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Abundance and composition for the plant functional groups of trees, shrubs, grasses, and forbs covering 154 plant taxa from 52 fossil woodrat midden strata and covering the last 35,000 years were used to study temporal changes in the vegetation - climate relationships on a western Great Basin study site.� Middens were from 80 km2 of mountainous terrain covering 800 m in elevation and a range of topographic conditions.� Six time periods were identified, each with relatively stable taxa abundance, taxa composition, and climate conditions.� There were rapid, significant changes in both vegetation and climate during the five transitions between the six time periods. �The most important temporal changes in plant taxa composition that have occurred in response to these climate changes are significant functional trade-off relationships between declining forb and increasing shrub composition, particularly as global climate warmed over the last 15,000 years.� These patterns represent long-term changes in climate and vegetation that have important implications for the Great Basin.� When European settlers reached the Great Basin the native herbaceous species in its plant communities were already impacted by 15,000 years of increasing stress from the combination of climate change and increasing woody dominance.� During the last century the functional trade-offs, and the associated increase in woody dominance, have facilitated the establishment and dominance of invasive species in Great Basin plant communities.� The increase in global temperature, the land use and management practices, and the establishment of exotic plant species over the last century have added to the decline of native herbaceous species and permanently changed community dynamics.� Great Basin plant communities will continue to experience an increasing rate of change in vegetation composition and dynamics, with increasing management challenges, as global temperatures increase through the rest of this century and beyond.