Forb seeds originating from dry environments have higher emergence and survival across multiple levels of water availability

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Tessa A. Bartz and Elizabeth A. Leger, Department of Biology, University of Nevada - Reno, Reno, NV, Sarah C. Barga and Francis F. Kilkenny, Rocky Mountain Research Station, USDA Forest Service, Boise, ID, Fred Edwards, Bureau of Land Management

Background/Question/Methods
Restoration is an increasingly important part of our landscapes, but effective restoration can be difficult to achieve, especially in dry, invaded systems like the Great Bain, US. One aspect of restoration that has not been well studied in the Great Basin is the role of local adaptation in forb restoration. Forbs are an essential component of these ecosystems, and applying evolutionary concepts to their restoration may improve restoration outcomes. For example, locally-sourced native populations may have a greater chance of restoration success because of their adaptations to local conditions, and experiments with shrubs and grasses have confirmed these relationships. However, the characteristics responsible for local adaptation can differ drastically between taxa and environments, so it is important to conduct research on a diversity of species and populations to better understand which characteristics influence survival and performance among groups. To that end, we conducted a common garden experiment examining the effects of 3 water availability treatments on seed emergence and seedling survival among 10 populations of a common widespread forb: Chaenactis douglasii. Plants were seeded into a garden environment and given water equal to dry ambient conditions, mean, and 1.75 times the mean precipitation values per the natural range of these collections.
Results/Conclusions
Populations of Chaenactis douglasii originating from locations with less annual precipitation had higher emergence and survival in a dry ambient treatment when compared with populations originating from locales with higher annual precipitation. Furthermore, populations from dry environments responded more readily to increased water treatments, emerging more often than those from wetter environments. There was variation in response to watering treatments, with some populations performing better under drier scenarios than others. Increased emergence and survival in early life stages is an especially desirable trait in arid-climate restoration projects that rely on direct-seeding and in areas with a high rates of invasive species seed in their seedbank. Therefore, these traits found in populations from drier environments-of-origin may be a valuable tool in increasing restoration efficacy.