Population Growth Rate is the rate at which a population changes in size.
Four core factors determine the growth rate of a population:
1. Births
2. Deaths
3. Immigration of new members into population
4. Emigration of members out of population
Population growth rate is relevant to the science and policy of natural resource management because it has a direct correlation with how soon the carrying capacity for a certain ecosystem will met or exceeded.
Image Source: http://www2.estrellamountain.edu/faculty/farabee/BIOBK/expgrowth.gif
Find additional information about population growth rate at: http://www.eoearth.org/view/article/51cbeea77896bb431f69961a/