The Grizzly bear population in Yellowstone National park is thriving and the genetic diversity remains stable since the 1980s, says a new study by the Interagency Grizzly Bear Study Team. The report says that there is a potential that the bears will continue to thrive in the future.
Published in the journal Molecular Ecology, the collaborative study by the U.S. Geological Survey (USGS), Wildlife Genetics International, University of Montana, and Interagency Grizzly Bear Study Team, included 729 bears and it shows that the effective population or the ones passing down genes to the next generation quadrupled over a 25-year period.
The report says that the number of Grizzly bears that were passing the genes to their offspring increased from 100 in the 1980s to 450 in the 2000s. The numbers of bears are lesser than the actual population because not all of these animals breed.
This means that the Grizzlies in Yellowstone are going towards having the effective size needed for a continuing genetic sustainability and survival. As of 2014, there are an estimated 674 to 839 Grizzly Bears in Greater Yellowstone. However, U.S. Geological Survey estimated the total Yellowstone grizzly population at 757.
Gene variations help Grizzlies evolve and adapt in order for them to survive alongside changes in the environment. This is very important especially that the environment faces various predicaments including climate change.
"The increase in effective size of the Yellowstone grizzly bear population over the past several decades, with no significant change in genetic diversity, supports evidence of population growth based on traditional surveys," said lead author and USGS ecologist, Pauline Kamath.
She cited that their finding is a 'key genetic indicator' of the ability of a population to adapt to future changes in the environment that could affect the animals and their habitat.
"This is a key genetic indicator of a population's ability to respond to future environmental change," she added.
The bear was listed in the Endangered Species Act in 1975 and multiple efforts were made to help the population of Grizzlies to recover and thrive in the long term. The researchers used several newly available techniques to assess Grizzly population since data on wildlife population are limited due to difficulty in measurement and the long period of time needed for measuring individuals in the population.
Thus, this study has shed light on how genetic monitoring is needed to complement traditional demographic-based monitoring. This will provide useful tools for population managers in the present and future in order to accurately estimate the survival rate and population of endangered animals.
Photo: Steve Jurvetson | Flickr
