News Release

Temporary Closures for Herbicide Application

News Release Date: May 31, 2023

Contact: Tom VandenBerg, 432-477-1107

BIG BEND NATIONAL PARK, TEXAS – From June 3 to June 7, a team of biologists and resource staff will be applying herbicide to control non-native giant cane (Arundo donax) along the river in the Rio Grande Village area. This is a follow-up treatment to a successful prescribed burn in early May. The herbicide Imazapyr will be directly applied to all resprouts of the invasive plants post-fire. During this time, visitors may encounter temporary closures along sections of the Rio Grande Village Nature Trail, specifically the spur of the trail that leads to the banks of the river. The Rio Grande Village boat ramp will remain open, and use of the river will not be closed. 

Giant cane is an aggressive non-native grass. Over the decades, the Rio Grande has become increasingly channelized, as invasive giant cane forms dense thickets and traps sediment. The combination of prescribed fire followed 4 -6 weeks later by herbicide treatment of regrowth has been an effective approach for reducing stands of giant cane in the park. Imazapyr is approved by the EPA for aquatic use. It is a systemic herbicide that moves throughout plant tissue and prevents plants from producing a necessary enzyme, which is not found in animals. Susceptible plants simply stop growing after treatment and soon die back.

With the removal of this cane, the river can carry the sediment downstream, opening up gravel bars and wider flood plains again. This in turn benefits native willows, and wildlife, such as mussels, fish, and beaver. Removing thickets of giant cane also opens up the banks of the river for recreational use.

This temporary closure and signage will be in place while herbicide is being applied, after which the area will reopen to entry. Once the signs have been removed, the closures will no longer apply.

The project area is located along the river corridor from the Rio Grande Village Nature Trail

NPS