A Wilder View: Fox dens help Montana’s ecology

Posted at 3:07 PM, Jul 28, 2021
and last updated 2021-07-28 22:07:21-04

MISSOULA — This edition of A Wilder View takes a look at how the engineering of red fox dens does much more than just raise their young.

Red foxes occupy the largest distribution of any carnivore on land globally; you can find them in pristine forests or even cities.

They are extremely successful hunters and great at raising families. But they're also doing great things for their surrounding ecosystem that they may not even realize.

Fox dens may be used for adorable little kits to grow but denning foxes can help build on ecosystems. These den sites can help plants flourish by transporting and recycling nutrients. This process of helping their environment can be coined as eco-engineering.

Just like you may till your lawn or garden to stimulate growth, the act of churning soil as foxes dig their dens provides the soil with the same enrichment. Moving dirt helps rock hard soil soften up, increasing pH making it easier for plants to grow.

Now, when fox pups are born, they stay inside the den for several weeks before emerging, This means that they handle all their business below ground.

So fecal matter and urine can pile up in the den. Standing in your own fecal matter sounds gross but it’s rich in nitrogen which is a vital nutrient for plant growth.

The parents of the babies will also bring in plenty of food to the den sites. From voles and squirrels to crows and turkeys. These aren’t always fully eaten. So multiple carcasses can be found in the den and surrounding area.

These carcasses then start to decompose, excreting their nutrients into the soil. This is essentially acting as a fertilizer for the area. The carcasses can also serve as food for other animals. Like magpies and insects taking advantage of the scraps left behind.

Foxes can disperse seeds that have attached to their fur allowing new plants to grow in the area. They also may facilitate the germination of seeds that are already present in the soil.

This means that seeds from all of the species found on dens may also be present in surrounding areas, but are unable to grow in the absence of specific soil conditions, brought on by nitrogen concentrations or disturbances caused by fox dens.

Foxes aren’t the only carnivore that can be considered an ecosystem engineer. Grizzly bears and mountain lions contribute to the ecosystem in similar ways and also fall under that category.