Interactions among closely-related species and the evolution of biodiversity

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What factors promote or constrain local biodiversity, and why does it vary in space and time? These questions are central to our understanding of nature, and yet we lack the answers necessary to accurately predict and mitigate the impacts of human activities on biodiversity. The goal of our proposed research program is to advance our understanding of biodiversity by studying how closely-related species coexist. We focus on closely-related species because they represent the earliest stages in the evolution of local biodiversity, and their shared ecological preferences and traits provide a challenge to coexistence. Objective 1. Understand how and why closely-related species partition resources. Seven species of Nicrophorus burying beetle live together in southern Ontario, all relying on small vertebrate carrion for breeding. We will study species that partition resources by breeding at different temperatures and occupying distinct habitats two environmental axes that influence many species in nature. The goal of this work is to understand the mechanisms that underlie resource partitioning among species, using a tractable system for detailed selection, transplant, competition, and thermal tolerance experiments. Objective 2. Understand the evolutionary consequences of direct, competitive interactions among species. Species are continuously signalling, displacing, and fighting with each other, revealing the importance of direct competitive interactions in nature. We will examine the consequences of direct interactions among species for signals, hybridization, and evolution by comparing species of birds that interact aggressively, with a consistently dominant and subordinate species. Objective 3. Identify broad processes and constraints that influence resource partitioning and the response of species to environmental challenges. Repeated patterns of resource partitioning in nature suggest recurrent underlying selective pressures and constraints. Using an extensive dataset on birds, we will test the hypotheses that adaptation to new and challenging environments compromises competitive ability, and that species confronted with environmental challenges will either struggle to persist when confronting additional new challenges, or will be preadapted to novel challenges as they occur. Impact. An understanding of the processes that structure biodiversity should play a central role in guiding how we interact with nature, from conserving species to managing resources. The research proposed here will improve our understanding of biodiversity by elucidating the mechanisms underlying resource partitioning, the consequences of direct interactions among species, and the broader processes that constrain how species partition resources, and thus determine when and how species can live together in nature. The proposed work would train 4 PhD, 5 MSc, and 12-15 BSc students.