examined across free-ranging populations that included both wild and HS-reared turtle, and among hatchlings reared in HS programs under conventional management with stringent hygiene practices and less intensive biofiltration management. Our findings indicated that managed-care systems generally exhibited reduced microbial species richness and altered microbial community structure relative to native systems. Less stringent habitat management (i.e., less microbial disturbance) within the HS program shifted the fungal microbiome of hatchling turtles toward those of disease-free animals and reduced their exposure to Emydomyces testavorans. This research provides support for the positive health potential of incorporating the microbiome into existing species conservation efforts, as well as improves our understanding of the ecology of an emerging pathogen and disease that pose a significant challenge to decades of successful species recovery efforts. Enhancing habitat management practices through the cultivation of robust microbiomes will enable these animals, and conservation programs overall, to have the greatest chance to overcome threats to species recovery.

Graduation Semester

2020-08

Type of Resource

Thesis

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http://hdl.handle.net/2142/108555

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Copyright 2020 Monique Hazemi

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