From Russia with…Knapweed?
Grand Canyon National Park is home to over 1600 species of plants, demonstrating some of the greatest biodiversity of any national park. Unfortunately not all of these botanical residents were invited guests. Non-indigenous plants (otherwise known as "exotics") have increasingly become a disruption to the park's natural balance. Plants such as Russian knapweed and tamarisk have frustrated the parks vegetation specialists for years as they continue to spread despite concerted efforts towards eradication.
It was recently announced that the latest initiative to battle these non-native plants, including the use of herbicides, will be extended through the end of the year. With a little luck, the National Park Service Vegetation Program will gain the upper hand on a few of these unwelcome guests. Find out more by reading this document. 
Here are some ways you can help.