Hunting tugs at many strings in the complex web of interactions between survival, recruitment, individual characteristics, and environmental conditions.
The paper in Nature Ecology & Evolution is here: http://go.nature.com/2C1tdTs
During 2015/2016, several colleagues and I were invited to the Center for Advanced Study (CAS) at the Norwegian Academy of Science and Letters in Oslo to spend a year studying the role of climate change on hunted large mammal populations. We - an international group of ungulate and carnivore researchers - quickly agreed that we would estimate the effect of environmental variables on demographic rates of brown bears. Not a surprising choice, with the Scandinavian Brown Bear Research Project sharing the helm of our CAS project and given their long-term monitoring study on bears in central Sweden.
Instead of piecing together a picture from multiple analyses that focus on each vital rate and process in isolation, we opted for a joint approach that integrated the key demographic processes into one analysis. We were primarily interested in obtaining estimates of vital rates and important factors that influence them. Having used a comprehensive model to estimate all parameters jointly, we next wanted to also display the relationships in one comprehensive diagram. What jumped out, as we began visualizing relationships and influences, was the pivotal role of hunting among the relationships in our diagram (Figure 2 in the article).
This became the story of our paper. Lest anyone should get that impression, this article is not intended as criticism of large carnivore hunting per se. Regulated hunting of bears can be practiced sustainably in central Sweden, as evidenced by three decades with a growing and eventually stable bear population. We simply make a point that wildlife managers and policy makers should be aware of: in our study population, hunting plays a very dominant role in a bear’s life history. It is the cause of death for the majority of adult individuals and it tugs at many strings in the complex web of interactions between survival, recruitment, individual characteristics, and environmental conditions. Finally, we did not end up with 30 years-worth of large carnivore monitoring data without lots of help. Generations of volunteers and students have tracked bears, scoured the forest for evidence of their activity and habitat associations, and – on lucky occasions – sneaked a glimpse at the animal itself. Each year, researchers and field staff captured and tagged bears, and searched for collared females to check whether they were with cubs or not. None of it easy, this work made our study possible. Thank you!