A Wilder View: How wildfire fire suppression may help mountain lions prey on bighorn sheep

Posted at 12:29 PM, Apr 27, 2022
and last updated 2022-04-27 14:29:18-04

MISSOULA - Bighorn sheep have evolved with the presence of mountain lions for thousands of years.

With so many years of living in the same place, bighorn sheep have found pretty effective ways to avoid these sleek predators.

Bighorn sheep take to steep and rugged terrain that deters predators to move in those areas.

They also use open areas so any lurking predator can be seen before they get too close.

These strategies are of increasing interest because mountain lion predation on bighorn sheep has been identified as a leading cause of death in certain sheep populations.

This concern has stemmed researchers to wonder why mountain lions have been killing so many bighorn sheep.

One of the reasons why is because of fire suppression.

When certain fire suppression efforts take place, the brush in the area grows thick.

Artificial water sources such as water troughs can also be a large factor.

These water sources can cause bighorn sheep and mountain lions to overlap more frequently as they drink water.

Historically, some areas where bighorn sheep lived were adapted to wildfires which created fewer areas for mountain lions to hide and ambush their prey.

However, decades of fire suppression have developed a high number of areas making plenty of cover for mountain lions.

Typically, deer are the primary choice of prey for mountain lions, but bighorn sheep are also key prey items.

This choice may be elevated as these lions now have more of an ability to hunt sheep.

Understanding the predator-prey relationship between mountain lions and bighorns is critical to their management.

A new study published in the Journal of Wildlife Management looked to determine the factors that affect bighorn sheep population decline due to mountain lions.

Researchers tracked 103 reintroduced bighorn sheep fit with radio collars.

They then recorded the different types of habitats bighorn sheep lived in and the number of individuals in a group.

The study further looked at the cause of death for each collared individual.

They found that bighorn sheep lived in thicker areas of vegetation even thoough historically these were much more open habitats before fire suppression efforts

The publication implies that increased prescribed burns can increase suitable habitat for bighorn sheep.

This can not only provide more open areas but also may help improve habitat quality.

They also found that sheep that lived in larger groups were less likely to be killed by mountain lions. With more individuals there’s better awareness.

This is a critical element for biologists and managers to use during translocation and conservation efforts.