Transplanting Coral Fragments to Damaged Coral Reefs in a National Park - Planting the Seeds to Recovery?

Background

National Park Service and U.S. Geological Survey scientists and student volunteers at work.

Project Publication:
Storm-generated coral fragments – A viable source of transplants for reef rehabilitation
(463 KB PDF)

Coral reefs make up the most complex marine ecosystem on earth, essential to literally millions of plant and animal species. Over the past three decades, coral reefs in the western North Atlantic, including those in Virgin Islands National Park, have been damaged by diseases, storms, coral predators, high water temperatures, and a multitude of direct and indirect human activities. To date, there has been little to no recovery on damaged reefs. Diseases, storms and high seawater temperatures have played a major role. Degradation from human impacts continues to escalate simply because there are more and more people living near or dependent on the sea. A damaged coral reef cannot be restored to its original condition. True recovery of a reef could take decades to centuries, making damage prevention the priority management strategy. Nonetheless, with the increased incidence of damage and the continuing lack of recovery on Caribbean reefs, interest in rehabilitation and enhancement of reefs has heightened, specifically in transplantation of coral colonies to reefs of importance to local communities or in protected areas.

If reef enhancement or rehabilitation is to be undertaken, two questions must be answered:

What is the best source for transplanted colonies (degrading one reef to restore another is not an option)?
Do the survival and growth rates warrant the cost and time required to transplant coral colonies (will it work)?

Project

This research was conducted in the nearshore waters of Virgin Islands National Park, St. John, US Virgin Islands. Storm-produced fragments of the three fastest growing species of Caribbean coral (elkhorn, staghorn and finger corals) were collected from habitats inhospitable to survival and transplanted to other reefs (Trunk and Whistling Cay). Inert nylon cable ties were used to secure the fragments to the sea bottom (dead coral). At the beginning of the project, little was known about survival and growth of small coral colonies. Sixty transplanted and 75 control colonies were monitored for survival and growth for 5 years (1999-2004). Over 70 volunteers from Friends of Virgin Islands National Park and 5th and 6th grade classes from Pine Peace School monitored the colonies monthly (1999-2001).

Results

	# colonies monitored	colonies alive at 5 years	transplant survival at 5 years	control survival at 5 years
All colonies	135	34 (25%)	10 (17 %)	24 (32%)
Elkhorn coral	75	27 (36%)	6 (20%)	21 (47%)
Staghorn coral	30	1 (3%)	0	1 (7%)
Finger coral	30	6 (20%)	4 (27%)	2 (13%)

Only one of the three species (elkhorn coral) was found to be a viable candidate for transplantation. (Note: this species is listed as threatened.) One-fourth of the 135 monitored colonies were alive after 5 years. Of the colonies that did not survive, 58% had disappeared and 42% had died in place. Damage to colonies did not predict survival/morality, or – many colonies sustained serial damage only to survive and grow!
A plentiful source of healthy coral fragments to transplant was identified: naturally-occurring, storm-produced elkhorn coral fragments.
The shallow reef environment was found to be highly dynamic, with corals recruiting to the reef, growing and dying.
Nylon cable ties were effective at attaching fragments, inexpensive and easy to use.
The method was found to be simple, inexpensive and easily conducted by community volunteers and/or resource managers wishing to enhance or repair a reef. (e.g., damage from boat groundings).

Conclusions

July 1999	July 2004

Five years of growth of Elkhorn coral fragment transplanted to Trunk Cay reef.

To reiterate, damaged and degraded reefs cannot be restored or rehabilitated to their original condition. Until the basic processes driving declines on coral reefs worldwide are understood and forcing factors such as increasing human-population pressures on marine and coastal resources are addressed, the future does not look bright for coral reefs. However, there is a place for small-scale rehabilitation efforts. For little expense and using readily available materials, local communities can effectively, albeit modestly: 1) increase the live coral cover and spatial complexity of a reef without damaging other reefs; 2) minimize damage to intact corals by stabilizing loose fragments; 3) decrease incidence of reef damage from humans through community education; and, 4) contribute to the conservation of threatened species (in this case elkhorn coral). Conducted at multiple locations throughout a region and sustained over time, these efforts become regional in scale and may buy time for threatened coral species and reefs.

Publications

Garrison, V., Ward, G. 2008. Storm-generated coral fragments – A viable source of transplants for reef rehabilitation. Biological Conservation 141: 3089-3100. [URL: http://dx.doi.org/10.1016/j.biocon.2008.09.020]

Contact Information

VH Garrison (US Geological Survey, 600 Fourth St S, St. Petersburg, FL 33701; 727 803-8747 ext. 3061; ginger_garrison@usgs.gov)

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