Reintroduction and conservation of the American beaver (Castor canadensis) has resulted in the population increasing from 60 000 to 250 000 individuals in one area of British Columbia, Canada in the period from 1970 to 2020.
The American beaver (Castor canadensis)
CC BY-SA 2.0, Steve, Washington DC, via Wikimedia Commons
The mean death rate over that period is estimated to be 1 200 animals per year
Calculate the average birth rate of population during the period 1970 to 2020.
Worked answer
Change in population = 250 000 - 60 000 = 190 000 beavers
Change in time = 2020 - 1970 = 50 years
3 800 = Birth rate - 1 200
Average birth rate = 5 000 per year