Ohio: Too many Deer in forests might be more beneficial than was first thought

Reducing the number of deer in forests and parks may unexpectedly
reduce the number of reptiles, amphibians and insects in that area,
new research suggests. A recent study by researchers at Ohio State
University and National Park Service found that higher deer activity
is modifying forest ecosystems in unexpected ways. Research was
conducted in Cuyahoga Valley National Park, a 51-square-mile park in
northeastern Ohio with an estimated deer population of 2,300 to 4,600.
The park’s large population of deer and varying landscape made it an
ideal place to test for the effects of these animals, she said. Out of
several species of snakes, salamanders, and invertebrates studied, a
greater diversity of animals were found in areas with deer populations
than were in areas with no deer activity.

The study, which comes at a
time when many states have begun to selectively control deer
populations, challenges previous research that has suggested deer
populations can negatively impact forest ecosystems through eating
plants that many smaller animals may depend on. Instead, researchers
found that high numbers of deer may in fact be attracting a greater
number of species. This may be because their waste creates a more
nutrient-rich soil and as a result, areas with deer draw higher
numbers of insects and other invertebrates. These insects then attract
larger predators which thrive on insect lava such as salamanders, and
the salamanders in turn attract even larger predators such as snakes.
The results, which were published recently in The Journal of Wildlife
Management, highlight how recent attempts to control deer populations
in and around forests may indirectly affect other animals in the
forest.

“By just reducing the number of deer in the forest, we’re
actually indirectly impacting forest ecosystems without even knowing
the possible effects,” said Katherine Greenwald, co-author of the
study and doctoral student in evolution, ecology, and organismal
biology at Ohio State. “Smaller creatures like salamanders and insects
are all part of the base of a larger food web that can be affected by
small changes.” “We thought the salamanders especially would be very
sensitive to areas with deer because in those areas the whole
undergrowth is basically gone.

So we thought these creatures were
going to be much more abundant in the fenced exclosures because it is
just bursting with plants and other studies have shown that amphibians
prefer damp, covered areas,” she said. Instead, they found that many
of the species studied favored the unfenced areas where deer grazed
frequently. Pill bugs, centipedes, millipedes, and beetles were found
equally in grazed and fenced areas, but many other creatures were
found in greater numbers in grazed areas. Researchers found nearly
three times as many red-backed salamanders and five-and-a-half times
more snakes in sites with deer than those without deer. Among
invertebrates, snails were 11 percent more abundant in grazed areas
than in exclosures and the diversity of arthropods was also 14 percent
greater in these areas. Greenwald speculates that the areas with
higher deer populations may appear to lack the high variety of
low-lying plants found in exclosures, but the deer may be creating a
richer soil mixture through their droppings.
http://researchnews.osu.edu/archive/deer.htm