by Whit Gibbons

May 6, 2012

Where might you look for triclopyr, sethoxydim, and imazapyr? Should you be concerned about the fate of the addax, dama, and scimitar-horned oryx? And what do these odd words have to do with ecology?

The answer to the last question is that all were mentioned in recent news updates from the Wildlife Society, whose mission is "to represent and serve the professional community of [those] who work actively to study, manage, and conserve wildlife and its habitats worldwide."

As for triclopyr, sethoxydim, and imazapyr, they are neither former states of the Soviet Union nor invasive insects from North Korea. They are compounds found in herbicides that you might find in your garden shed or garage. You are not apt, however, to find an addax, dama, or scimitar-horned oryx in your yard, as they are endangered African antelopes. Both the herbicides and the antelopes present the kind of environmental dilemmas that are likely to become more common in the future.

Some herbicides do not mix well with insects. An article in the international journal Environmental Pollution reported on the negative effects of herbicides on a butterfly known as Behr's metalmark. The relatively common butterfly was chosen for the study because Lange's metalmark butterfly, a close relative, is endangered and near extinction. One reason Lange's metalmark is on the last of its six legs is that it occurs in a small habitat in California where its primary food source, naked stem buckwheat, is being overcome by invasive exotic plants. The invasive plants are controlled with various herbicides.

Research on the response of Behr's metalmark to the three herbicides revealed that toxic effects reduced the number of pupa that emerged as adults. These results are presumably indicative of how the herbicides affect Lange's. The reasons for the effects vary among the herbicides, but the conclusion is the same--herbicides can have potentially serious detrimental effects on butterflies. What irony. Herbicides that reduce the viability of the metalmark are necessary to keep invasive plants from eliminating the buckwheat that is essential for the butterfly. A true California conservation conundrum that might best be addressed by letting nature decide the outcome without any more human input.

The controversy surrounding the antelopes stems in part from their being found in Texas. Here's the situation. The IUCN classified the magnificent scimitar-horned oryx extinct in the wild more than a decade ago. The addax antelope and dama gazelle are critically endangered, thus approaching extinction, in their native North Africa. The threat to the three antelopes might appear to be ameliorated because populations of captive-bred oryx (11,000), addax (5,000), and dama gazelles (800) flourish on Texas ranches. Could they ultimately be transported to their native lands in Africa to replenish the lost herds that were once abundant? Not likely. Threats from poaching and habitat loss in Africa make reintroductions unlikely to succeed without stringent regulations and fundamental changes in deep-seated cultural and political attitudes across several countries.

Meanwhile, the U.S. Fish and Wildlife Service had already listed the three antelopes as endangered species. Two words ("wherever found") added to the listing of each may have a major impact on the captive-bred animals in Texas. Until this year, free-roaming antelopes on Texas ranches could be legally killed in controlled, paid-for hunts. Not any longer. Animal rights activists who want to protect individual animals from being hunted and killed have worked to have the "wherever found" provision enforced.

Are such antihunting actions justified? Some conservationists appreciate that each antelope species has a relatively large population, even if they are not on their home continent and are preserved for the purpose of sport hunting. By removing the incentive for Texas ranchers to continue increasing the world population size of the antelope species, will nature now continue its trajectory toward extinction for all of them, with no chance for recovery because none are left anywhere on Earth? Will a victory for individual animal rights result in the loss of three entire species? Another conundrum to reflect on.

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