Posted by:
BigBrother
at Thu Feb 26 00:31:08 2004 [ Email Message ] [ Show All Posts by BigBrother ]
Chris, Katrina and Tim,
You guys are great! And especially you Chris for taking a look at things from my perspective on this one!!! I really appreciate that. I’m not going to give you guys the usual spiel this time, cause you all know what I would say anyway, but forgive me for just sticking in a couple of small points here
First, don’t make the mistake of comparing reptiles to mammals, because reptiles are much more important to ecosystems than mammals are. Why, basically it all comes down to metabolic and trophic efficiency. About 90-95% of the energy (food) a mammal takes in is used for its metabolism (i.e. maintaining the body temperature within the narrow range its enzymes are most efficient in), which only leaves about 5-10% of its energy intake for growth and reproduction. Further, the more rapid metabolism of mammals reduces the efficiency of energy “extraction,” so mammals can only extract about 25-30% of the energy produced by the next level down in the “food chain,” and this is generally measured in biomass or carbon cycling in the ecosystem. Reptiles, on the other hand, do not need to maintain a narrow range of body temperature for their enzymes to function efficiently and they use an external heat source (i.e. ectotherm), so about 90% of the energy they take in can be used for growth and reproduction, and when coupled with their slower metabolism, reptiles are much more efficient at extracting energy from the next trophic level down in the “food chain” (on the order of say 40-60%, but the exact amount is a bit tough to pin down for a variety of reasons that are beyond our needs here). Thus, 100 lbs of mice can be turned into 36-54 lbs of snake or it can be turned into 0.5-1 lb of say coyote, so which group of animals do you think has greater biomass in the ecosystem? And which group of animals do you think is more important in terms of carbon cycling in the ecosystem? If it wasn’t for the changes in physical structure of the habitat caused by mammals, they would be completely irrelevant to the functioning of most ecosystems. Further, reptiles can occupy niches in the ecosystem that mammals simply cannot even come close to occupying. Can you imagine a long skinny mammal? The surface to volume ratio alone would be so great the “snammal” would loose body heat so fast it would have to suck down sugar water at twice the rate of a humming bird just to stay alive!
The gene frequency in a population is the result of the selective pressure placed on the population by the environment where that population resides at that time. Breeding an animal in captivity (under different selective forces than those that are found in the wild) will alter the gene frequencies after one generation even if you started with the exact same gene frequencies as the wild population (this is where Hardy-Weinberg equilibrium and Mendelian genetics that you love so much comes in Chris and yes, it has been proven experimentally), so if you re-release individuals into the wild from captive breeding individuals from the exact same population as the parent stock came from, you will still alter the naturally occurring gene frequencies. Your best chance of success with such a program would be to re-introduce individuals into reclaimed habitat where the original populations were extirpated, for whatever reason, but the habitat remains or can be reclaimed. This also helps to eliminate the potential introduction of exotic diseases to the natural population, assuming the new population is a great distance away and thus isolated by distance and unsuitable habitat (this is what worked out so well with the wolf reintroduction, for example).
And just because I can’t keep my mouth shut… commercial breeders will offer the greatest risk of exotic disease and parasite spread due to the variety of animals they are exposed to. Ideally, the best breeder would be the person that only breeds the endangered species, which would minimize the potential disease/parasite transition. Further, the non-commercial breeder is your best bet for eliminating the perception of commercial exploitation, and it would make the permit/inspection process much easer to deal with.
Of course the biggest hurdle is trying to convince the Gov’t people with all the veto power that you herpers are serous about this, and not just trying to pull one over on the Goberment. In other words, your biggest fight is really against the poachers, smugglers and slimy animal dealers that give the herp community such a bad reputation! Until the herp community cleans house, your never going to be taken seriously. Just one man’s opinion, but I hear this sentiment all the time.
And I’m going to stop there… for now, because I’m too tempted keep right on going with about five more points and bore you all to tears =)
Again, this is a great exchange! And exactly what we need more of in this community!
Big Brother
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RE: Closing Big Brother's "Feedback Loop" (Proposal)>>> - BigBrother, Thu Feb 26 00:31:08 2004