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Plant species invasions are problematic due to their ability to alter rangeland function, including biodiversity and the provision of environmental goods and services such as forage production. A grassland's susceptibly to invasion may also vary as a function of climate and disturbance. In this study, detailed species composition data were used from approximately 120 long-term grassland study sites across southern and central Alberta to evaluate the relative abundance of introduced species in relation to 1) agro-climatic gradients, including rainfall (272 – 437 mm) and soil conditions, and 2) the presence or absence of livestock grazing (inside and outside of long-term exclosures). Preliminary data has shown that species diversity increased along the precipitation gradient for both grazed and ungrazed plots. In high precipitation areas invasive species cover was higher in grazed plots but in low precipitation areas it was higher in ungrazed plots. We will further assess plant community composition, including the proportion of diversity comprised of invasive species, and related to the fore-mentioned factors. Results of this study will have implications for the ongoing management and conservation of native grasslands across the region.