I listened to Dr. Don Waller, UW-Madison professor of botany and environmental studies and editor of “The Vanishing Present: Wisconsin’s Changing Lands, Waters, and Wildlife” give a presentation on long-term changes in Wisconsin forests last week as part of the UW-Arboretum Winter Lecture Series. He shifted my forest focus from an upward-tilted gaze into the branches to a down-to-earth look at the ground.
I expected a talk on forests to be about trees, and yes, trees did make an appearance, but the real action is in the understory. We all know trees are under siege from loggers, deer browse, insects like Emerald Ash Borer and climate change. But Waller said it is damage to the spring ephemeral plants that are putting the entire ecosystem at the greatest risk.
Some of the things that are threatening the understory are issues that have escaped our notice. One rare plant in the UW Arboretum has stopped reproducing because that area has lost a certain type of ant that disperses its seed.
So, one silly little ant species is gone. Who cares? This plant species cares. And what will the one plant species loss cause? We may not know which other species will die without it, but it could be many. This is how cascading species loss begins.
It’s very difficult for us to even tell what we are losing on the forest floor because we don’t have a good base line with which to compare it. John Curtis did a great job of documenting what was going on in Wisconsin’s forests half a century ago. He kept meticulous records, creating a gold vein of info that is being mined to this day. His records are how we know precisely how our forests have changed.
Unfortunately, Curtis paid very little attention to the forest understory.
We do know that the forest is hemorrhaging its diversity of species, and this seems to be happening most rapidly in the understory.
The delicate wild flowers of the forest floor are the big losers. They are being deer browsed right down to the ground. Wild lilies and orchids are vanishing. Rose Twisted Stalk has suffered an 82% decline, and for Bellwort, it’s down 70%. Large-leaf White Violet, Sidebells Wintergreen and all the other species whose flowers and berries are bright flags that draw hungry deer. They are sitting ducks in our deer-saturated world. Milder winters mean even more deer in the future.
Part of what is hitting understory diversity hard is that in Southern Wisconsin (the northern woods are a different story – not necessary more cheerful, but different) agriculture and urban development have sliced and diced the woods into tiny, scattered remnants, and these bits and pieces are so disconnected that they cannot replenish each other. In a healthy, larger ecosystem, populations are being decimated and restored on a local level all the time.
A tree falling and letting more sun to the ground might wipe out an area’s population of Yellow Lady Slippers. But the Yellow Lady Slippers growing a mile away would be able to replenish that area as the trees filled back in and the shady ecosystem recovers.
More and more, when those lady slippers die out, there are no nearby clumps to repopulate them. They are gone permanently from that patch of woods. The loss of Yellow Lady Slippers is playing out on my own land right now.
Roads can cut a natural supply line. A new housing development that surrounds a once-connected woods denies it any new input and dooms its diversity.
How do we replenish our forest floors? Many people have been trying to protect native areas, but is that enough? Waller fears we may be passing ecosystem thresholds, and it will be very difficult to bring many of these vanishing species back.
Some people would like to just mix it up – plant everything everywhere and revive diversity with a kickstart. But Waller cautions that we need to know more before taking that approach. There is some evidence to suggest that creating overall diversity is not the same as a healthy range of diversity between neighboring but distinctly different forests.
You wouldn’t fly a 747 without a panel of instruments feeding you information, and guiding the ecosystem is a lot more complicated than a plane. We need to get out there and do some serious documentation of what we are seeing and only then try some careful, assisted translocation.
First and foremost, we should all be keeping as careful records as we can about the parts of the natural world we are close to. Every one of us who cares must lay down the next vein of info gold for future environmentalists to mine.
This may be the best way we can help save the understory and other threatened ecosystems.
Have you ever written down something about your favorite natural area? Start documenting this spring!
Categories: CITIZEN SCIENCE