New research on ecotypes clarifies how they can illuminate our understanding of adaptation and evolution

New research looks at an important intersection between evolutionary biology and conservation management. Ecotypes are variants within a species, which have unique adaptations to their specific environment – such as coastal wolves, which are adapted to marine diets. However, defining an ecotype is difficult – whether genetic and physical differences are adaptive or not, and whether these differences clarify or obscure differentiation within a species is unclear and inconsistently applied. 

The authors identify confusion around how genetic structure delineates ecotypes. In their literature review of recent publications on ecotypes, conservation, and management, 60%  of papers identify ecotypes through a focus on habitat use, whereas only 53% use genetic analyses. The authors highlight  a gap and an opportunity to use genetic analyses as ecotype designation evidence, especially for species that are less widely studied and receive less popular and science attention. The authors present a framework for identifying ecotypes (Box 1), in which genetic analysis supports their delineation. 

Crucially, the ecotype framework the authors propose can connect evolutionary biologists with conservation practitioners. Identifying ecotypes has consequences for conservation management. Recognizing ecotypes, or populations more specific than the species and subspecies level, is vital to conserving genetic diversity, protecting populations that may be uniquely at risk or vulnerable, and safeguarding the ongoing adaptation – evolution in progress – which has the potential to help species adapt to climate change in the future. A robust framework in which to apply genetic analyses to identify ecotypes is therefore an important tool which can help inform conservation planning.

Citation

Stronen, A. V., Norman, A. J., Vander Wal, E., & Paquet, P. C. (2022). The relevance of genetic structure in ecotype designation and conservation management. Evolutionary Applications, 15, 185– 202. https://doi.org/10.1111/eva.13339

Abstract

The concept of ecotypes is complex, partly because of its interdisciplinary nature, but the idea is intrinsically valuable for evolutionary biology and applied conservation. The complex nature of ecotypes has spurred some confusion and inconsistencies in the literature, thereby limiting broader theoretical development and practical application. We provide suggestions for how incorporating genetic analyses can ease confusion and help define ecotypes. We approach this by systematically reviewing 112 publications across taxa that simultaneously mention the terms ecotype, conservation and management, to examine the current use of the term in the context of conservation and management. We found that most ecotype studies involve fish, mammals and plants with a focus on habitat use, which at 60% was the most common criterion used for categorization of ecotypes. Only 53% of the studies incorporated genetic analyses, and major discrepancies in available genomic resources among taxa could have contributed to confusion about the role of genetic structure in delineating ecotypes. Our results show that the rapid advances in genetic methods, also for nonmodel organisms, can help clarify the spatiotemporal distribution of adaptive and neutral genetic variation and their relevance to ecotype designations. Genetic analyses can offer empirical support for the ecotype concept and provide a timely measure of evolutionary potential, especially in changing environmental conditions. Genetic variation that is often difficult to detect, including polygenic traits influenced by small contributions from several genes, can be vital for adaptation to rapidly changing environments. Emerging ecotypes may signal speciation in progress, and findings from genome-enabled organisms can help clarify important selective factors driving ecotype development and persistence, and thereby improve preservation of interspecific genetic diversity. Incorporation of genetic analyses in ecotype studies will help connect evolutionary biology and applied conservation, including that of problematic groups such as natural hybrid organisms and urban or anthropogenic ecotypes.

Select Figures (box 1)

Problems with the ecotype concept

1. A lack of consistent ecotype definition limits broader application, and the role of genetic structure in delineating ecotypes currently ranges from all important to unspecified;
2. Current discrepancies between genetic structure and ecotype may, at least in part, reflect the large variability in available genomic resources across taxa, which has hampered investigation of adaptive vs. neutral differentiation.

A framework for resolution of ecotypes

Affiliations

Astrid V. Stronen^{1, 2, 3} 
Anita J. Norman⁴ 
Eric Vander Wal⁵ 
Paul C. Paquet^{6, 7} 

1. Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia 
2. Department of Biotechnology and Life Sciences, Insubria University, Varese, Italy 
3. Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark 
4. Department of Fish, Wildlife and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden 
5. Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada 
6. Department of Geography, University of Victoria, Victoria, BC, Canada 
7. Raincoast Conservation Foundation, Sidney, BC, Canada

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