A multidisciplinary approach to informing conservation decisions for the threatened frog Mantella cowanii

The island of Madagascar is renowned for its endemic biodiversity yet faces many conservation challenges, especially for its amphibians. All amphibians in Madagascar are frogs, with >500 endemic species. Despite such high levels of species richness and endemism, we know little about most species’ basic ecology and lack the data necessary for making informed conservation decisions. In my dissertation, I integrate population ecology, conservation genomics, and environmental psychology to inform a conservation strategy for one of the island’s most threatened frog species, the harlequin mantella (Mantella cowanii). Working with local communities, I surveyed across the species’ entire known distribution, revealing ongoing population decline, local extirpations, and two previously undocumented populations. I used photographic capture-recapture surveys to estimate population sizes, showing three are small (13–137 adults), with one declining during 2015–2024. Genomic analyses using ddRADseq data revealed low to no inbreeding, limited population structure among sites, and evidence of hybridization with the closely related M. baroni. The hybrid populations clustered more closely with M. baroni than M. cowanii, and admixture was detected even in geographically distant populations, implying greater historical connectivity than is apparent today in Madagascar’s central highlands. To explore the human dimensions of conservation, I surveyed 455 residents across 70 villages in two regions where conservation strategies have been implemented for endangered Mantella. Structural equation modeling revealed trust in biodiversity conservation organizations was mediated by residents’ familiarity with action plans and their ecological knowledge level, which in turn were influenced by the types of information sources people relied upon to learn about the environment. Community- and education-based information sources positively influenced ecological knowledge, whereas information from government and church showed negative associations. Notably, familiarity with an action plan was the strongest predictor of trust. My dissertation chapters illustrate the need for and benefits of combining scientific disciplines to inform conservation strategies, while assessing M. cowanii‘s population status and making recommendations for its recovery. Averting continued decline and eventual extinction requires active habitat management of the small forest fragments where the species persists, monitoring for and preventing illegal collection for the international pet trade, and greater involvement of local communities who live near the sites.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Edmonds, Devin

Contributors dc:contributor

• Dreslik, Michael J
• Larson, Eric R
• Schooley, Robert
• Griffiths, Richard
• Crottini, Angelica

• Madagascar
• amphibian
• biodiversity conservation
• species action plan
• endangered species
• community-based conservation
• population ecology
• capture-mark-recapture
• ddRADseq
• conservation genomics
• population structure
• hybridization
• environmental psychology
• trust
• structural equation model

Statement dc:rights

• Copyright 2025 Devin Edmonds. All rights reserved.

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/132521

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/132521