Data from: Can we condition native plants to increase drought tolerance and improve restoration success?

A common method in ecological restoration is the outplanting of
nursery-grown seedlings to the field, and with proper resources this
technique can be highly successful. However, stressors such as drought may
negatively impact plant performance and restoration success, especially in
dryland ecosystems. Furthermore, increasing environmental change may
hamper the ability of practitioners to restore native vegetation. A
growing body of research suggests that exposing plants to a stressor may
improve tolerance to subsequent stress events later in life. We sought to
understand if such a phenomena could be exploited in order to improve
plant drought-tolerance and aid native plant restoration in southern
California. In a multi-phase experiment, we first exposed seedlings of
native perennials to episodic drought, and then later compared the
response of these plants to a second drought event to that of well-watered
controls. We also transplanted replicates of both treatments to a
restoration site in the field to test if exposure to drought as a seedling
could improve plant performance. Plant species responded to drought
differently, with species exhibiting the full range of positive, neutral,
and negative responses to temporal variability in water stress. However,
some species appeared to benefit from drought preconditioning, exhibiting
greater growth and increased water-use efficiency compared to well-watered
plants. This suggests that simple applications of stress treatments could
improve plant growth and stress tolerance, but the success of this method
is likely very species-specific. Restoration practitioners should consider
conducting pilot studies with target plant species to better understand if
this technique could assist in achieving restoration goals.