As It Turns Out, Deer Munching on Plants is Good for the Environment

Conventional wisdom says that grazing deer are enemies to fledgling trees and plants, but have we been wrong all this time? New research suggests we might have been.

The latest study, published this month in the journal Proceedings of the Royal Society B, saw researchers test the effects of allowing foraging white tailed deer access to plots of land where young saplings are growing. Traditionally, white tailed deer’s numbers are restricted in such areas — often times through the use of controlled culls — because it was feared that the voracious eaters would damage the fledgling trees.

However, more recently, this wisdom has been called into question. Researchers had previously observed that by allowing deer into grassland areas, those areas would then produce a more diverse range of plants. Ecologists therefore wanted to test whether the results could be repeated in a different setting and whether it would give them insight into why this might happen.

The researchers, a team from the Smithsonian, chose a Maryland forest as their setting and planted 140 3x3 plots of saplings that were all a year old. A proportion of those plots contained only one sapling selected from fifteen species. Others contained fifteen saplings but they were all from the same species.

The researchers then tested what would happen when they left the area alone for the white tailed deer to roam through or, in some plots, what happened if they prevented the deer from accessing the saplings.

What they found might at first sound counter intuitive. After three years, the researchers discovered that the plots with higher diversity were the ones the deer had grazed. The researchers believe that the deer acted, in a sense, as instinctual gardeners. The tended to favor nibbling the faster and more hardy species of saplings. This stopped those saplings from outpacing their slower and less ruddy counterparts, meaning that they couldn’t strangle or simple muscle out their competition. In effect, the deer disadvantaged the hardy plants and therefore created more of a balance in what was able to grow.

Unsurprisingly, in the areas where the deer weren’t allowed to graze, a monoculture quickly took hold where only the fastest-growing species flourished. This, the researchers suggested, might be what would happen if we continued under the misapprehension that deer are always bad for cultivating young trees and plants.

Said John Parker, one of the researchers involved in the study: “Seeing a positive effect was really surprising. If we protect plants from browsing, maybe we’re eliminating the very factor that makes diversity work.”

So could our quick-cull mentality actually be causing less diversity and not more? Well, this study certainly gives us pause. However, we can’t say for certain that this phenomena will hold up on a wider scale. We know, for instance, that restricting deer from accessing certain areas when the deer populations have boomed — usually thanks to a lack of predators — is sometimes necessary because the deer will quickly graze the land to a state where very few young saplings of any kind survive. That, by the way, is not to advocate culling in any way but rather to emphasize that some kind of action is sometimes necessary.

The question seems to be about balance: what is the threshold where deer numbers are beneficial to diversity and at what point are their numbers antagonistic? Parker and his research team have recently planted a new forest containing as many as 24,000 trees. They expect to be able to gather meaningful data for many years and probably decades, to really see whether the effect holds up on a much wider scale and answer those kinds of questions.

What should we take from this research in the meantime, though? The research highlights how difficult ecology can be and how subtle influences from seemingly hostile species can actually play an important part in maintaining an eco-system’s balance.

This research, then, demonstrates in quite stark terms the limits of our knowledge when it comes to attempting to manipulate biodiversity and how, even when we think we are doing good, in the absence of a more complete understanding, drastic measures like culling and severely restricting grazing access might actually be bad for the habitats we are trying to maintain and save.

Photo credit: Thinkstock.


Carrie-Anne Brown

thanks for sharing :)

Charles L.
Charles L.3 years ago

Janice Thompson
Janice Thompson3 years ago

Mother Nature knows what she is doing. We just need to let her be.

angela l.
Angela L3 years ago

That's why it's called evolution and balance. Hunting whatever most in season is just an excuse, nature itself can take care of that part, it's just humans come to this surface of the earth just to destroy everything. Why not control human birth rate before they kill every soul on this planet to feed more evil!!!
Fishermen destroy dolphins and sea lions to fight for more fish, hunters kill elk and deer for food that they don't really need, Japanese massacre whales, Chinese kill for ivory. The list of greedy evil acts go on and all these are the destroyers of the planet and other beings.

Jennifer H.
Jennifer H3 years ago

Nature always knows best. Humans always think we do but, in fact, we make a mess every time.

Ann Razumovskaya
Ann Razumovskaya3 years ago

No doubt, animals are good for environment. But some humans think they're smarter than the planet Earth. Of course, destroying is way more simpler than creating... ;(

Val M.
Val M3 years ago

The web of life is complex. We need to know and learn more so that we can work with nature to restore balance.

Gerald L.
Gerald L3 years ago

There are variables, Deer eating in our vegetable gardens, fruit trees, grape vines, are what can I say, a tragedy. Especially when the Bambi Disney sympathetics are feeding them. They are a beautiful creature, BUT don't alter nature by feeding them! An unnatural diet of grains that makes them sick. Plus enables them to over-populate and spread LYME disease, a curse!

And for a real comparison when wolves eat deer and keep their numbers down.

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Ruhee B.
Ruhee B3 years ago

I've had enough of these awful animal culls! The only species whose numbers need to seriously be brought into check is the most destructive, invasive and polluting species ie the human!! Why can humans breed non stop and no one even see that there IS a problem in that? Before we try to control other animal population numbers, we need to start with our own!

Glenda L.
Glenda L3 years ago

We always screw things up when we interfere, nature does it just fine on her own.