New Research Published - Excessive deer populations facilitate garlic mustard invasion

Just last week we posted on this blog about a recent article about deer overabundance impacting aboveground vegetation and seed bank and how they influences the forest community.  (See original post HERE).

Now, new research has been published that further investigates the specific relationship between deer populations and invasion by garlic mustard, Alliaria petiolata.  In the latest issue of Proceedings of the National Academy of Sciences (vol. 111, no.12), Kalisz et. al  published an article titled "In a long-term experimental demography study, excluding ungulates reversed invader's explosive population growth rate and restored natives."  In this article, the authors argue that successful garlic mustard invasion is dependent upon high deer populations.

From a release about the article on Science Daily -
(http://www.sciencedaily.com/releases/2014/03/140320111932.htm)

To study the effect of rampant deer on trillium and garlic mustard populations, the researchers established multiple 196-square-meter plots in the forest. Half were fenced to exclude deer. Years of observation and hours of statistical analysis later, the team found that in plots where deer were excluded, the trillium population is increasing, and the garlic mustard population is trending toward zero.  "This demonstrates that the high population growth rate of the invader is caused by the high abundance of deer," says Susan Kalisz, professor of evolutionary ecology in the University of Pittsburgh's Department of Biological Sciences and principal investigator of the study. This effect is reversible with deer exclusion.

The full research article can be found here:
http://www.pnas.org/content/111/12/4501