Excerpt: Laura Martin on the Future of Habitat

The term habitat is widely used when describing threats to our future because of climate change, but how did our concept of habitat come about? In LA+ ENVIRONMENT, the latest issue of Weitzman's interdisciplinary journal of landscape architecture, Laura J. Martin, an associate professor of environmental studies at Williams College and author of Wild by Design: The Rise of Ecological Restoration (Harvard University Press), tells the story of how “habitat” emerged in natural history, and how we can reconceive this idea in a changing environment.

Climate change and persistent pollutants threaten to make habitat uninhabitable. What happens then? When we look to a future with less available habitat, we imagine suffering (mass death, forced migration, and societal collapse), epic escape (technological miracles, enclaved utopias, and colonizing the moon), or dismal compromise (such as Tuvalu’s plans for “digital migration”).¹ The Intergovernmental Panel on Climate Change warns of permanent habitat loss due to flooding, sea level rise, and erosion.² Recent news headlines include “23% of Earth’s Natural Habitats Could Be Gone by 2100,” “Climate Change and Habitat Loss Push Amphibians Closer to Extinction,” and “Animals are Running Out of Places to Live.”³

Since ideas of environmental threat and environmental futures are so often about habitat, we must question what habitat is, where it came from as an idea, and most importantly, how we might think beyond habitat. This is not just a theoretical exercise but a crucial step toward a more sustainable and inclusive future.

The word habitat emerged from the discipline of natural history, and its first known use was in W. Withering’s Arrangement of British Plants (1796) as “the natural place of growth of a plant in its wild state.”⁴ Habitat appeared sporadically in 19th-century European biogeographical literature, although Darwin did not think in terms of habitat. In On the Origin of Species, Darwin explained speciation as the result of selection for variations “in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to external nature” – a much more extensive rendering of selective forces than habitat.⁵

In the early 20th century, however, ecologists organized their new scientific discipline around the concept of habitat. In 1905, English botanist Arthur G. Tansley defined ecology as the study of “those relations which depend directly upon differences of habitat among plants.”⁶ Early ecologists worked to describe and differentiate habitats by their “life conditions” (environmental variables), which they believed drove selection. As Tansley putit: “We find the plants of the mountain differing from those of the valley, the plants of marshy land differing from those of the dry plain, the plants of the coast differing from those of the interior, the plants of the sand-dunes differing from those of the salt-marshes.”⁷ Ecology was the science of explaining plant forms shared across vast geographic differences; why, say, montane plant species in Switzerland looked like species in Colorado. Ecologists contended that habitat determined form.

Habitat remains a foundational concept in ecology, and ecologists have used it in two ways: to refer to a geographic space (the area a species occupies) or to a conceptual space (a set of biophysical conditions necessary for a species’ survival).⁸ Both senses have structured experiments, theories, and legal frameworks like the US Endangered Species Act.⁹ Just as importantly, the two meanings of habitat have created intellectual and political impasses for evolutionary ecologists and environmentalists.

Intellectually, the idea that species are adapted to habitat fails to explain the success of invasive non-native species. If species evolve to fit their habitats, what are we to make of species that thrive everywhere?¹⁰ Further, what is a “natural place of growth” when people have been moving and cultivating organisms for millennia? Separately, the idea that species need particular biophysical conditions to survive fails to account for those species that directly modify their habitats. The beaver dam and the superhighway alike suggest that habitats are not rigid molds that shape species because species, in turn, remake those molds. This insight underpins niche construction theory, which emphasizes the capacity of organisms to modify environments and hence evolution, and it motivated me and my collaborators to develop the field of indoor biome studies.¹¹

Read the full article on ISSUU.

1) “The First Digital Nation,” https://www.tuvalu.tv/ (accessed July 3, 2024).

2) Intergovernmental Panel on Climate Change (IPCC), Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems (IPCC, 2019), 148, 358, https://www.ipcc.ch/site/assets/uploads/2019/11/ SRCCL-Full-Report-Compiled-191128.pdf. See also IPCC, Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge University Press, 2022).

3) “Climate Change and Habitat Loss Push Amphibians Closer to Extinction,” Nature (October 4, 2023), https://www.nature.com/articles/d41586-023-02785-1; Carly Nairn, “23% of Earth’s Natural Habitats Could Be Gone by 2100, Study Finds,” World Economic Forum (November 12, 2020), https://www.weforum.org/agenda/2020/11/earthnatural-habitats-destroyed-…; Catrin Einhorn & Lauren Leatherby, “Animals are Running out of Places to Live,” New York Times (December 9, 2022), https://www.nytimes.com/interactive/2022/12/09/climate/biodiversityhabi….

4) Oxford English Dictionary, “Habitat,” https://www.oed.com/dictionary/habitat_n?tab=factsheet#2153169 (accessedJuly 1, 2024).

5) Charles Darwin, On the Origin of Species by Means of Natural Selection (D. Appleton and Company, 1861), 61.

6) A. G. Tansley, “The Problems of Ecology,” The New Phytologist 3, no. 8 (1904): 191–200.

7) Ibid., 194.

8) Peter S. Alagona, “What is Habitat?,” Environmental History 16, no. 3 (2011): 391–97.

9) On habitat and law, see Alagona, After the Grizzly: Endangered Species and the Politics of Place in California (University of California Press, 2013); Laura J. Martin, Wild by Design: The Rise of Ecological Restoration (Harvard University Press, 2022), Chapter 6.

10) I take up this question in Wild by Design.

11) K. Laland, B. Matthews & M. W. Feldman, “An Introduction to Niche Construction Theory,” Evolutionary Ecology 30 (2016): 191–202; Laura J. Martin, et al., “Evolution of the Indoor Biome,” Trends in Ecology & Evolution 30, no. 4 (2015): 223–32.