Population Changes

Changes in populations can increase or decrease with the involvement of four factors. The first factor, birth rate, can increase the population if organisms are born faster than they die. The second change in population can occur with death rates. Opposite to birth rates, death rates can decrease the population if they occur faster than birth rates occur. Dispersal, or the movement from one region to another, has two types; immigration and emigration. Immigration is the movement of people into a population that increases its size, and emigration is the removal of people that decreases the population size. In order to stabilize the population, birth rates and death rates must be equal, but with the leap in health care, vaccinations, technology, and improvements in sanitation, although birth rates have been on the decline, so have death rates which are increasing the world population.
    In the video, immigration and birth rates are affecting the population of the nutria. Nutria breed multiple times and at a young age, so the birth rate is much greater than the death rate. The nutria population immigrated to Louisiana from South America and was brought here for fur trapping, but they have exploded in population and are creating havoc in bayous of Louisiana. Once the vegetation and food sources for the nutria have been depleted, they will surely emigrate and find a new source of food elsewhere. If they are unable to sustain a food source, nutria will either evolve to establish a new diet, or experience a high death rate and eventually become extinct.