Non-native plants have invaded most low-elevation habitats and physically disturbed sites in Waterton Lakes National Park (WLNP). Parks Canada devotes substantial resources annually to efforts to control or eradicate the most invasive and persistent non-native plants. A Non-native Plant Condition Monitoring protocol was developed to detect changes in the abundance and distribution of non-native plant species across vulnerable regions of WLNP, and to gain an understanding of the severities and differences in impacts that non-native plants have on native plant communities. Relative abundance (I.e. percent cover) of non-native invasive plant species in the fescue grasslands and aspen parkland regions in the WLNP is estimated using spatially balanced random sampling.