Managing Baseball... Managing Nature

Or: A Tale of Three Species

Baseball

It's World Series time and I can't help but think about baseball. I grew up in a baseball-obsessed town with and even more baseball-obsessed father. Genotype + environment = phenotype. In other words, I grew up playing a ton of baseball. I don't know how our parents found the inner strength to let a bunch of six-year olds throw a hard ball at, around, and away from each other. But they did; and I'm forever grateful.

I bring up my baseball-playing early childhood because the salient feature of a story that I wish to relate about nature puts in mind a regular feature of our early games. With, say, "men" on first and second, the hitter would squib a ball on the ground to the second baseman. The field, more resembling a bombing range than a level playing field, would redirect the ball in interesting ways beyond the anticipatory acumen of the fielder. As the ball scooted away from him, the runner from second would round third and head for home. Gamely chasing the ball, picking it up, and eager to redeem his error, the second baseman would throw to the catcher to try to cut down that lead runner at home. The phrase "to the catcher" had to be inferred from the general direction in which the second baseman was looking — for the direction of the ball was quite different. One run. The third baseman and catcher would give chase to the errant ball. The catcher, arriving first, would pick it up, then throw to third to try to catch the runner who had started his journey from first. Unfortunately, the third baseman, who had joined the catcher in pursuit of the second baseman's errant throw, was not at third to catch the catcher's throw. Two runs. Out to the outfield went the ball — picked up there as the batsman, the last remaining base-runner, was rounding second and heading for third. It was about then that the parents of the fielding team would break into the memorable chant:

"HOLD THE BALL, HOLD THE BALL".

There was a wisdom to that urgently offered advise. Evidence was, with another throw from another frenetic fielder, another run would score, leaving the fielding team yet deeper in the hole.

From managing baseball we go to managing nature.

A short history of Opuntia spp. - H. sapiens interactions

Drooping tree pear (Opuntia vulgaris) was brought to New South Wales Australia in 1788 on the First Fleet to establish a cochineal dye industry there — a spirited bid to keep those British red coats red and keep the green in the Commonwealth.

No problem.

Sometime later, in the early 1800's) prickly pear cactus (O. stricta) was brought in — this time, for stock fodder. In drought-prone Australia, it seemed prudent to have a drought-resistant plant to feed stock.

Big problem. Very big.

By 1925, prickly pear was completely out of control. At that time, it infested some twenty-five million hectares in New South Wales and Queensland, and was spreading at the rate of half a million hectares per year. This was one of the most astounding biological success stories of all time — for the prickly pear. And one of the greatest agricultural disasters — for humans.

With the experiment in managing stock fodder not going according to plan, it was time for another management decision. Perhaps some chemical management? In Queensland alone, that state's Prickly Pear Land Commission reported that in just one year (1926), the amount of poison sold was enough to treat 9,450,000 tons of prickly pear. Chemicals included 31,100 (10 and 20 lb.) tins of arsenic pentoxide and 27,950 containers (ranging in size from 2 gal. earthenware jars to 100 lb. (5.5 gal.) steel drums) of Roberts Improved Pear Poison — a cocktail of 80% sulfuric acid and 20% arsenic. We are not aware of how many plants and animals — human and otherwise — were poisoned. But evidently, the prickly pear were not. They continued to proiferate. Another management decision had to be made.

Enter the cactus moth (Cactoblastis cactorum). Brought in from Argentina where it was observed to be a singularly well-evolved weapon of mass prickly pear destruction, it, or 2.25 million or so of its eggs, were released in 1926. Six years later, by 1932, the moth, or more precisely, its larvae, had eaten, indeed, gorged themselves to agricultural glory and immortal fame — virtually eliminating all major stands of O. stricta in Queensland and New South Wales. The spectacular biological triumph of O. stricta had been utterly and even more spectacularly reversed in one of the most astounding biological control success stories of all time.

C. Cactoblastus v. Opuntia — cactus moth larvae doing what sulfuric acid and arsenic cannot

An innocent and interested but unrepresented North American party — Leptonycteris curasoae

There's more to the Australian story (summarized at http://www.northwestweeds.nsw.gov.au/chronology_of_events.htm). But let's leave it to fast forward to the middle of the 20th century.

In the Caribbean, various Opuntia spp. are endemic (not invasive), but annoying — at least to H. sapiens. In the 1950's, the level of annoyance was high. With the spectacular success of C. cactorum in Australia, it was clearly time for the moth to be brought back for an encore performance. It did not disappoint. According to Habeck, D.H, and Bennett F.D. , "Cactoblastis cactorum Berg (Lepidoptera: Pyralidae), a Phycitine New to Florida", Entomology Circular No. 333, Florida Dept. Agric. & Consumer Serv. Division of Plant Industry, August 1990 (http://www.doacs.state.fl.us/pi/enpp/ento/entcirc/ent333.pdf):

In 1957 [C. cactorum] was introduced into the Caribbean, in Nevis, where the control of Opuntia curassavica and other Opuntia spp. was rapid and spectacular (Simmonds and Bennett 1966). Eggs and larvae, or infested cladodes, were sent from Nevis to Montserrat and Antigua in 1962 and to Grand Cayman in 1970 (Bennett et al. 1985). By 1963 it had naturally spread from the Lesser Antilles to Puerto Rico (Garcia-Tuduri et al. 1971) and is now present in Haiti, Dominican Republic, and the Bahamas (Starmer et al. 1987).

Unfortunately, this management decision failed to account for the proximity of these Caribbean islands to the mainland. And sure enough, C. cactorum rode winds or perhaps took a boat ride over to Florida. Six Opuntia spp. are endemic to Florida. Three of them, including O. spinosissima and O. tricantha, are rare and threatened. But they are just as tasty to the moth.

The moth did not sat tight. It has steadily, inexorably made its way up the east coast and, more alarmingly, around the Gulf coast towards the Southwest and Mexico. Since the year 2000, it has spread at the stunning rate of 130 km. (100 miles) per year — far faster than it did in Australia. Apparently, the moth is intent on eclipsing its earlier down-under performance, as spectacular as it was. Most recently (in the summer of 2006) and most ominously, it showed up at Isla Mujeres, just 8 km. (less than 6 miles) offshore from the Mexican mainland near Cancun.

Opuntia natural and cultural history

Opuntia spp. are environmental keystones in semi-arid and desert regions. They retain precious moisture in the soil, stabilize it, and prevent its erosion. Many semi-arid areas in Mexico would almost certainly become desert without Opuntia. Opuntia provides habitat (nest sites and protection from predators) for various birds, reptiles, and mammals — including bobwhite quail, cactus wren and curve-billed thrasher. Many herbivorous insects feed on the flowers, pads, or plant; and these, in turn are food for vertebrates. A number of birds, reptiles, and mammals also feed directly on the plant. The Texas tortoise (Gopherus berlandieri) , which is listed internationally as a CITES II (Convention on International Trade in Endangered Species Appendix II — http://www.cites.org/eng/app/index.shtml) species and federally under the US Endangered Species Act, feeds heavily on Opuntia flowers and fruit. The also-endangered lesser long-nosed bat (Leptonycteris curasoae) — listed in both the US and Mexico — feeds on its nectar and pollen while Opuntia flowers, and its fruit afterwards. Opuntia spp. comprise more than half of the winter diet of white tailed deer and peccaries in south Texas.

The coat of arms of Mexico — a Mexican golden eagle perched upon an Opuntia cactus and devouring a snake

Among the mammals that sustain themselves from Opuntia is H. sapiens. Opuntia is a staple food for the Mexican rural poor.

Mexico is home for 76 Opuntia spp. 38 of them are not found anywhere else. According to Stiling, P., "Potential Non-target Effects of a Biological Control Agent, Prickly Pear Moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), in North America, and Possible Management Actions", Biological Invasions, 4:3 (2002), pp. 273-281(9), http://www.springerlink.com/content/lm432w8415149103/) Cactoblastis can be expected to attack at least 31 Opuntia spp. in the US and 56 species in Mexico.

Opuntia is also a Mexican cultural icon. The Mexican flag depicts an eagle perched on a prickly pear cactus. The Opuntia crop enables many subsistence farmers to stay on their land.

Opuntia economics

Economically, in the American southwest and in Mexico, Opuntia is a source of pharmaceuticals, cosmetics, fodder, cochineal dye (still!), hunting (for the peccaries and white-tailed deer that feed on it) and its lease revenue, and ornamental uses. The Mexican cactus industry is 2.5% of the value of its total agricultural production. (See the assessment in www.aphis.usda.gov/plant_health/plant_pest_info/cactoblastis/downloads/whitepaper.pdf.)

And now?

With the situation looking dire, we feel compelled to make another management decision. Ecologists are looking at importing the natural enemies of C. cactorum from its native home in Argentina. For example, Habeck and Bennett (cited above) recommend that:

Classical biological control should be considered. In its native habitat in South America several natural enemies are known including Apanteles alexanderi Brethes (Braconidae), Phyticiplex doddi (Cushman) and P. eremnus (Porter) (Ichneumonidae), Brachymeria cactoblastidis Blanchard (Chalcididae) [a chalcidid wasp], and Epicoronimyia mundelli (Blanchard) (Tachinidae) [all parasitoid wasps].

According to Peter Stiling, "Ecology, Theories and Applications", Prentice-Hall, 4th ed., p. 203,

Only about 16 percent of classical biological control introductions attempted so far qualify as economic successes (Hall, R.W., L.E. Ehler, and B. Bisabri-Ershadi, "Rates of success in classical biological control of arthopods", Bulletin of the Entomological Socoiety of America, 26: 114-14, 1980.) Usually, organisms are released in a hit-or-miss technique. Some authors believe that this approach makes the best economic sense, given the high cost of research into the biology of natural enemies (van Lenteren, J.C., "Evaluation of control capabilities of natural enemies. Does art have to become science?" Netherlands Journal of Zoology, 30: 369-81, 1980). Just release a bunch of parasitoids and predators, and hope that one of them does the job.

For the moment, put aside any moral or aesthetic responsibility we have to respect the natural complexity and richness of our world and to refrain from reducing it to a human-designed state of degraded simplicity. Forget for now whether we have a responsibility to live with, as well as from that richness. Just focus on our most narrowly defined, most mean-spiritedly selfish interests in wringing from the land living as much material wealth as possible as soon as possible.

Can anything be more clear? We have met the biological enemy, and it is us. We, the creature so highly endowed with a rational capacity, cannot bring ourselves to admit its limits. We cannot recognize our profound inability to understand natural systems well enough to avoid disaster in our nature-management experiments. Instead, we have an escalating spiral of management decisions — each successive one a "solution" to the mess left by the last, and almost always leading to a bigger mess. With Opuntia and the cactus moth, we have the biggest success... leading to the biggest failure.

Is this "merely" an dilemma that reflects the current state of our knowledge? Is our current helplessness in predicting the consequences of our natural management decisions a matter of the current, nascent state of the ecological science, which is clearly advancing as rapidly as some of the best scientific minds can make it go? Or is there some more fundamental barrier to this epistemological limitation? Is this distinction important?

As matters stand, with greater than 6 to 1 odds for failure and a significant chance for disaster for even "proven" management techniques, would a sober gambler place her chips on "going for it"? Do the odds in the nature casino, unlike those in Las Vegas, improve after an initial string of losses? With two runs across from two successive errors, and another threatening to score if the rubber-armed and frenzied outfielder throws away the ball again, I hear

"HOLD THE BALL. HOLD THE BALL."