Quercus pacifica

Abstract: The following five names are proposed for California oaks: Quercus john-tuckeri, nom. et stat. nov. for Quercus turbinella subsp. californica J. M. Tucker; Quercus pacifica, sp. nov.; Quercus x kinselae, stat. nov. for Quercus dumosa Nuttall var. kinselae C. H. Muller; Quercus durata var. gabrielensis Nixon & C. H. Muller, var. nov.; and Quercus parvula var. shrevei (C. H. Muller) Nixon, stat. nov. for Quercus shrevei C. H. Muller. In the course of preparing a treatment of the genus Quercus in California, we have found it necessary to provide new names for the following five taxa. We are publishing these names in advance of the full study, in order to make them available for floristic treatments currently in preparation. 1. Quercus john-tuckeri Nixon & C. H. Muller, nom. et stat. nov. Basionym: Quercus turbinella E. Greene subsp. californica J. M. Tucker, Madronio 11: 240. 1952. TYPE: U.S.A. California: San Luis Obispo County, ca. 2 mi. NE of summit of Caliente Mountain, 2 Oct. 1948, J. Tucker 1886-16 (holotype, UC 938396; isotypes, DAV, BH). Shrubs 1-3(-5) m tall, subevergreen or evergreen; bark scaly; twigs yellowish or dingy gray, 11.5(-2) mm thick, densely tomentulose; buds brown, ovoid or globose, 1.5-2(-3) mm long, glabrous except for the ciliate margins of the scales, lowermost scales often yellowish puberulent. Petiole 1-4 mm. Leaf blade unicolored, elliptic or obovate, thick and coriaceous, often brittle, (10-)15-30(-40) mm x (8-)10-15(-20) mm; base squarrose or roundedattenuate, rarely subcordate; secondary veins (3-)47, often some of the veins branching near margin and passing into more than one tooth; margin irregularly spinose-toothed, occasionally shallowly lobate; apex acute or rounded; abaxially waxy grayish or light green, with sparse to moderately dense vestiture of (8-)10-12-rayed (loosely) appressed stellate hairs, these often 0.2-0.5 mm diam., and sparse to dense yellowish glandular hairs; adaxially grayish, stellate similar to abaxial surface. Fruits solitary or paired, subsessile; cup cup-shaped or obconic to hemispheric, thin, 10-15 mm wide x 5-7 mm deep; scales whitish or yellowish, moderately or scarcely tuberculate, puberulent. Nut fusiform, ovoid or conic, apically acute, 20-30 mm long. Cotyledons free. Dry slopes, chaparral, pinion and juniper woodland, margins of oak woodland and sagebrush; 9002,000 m. Endemic to California, from Los Angeles County north in the interior Coast Ranges and Sierra Foothills to the northern edge of the Sacramento Valley. Quercus john-tuckeri bears some resemblance to both Q. turbinella and Q. berberidifolia Liebmann; however, the former has pedunculate fruit and typically cordate leaf bases, while the latter has a glabrate upper leaf surface, substantially smaller stellate trichomes with fewer rays on the lower leaf surface, heavier, tuberculate acorn cups, and typically nonacute acorns. At the species level, the epithet californica is preoccupied by the illegitimate (but validly published) name Quercus californica Torrey ex J. G. Cooper (= Q. kellogii Newberry). 2. Quercus pacifica Nixon & C. H. Muller, sp. nov. TYPE: U.S.A. California: Santa Barbara County, rocky slope E of Pelican Bay, Santa Cruz Island, alt. 100 ft., Ira W. Clokey 4893 (holotype, BH-CHM). Frutices ad 2 m vel raro arbores ad 5 m, subsempervirentes. Petioli 2-5 mm longi. Lamina foliorum obovata vel oblonga, 15-40 mm longa, 7-20(-40) mm lata, margine integra vel dentata; pagina abaxialis ceracea, glandifera, sparsim stellato-pilosa, pilis paginae abaxialis adpressis; pagina adaxialis viridis, glabra. Nux sessilis, cylindrica vel fusiformis, (15-)20-30 mm longa, (6-)915 mm lata, apex acutus. Shrubs to 2 m tall, rarely small trees to 5 m or taller, subevergreen; bark scaly on older branches and trunk; twigs brownish or reddish and minutely NOVON 4: 391-393. 1994. This content downloaded from 157.55.39.138 on Sun, 26 Jun 2016 06:12:46 UTC All use subject to http://about.jstor.org/terms

Abstract: Arthropods have been understudied on Santa Cruz Island, resulting in an incomplete understanding of these diverse and ecologically important members of island ecosystems. To enhance the current understanding of Santa Cruz Island biodiversity, we sampled arthropods in 2 native plant habitats: island scrub oak (Quercus pacifica) woodland and patches of island morning glory (Calystegia macrostegia ssp. macrostegia). We used 4 standardized sampling techniques to sample arthropods in 16 Q. pacifica woodland plots. We sampled arthropods associated with C. macrostegia by pan trapping within 1 m of blooming morning glory individuals. In total, we sampled over 18,000 arthropod specimens, sorted the specimens to morphotypes by order, and had taxonomic specialists identify 10 orders to the narrowest possible identification (n = 458 total species or morphotypes). The taxonomic distribution of our identified specimens is as follows: 1 species of Scorpiones, 5 morphospecies of Pseudoscorpiones, 74 species of Araneae, 4 species of Orthoptera, 10 species of Psocodea, 10 species of Hemiptera, 1 species of Neuroptera, 60 species of Coleoptera, 8 species of Lepidoptera, and 42 species of Hymenoptera (Formicidae and Apoidea). Of these, 62 species represent newly recorded arthropod species on Santa Cruz Island. The diversity of our collections within the Quercus pacifica and Calystegia macrostegia habitats, the deficiency of current knowledge of Channel Island arthropods, and the fundamental role of arthropods in island ecosystems emphasize the need for a more comprehensive arthropod inventory across the California Channel Islands.

Abstract: Quercus tomentella (island oak) is an endemic species that plays a key functional role in Channel Island ecosystems. Growing in groves on highland ridges, Q. tomentella captures fog and increases water inputs, stabilizes soils, and provides habitat for flora and fauna. This cloud forest system has been impacted by a long history of ranching, and restoration efforts are underway that include erosion control, leaf litter capture, fog capture, and reforestation. To inform retoration efforts, we explored tree regeneration and the potential for Q. tomentella grove expansion on Santa Rosa Island. We delineated current and historic groves at Black Mountain by comparing stand maps from 1989 and aerial photographs from 1994 and 2015. We evaluated regeneration in the outlying areas by recording the location, diameter at breast height, number of trunks, height class, percent crown mortality, nurse plant species (if present), and reproductive status for all 4355 outlying seedlings, saplings, and mature trees. We defined outliers as individuals that were 15 m outside of the canopy of island oak groves. There are 14 groves at Black Mountain, and grove size expanded by an average of 36.9% (SD 18.5%) between 1994 and 2015. Nurse plants correlated positively with outlier tree height and reduced percent crown mortality. This effect is potentially due to increased fog drip from nurse plant species such as Quercus pacifica (island scrub oak), Heteromeles arbutifolia (toyon), and Baccharis pilularis (coyote brush). These results indicate that Q. tomentella is regenerating and that nurse plants can serve as catalysts for ecosystem restoration.

Abstract: Island scrub oak (Quercus pacifica), a keystone chaparral species on Santa Rosa, Santa Cruz, and Santa Catalina islands, provides habitat for a diverse assemblage of plant and animal species. The restoration of oak habitat is a management priority, but little is known about Q. pacifica stand structure and acorn production, 2 parameters that are important in the species' recovery. To investigate whether species interactions and abiotic conditions have an effect on stand structure and acorn production, we sampled within-stand densities, tree sizes, and acorns in the 3 island populations that have been exposed to different herbivores, seed predators, and climate conditions. Stand densities varied more within than between islands; but Santa Rosa, the coldest of the 3 islands, had smaller trees with smaller acorns than the other 2 islands. To quantify the temporal and spatial variation in acorn production on Santa Cruz Island, we conducted acorn counts at 2 spatial scales: (1) an island-wide survey of 200 trees along the east—west axis of the island (2008–2012) and (2) small-scale surveys within three 100-ha study plots (150 trees; 2009–2012). Acorn production varied strongly, both temporally and spatially, with little temporal synchrony and spatial autocorrelation. Trees at higher elevations produced more acorns, but the roles of temperature and precipitation were unclear in this relatively short study. To increase our understanding of the drivers of Q. pacifica acorn production, we propose that annual oak surveys be incorporated into a long-term monitoring program across the California Channel Islands.