From Readers

Your Letters and Comments

Artificial Reefs

I have read Michael Moore and Mark Erdmann’s article, “EcoReefs: A New Tool for Coral Reef Restoration” (Summer 2002). My experience has made me a skeptic.

• In the late 1970s, we worked on “Randall’s Reef,” made of concrete blocks by Jack Randall in 1960 on the south coast of St. John. It was then still a pile of blocks and remains so today — albeit covered from time to time with coral recruits that are attractive to fishes to be sure (Ogden, J.C. and J.P. Ebersole. 1981. Scale and community structure of coral-reef fishes: A long-term study of a large artificial reef. Marine Ecology Progress Series 4(1) 97-103).
• The experimental concrete block reefs that we built on St. Croix through the 1970s and early 1980s for studies of recruitment are still block reefs, again with periodic bouts of recruitment. There is no overgrowth, and I have to say that I suspect there never will be — although I’m not sure why.
• In the mid to late 1970s, Wolf Hilbertz and his colleagues fairly covered the bottom of Tague Bay in front of the West Indies Laboratory on St. Croix with chicken wire structures connected to power supplies by electrical wiring. They spun dreams of accreted reefs and even cities under the sea. After they left, we cleaned up the bay; there was just chicken wire there, which of course, was attractive to the fishes. Hilbertz et al. are still at it, albeit farther and farther afield. At best, they’ve left some people disappointed and at worst, furious. Incredibly, they have never done a controlled experiment.
• The National Oceanic and Atmospheric Administration (NOAA) is building what I fondly call the “Great Pyramids” of reef restoration in the Florida Keys. Legally, NOAA must use penalty payments from ships that have damaged reefs for direct reef restoration. The M/V Maitland grounding site in the Upper Florida Keys has to be seen to be believed. Over US$1 million buys you huge preformed blocks delivered by crane barge to the reef and set into the damaged areas. Rugosity is built in, and corals are glued on. The spur and groove system at Looe Key similarly is being duplicated in concrete at the R/V Iselin grounding site. I am not optimistic that these structures will ever become functioning reef ecosystems.
• Investigators at the University of Newcastle-upon-Tyne used a mesh mat technique in the Maldives to hold coral rubble in place. The mat was studded with transplanted live corals. There were papers published on the technique but no follow-up that I am aware of, and I think I know why.
• Finally, there are all the ships, railroad cars, power plant ash blocks, and so on that have made some regions little more than solid waste disposal sites in the name of reefs.

So what Moore and Erdmann say will happen with EcoReefs hasn’t happened in all of the above cases. Arguably, the idea that reefs can be easily restored with artificial corals (abundantly implied in the article) encourages false hopes and false impressions that people can continue business as usual.

It is a conundrum. But wouldn’t the cost of EcoReef projects be better spent other ways? After all, in the best of worlds, hardly the trajectory we are on, we could manage only a few km2 of EcoReef restoration in the face of thousands of km2 of damage. I have a long list of alternatives.

JOHN C. OGDEN, DIRECTOR

Florida Institute of Oceanography

The author responds:

We’re skeptical too. We’ve both seen a lot of bad ideas put to the test. We are just in the beginning stages of experimenting with nontoxic ceramic and so far the results in the Pacific have been pretty good. We are seeing good small fish colonization, good grazing levels, and some coral recruitment after six months.

As you correctly point out, we won’t know for many years if our intervention has successfully catalyzed reef growth. The main advantages of ceramic are that it is not too expensive to produce, it won’t last forever, and it is one of the better materials for promoting invertebrate settlement. It can be formed in a variety of shapes, and per-piece costs are low once production molds are made.

The Caribbean has its share of problems, and I would agree that reef restoration in some areas is basically impossible because water quality is so poor and larvae are in short supply (especially A. palmate and A. cervicornis). I’ve had long conversations with Harold Hudson, and he is very discouraged in general.

I also would add that our thinking about EcoReefs is based on my experiences in Southeast Asia where physical and biological conditions are generally good, and the main ecological problem is habitat loss from widespread, uncontrolled dynamite fishing. When these reefs are brought under better management, there is usually discussion about how to improve local fisheries and tourism potential. This is where I feel EcoReefs can be beneficial. I expect costs to come down, perhaps as low as US$25 per square meter if order volumes are high enough, and even less if production is local. One of my goals is to create a system that can be deployed at large scales for maximum benefit. This requires low cost materials, mass production, and an ecologically useful and physically practical design.

MICHAEL MOORE

President, EcoReefs

Wildlife Corridors and Disease

I have read with interest “Conservation Corridors and the Spread of Infectious Disease” by Leslie Bienen (Spring 2002). The article is pertinent, but there are some issues that need to be discussed. The issues concerning corridors in the developed world compared to the developing world are far from the same and cannot be lumped together. Knowledge of rinderpest has increased since the 1980s, which appears to be as far as the author has researched, and rinderpest still is not controlled. In fact, a major pan-rinderpest eradication program was initiated in the 1980s; and significant work has been undertaken in recent years in understanding the epidemiology of the disease, particularly related to wildlife. The issue with rinderpest and wildlife has nothing to do with corridors per se. Recently, pockets of the rinderpest virus have been fulminating in wildlife in East and Central Africa precisely because of the movement of humans and their cattle into wildlife areas and the absence of veterinary services due to civil war, etc.

The issue here is the movement of domestic livestock, not one of wildlife moving between areas of biodiversity within corridors. There are still vast areas of Africa that are wilderness, and the potential spread of disease via corridors pales into insignificance when other factors are looked at, such as illegal movement of livestock, human poverty, lack of finances, political machinations, etc. It is important in this debate not to forget that when humans were few, wildlife were moving between bits of habitat far and wide all the time, living with diseases, and surviving. Wildlife has an inherent immunity to many diseases acquired over many centuries, and in my opinion, the disease threat posed by wildlife has been overstated. Therefore, in the evolution of conservation policy, it should be recognized that there may be a positive relationship between wildlife hosts and their pathogens, with minimal concern for impacts between and amongst wildlife species.

The issue today is the introduction of the human factor. It seems that human impacts are gaining greater importance in the developed world than in the undeveloped because of habitat loss and fragmentation, urban development leading to encroachment, islands of habitat, threats to traditional ranching practices, etc. That the human element is an issue in countries such as Africa is a given; but to most Africans the fundamentals of survival (until tomorrow) are the issue, not the environment or wildlife, and certainly not corridors.

I agree, in part, with the sentiments of the author where she quotes Gary Tabor as stating that the design and management of conservation reserves needs to be open to the consequences of disease threats. This is a noble sentiment. But the design and management of conservation reserves in Africa, for example, go way beyond any disease considerations and come down to fundamentals such as communities and rural livelihoods, sustainability, implementations, finances, etc. Indeed, the example of brucellosis in bison and elk parallels the issue of African buffalo and foot-and-mouth-disease. Ultimately, the value of African buffalo, bison, or elk in terms of ecotourism, meat, hides, sport hunting, and potential diseases must be weighed against the value of a cow in terms of meat, hides, and milk: it is no contest, wildlife wins.

Corridors and the potential spread of infectious diseases are important in the new millennium, but they are very much a first-world concern. They need to be considered in light of the multitude of contrasting issues and risk factors that effect biodiversity conservation in different parts of the world. A final word: “disease ecology” is nothing new; epidemiology has been examining these issues for decades if not centuries.

MICHAEL D. KOCK

Wildlife Health Centre,

School of Veterinary Medicine,

University of California-Davis

The author responds:

Michael Kock’s letter raises good points about disease interplay amongst wildlife, livestock, and humans. I agree that more direct human factors (poaching, habitat loss, etc.) are probably more pressing problems for Africa’s wildlife than disease — though there have been interspecies disease transmissions that devastated entire populations of African wildlife.

Unfortunately, due to space, we could not include a full discussion of rinderpest control/recurrence. I would like to emphasize, however, that I did not choose rinderpest with any intention of implying that disease ecology concerns are similar around the world. Rather, I chose rinderpest because 1) it shows that wildlife disease ecology is an old discipline; 2) the epidemic at its worst made people realize that the consequences of disease exchange between livestock and wildlife reached far and wide; and 3) most importantly, the rinderpest case demonstrates that when a disease is passed back and forth between livestock and wildlife, usually wildlife pay the price. This, I fear is what has not changed since the heyday of rinderpest, and the potential parallel here is with brucellosis. Conservationists need to understand disease ecology not because disease transfer is the most urgent problem out there — though you never know when it may be — but because foreknowledge, not knowledge, is power. Foreknowledge of disease ecology could prevent or halt an outbreak, gain a land easement, or save money that could go toward other conservation problems. Armed with foreknowledge, we’ll hopefully never revisit the days when wildlife species were slaughtered wholesale to try to eliminate them as disease reservoirs.

LESLIE BIENEN
Freelance writer and veterinarian