Population Management

Humans are destroying the earth. We are fed this idea by various scientists and environmental advocates who are very much right in their attribution of much of today’s ecological problems to the advent of urban human society. These opponents of humanity’s role in the environment around them have almost always focused solely on the roles of Homo sapiens in disrupting ecosystems, a view that is probably somewhat narrow minded and very limited in scope.

This limited scope can be rather deceptive. Many other populations besides that of the human population have a detrimental influence on the habitat in which they live and even on other species and populations within that same environment (Ross, Pollett, 2006).

Examples of negative population effects include that of the Koala in Australia. The Koala, now considered a pest, had caused damage to the well-being of the native Rough-barked Manna-gum on Kangaroo Island, Australia. A second, more abstract example is the impact that weeds have on their environment. Not only do they compete with other plants for habitat and resources, but they can cause damage to animals such as humans by damaging a source of their nourishment. An estimate of AU$ 3.5 billion (~US$ 2.7 billion) was made to approximate the financial costs incurred by the agricultural community in Australia due to the effects of weeds (Ross, Pollett, 2006).

Understanding the (possibly negative) roles of other organisms on the environment is crucial in allowing us to create a better living standard for humans and also keeping a balance or harmony within the environment we have immediate influence over. As humans we understand the negative impact we are having on the environment and so we are consequentially able to change our actions and change the actions of other humans in order to better coincide with our habitat. However, due to the biological nature of all other populations we are unable to communicate and therefore unable to reach agreements in dealing with other species and their environments.

Because we cannot change the lifestyles and patterns of other, nonhuman populations, we must turn to regulating the size of the populations themselves. Ross and Pollett’s “On Costs and Decisions in Population Management” proposes that the two applicable methods of population regulation are reduction and suppression.

The suppression regime is the process by which a certain population is closely monitored to make sure a certain threshold for the population size is not surpassed. Suppression is exacted through continuous control, where culling of populations is done relatively often until the certain group falls below a pre-determined benchmark. This continuous control is in contrast to culling a population in intervals; relatively fewer and more spread out in nature (Ross, Pollett, 2006).

Before I continue, I think I need to explain what the culling of populations is. “Culling is the process of selection of surplus animals from an animal population” (Wikipedia). While some might argue against culling, the purpose of this article requires it as a necessary practice. There are a multitude of factors that go into deciding on the final population sizes that will be created by culling, the most important of which is finding the minimum number of the population that need to be present in order for the population to be able to persist in spite of their reduction; this comprehensively referred to as “population persistence” (Ross, Pollett, 2006). Throughout their article, Ross and Pollett develop formulas that dictate the scope of culling that needs to take place in observance of the population’s current birth and death rates.

The second regulation method of reduction is fundamentally different from suppression in that instead of stopping a population from growing beyond a certain point, that population is reduced to a pre-determined size and then maintained at this newly created level. However, reduction is also usually more educationally based and better at addressing various genetic issues that arise from a reduced population size. In order to control a population ethically and efficiently special emphasis needs to be made on genetic diversity. Genetic diversity will not only reduce the problems proposed by inbreeding, but will also allow for the species to continue evolutionarily, not being stunted by a lack of variance in the genetic makeup. Also, reduction’s culling intervals are usually more researched and causally more infrequent (Ross, Pollett, 2006).

Even though population regulation is performed in order to benefit the overall environment, there are some costs to its practice. The first cost is incurred by the species that is being controlled. The cost is extinction. While extinction “is contrary to the management objective” (Ross, Pollett, 2006) it is effectively inevitable in many, if not most situations. This may seem somewhat inhumane at first, but we can look at examples such as the koala population on Kangaroo Island to see that it is not. Like I referred to before, the koalas of Kangaroo Island are reproducing at an unprecedented rate. This rate will almost definitely lead to the extinction of the population sooner than an extinction incurred by management because of overpopulation, competition, and resource exhaustion. Resource exhaustion from a certain habitat almost definitely can lead to the extinction or impairment of other species, so even if population management eventually leads to extinction, there is no reason to think that reduction or suppression are inherently malignant for the given population.

A second, less objectionable cost is that controlling populations is going to cost a large amount of money. This is pretty obvious, as the resources required to intensively regulate a certain population are quite expensive. The only major difference in cost between the two regulation methods are that reduction costs large amounts occasionally (during its culling periods), and suppression costs small amounts at a relatively constant pace.

As the human population continues to increase its sphere of influence we will definitely be coming more closely into contact with local species such as kangaroo. The fact that animal species can be maladaptive in their environments is crucial to ascertain. I feel it is very important that we are able to coexist (and sometimes intercede) peacefully and effectively with nature, and understanding population regulation is an integral part of that.

Sources:

J.V. Ross, P.K. Pollett; “On costs and decisions in population management.” University of Queensland, St. Lucia, Qld , Australia. 7 September 2006. 1 February 2007. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VBS-4KV3Y45-2&_user=130907&_coverDate=02%2F10%2F2007&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000004198&_version=1&_urlVersion=0&_userid=130907&md5=a32e7c905ca9d9c77f95a734abc4b8c2#sec18