The name of the Nature Preserve shown below isn't mentioned here - for good reasons (see Endnote).
Excess and uncontrolled numbers of white-tailed deer are degrading rare, high-quality ecosystems widely. As a result, some species of plants persist but fail to flower. Any pollinator that is specially adapted to such flowers may die out. Some plant species survive as a few leaves and depleted roots; other plant species are lost from these preserves. The ecosystems suffer loss of biodiversity.
The deer exclusion cage above is a rusty mess. It was half fallen apart when new Friends stewards discovered and repaired it (and others nearby) last winter. But this spring showed how well it had been working.
Largely bare ground surrounds these cages. Most striking within was the large-flowered white trillium. Also present and blooming on May 15 were wild geranium and wood anemone - two species not thought especially vulnerable to deer damage. But outside the cages in this heavily grazed area all three were largely absent or barely identifiable as a few small leaves.
A healthy ecosystem is a beautiful and inspiring thing. Much biodiversity survives best or only in the diverse stability of healthy ecosystems. Management of rich nature requires restoration of the conditions in which the diverse species evolved over millions of years. For many areas, that means regular fire, undisrupted hydrology, and a balance between predators and prey.
For understandable reasons, some people see deer control as evil. But badly overpopulated deer cause many other evils.
In the past, deer numbers have been regulated by such predators as mountain lions, bears, wolves, and humans. In the absence of the first three (which have little recovery potential in many areas today), the balancing depends on humans. For many sites, landowning agencies wisely employ sharp-shooters to cull deer - and donate the venison to food pantries. It takes work and sometimes courage to establish good deer management programs. More of them are needed.
Endnote
The name of the preserve where the photo was taken is omitted here in part because the deer over-population problem needs to be seen as widespread. It's also true that a focus on one or a few sites can create public relations problems for those sites.
Deer control programs require a sensitive balancing of community interests and aspirations. Such balancing does best when people avoid discord and conflict, instead seeking workable consensus based on diverse points of view.
Most people do not care much about the forest preserves. The forest preserves are for protecting nature. Most people think, “Deer are a part of nature, right?”
ReplyDeleteHowever, when the deer go into these same people’s yards to eat their tens of thousands of dollars of landscaping and gardens, these same people want the deer controlled. If you want to prevent deer becoming over populated and damaging the forest preserves then it would be better to post pictures of deer ravaging people’s landscaping.
From Prof. Tom Givnish via Facebook:
ReplyDeleteIn Wisconsin, you see the same story at exclosure after exclosure. And it's not just the understory herbs, but shrubs and tree seedlings. The current deer densities are a disaster for ecological communities. And, often, for the deer themselves. Almost sure CWD spread is more rapid the greater the density of the host deer population.
From Dennis Dreher via Facebook
ReplyDeleteThis has to be terribly frustrating for site stewards. A suggestion: Place deer exclusion cages in highly visible locations -- trailside and near visitor centers -- with interpretive signage describing their function. Perhaps if members of the public (and decision makers?) were more aware of the huge impact of deer overpopulation, more would be done about it.
From Tom Givnish via Facebook
ReplyDeleteI've travelled extensively as an ecologist for 50 years, and I must tell you that trilliums will not tolerate moderate or heavy browsing by deer. They will vanish or become quite rare. And they are joined by lilies, many orchids, and many other broad-leaves monocots. In areas where deer are absent or nearly so ... due most to large landscape dominated by forests, with few if any large openings, or on isolated islands, or in areas heavily hunted ... those species are often found. Seed regeneration has its advantages, but it will not IMO bring back these sensitive species unless deer are removed, directly or indirectly.
People tend to like more of what they like -think of money, but biological populations are about getting a good balance of abundance. Each species can be too abundant and too few in a natural community, but there are thousands of species some of which hardly anyone knows about. Most imbalance is created by people. Sometimes thru the introduction of exotic species, but also thru modeling money ideas (more versus less), ie, making rules stopping tree harvest, hunting and trapping. Those ideas worked when tree harvest and hunting were excessive, but eventually those ideas led to the excessive abundance and shade from trees and the excessive abundance of herbivores, particularly deer. There are other mammals that may be too abundant, ie, raccoons. The most likely plan to preserve natural communities would have biologists that love natural areas regulate, hunting, trapping and plant and fungi foraging to achieve an abundance balance that would preserve the most autochthonous species in the area selected for preservation. For species one wants to increase in abundance to reach balance, seed gardens are important contributors.
ReplyDeleteFrom David Mauger via Facebook:
ReplyDeleteDon't have to convince me of the effects deer can have - know it well, especially from enclosure studies done long ago at Thorn Creek Woods. Deer eat a lot daily basis and when there numbers high, no natural predators or hunting, population numbers increase fast, especially when does in good health and food resources and "twin" births of fawns...sometimes triplets!
Of how long ago do you speak?? I lead a team doing the botany work for a deer-browse study in 2006-07 in several preserves throughout Will County including Thorn Creek. I was aware of the problem before hand, but seeing it so clearly in-person really drove home the disaster that is unfolding in our natural areas. A few take-aways:
Delete- in on preserve, I think it was an eastern part of Thorn Creek, on the first year of the study, we thought we were seeing sometimes dozens of 2” tall white oak seedlings per square meter quadrat. The next year the ones inside the deer exclusion fencing were. Early a foot tall. The ones outside were all still 2” tall. Upon closer inspection, it was clear that the deer were browsing perhaps hundreds of thousands of oak saplings to the ground every winter. Some of those saplings had a half-dozen chomped leaders. They were several years, or even decades old. All that time without any effective oak recruitment despite there being enough light for many to germinate.
- In Thorn Creek we say cages from an older study (perhaps this is the one you are speaking of), similar to the one in the photo but lager, taller. These were a virtual jungle of what I would consider rare to uncommon shrubs. I don’t remember them all now, but they included red elderberry, maple-leaf viburnum, and paw paw… several species of shrubs in these cages where the deer couldn’t get at them, and barren leaves and a few specs of short weedy perennials around them.
- The study was meant to last 3-4 years. Is was called-off after 2 as the results were so clear and striking, there was no purpose in continuing.
Steve, thanks for all your writing, this one in-particular is clear, to the point and unapologetically factual.