In a long-term experimental demography study, excluding ungulates reversed invader’s explosive population growth rate and restored natives

In a long-term experimental demography study, excluding ungulates reversed invader’s explosive population growth rate and restored natives
Proceedings of the National Academy of Sciences of the United States of America, vol. 111 no. 12, Mar 25, 2014
Susan Kalisz, p. 4501–4506.

In a long-term experimental demography study, excluding ungulates reversed invader’s explosive population growth rate and restored natives.

The study was long-term, over six years in a PA woodland with a deer population of 20-42 deer per km-sq (51-107 mi-sq), a population similar to some areas of Washtenaw County. There’s a lot of data and statistics in the report, and it shows that the garlic mustard population “explodes” (their “technical” term) where deer had access, but declines where deer were excluded. The ability of native plants to successfully compete with garlic mustard was dependent on the extent of deer browse. Deer never browsed on the garlic mustard, but selectively browsed the native plants.

For our natural areas to sustain the native plants that support a community of other wildlife, the PA study shows that the deer need to be managed at a level where the native flora can survive.