California Foothills Research Articles

Impact of Drought on Ecohydrology of Southern California Grassland and Shrubland

Through their rooting profiles and water demands, plants affect the distribution of water in the soil profile. Simultaneously, soil water content controls plant development and interactions within and between plant communities. These plant-soil water feedbacks might vary across plant communities with different rooting depths and species composition. In semiarid environments, understanding these differences will be essential to predict how ecosystems will respond to drought, which may become more frequent and severe with climate change. In this study, we tested how plant-soil water feedbacks responded to drought in two contrasting ecosystem types—grassland and shrubland—in the coastal foothills of southern California. During years 5–8 of an ongoing precipitation manipulation experiment, we measured changes in plant communities and soil moisture up to 2 m depth. We observed different water use patterns in grassland and shrubland communities with distinct plant functional types and water use strategies. Drought treatment did not affect perennial, deep-rooted shrubs because they could access deep soil water pools. However, mid-rooted shrubs were sensitive to drought and experienced decreased productivity and die-off. As a result, water content actually increased with drought at soil depths from 50–150 cm. In grassland, biomass production by annual species, including annual grasses and forbs, declined with drought, resulting in lower water uptake from the surface soil layer. An opportunistic “live fast, die young“ life strategy allowed these species to recover quickly once water availability increased. Our results show how drought interacts with plant community composition to affect the soil water balance of semiarid ecosystems, information that could be integrated into global scale models.

Foraging Habitat and Its Effects on the Tricolored Blackbird’s Breeding Distribution and Abundance in the Sierra Nevada Foothills, California

The grassland-dominated eastern Central Valley and Sierra Nevada foothills of California, from Placer to Stanislaus counties, supported at least 43,000–55,000 breeding Tricolored Blackbirds (Agelaius tricolor) annually from 2014 to 2018—about 30% of the statewide population. We found that within 5 km of a colony, the extent of land cover used for foraging, grassland–herbaceous, and to a lesser extent annual crops and irrigated pasture, exceeded their proportions in this region as a whole, suggesting that nesting Tricolored Blackbirds select colony sites where these habitats are more abundant. Other land-cover types were underutilized for foraging, suggesting avoidance. The probability of Tricolored Blackbird occupancy of blocks of 100 km2 was strongly associated with the extent of the selected land-cover types. The relationship between average density of the breeding population and the extent of the selected land-cover types was significant but weaker, implying that other factors are important in determining density. From 2014 to 2018, development and mining eliminated or degraded 9 of 79 colony sites and made 4 others unsuitable by reducing the extent of nearby foraging habitat, although the total breeding population in the region did not decline. We recommend that conservation measures for the Tricolored Blackbird in federally and state-approved habitat-conservation plans in Placer and Sacramento counties, which support the largest breeding populations in the central Sierra foothills but where urban development is rapid, be reevaluated on the basis of recent colony locations and recognition of the critical role of grassland, annual crops, and irrigated pasture as foraging habitat.

Impacts of burn severity on short-term postfire vegetation recovery, surface albedo, and land surface temperature in California ecoregions.

Wildfire burn severity has important implications for postfire vegetation recovery and boundary-layer climate. We used a collection of Moderate Resolution Imaging Spectroradiometer (MODIS) datasets to investigate the impact of burn severity (relative differenced Normalized Burn Ratio, RdNBR) on vegetation recovery (Enhanced Vegetation Index, EVI), albedo change, and land surface temperature in seven California ecoregions, including: Southern California Mountains (SCM), Southern California Coast (SCC), Central California Foothills (CCF), Klamath (K), Cascades (C), Eastern Cascades (EC), and Sierra Nevada (SN). A statewide MODIS-derived RdNBR dataset was used to analyze the impact of burn severity on the five-year postfire early-summer averages of each biophysical variable between the years 2003-2020. We found that prefire EVI values were largest, and prefire albedo and temperature were lowest in the K, C, EC, and SN ecoregions. Furthermore, the largest changes between prefire and first-year postfire biophysical response tended to occur in the moderate and high burn severity classes across all ecoregions. First-year postfire albedo decreased in the K, C, EC, and SN but increased in the SCM, SCC, and CCF ecoregions. The greatest decreases, but most rapid recovery, of EVI occurred after high severity fires in all ecoregions. After five-years post-fire, EVI and land surface temperature did not return to prefire levels in any burn severity class in any ecoregion.

Beyond the Horizon

Beyond the Horizon

Toddler With Fever and Limp.

Toddler With Fever and Limp.

An innovative temporary escape ramp for deer and other wildlife

Concrete-lined water conveyance canals can be a significant source of mortality for ungulates and other wildlife, which can drown or become entrapped. Various types of wildlife escape structures have been deployed in canals with limited success. From 2011 to 2018, we used camera traps to monitor mule deer (Odocoileus hemionus) use of three different temporary wildlife escape structure designs with the goal of developing an effective escape structure for fawns. We monitored three to five locations at a hydroelectric water conveyance canal, operated by Pacific Gas and Electric Company in the foothills of Central California on the Sierra National Forest, in which trapped fawns had been detected previously during the maintenance period when the canal was dry. Mule deer activity and ramp use varied by year. During the monitoring period, deer were detected in the canal in all years except 2016 and 2017. Fawns and adults used the temporary escape structures to exit the canal in four of these years and 50% of mule deer detections showed ramp use overall. No deer were detected using the escape structures until jute netting and debris were added to the surface of the escape ramps in the third monitoring year. Prior to this modification, fawns were detected trapped in the canal investigating the ramps, but not using them to exit the canal. Deer may be more likely to utilize ramps covered with materials that mimic native ground cover. Seven other wildlife species were detected entering and exiting using the ramps with a general increase in use over years. Our temporary escape ramp design for small canals, when dry, appears to be novel and may be applicable in other areas. When compared to fencing or covering the canal, it is a relatively low-cost solution to reduce animal entrapment.

A Comparison of Questing Substrates and Environmental Factors That Influence Nymphal Ixodes pacificus (Acari: Ixodidae) Abundance and Seasonality in the Sierra Nevada Foothills of California.

In California, the western blacklegged tick, Ixodes pacificus Cooley and Kohls, is the principal vector of the Borrelia burgdorferi sensu lato (sl) complex (Spirochaetales: Spirochaetaceae, Johnson et al.), which includes the causative agent of Lyme disease (B. burgdorferi sensu stricto). Ixodes pacificus nymphs were sampled from 2015 to 2017 at one Sierra Nevada foothill site to evaluate our efficiency in collecting this life stage, characterize nymphal seasonality, and identify environmental factors affecting their abundance and infection with B. burgdorferi sl. To assess sampling success, we compared the density and prevalence of I. pacificus nymphs flagged from four questing substrates (logs, rocks, tree trunks, leaf litter). Habitat characteristics (e.g., canopy cover, tree species) were recorded for each sample, and temperature and relative humidity were measured hourly at one location. Generalized linear mixed models were used to assess environmental factors associated with I. pacificus abundance and B. burgdorferi sl infection. In total, 2,033 substrates were sampled, resulting in the collection of 742 I. pacificus nymphs. Seasonal abundance of nymphs was bimodal with peak activity occurring from late March through April and a secondary peak in June. Substrate type, collection year, month, and canopy cover were all significant predictors of nymphal density and prevalence. Logs, rocks, and tree trunks had significantly greater nymphal densities and prevalences than leaf litter. Cumulative annual vapor pressure deficit was the only significant climatic predictor of overall nymphal I. pacificus density and prevalence. No associations were observed between the presence of B. burgdorferi sl in nymphs and environmental variables.

Making (a) place: wine, society and environment in California's Sierra Nevada foothills

ABSTRACTThis paper explores the role of the wine industry, writ large, in place-making via a case study of the wine industry, from ‘grape to glass’, in the Sierra Nevada foothills of California, which examines how wine production and consumption has influenced the sociocultural and physical–environmental landscape of the region. Using qualitative field methods and secondary data analysis, the paper investigates the impacts of the ‘emerging’ wine industry of the Sierra Nevada foothills by engaging with industry actors at all levels. We find that, while not new, wine grape production and winemaking have become increasingly prominent economically and culturally as evidenced by (in)visible infrastructure and growing direct and indirect contributions to foothill counties’ economies. Moreover, we argue that, in the Sierra Nevada and beyond, wine growing and winemaking provide a powerful mechanism for identity and material landscape production in the area. The pursuit and construction of the Sierra Nevada foothills as ‘wine country’ becomes a means through which the place ‘makes’ itself and, in turn, makes a place for itself across a variety of economic and cultural contexts.

California Gold Country’s Digital Heritage: Innovations in Community Engaged Research and Training

This article presents the results of the Historic Coulterville Digital Preservation Project, an important digital humanities research collaboration which started in the Fall 2015 between the University of California Merced Resource Center for Community Engaged Scholarship, the John Muir Geotourism Center, the Northern Mariposa County History Center, and faculty and graduate students of the Interdisciplinary Humanities Graduate Program at UC Merced. Dictated by the needs and goals of the community members of the gold rush town of Coulterville, in the Sierra Foothills of California, who are invested in the preservation of their cultural heritage, the project focused on digital historic preservation in four areas of focus: i) the archives and photographs at the Northern Mariposa County History Center, ii) the Coulterville cemeteries, iii) oral histories of Coulterville, and iv) the digital documentation of Coulterville Main Street Historic District. Combined, these four areas of focus presented a breadth of subject matter through which to test various digital preservation methods in a real-world scenario as well as provided both the students and the community members the opportunity to study subjects in greater depth that were of mutual interest. The project provides an example of the potential for community-university research collaborations to benefit local communities while also providing training and networking opportunities for students, and new scholarship case studies for the scholars.

Beyond the Edge and in Between: (Re)conceptualizing the Rural–Urban Interface as Meaning–Model–Metaphor

As examinations of the rural–urban interface move beyond a focus on the rural or urban fringe as a location and move toward examining the patterns and processes that both divide and link rural and urban places, a broader (re)conceptualization of the rural–urban interface becomes increasingly important. Thus far the question of boundaries and interfaces between so-called urban and rural locales has mostly revolved around where and when such boundaries occur (including significant coverage of the differences and conflicts between urban vs. rural people), rather than asking what physical or social functions are being served by the rural–urban interface itself. In response, I (re)frame the rural–urban interface not only as a boundary between two distinct spaces but also as a conduit, a place of exchange, and a flux point between them. Using a particular case of contested ecologies in the exurban Sierra Nevada foothills of California, I (re)conceptualize the rural–urban interface as meaning, model, and metaphor (MMM), situating contrasting people and places in an ongoing negotiation of place and environmental meaning along the (ex)urbanizing edge. Although the differences between rural and urban are increasingly unclear, the division continues to be compelling from environmental and sociopolitical standpoints. I argue that (perceived) boundaries are instrumental in understanding physical–material change and for mitigating social conflicts occurring across them. As such, attention to the patterns, processes, and flows that connect or separate rural and urban areas is critical to forging effective and long-lasting solutions to contemporary social, economic, and environmental problems.

English

Spenceville Mine is an abandoned copper mine located in the Sierra Nevada foothills of California. The mine was operated intermittently from the 1880's until 1918. The site was covered with mine tailings and overburden materials. In addition, the central portion of the site was occupied by a flooded open pit, which contained approximately 6 million gallons of acidic water with a pH averaging 2.5. The U.S Army owned the site from 1941 to 1962, at which time it was transferred to the California Department of Fish and Game (DFG) with the creation of the Spenceville Wildlife Refuge. The closure plan was approved by the regulatory agencies in early 2001, and mine closure activities began in April 2001. In subsequent months a water treatment plant was constructed and used to treat the pit water. The treated water was then applied to land in the vicinity of the site. The mine waste was excavated, treated with lime, and placed in the dewatered pit. A two foot layer of local soil was placed as cover over the entire site, and a mine-impacted stream was restored to its original channel. In addition to these tasks, closure activities had to address the potential for unexploded ordnances, reclamation of shafts and tunnels in the dewatered pit, and documentation of cultural resources.

Microhabitat and House Use by Dusky-Footed Woodrats (Neotoma fuscipes) in Northwestern California: Insight from Trapping Data

Abstract. Capture data differed at woodrat houses associated with selected microhabitats in a chaparral-oak woodland site in the foothills of northwestern California. Mean trapping success was significantly higher at houses located under dense tree canopy (and in low scrub cover) compared with houses in high scrub cover (and under less tree canopy), as was trapping success at houses found in non-edge versus edge habitat. Woodrats trapped at houses under dense canopy also were significantly heavier than those captured in high scrub cover; however, mean body masses at edge- and non-edge houses were similar. Broadly, our results mirror existing research but indicate the need for more study of the specific microhabitat factors that influence woodrat house use in chaparral-oak habitat.

Notice of Release of Antelope Creek and Pleasant Valley Germplasms of Bottlebrush Squirreltail

Two new natural-track pre-variety germplasms (selected class), Antelope Creek and Pleasant Valley bottlebrush squirreltail ( Elymus elymoides (Raf.) Swezey “ssp. C” [Poaceae]), were released by the USDA Agricultural Research Service and the Utah Agricultural Experiment Station in 2009 and 2010, respectively. Antelope Creek Germplasm is recommended for use in the western Blue Mountains of Oregon and the eastern Cascade slopes and foothills of Oregon and northeastern California. Pleasant Valley Germplasm is recommended for use in the eastern Blue Mountains of Oregon, Washington, and Idaho. Both germ -plasms are members of the unofficially designated bottlebrush squirreltail “subspecies C,” which possesses a distribution that is centered in central and eastern Oregon. Jones TA, Parsons MC, Larson SR, Mott IW. 2014. Notice of release of Antelope Creek and Pleasant Valley germplasms of bottlebrush squirreltail. Native Plants Journal 15(1):57–64.

Estimating plant crown transpiration and water use efficiency by vegetative reflectance indices associated with chlorophyll fluorescence

This research developed estimates of plant crown transpiration and water-use-efficiency using reflectance and derivative indices extracted from remotely sensed chlorophyll fluorescence measurements under natural conditions. Diurnal changes of leaf-level gas exchange (carbon assimilation rate (A), stomatal conductance (gs), transpiration rate (E)), chlorophyll fluorescence and canopy-scale remote sensing were measured on top crown of valley oak (Quercus lobata) in the foothills of central California, USA. The results indicated Q. lobata experienced saturating irradiance (PAR), which induced photoinhibition indicated by a decrease in the quantum efficiency of photosystem II (r2 = 0.648 with Fv ′/Fm′ and r2 = 0.73 with FPSII) and open reaction centers (qP; r2 = 0.699). The excess absorbed quantum energy was dissipated as heat through the Xanthophyll cycle and other processes (photorespiration and the water-water cycle) rather than energy emission as steady state chlorophyll fluorescence (Fs). An increase in leaf temperature caused by the activity of Xanthophyll cycle was correlated to a decrease in Fs (r2 = 0.381) and an increase in evaporative cooling through E (r2 = 0.800) and water use efficiency (WUE; r2 = 0.872).

Helianthus winteri (Asteraceae), a New Perennial Species From the Southern Sierra Nevada Foothills, California

Helianthus winteri is described from Fresno and Tulare Counties in the southern Sierra Nevada foothills of California. It is distinguished from H. annuus by its woody trunk, year-round blooming, and morphological characteristics. It occurs in open, ungrazed foothill woodlands and annual grasslands on well-drained, granitic soils, generally on lower-elevation, south-facing foothill slopes east of the San Joaquin Valley.

Absentee Ownership in the Fire-Prone Northern California Foothills

Absentee–owned parcels make up one-third to one-half of private properties in wildland–urban interface areas of the United States. The prevalence of absenteeism in fire-prone areas is of concern to resource management agencies, community fire-safe councils, and homeowners who share boundaries with these parcels. In the foothills of Butte County, California, absentee-owned parcels make up over half of privately owned noncorporate parcels. The concern by fire-safe councils in this fire-prone wildland–urban interface is that absentee owners will not participate actively in fuel reduction. We used geographic information systems to illustrate the extent and geographic distribution of absentee parcels in the foothills and in one community, Concow. The article provides some initial findings about the impressive acreage and complex spatial distribution of absentee-owned parcels in relation to owner-occupied parcels. The article also raises some methodological issues about the definition of absenteeism.

Impact of cattle grazing on the occupancy of a cryptic, threatened rail

Impacts of livestock grazing in arid and semiarid environments are often concentrated in and around wetlands where animals congregate for water, cooler temperatures, and green forage. We assessed the impacts of winter-spring (November-May) cattle grazing on marsh vegetation cover and occupancy of a highly secretive marsh bird that relies on dense vegetation cover, the California Black Rail (Laterallus jamaicensis coturniculus), in the northern Sierra Nevada foothills of California, U.S.A. Using detection-nondetection data collected during repeated call playback surveys at grazed vs. ungrazed marshes and a "random changes in occupancy" parameterization of a multi-season occupancy model, we examined relationships between occupancy and habitat covariates, while accounting for imperfect detection. Marsh vegetation cover was significantly lower at grazed marshes than at ungrazed marshes during the grazing season in 2007 but not in 2008. Winter-spring grazing had little effect on Black Rail occupancy at irrigated marshes. However, at nonirrigated marshes fed by natural springs and streams, grazed sites had lower occupancy than ungrazed sites. Black Rail occupancy was positively associated with marsh area, irrigation as a water source, and summer vegetation cover, and negatively associated with marsh isolation. Residual dry matter (RDM), a commonly used metric of grazing intensity, was significantly associated with summer marsh vegetation cover at grazed sites but not spring cover. Direct monitoring of marsh vegetation cover, particularly at natural spring- or stream-fed marshes, is recommended to prevent negative impacts to rails from overgrazing.

Standards vary in studies using rainfall simulators to evaluate erosion

Rainfall simulators are often employed to measure erosion rates, in order to estimate stream loading of sediment and nutrients in California foothill watersheds. The rainfall simulator enables the precise application of artificial rain with controlled drop sizes, intensity and duration. In addition to rain factors such as drop energy and intensity, several soil- and cover-related factors affect erosion rates. While computational models have evolved to quantify erosion based on field measurements taken by rainfall simulators, there has not been a consensus on the methodology to be deployed, especially in forested and remote landscapes. In addition, it is challenging to apply study results from small plots to entire watersheds. To guide future fieldwork on sediment loading to water bodies, we review key concerns related to rainfall simulator studies.

A Silent Force

Click to increase image sizeClick to decrease image size Acknowledgments Anthony Loverde was raised in Sacramento and in the Sierra foothills of California. He was raised in a family of full-time professionals and part-time artists. His love for photography grew as memories were shared through family albums that spanned many decades. Anthony served in the USAF for seven and a half years. He served five of those years overseas in Germany and the Middle East in support of Operation Enduring Freedom and Operation Iraqi Freedom. Unfortunately, his professional career would suddenly end in the midst of his tour in Germany due to the Don't Ask, Don't Tell law that required his commander to discharge him based on the mere knowledge of Anthony being a gay man. It was through this discriminating experience that convinced Anthony to pursue a MFA in photography with the sole intention to tell the story of the men and women most affected by the Don't Ask Don't Tell law through his chosen thesis project. Anthony has found his project to be very fulfiling and therapeutic for all involved. He hopes his work will be another spear in killing discrimination against the gay and lesbian community. All photographs are © 2010 by Anthony Loverde.

Controlling invasive species in complex social landscapes

Control of biological invasions depends on the collective decisions of resource managers across invasion zones. Regions with high land‐use diversity, which we refer to as “management mosaics”, may be subject to severe invasions, for two main reasons. First, as land becomes increasingly subdivided, each manager assumes responsibility for a smaller portion of the total damages imposed by invasive species; the incentive to control invasives is therefore diminished. Secondly, managers opting not to control the invasion increase control costs for neighboring land managers by allowing their lands to act as an invader propagule source. Coordination among managers can help mitigate these effects, but greater numbers – and a wider variety – of land managers occupying a region hinder collective action. Here, we discuss the challenges posed by management mosaics, using a case study of the yellow starthistle (Centaurea solstitialis) invasion in the Sierra Nevada foothills of California. We suggest that the incorporation of management mosaic dynamics into invasive species research and management is essential for successful control of invasions, and provide recommendations to address this need.