Point- and reach-scale measurements are important for determining accurate seepage rates in controlled flow channels

A critical component of water-resources management in the irrigated agriculture landscape, particularly those landscapes dependent on groundwater availability, is determining groundwater recharge rates from streams and other channels. In California, flows in many such channels are “controlled” by upstream reservoir releases to meet downstream urban, irrigation and environmental water requirements. Seepage volumes from these channels and how they might vary during controlled release periods is a key component of meeting downstream riparian and groundwater-pumping needs. Understanding annual seepage from streamflow channels is also important in developing water budgets as part of the management of groundwater resources under the Sustainable Groundwater Management Act (SGMA) in California. However, direct measurements of channel seepage rates are infrequent or unavailable, and these rates, or associated volumes, are most often only estimated. Here we describe direct point- and reach-scale field measurements of channel seepage rates in Lower Putah Creek (Solano County) and in distribution lateral channels of the Oakdale Irrigation District on the east side of the San Joaquin Valley (San Joaquin and Stanislaus counties). We measured overall average seepage rates of about 2 feet (610 mm) per day at both locations and determined how these rates varied spatially and temporally during the summer when channel flows are controlled for downstream requirements.

Taxonomic revision of black salamanders of the Aneides flavipunctatus complex (Caudata: Plethodontidae)

We present a taxonomic revision of the black salamander (Aneides flavipunctatus) complex of northwestern California and extreme southeastern Oregon. The revision is based on a number of published works as well as new molecular and morphological data presented herein. The subspecies Aneides flavipunctatus niger Myers & Maslin 1948 is raised in rank to a full species. It is isolated far to the south of the main range on the San Francisco Peninsula, south and west of San Francisco Bay. Another geographically isolated set of populations occurs well inland in Shasta County, northern CA, mainly in the vicinity of Shasta Lake. It is raised from synonymy and recognized as Aneides iecanus (Cope 1883). The remaining taxa occur mainly along and inland from the coast from the vicinity of the Russian River and Lake Berryessa/Putah Creek, north to the vicinity of the Smith River near the Oregon border and more inland along the Klamath and Trinity Rivers and tributaries into Oregon. The northern segment of this nearly continuous range is named Aneides klamathensis Reilly and Wake 2019. We use molecular data to provide a detailed examination of a narrow contact zone between the northern A. klamathensis and the more southern A. flavipunctatus in southern Humboldt County in the vicinity of the Van Duzen and main fork of the Eel rivers. To the south is the remnant of the former species and it takes the name Aneides flavipunctatus (Strauch 1870). It is highly diversified morphologically and genetically and requires additional study.

Host Plant Recognition and Performance of Klambothrips myopori (Thysanoptera: Phlaeothripidae) Across Myoporum Cultivars in Southern California

Myoporum spp. (Lamiales: Scrophulariaceae) native to Australia and New Zealand have been introduced into North America and have been widely planted as shrubs and ground covers in the California urban landscape. The invasive thrips, Klambothrips myopori Mound and Morris, invaded California in 2005 and feed exclusively on Myoporum. However, some commercial cultivars have suffered extensive damage, whereas others have not. In field studies and laboratory feeding tests of six different potential host species or cultivars, Myoporum laetum and Myoporum ‘Pacificum’ were identified as most suitable host plants of K. myopori. In laboratory trials, K. myopori failed to complete development on M. ‘Clean n Green’ and M. ‘Putah Creek’. Of the six varieties of Myoporum tested, K. myopori damage was only observed on M. laetum and M. ‘Pacificum’. Although K. myopori can successfully colonize and reproduce on several varieties of Myoporum, they demonstrated a preference for M. laetum and M. ‘Pacificum’ in laboratory and field trials.