Rainfall interception shelters are frequently used to study the ecological consequences of drought. One common shelter design employs V‐shaped plastic troughs spaced on a supporting frame to intercept rainfall. Shading, reflection, and infrared radiation may alter the radiative environment under shelters in ways independent of their intended effect on soil moisture. We measured microclimate and several photosynthetic variables for watered, potted plants under rain‐out shelters and in open‐air, unsheltered plots. We tested whether the shelter infrastructure altered aboveground micrometeorology and photosynthesis for watered, potted plants of native Californian species: Elymus glaucus, Eriogonum latifolium, Mimulus aurantiacus, and Morella californica. We quantified the effects on photosynthesis in terms of light harvesting by photosystem II (PSII) and leaf‐level gas exchange on open‐air and shelter plots, the quantum yield of PSII for darkened leaves, dark respiration, and nocturnal stomatal conductance. The rain‐out shelter reduced daily integrated photosynthetically active radiation by 20%. Air temperature, leaf temperature, and leaf‐to‐air vapour pressure difference were not different under shelters compared with controls during the day. Likewise, there were no effects of shelters on net CO2 assimilation, stomatal conductance to water vapour (gs), internal leaf (CO2), or electron transport rate through PSII during the daytime. At night, Tair was 0.6°C higher under shelters, but there were no effects on dark respiration or stomatal conductance. Despite some differences in micrometeorology under rain‐out shelters compared with open‐air plots, there were little or no aboveground nondrought effects of the shelters on leaf‐level photosynthesis for watered, potted plants of these California native plant species.

Restoration frequently aims to improve native species biodiversity at a site, but practitioners have limited resources. In diverse ecosystems, the selective use of certain guilds or species can come at the cost of species that are more challenging to incorporate, resulting in the overall homogenization of the ecosystem and a relative loss of biodiversity. We surveyed practitioners who restore California prairies to understand their use of native annual forbs, an important component of the biodiversity in this ecosystem. We found that practitioners preferentially planted native perennial species, mainly grasses. Despite practitioners' recognition of the high conservation value of native annual forbs, they were hesitant to include this guild in their planting palettes because of high costs, low and unpredictable establishment, and lack of seed. We recommend that California annual prairie forbs be seeded in multiple years to enhance establishment, and that monitoring targets be designed to better reflect the high variability in interannual abundance of native annual forbs. These issues are not unique to California prairie, and more broadly, restoration objectives and research across a range of ecosystems should prioritize guilds that are more challenging to establish but are of high conservation concern.

Reintroduction is an increasingly common practice to conserve and recover threatened and endangered plant species, so understanding how practitioners view their work and identifying persistent resource mismatches are key to the long-term viability of these listed species. We interviewed practitioners involved in reintroduction projects for 14 species in the state of California to understand (1) how they defined recovery; (2) their assessment of the likelihood of recovery; (3) what advice they would share with other practitioners to improve reintroduction efforts; and ( 4) what resources could make future projects more successful. Practitioners' definitions of recovery aligned with ecological theory and emphasized the importance of self-sustaining populations and large populations, as well as the presence of multiple populations. However, most practitioners felt that recovery was unlikely or did not think the species they worked with should or would be de-listed without the guarantee of perpetual future interventions. Practitioners thought that studying basic biology and natural history, using experiments to determine the best techniques, and repeatedly planting populations were important to project success. However, practitioners also felt they were missing critical resources, including long-term funding for implementation and maintenance, successful and positive relationships between members of the practitioner-agency-scientistlandowner nexus, and assurances/safe harbor agreements for experimental populations. Overall, rare plant reintroductions are complicated by persistent mismatches in timing and goals, but some individuals have been able to successfully navigate these challenges. Longer duration funding mechanisms for monitoring and maintenance and better data handling, storage, and dissemination would benefit future projects.

No abstract

Applied nucleation (i.e. planting vegetation patches) is a restoration strategy that better recreates natural ecosystem heterogeneity and requires fewer resources compared to planting the entire area. Whereas applied nucleation shows promise as a forest restoration strategy, this approach has received little study in grassland restoration, where the spread of planted vegetation nuclei may be impeded by aggressive non-native species. We compared the establishment and cover of restored native grass, forb, and rush species for 7 years in applied nucleation and full planting treatments in a former agricultural site dominated by non-natives along the central California coast. We planted seedlings of the same nine coastal prairie species in all treatments, but the applied nucleation plots had four nuclei with only 30% of the seedlings as the full planting plots. We also evaluated the effect of adding wood mulch to reduce non-native plant competition. Native forb cover increased over time and was similar across treatments in the final study year. Native grasses increased for the first 4 years and then declined sharply in all treatments. Native forb cover spread into unplanted areas in applied nucleation plots, whereas grasses showed minimal spread. Of the five planted forb species, the two that persisted until the final study year both spread via rhizomes. Wood mulch reduced non-native cover in the first 2 years and had a longer-term effect on species composition. Our results suggest that applied nucleation can be an effective restoration strategy at a small scale in non-native-dominated grasslands for species that spread vegetatively.