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Predicting drought tolerance from slope aspect preference in restored plant communities

Citation

Kimball, Sarah; Lulow, Megan; Balazs, Kathleen; Huxman, Travis (2017), Predicting drought tolerance from slope aspect preference in restored plant communities, UC Irvine Dash, Dataset, https://doi.org/10.7280/D1JD4X

Abstract

Plants employ strategies of tolerance, endurance, and avoidance to cope with

aridity in space and time, yet understanding the differential importance of such

strategies in determining patterns of abundance across a heterogeneous landscape

is a challenge. Are the species abundant in drier microhabitats also better able to

survive drought? Are there relationships among occupied sites and temporal

dynamics that derive from physiological capacities to cope with stress or dormancy

during unfavorable periods? We used a restoration project conducted on two

slope aspects in a subwatershed to test whether species that were more abundant

on more water-limited S-facing slopes were also better able to survive an extreme

drought. The attempt to place many species uniformly on different slope aspects

provided an excellent opportunity to test questions of growth strategy, niche

preference, and temporal dynamics. Perennial species that established and grew

best on S-facing slopes also had greater increases in cover during years of drought,

presumably by employing drought tolerance and endurance techniques. The

opposite pattern emerged for annual species that employed drought-escape

strategies, such that annuals that occupied S-facing slopes were less abundant

during the drought than those that were more abundant on N-facing slopes. Our

results clarify how different functional strategies interact with spatial and temporal

heterogeneity to influence population and community dynamics and demonstrate

how large restoration projects provide opportunities to test fundamental ecological

questions.

Methods

Each May (late Spring at our study site), from 2012 to 2015, we used

point-intercept,

with 24 points per 5 × 5 m plot, to determine the percent

cover of all species.

References

Location

33.765571, -117.739561