Invasive Plant Early Detection & Rapid Response

Climate Resilience

Starting in 2021, this project will provide support for surveillance for new or uncommon invasive plants (early detection) and removal of new and documented occurrences of these species before they become widespread (rapid response). Funds will be used to hire two seasonal GS-5 Biological Science Technicians for 14 pay periods (~6 months) each, over four years. A multi-year project is required because all of the targeted species have persistent soil seed banks and/or resprout following a single treatment. A four-year effort will also permit completion of a full sampling cycle of all 133 invasive plant surveillance locations in the park. Significant in-kind funding is available to commit to this project, including project oversight, field assistance and all necessary supplies and equipment for the effort.

Management of well-established invasive plants is often expensive. Treatment of a moderate to heavy infestation of a forest invasive plant may cost thousands of dollars per hectare.

Because control methods are often not completely effective, because seed may persist in soil or because of dispersal from other areas, management often involves a long-term to open-ended commitment of resources.

Prevention of the establishment of invasive species is less costly, both in environmental and economic terms, than long-term control of established weeds. Despite our best efforts, weed establishment cannot always be prevented. The next most cost-effective, feasible management approach involves locating species while populations are small—early detection—and promptly eradicating or containing the new invader – rapid response—before it becomes abundant. Unfortunately, resource managers often do not take notice of invasive species until they have become widespread and/or impacts are evident. Identifying potentially invasive species before they reach this stage not only protects natural resources, it can result in savings of money, staff time and potential non-target effects of control measures.

The park has a number of tools in place to make early detection of invasives more likely. Areas of the park most likely to be invaded by new weeds have been mapped. One hundred thirty three surveillance points have been established in these locations for periodic surveys. A watchlist of relatively new, rare invasives and species likely to establish in the near future—currently at 144 taxa–has been produced and is regularly updated. A project and field guide in the free iNaturalist smartphone application have been developed for mapping new discoveries.

What the park doesn’t currently have is the staff to make full use these tools for finding new invasives before they become a significant problem. Over the past two decades, an average of one new known or potentially invasive plant has been discovered in the park (see photos above). And a handful of new occurrences of many still rare invasives are found. Unfortunately, only some of these species/occurrences have been targeted for removal and very few have been revisited to ensure that they’re gone or under control. We have also only been able to visit a minority of the surveillance locations over the past five years.

The goals of this project are to:

  • Minimize the chance that roughly three dozen established but still uncommon invasive plants become major problems in SHEN.  
  • Increase surveillance for new invasive plants and new occurrences of still uncommon species.
  • Initiate management of any new discoveries.
  • Initiate restoration of several sites (Front Royal, Thompson Hollow, Thornton Gap) with significant infestations of early detection and other invasive plants.

Obviously, this effort will not eliminate the threat of new invasive plants establishing in SHEN.  Ongoing surveillance and removal of new occurrences will require resources beyond the conclusion of this project.  But having staff devoted to this effort for four years will substantially reduce the time and money required to maintain control of existing occurrences of these species, fully eliminating a majority of them.  Having the resources to conduct surveillance across the park should allow us to refine and better target limited resources for future surveys.  Additionally, initiating restoration of some more heavily infested areas should eventually make them more resistant to new invasions.

Support Shenandoah

Preserving national parks is made possible by people like you.
Consider supporting Shenandoah today.