RESEARCH
Our current research addresses the causes of distributional limits, adaptation to benign versus challenging environments, aggression among species and its consequences, and latitudinal gradients in diversity.
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Natural history is an important component of our work, creating a foundation from which to address broader questions in biology.
We frequently collaborate on projects outside of our research foci, and extend our work to address the impacts of climate change, urbanization, and introduced (non-native) species on biodiversity. ​
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Boissonneaua jardini (left or above) signals aggressively towards other hummingbird species using its extensive black head and contrasting black and white tail, both of which signal dominance (Kenyon & Martin, Am. Nat. 2023).
Causes of Distributional Limits
What limits the distributions of species? Can we identify general processes that limit the distributions of most species?
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We address these questions using closely related, ecologically similar species that segregate their distributions along environmental gradients (in space, time, resources).
We test among alternative hypotheses using experiments in nature (Nicrophorus beetles) and comparative studies, mostly on birds.
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The relative abundance of Ara ararauna (right or above) based on eBird Status and Trends.
Adaptation to Benign versus Challenging Environments
For closely related species, some environments are relatively benign, while others are challenging.
How do species adapt to these environments? Do adaptations for benign environments trade-off with adaptations to challenging environments, do they sometimes align, or are they independent? What traits covary with adaptations to distinct environments, and why?
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We address these questions using comparative studies of plants, invertebrates, and vertebrates, and field and lab experiments on beetles (Nicrophorus).
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Nicrophorus sayi (left or above) is uniquely cold-tolerant, allowing it to be active in the early spring before other Nicrophorus beetles have emerged (Wettlaufer et al. 2021, 2023).
Aggression among Species & its Consequences
Our recent work found that competitive exclusion typically limits the distributions of subordinate species along environmental gradients, with dominant competitors excluding subordinates using aggression and signalling.
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What is the role of aggression in setting ecological limits in nature? What are the consequences of aggression and signalling for ecological strategies and related traits? How common is character displacement versus convergence or mimicry? How consistent are behavioural dominance hierarchies?
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We address these questions using closely related, ecologically similar species of birds and beetles.
Selected Papers
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Diomedea epomophora bites the smaller but quicker Thalassarche cauta off Stewart Island/Rakiura, New Zealand (right or above) (Martin & Briskie 2021, Nortornis; Basham et al. 2023, NZ J. Zool.).
Latitudinal Gradients in Diversity
The latitudinal increase in diversity from the poles to the equator is one of the most exciting patterns in biology. We study how evolution varies with latitude to influence patterns of diversity and the traits of species.
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Our work has examined latitudinal variation in species interactions, sexual selection, population differentiation, colour patterns, physiology, and life history, and has included direct tests of mechanisms thought to underlie latitudinal variation in diversity.
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Variation in species richness (left or above) of two diverse groups of birds in the Americas (Trochilidae, Emberizoidea, combined).
Applications
​Our work on fundamental questions extend to inform the impacts of climate change, urbanization, and introduced (non-native) species on biodiversity.
For example, competitive interactions among species determine which urban-adapted species occupy cities (Martin & Bonier 2018, PNAS); identifying the causes of distributional limits of species help us to understand and predict species' responses to climate change (Wettlaufer et al. 2023, Ecol. Entomol.); and fundamental trade-offs can help us to understand why some introduced species become invasive (Martin & Ghalambor 2023, Am. Nat.).
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Colluricincla harmonica (right or above) feeds at a garbage dumpster outside Brisbane, Australia.
