Demographic Side Effects of Selective Hunting in Ungulates and Carnivores.
Who conducted the research: Milner, J.M., Nilsen, E.B., and Andreassen, H.P.
Published in: Conservation Biology 21: 36 – 47.
Selective hunting systems are often applied due to different factors having an effect on populations and the preferences of hunters. Demographic side effects on populations were studied by Milner, Nilsen and Andreassen (2007). The effects of removing a large population with particular traits, and the effects of selective hunting a few specific individuals (trophy species) were examined. There was stated that more experimental studies were done on the demographic side effects, rather than observational studies. The authors of this study urged for more studies to be done on hunted populations with marked individuals that could further elaborate on the effects on populations. They also urged for theoretical models to be investigated on how the effects would influence a population’s growth rate.
The hunting of animals has few advantages in comparison to the many disadvantages. One of the most crucial disadvantages is that a particular species would become non-sustainable and be entirely wiped off of Earth. It is indicated that over 30% of animals listed on the World Conservation Union Red list as endangered is due to overexploitation and of the animals listed, the most targeted are ungulates and carnivores. Random hunting does still occur, but due to economic pressures and the precise specifics of hunters, this has led to an increase in selective hunting systems. Selective hunting has caused effects on the size of a population, the demographics of a population, as well as the social systems of populations.
Populations made up of various numbers have different population dynamics. Populations with female-biased ratios are more productive than those of male-biased ratio populations. It was found that prime-aged ungulate adults that were hunted had a higher mortality rate than unhunted ungulate populations. It was also found that in populations that were hunted, there was a decrease in male age due to trophy hunting and there were fewer older males within the population.
Even though more males are hunted than females, his does not always have an impact on reproduction rates. In many mating systems, males inseminate more than one female. This would help balance the population out again in terms of animal sex ratios. It is however possible for males only to mate with one female, and due to selective hunting, this could the cause a population to have a skewed sex ratio. It is explained that in populations where there is a low male to female ratio, there is also a tendency of a low average age of males. In a population where more females are hunted than males, the female’s calf quicker to try restore the sex ratio within the population because of the decline in age average of the females.
Offspring of parents have a great...