Zachary Arnold

Candidature

PhD Candidate

Thesis title

The ecology and conservation of the Christmas Island Thrush, Turdus erythropleurus

Research Project

My PhD research focuses on the ecology and conservation of the Christmas Island Thrush (Turdus erythropleurus), a newly split species endemic to Christmas Island. This project will provide foundational ecological knowledge of the species.

Islands have long been recognised as "natural laboratories" for the study of evolution, ecology, and environmental change. Their discrete boundaries, isolation, and simplified biotic communities allow for the examination of ecological processes without the confounding factors of high interspecific competition and complex food webs typical of continental systems. Island endemics often evolve under these depauperate communities, developing unique life history traits such as broadened ecological niches and naiveite to novel threats

Beyond their value as natural laboratories, islands are globally significant centres of biodiversity, harbouring exceptionally high levels of endemism while also experiencing disproportionately high rates of extinction. Since European colonisation, approximately 75% of all recorded extinctions and 94% of bird extinctions have occurred on islands. Consequently, islands function simultaneously as biodiversity and extinction hotspots, making them priority systems for understanding how ecological and evolutionary processes interact under rapid environmental change.

Specifically, this research aims to use the Christmas Island Thrush as a model system to examine how ecological release, island syndrome traits, and rapid anthropogenic change interact to shape diet, life-history strategies, and communication systems in island songbirds. By integrating feeding ecology, reproductive success, and vocal ecology across gradients of habitat modification and invasive species pressure, the project seeks to test fundamental predictions about adaptation, drift, and ecological naivete in simplified island systems. Simultaneously, by working closely with Christmas Island National Park, I will generate data that directly supports evidence-based management and long-term conservation of this imperiled island endemic.

Website: https://www.animalecologylab.org/zachary-arnold.html

Publications

Arnold ZJ, Wenger SJ, Hall RJ (2021) Not just trash birds: Quantifying avian diversity at landfills using community science data. PLoS ONE 16(9): e0255391. https://doi.org/10.1371/journal.pone.0255391

Arnold ZJ, Ceska JF, Hall RJ (2021) Establishing bird-friendly grassland habitat at landfills in the southeastern United States. Academia.edu.

Supervisors