Posted by:
dustyrhoads
at Mon Jun 28 12:55:19 2010 [ Email Message ] [ Show All Posts by dustyrhoads ]
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>>You really think that subocs from only one mile away would not survive if relocated? I seriously doubt that. I don't think we would have to preserve each of the tiniest variations of each species for them to be successful. They can adapt and suvive with good habitat and food supply.
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>>King Snakes! Who can make a better mouse trap?
>> J Sierra
Research shows otherwise, my friend. It has nothing to do with my opinions or what I or you or anybody else thinks. For species like Yellowstone Gray Wolves, sea turtles, and birds that have enormous ranges, a mile won't make a difference, but this is not the case with terrestrial herps with tiny home ranges.
For highly variable species like Subocs and Desert Horned Lizards, for instance, populations vary from canyon to canyon, or from outcrop to outcrop. Yes, even from much less than a mile away, in many cases. A population among a volcanic outcrop will typically match that outcrop in color, often black or very dark. Now visit a population adjacent to that one with a limestone outcrop, and the specimens will be light-colored again. You see this in nature just about everywhere you look. For an example of some original research in this arena, check out this page at the University of Idaho --> people.ibest.uidaho.edu/~bree/research.html, and read the section called "Ecological Divergence in Reptiles". You can't ignore selection. Taking population genetics into account is a major part of what is called assessing the competence of a reintroduction program group or augmentation program group prior to release.
From Daniel Fairbanks' book Relics of Eden, he was referring to some of Darwin's postulates when he said that, "Varieties in nature usually occupy specific geographic regions, and members of the same variety preferentially mate with one another. Geographic barriers (such as rivers, canyons, mountain ranges, etc.) typically isolate then from other varieties of the same species." This is what is going on in the research I linked to above.
Not only do those geographic barriers exist, but there are reproductive barriers to boot, called sexual selection. Females will often only choose males that have the best genes -- genes that are adapted to the environment in which they live, NOT a genetically isolated canyon one or two miles away. This is also going on in the Rosenblum research above.
Are there distinct canyons in Trans-Pecos habitat from one mile to another that isolate gene flow and drive selection? Yes. How do we know? The snakes from those canyons match the substrate found in each canyon. Are these traits selected for? Certainly. Does that play a role in survival and selection? You betcha.
Here's some more resources for the role of genetics in reintroduction programs:
Vergeer, P., E. Sonderen, and N. Joop Ouborg. 2004. Introduction strategies put to the test: local adaptation versus heterosis. Conserv. Biol. 18:812–821.
Sawyer, M. W., and J. T. Baccus. 1996. Movement ecology and thermal biology of Bogertophis subocularis (Brown) from Texas (Serpentes: Colubridae). Southwestern Nat. 41: 182-186.
There was also an interesting study looking at the fate of relocated rattlesnakes here --> Nowak, E.M. (1998) Implications of nuisance rattlesnake relocation at Montezuma Castle National Monument. Sonoran Herpetologist, 11(1). Pp. 1-4.
*This page addresses the rattlesnake study some: webspinners.com/coloherp/cb-news/Vol-28/cbn-0110/RamblingReptiles.html.
Also, individuals do not adapt. Populations adapt. Adaptation, in the biological meaning of the word, is passing on genes that are beneficial to the next generation. A genetically incompetent group reintroduced or augmented to a wild population will not survive, will not reproduce, and thus, no adaptation will take place.
DR
Suboc.com
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RE: the Noah's Ark method of conservation... - dustyrhoads, Mon Jun 28 12:55:19 2010