Biogeography is the study of the distribution of species and ecosystems through space and time. Despite the broad relevance of biogeographic principles to marine environments, protected area networks often don’t explicitly incorporate them. A new review highlights the link between biogeography and the success of marine protected areas (MPAs), and provides several new recommendations to ensure the effectiveness of MPAs under climate change.
As the review points out, although MPA network design focuses on biogeographic representation and replication as a conservation target, it often ignores the dynamic nature of species’ ranges. Processes such as larval dispersal and adult spatial dynamics are critical to understanding range shifts and connectivity between metapopulations. Anticipating the influence of climate change on MPAs will require modeling both current distributions and persistence probability. Marine biogeographic boundaries, such as breaks in coastal currents, may play a large role in mediating the response of species to climate change.
The review also highlights the mismatch between the spatial scale of most MPAs and the amount of space species and communities need to successfully adapt to climate change. There are 75 MPAs across the globe larger than 100,000 km2, but almost 14,0000 that are under 100 km2. The mean latitudinal extent for MPAs is just 2.7 km – much smaller than the range shifts already observed in some species.
Given the scale mismatch and projected climate change, future recommendations for improving MPA design include:
- Single MPAs have the potential to have a greater impact if sited at the leading edge rather than the trailing edge of a geographic range (although this approach may be most practical for protecting single species).
- In places where species are predicted to shift ranges, large MPAs could be designed as “tall” rather than “wide,” to encompass more future suitable habitat for key species of interest.
- A series of small MPAs could be set up in a chain, much as terrestrial ecosystems are set up to support “stepping stones” as corridors for movement. This chain could extend latitudinally far beyond the reach of any one single MPA, and could even be implemented in stages to track climate.
- Protected areas should focus on places with high conservation value, such as regions with genetically diverse populations, in addition to areas with unique biophysical features, such as seamounts.
Fredston-Hermann, A., S. D. Gaines, B.S. Halpern. 2018. Biogeographic constraints to marine conservation in a changing climate. Annals of the New York Academy of Sciences. DOI: 10.1111/nyas.13597.
Burrows, M. T., D. S. Schoeman, L. B. Buckley, P. Moore, E. S. Poloczanska, et al. 2011. The pace of shifting climate in marine and terrestrial ecosystems. Science 334: 652-655.