Problem pigs in a poke: a good pool of data.

Abstract

A massive effort to remove introduced species, largely feral animals, from the Galapagos Islands is the topic of, as Jocelyn Kaiser's article “Galapagos takes aim at alien invaders” (News Focus, 27 Jul., p. [590][1]). As with many other eradication programs of feral populations, the Galapagos project is missing an opportunity to collect basic demographic and ecological data from these populations, just the sort of data needed to better “know thy enemy.” Data such as population sex/age composition, reproductive parameters, and food habits that can be gathered from the carcasses can provide information toward determining where and when the most vulnerable stages in the life history of these unwanted invaders might occur. Investing some small amount of resources into such research efforts would enable managers to develop the most effective future removal efforts. In contrast, sometimes the enemy turns out not to be all bad. Data collected from feral animal populations, especially long-isolated ones, can reveal interesting cases of environmental adaptation and provide basic genetic and evolutionary information. For example, in the feral pigs ( Sus scrofa ) of Ossabaw Island off the coast of Georgia, 30 years of data has shown that this population has developed a number of traits over ∼500 years that are not exhibited by any other pigs, wild or domestic ([1][2]). These traits include the ability to tolerate unusually high concentrations of salt in food (marsh grass, Spartina species) and drinking water (seawater) ([2][3]), the development of the highest levels of total body lipid reserves known of any ungulate ([3][4]), and a unique system for handling body lipid that produces a state of noninsulin dependent diabetes ([4][5]). These traits make the Ossabaw Island feral pigs a unique component of the world's total suid biodiversity and, moreover, one of interest to several lines of physiological and biomedical research. In fact, the Pigs and Peccaries Specialist Group of the International Union for Conservation of Nature and Natural Resources (IUCN) has named this pig as one of only two feral pig populations in the world being worthy of conservation consideration ([5][6]). As emphasized by this group's evaluation, however, any such consideration for the possible conservation of a feral population must be tempered by the assurance that these populations be so managed as to ensure that their impact is either minimal or nonexistent on endemic flora, fauna, or other ecological resources in the habitats where they are found. In some cases, this might argue for ex situ conservation of remnant captive populations ([5][6]). In any case, the possibility of a unique and hitherto unsuspected component of world biodiversity lurking within the feral animal populations themselves should not be overlooked. 1. [↵][7]1. J. J. Mayer, 2. I. L. Brisbin Jr. , Wild Pigs of the United States: Their History, Morphology, and Current Status (Univ. of Georgia Press, Athens, GA, 1991). 2. [↵][8]1. S. M. Zervanos, 2. W. D. McCort, 3. H. B. Graves , Physiol. Zool. 48, 67 (1983). [OpenUrl][9] 3. [↵][10]1. H. L. Stribling, 2. I. L. Brisbin Jr., 3. J. R. Sweeney, 4. L. A. Stribling , J. Wildl. Mgt. 48, 635 (1984). [OpenUrl][11][CrossRef][12] 4. [↵][13]1. P. J. Wangsness, 2. R. J. Martin, 3. J. H. Gahagan , Am. J. Physiol. 233, E 104 (1977). [OpenUrl][14] 5. [↵][15]1. W. L. R. Oliver Pigs, Peccaries and Hippos: Status Survey and Conservation Action Plan (IUCN, Gland, Switzerland, 1993). [1]: /lookup/doi/10.1126/science.293.5530.590 [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #ref-4 [6]: #ref-5 [7]: #xref-ref-1-1 View reference 1 in text [8]: #xref-ref-2-1 View reference 2 in text [9]: {openurl}?query=rft.jtitle%253DPhysiol.%2BZool.%26rft.volume%253D48%26rft.spage%253D67%26rft.atitle%253DPHYSIOL%2BZOOL%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [10]: #xref-ref-3-1 View reference 3 in text [11]: {openurl}?query=rft.jtitle%253DJ.%2BWildl.%2BMgt.%26rft.volume%253D48%26rft.spage%253D635%26rft.atitle%253DJ%2BWILDL%2BMGT%26rft_id%253Dinfo%253Adoi%252F10.2307%252F3801207%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [12]: /lookup/external-ref?access_num=10.2307/3801207&link_type=DOI [13]: #xref-ref-4-1 View reference 4 in text [14]: {openurl}?query=rft.jtitle%253DAm.%2BJ.%2BPhysiol.%26rft.volume%253D233%26rft.spage%253DE%2B104%26rft.atitle%253DAM%2BJ%2BPHYSIOL%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [15]: #xref-ref-5-1 View reference 5 in text