Managing Food Webs: Field Testing Systems Ecology

Systems ecology. Born of nuclear weapons production and the Cold War, forging science and engineering into an explanatory alloy of great power. Unprecedented insights into dynamics of tropical, tundra, desert, deep marine, and many other biomes were generated by systems ecologists. In systems dominated by humans, probably the most progress was made in terrestrial agroecology. Urban ecosystems turned out to be such a stew of economics, sociology, and biology that the tools of systems ecology provided few breakthroughs. Similarly, fisheries management, traditionally conducted on the basis of population biology, was a weak spot in the ecosystems armor.

But. Fisheries ecology, perhaps via aquacultural multidisciplinary bridge building, has made serious systems headway in the past couple of decades. Massive academic efforts have been thrown at characterizing and parameterizing a wide range of aquatic tropic webs around the world. An enormously successful estuarine restoration project (the Delaware Estuary Enhancement Program, http://www.pseg.com/info/environment/estuary.jsp) put a consortium of regulators, academics, consulting scientists, and other local and environmental stakeholders into play to institute a systems-driven impact offset of great overall value. And recently the Atlantic States Marine Fisheries Commission voted a deep reduction in the allowed harvest north Atlantic menhaden stocks.

Menhaden.  A schooling fish species not too small, not too large, just right to serve as a primary food source for predators ranging from barracuda to whales. And whose population behavior puts massive schools of lipid- and protein-rich fish not too deep, not too shallow, just at the right depth of the ocean to be the base of food chains yielding everything from commercially harvested mackerels, tuna and billfish to dolphins, porpoises, and squids. Really, really important component of the Atlantic marine ecosystem.

And a really important source of industrial materials as well. Massively harvested for processing into commercial fish bait, fish oil and protein meal and other useful materials. Valuable.

But vulnerable. A debated but substantive proportion of the annual menhaden production is being diverted from ecosystem to industry. How much to cut that diversion and how intensively to regulate the fishery were serious matters of debate. Remarkably, there was little debate, even among diverse stakeholders, over the need for some diversion.

Thus, the vote. The council voted heavily in favor of a 20% catch restriction and additional monitoring and population evaluation.

Score one for systems ecology. A field holding up on skinny legs in a world built on sturdy plinths of heavily funded subcellular engineering and molecular biochemistry. For a sustainable world, we need all our scientific tools, applied rationally, cogently, effectively. The wisdom and the will and the logistics and the politics involved in doing so are not going to be easy to come by. But maybe this menhaden decision is a sign that thing could shift in our direction. Let’s hope so!

Creative Methods for Biodiversity Maintenance

Last week we considered the potential for substituting holographic phantasms for actual individual organisms, from the perspective of making ecosystems seem psychologically whole even when they are physically depauperate. Unlikely, implausible and unsatisfying, you say? OK, you got me. But how about some more down-to-earth, practical yet oddball ideas for maintaining biodiversity in the face of powerful forces against? 

As I started this week’s column (9 December 2012), CBS Sunday Night news show “60 Minutes” ran a story about the desperate global network of specialists attempting to protect, preserve, breed and otherwise conserve increasingly rare and endangered species of turtles. Turtles are under pressure worldwide. In several trips to China involving series of more-or-less formal (and subsequently expensive) banquets, I have been fed at least 8 or 10 species of turtle, 3 of which I know to be critically endangered and a couple I have yet to identify so I’m not even certain they represent described and catalogued taxa!

Turtles are threatened both by harvest for food (of both eggs and adults), and for the illicit “pet” trade. Hobbyists are willing to pay enormous sums for individual animals, and the smaller the remnant populations, the more money the market will bear. At the moment, the answer for turtles, unfortunately, seems to be generally limited to habitat protection (expensive and often ineffective in the remote regions occupied by some species) and captive breeding. Despite administrative and technical challenges, the latter has so far seemed to keep at all species present and accounted for, even if only in artificially maintained colonies.

A couple of more interesting possibilities are available for certain other endangered animals. A web portal associated with American University (but otherwise of unknown provenance, http://www1.american.edu/TED/viagra.htm#r1 ) discusses the hope and hypothesis that Viagra and other legitimate anti-impotency medications might reduce pressure via traditional regional (primarily Asian) medicine on such reputed aphrodisiacs as rhinoceros horn. As the web site points out, many animal parts (such as tiger bone) are valued for other medicinal purposes and putative aphrodisiacs are only one class of traditional pharmaceuticals threatening animals and plants worldwide. I have myself witnessed the careless trade in endangered animal parts. Shops that I have frequented in Kuwait in search of tourist souvenirs and well-priced folk instruments from throughout Asia one night displayed a large shipment of raw (untanned) skins of tigers, leopards, wolves, and lions. I believe at least one of the lion skins was of the Asian variety, making it particularly rare. How and why a shop purveying dominoes, dart boards, and commercially made temple bells was suddenly offering a large stack of carnivore skins at bargain prices (I could have purchased a complete tiger skin of a large animal for the equivalent of a few hundred dollars U.S.) was and is beyond me.

But it does point to the ubiquitous and casual nature of the problem. In much of the developing world, poverty and isolation combine to minimize knowledge of and attention paid to conservation efforts. Someone who can sell a fortuitously encountered and killed tiger carcass for the equivalent of years or decades of normal earnings has powerful incentive to do so.

And thus we have the poaching wars in Africa. Increasingly sophisticated groups, sometimes with international logistical and funding support, hunt rhinos and elephants even where protection is a high priority and armed guards operate 24/7. 

Biodiversity problems are time-critical, in that on a species-specific basis there is a no-return threshold inherent in every population/density curve. Thus it is easy to sympathize with the gentleman attempting to protect his privately held rhinoceros conservation area by spiking the rhino horns, via several experimental technologies, with cyanide to limit their potential human uses (http://www.theweek.co.uk/politics/12775/put-cyanide-rhino-horn-one-way-deter-poachers ). 

Definitive quantitative linking biodiversity to sustainability are elusive, in many cases we don’t even know how to ask, much less answer, productive questions. That there IS such a relationship seems well beyond any scientific doubt. Seems to me that justifies a substantive level of financial, intellectual, and logistical investment. Precisely what that investment should be in a zero-sum, multiple-stressor world, may not be known or even knowable. Seems to me the more creative thinking we can throw at these problems, the better. What do you think?