From a release about the article on Science Daily - (http://www.sciencedaily.com/releases/2014/03/140308095500.htm)
Deer typically prefer to eat native, woody plants and rebuff invasive species. The study showed that when deer consume native plants, the non-native species are left to flourish, dropping seed in the soil.
"It's obvious that the deer are affecting the above-ground species, but it's like an iceberg. There are major effects below the soil surface. We are seeing a divergence of seeds contained within the soil from what should be there," says DiTommaso. "We are not seeing the seeds of woody plants. Instead, we're seeing an escalation of non-native seed and the virtual elimination of woody plant seeds."See the full research article here: