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A meta-analysis reveals edge effects within marine protected areas
Sarah Ohayon1, Itai Granot2, Jonathan Belmaker2,3
1School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. saraorca@gmail.com.
Nature Ecology & Evolution
|July 6, 2021
Summary
Marine protected areas (MPAs) show a 1km edge effect, reducing populations by 60% near borders. Buffer zones in MPAs are crucial for effective marine conservation.
Area of Science:
- Marine Ecology
- Conservation Biology
- Fisheries Science
Background:
- Marine protected areas (MPAs) are vital for marine conservation and restoration.
- MPAs can enhance populations within and outside their boundaries through organism export (spillover).
- Limited understanding exists regarding spatial variations in MPA performance, particularly concerning edge effects.
Purpose of the Study:
- To investigate spatial patterns and the extent of edge effects within no-take MPAs.
- To synthesize empirical data on fish and invertebrate populations across MPA borders.
- To assess the impact of MPA size and buffer zones on population dynamics.
Main Methods:
- Synthesis of empirical data from 72 taxa across 27 no-take MPAs.
- Analysis of population size and trends in relation to MPA boundaries.
- Comparison of MPAs with and without buffer zones.
Main Results:
- A consistent edge effect was observed, extending approximately 1 km into MPAs.
- Population sizes at MPA borders were 60% smaller than in core areas.
- Small MPAs (<10 km²) may hold only 45-56% of their potential population size due to edge effects.
- MPAs with buffer zones did not exhibit significant edge effects.
Conclusions:
- Edge effects significantly reduce population sizes within MPAs, especially in smaller areas.
- Buffer zones and expanded no-take areas are critical for mitigating edge effects and enhancing MPA effectiveness.
- Strategic MPA design, including buffer zones, is essential for maximizing conservation outcomes.
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