Conservationists emphasize the importance of corridors to conserve biodiversity. Corridors allow adults or the propagules of animal and plant species to spread widely in a given geographical area on their own power, or through the operations of natural dispersal agents such as wind or water currents.
The concept of corridors has been adopted in conservation projects in the country. The Foundation for the Philippine Environment approved a project some time ago to reforest a strip of land connecting two forest fragments on Mindanao to help ensure that forest habitats are restored for biodiversity conservation.
The Integrated Coastal & Marine Resource Management Project of the DENR has also emphasized the importance of corridors, by which ocean currents connect individual marine protected areas in networks of MPAs, in ensuring the ecological (ecosystem) connectivity of MPAs and areas outside MPAs (fished marine areas).
If provided with a favorable and continuous space (a corridor), a threatened terrestrial species that is barely surviving in a small and fragmented habitat should be able to colonize and maintain a viable population in adjacent areas in the course of time.
In the Philippines, there appears to be no reported case where corridors have been effective in conserving biodiversity. Perhaps the Mindanao corridor project mentioned above can provide a demonstration in the future.
In the same manner, propagules produced in an MPA serving as source are carried by ocean currents to other areas, including other MPAs serving as sinks and adjacent fished areas.
Fished areas also need marine propagules produced locally and propagules coming from MPAs upstream to replenish the biodiversity (e.g. fish) that are continually removed by fishers through fishing activities.
The overall result of ensuring the ecological connectivity of networks of MPAs, as well as adjacent fishing areas, could be sustainable production of goods and services provided by biodiversity resources, such as fishery products and tourist attraction.
The question is whether there is scientific evidence for ecological connectivity linking networks of MPAs in the Philippines to specific benefits.
Thus far, despite much-discussed theoretical knowledge of marine workers, I know of only one initial research finding (Abesamis et al., in manuscript) that shows that a network of some 39 small, community-based no-take marine reserves in the Bohol Sea, where a steady southwestward ocean current occurs the year round, could increase the fish larval settlement by 2.0 to 4.0-fold if these reserves are fully protected for five to 20 years.
Note that the reserves must be fully protected from fishing and from all extractive activities in order to work.
Thus far, fishing in the reserve is the most frequent violation of the rules of no-take marine reserves. Our people do not realize that MPAs will come nothing unless fully protected.
Indeed, we are challenged to demonstrate through research that setting up networks of marine reserves makes a big difference in the Philippines.