Transforming Adirondack Forests By Nature’s ‘Ecosystem Engineer’

To date, ecological studies on beavers’ impacts have mostly focused on their ponds and dams, and the effects these have on forest streams, nutrient cycling, and aquatic biodiversity. But in a new study, ESF researchers have found that beaver are just as effective in modifying the forest around their ponds, and in creating diverse habitat that benefits other wildlife in addition to themselves. Conducted by Mike Mahoney as an ESF undergraduate honors project working with Dr. John Stella, the findings are published this month in the journal Forest Ecology and Management.

So he as an intern he went around studying forests in the Adirondack for the Department of conservation and he found that the surviving forest are pretty homogenous. All about the same age. Same species. Same density. They survived on mass because the grew up without beaver during the decimation of the fur trade. When beaver are around they take out some trees and open up some spaces of light in the forest which become spaces for new growth, smaller growth to occur.

In other regions, disturbances such as fire, storms and forestry activities keep the forest ecologically diverse by making room for fast-growing, shade-averse trees like aspen and willow to persist. Due to a lack of disturbances – events needed to regenerate younger stands -Adirondack forests are “kind of in middle-age right now,” said Stella. “But also, they have not yet gotten to the old-growth stage, which means there aren’t many canopy gaps where trees die and fall, and new forest patches can regenerate.”

In other regions, disturbances such as fire, storms and forestry activities keep the forest ecologically diverse by making room for fast-growing, shade-averse trees like aspen and willow to persist. Due to a lack of disturbances – events needed to regenerate younger stands -Adirondack forests are “kind of in middle-age right now,” said Stella. “But also, they have not yet gotten to the old-growth stage, which means there aren’t many canopy gaps where trees die and fall, and new forest patches can regenerate.”

This leaves few patches of young trees and forage for wildlife that depends on them, such as moose, migratory birds, and bats. It also concerns the DEC, which has prioritized creating a more diverse forest structure through its Young Forest Initiative, a statewide management strategy to maintain 10 percent of the public forest lands under 10 years old.

To do well forests (and people) need diversity. And beavers bring diversity when they cut down some trees and make homes for others. And they have a favorite size of tree to harvest, the little saplings which means more little saplings get to grow after their cousins are utelized. I thought this was really interesting:

Why are beaver so important to the health of the forest? Many researchers, including previous students in Stella’s lab at ESF, have found that these young forests support a diverse variety of plants, mammals, birds, and amphibians not found in older, more homogenous forests, which have typically larger trees but little groundcover or leafy forage within reach. “If you’re a turkey or a moose, big trees are useless to you; you can’t get up there and there’s nowhere to hide,” said Stella. Areas disturbed by beaver, on the other hand, have a lot of underbrush and herbaceous plants, more canopy layers, and more light and water – all desirable qualities for supporting a diversity of other species.

I never thought of the importance of hiding places and cover. No wonder beavers are so important. Just imagine how dangerous it would be if every human was born on exactly the same day. We would all get old at the same time,and all start dying at the same time too. Beavers stagger the forests by giving other trees a chance to live it up.

This study is part of a larger program with Stella’s lab exploring the benefits of beavers in the Northeast. “You see this a lot when beavers create these massive wetland areas, which are all of a sudden, extremely productive – you’ve got a ton of amphibians,” said Stella, whose lab also documented that over 50 percent more bird species use disturbed beaver pond areas compared to intact forest nearby. “They also give some water purification benefits and create dynamic wetland areas. And then when they move on and the dams eventually blow out, the wetlands evolve into rich beaver meadows with positive benefits that remain for a very long time,” Stella said. Scientists and land managers in western states have exploited these processes to partner with beaver in restoring degraded stream for better fish habitat. “And now we’ve documented here in the east that they change the structure of the forest adjacent to their ponds and that has ongoing benefits for biodiversity in this region.”

Let the beaver do the work. You really don’t need a PhD to know why its logical. Of course the article ends with a bitter little reminder that beavers in urban areas are also a nuisance, but we’re enjoying this so much lets just leave it here shall we?