Monardella follettii (Jeps.) Jokerst and M. stebbinsii Hardham and Bartel are two rare endemic mints restricted to patchy ultramafic (serpentine) soil exposures in the northern Sierra Nevada. These species are rare because of small population sizes, low numbers of total populations, and limited availability of their specialized habitat. We collected samples from populations across the range of both species, and assessed genetic diversity, inbreeding, and genetic distance among populations. In the relatively more widespread M. follettii, we found low genetic diversity, little differentiation among populations, and no evidence of inbreeding. In contrast, we found significant inbreeding, higher genetic diversity, and high population differentiation over short distances in M. stebbinsii. We suggest continued protection and monitoring for M. follettii, but do not recommend any action intended solely for genetic management. To alleviate inbreeding in M. stebbinsii, we suggest pollen transfer from other conspecific populations.

Reproduction in alpine habitats is challenging because of the short growing season, low temperatures, and high winds. This predicts alternative strategies for sexual reproduction in plants: compensatory measures such as larger floral displays and greater floral longevity to attract scarce pollinators and maintain outcrossing, or high levels of autonomous self-fertilization to assure reproduction in the absence of reliable pollinators. Here, we assessed the roles of animals (crawling insects, flying insects, and vertebrates) on the reproductive success of Claytonia megarhiza (A. Gray) S. Watson (alpine spring beauty). We measured fruit set and leaf herbivory while excluding animals from individual plants at a single site in Yosemite National Park, California. We found that plants were capable of setting fruit in the absence of pollinators and that, in the presence of animals, there was a 42% reduction in fruit set and a 159% increase in leaf damage. This suggests that Claytonia megarhiza may reproduce primarily by self-fertilization, and that herbivory may limit the reproductive success of this species near its southern range edge in California.

Despite being one of the most extensive vegetation types in the North American Mediterranean Climate Zone, information on the amount of biomass and carbon stock associated with shrubland vegetation is still largely unknown. Efforts to quantify shrubland biomass through fieldwork consist of either direct measurement using destructive vegetation sampling or indirect measurement through the combined use of stem measurements and allometric equations. Both methods have their own benefits and shortcomings, resulting in substantial variation in how shrubland biomass is reported. Here we aim to provide a comprehensive review and synthesis of available shrubland biomass data from studies based in California to provide a concise and reliable source for natural resource managers. We conducted a literature review of 37 studies published over a span of 72 yrs to compile estimates of aboveground biomass (live, dead, and total), leaf biomass, stem biomass (live, dead, and total), litter biomass, and belowground biomass for three prominent shrubland communities and four shrubland species in the California Floristic Province. Overall aboveground biomass in shrub communities was greatest in mixed chaparral (3461 g/m²), followed by chamise chaparral (2114 g/m²), and coastal sage scrub (1583 g/m²). In each community total aboveground biomass increased with the age of the stand. Leaf, stem, and litter biomass estimates were also highest for mixed chaparral compared to the other communities. Of the four shrub species we summarized biomass data for, Ceanothus greggii A. Gray (Rhamnaceae) had the highest average aboveground biomass, followed by Adenostoma fasciculatum Hook. & Arn. (Rosaceae), Quercus berberidifolia Liebm. (Fagaceae), and C. cuneatus (Hook.) Nutt. By compiling these studies and summarizing the biomass data reported in them, we provide a single resource to characterize the amount of biomass of three different shrublands and four species over their life cycle. This is an essential resource for land managers and practitioners who need field-based biomass and carbon stock figures for monitoring and reporting purposes.

Exotic annual grasses now cover large areas of southern California that were once stands of native California sage scrub (CSS), or a mixture of native grasses, forbs, and CSS. Both CSS and California grasslands are threatened habitats, where restorations of type-converted landscapes are often burdened by the persistent dominance of non-native annual grasses. Research finds that once exotic grasses take hold in these areas, native plant communities are extremely slow to recover, if they recover at all. Coyote brush (Baccharis pilularis DC) is a native shrub common to CSS habitat and often appears in a complex mosaic with other vegetation types including grasslands. Coyote brush has been documented invading grasslands, resulting in a change of state from grassland to shrubland in northern California. This study investigates the long-term consequences of coyote brush invasion in a type-converted landscape of southern California. Stands of expanding coyote brush were transected to identify species composition along a spatial and temporal continuum. Results show that, following initial invasion, non-native species are gradually replaced by, not only coyote brush, but also several other noteworthy native species. This study finds that over the 37 yr timeframe, exotic grasses gradually decline while native plant cover increases in landscapes invaded by coyote brush. We conclude that in the Santa Monica Mountain areas studied, coyote brush invasion of type-converted landscapes leads to increased native plant diversity that includes native grasses and a variety of shrubs.

Two novelties from the Bear River Range of the northern Wasatch Mountains of Utah and Idaho are Musineon naomiensis L. M. Shultz & F. J. Smith, sp. nov. (Apiaceae) and Orthocarpus holmgreniorum (T.I. Chuang & Heckard) L. M. Shultz & F. J. Smith, comb. et. stat. nov. (Orobanchaceae). With these additions, the Bear River Range harbors 13 endemic plant species, most of which are edaphically restricted to dolomitic rocks in or near Logan Canyon. Most of the 260 species of the 2600 native species on the Utah state list of rare plants are in the warm-desert portion of the state. The montane endemics enumerated here demonstrate the unique habitats of the mountains of northern Utah and distinguish the Bear River Range as a hotspot of rarity.