Deer Account for Half of Long-Term Forest Change

A study released this week has linked that well over 40 percent of plant species changes in the forests of northern Wisconsin and Michigan over the past 60 years to the eating habits of white-tailed deer.


Donald Waller examined plant communities inside and outside 17 fenced “exclosures” built to keep out deer but not smaller mammals.  The study was published in the journal PLOS ONE.  Waller discovered that many of the plants commonly seen in early surveys now mostly occur inside the protective exclosures.

Where deer have been common, ferns and grasses — as well as several nonnative plants — have become more abundant.  Deer greatly reduced regeneration of native trees, the growth of shrubs, the height of forest understory plants, and the abundance of flowering plants that are neither woody nor grassy.

Some plants eliminated by deer need decades to recover, Waller says. “If a species is slow growing, or has seeds that are not dispersed readily by birds or as stick-tight burrs, it needs more time to reappear.”  The exclosures, he says, “serve as controlled experiments once they are run for 15 or 20 years, as these were.”


Waller says attributing at least 40 percent of the change in forest structure to white-tailed deer was surprising even to somebody like him who has studied deer for more than two decades. “It’s rare in ecology to find one factor that accounts for so much change,” he says.

Deer hunting is a political subject, and Waller would like to see greater harvests, especially of does.

Source Article:

Mark’s Rant:  This article is consistent with numerous others throughout the northeast, documenting that an overabundance of deer cause significant damage to vegetation structure.  Deer must be managed within their carrying capacity!