November 15, 2012 at 6:49am
Although he is always over my head on the deer biology too, Delta is right. Maximum productivity in wildlife populations is achieved at K/2, or 50% of the carrying capacity.
Mike, you are correct in saying that if the population is at carrying capacity, then there is enough forage to support the population. But, if as you said, the population goes over K, then the forage base cannot support the population any longer and body health will begin to deteriorate. So, taking this into account, if we want to maintain a population at its maximum productivity level without going over K and maintain our forage base, you want to shoot for about 50% of the carrying capacity. This provides adequate forage for all members of the population and future recruits (i.e., fawns) into the population.
Here's an example. Say we have hunt r's deer herd with a K = 20, 10 does and 10 bucks for an adequate 1:1 sex ratio. Hypothetically, there are 20 persimmon trees and each deer requires one persimmon tree (I know, not real world, but hang with me here) to MAINTAIN its current, healthy condition. Let's say we have a great fawn recruitment, 10 fawns are added. You harvest the maximum deer off the property, 6. You still have 24 deer on the land. Now, you are over carrying capacity. Instead of each deer getting one persimmon tree, you now get 1.2 deer to each tree. Not a significant increase, but less forage for each deer. Now take that same example, half your original number of deer, and even with a fawn recruitment of 10, you are still below your carrying capacity and there is more forage available to each deer. More forage = better health, higher survival, (potentially) higher fawn recruitment.
Simple population dynamics, that's all. lol.