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An overlooked phenomenon is a potential increase in the distribution and abundance of plants with the highly water-usage-efficient crassulacean acid metabolism (CAM). In the present article, we critically analyze recent research to investigate to what extent and why CAM plants may have recently expanded their range and abundance under global change. We discuss the ecophysiological and evolutionary mechanisms linked with CAM succulence and the drivers underlying potential CAM expansion, including drought, warming, and atmospheric carbon dioxide enrichment. We further map the biogeographic pattern of CAM expansion and show that some CAM plants (e.g. Cylindropuntia, Opuntia, and Agave) are expanding and encroaching within dryland landscapes worldwide. Our results collectively highlight the recent expansion of CAM plants, a trend that could be sustained under increasing aridity with climate change. We recommend that CAM expansion be evaluated in a data-model integrated framework to better understand and predict the ecological and socioeconomic consequences of CAM expansion during the Anthropocene. [ABSTRACT FROM AUTHOR]

Invasive plants are often sold as ornamental garden plants, but how often are species sold in the same locations as where they are invasive? To answer this question, we assessed the geography of ornamental plant sales in the United States in relation to existing invasions and potential invasion risk with climate change. Using a data set of 672 nurseries selling 89 invasive plants, we estimated the distance between nursery sales and invasive species' observed distributions. We also used species range maps to identify nursery sales within current potential invaded ranges, as well as within species' future potential ranges given climate change. Half of the species were sold by a nursery within 21 kilometers of an observed record of invasion. Under the current climate, horticulture could be seeding invasions for 73 of the 89 species studied, and horticulture could facilitate climate-driven range expansion of 25 of 89 species. Our results illustrate risks associated with horticultural introductions of invasive species, providing guidance for regulatory and educational interventions that reduce the spread of ongoing and future invasions. [ABSTRACT FROM AUTHOR]