The Cornell
Deer Management Study efforts are now complete and published in the peer-reviewed
literature. The findings are quite interesting. You can view a Video Abstract on
Vimeo. The full research paper entitled, Red oak seedlings as
indicators of deer browse pressure: Gauging the outcome of different
white‐tailed deer management approaches, is open access and can be viewed here.
Provided below are the highlights of their findings.
Introduction:
Different deer
management zones were established around the Cornell Campus including a deer fertility
control area, a recreational hunting area, and a “control” area where no deer
management occurred. The researchers individually marked more than 100 deer.
This allowed them to use annual camera surveys to assess the population, using
mark - recapture models. They also used planted red oak seedlings to assess
ecological outcomes. The combination of knowing the herd size while measuring
ecological outcomes is unique, no other study has done this in open
populations.
Results:
1. Fertility
control: despite a 90%+ sterilization rate, it did nothing to reduce the deer
population, this was not surprising.
2.
Recreational hunting: as presently implemented by agencies and executed by
hunters, also did not control the deer population. This may come as a surprise
to some, researchers allowed access to all lands available and killed hundreds
of deer, still to no avail.
3. Using planted
red oak seedling sentinels as indicators of ecological outcomes, the study showed
basically no difference in the fate of oak seedlings between the sterilization,
recreational hunting, and no management zones, with slight annual variations.
Other oak mortality factors, rodents etc., barely registered. Deer herbivory was
rapid in late spring and summer.
4. Halfway
through the study the researchers switched to the nuisance permits and
eliminated recreational hunting in a core area surrounding the campus. Only
then were they able to drop the deer population substantially. With the drop in
the deer population, deer browse rate declined linearly. This showed how
powerful the red oak sentinel method can be as it tracks changes in the deer
population. However, immigration of deer from the surrounding areas more than
offset deer kills, even with hunting over bait and at night, researchers were
unable to get the oak seedling browse rates below 20%, not low enough to allow for
successful forest regeneration.
5. The deer nuisance
permit approach provided benefits but researchers are not sure it will provide
the lasting deer reductions required to deliver the ecological and human health
benefits, i.e. highly palatable plants and Lyme disease, needed for a healthier
future. Ultimately, we need to fundamentally re-think and revise how we manage
deer and landscapes. Those advocating for no deer kills in the animal rights community
will likely not care for these results. Researchers also expect that many
hunters, who are now accustomed to seeing large numbers of deer, or folks in
state wildlife agencies may be surprised. For too long we simply believed that
recreational hunting will deliver benefits if access is provided without seeing
data showing that these assumptions were in fact true.
Summary:
The
complaints by foresters and conservationists about the erosion of biodiversity
assets have sounded loud and clear starting with Leopold some 80 years ago. It
is time that we take our social and ecological responsibilities seriously and
manage deer in ways that allows for a future that includes forest regeneration
without fences, a walk in the woods without dousing us, our kids and our pets
with tick repellent, and forests and landscapes to teem with the beauty and
biodiversity that is still possible.
Denuded forests that also will not allow for thriving deer populations
are the worst of all possible outcomes, unfortunately we are well on our way to
that. We hope that our work, the current paper, and others that will follow
will help chart a way to a better future. Will regulated market hunting and
allowing the return of big predators, wolves and mountain lions, be essential
to achieving this?
Dr. Bernd
Blossey
Associate
Professor
Department
of Natural Resources
206 Fernow
Hall, Cornell University
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