The objective of this project was to determine the impact of urbanization on the hydrologic characteristics of watersheds in the Berkeley Hills of central California. The initial approach was to calibrate three stream gaging station prior to the development of one watershed above one of these stations and to follow changes in hydrologic characteristics during and subsequent to development. Economic and political developments in 1974 and 1975 prevented the developer from building on the principal watershed. A summary of data on annual water yield, characteristics of flood peaks, sediment yield, and water quality for the three non-urban watersheds is presented.

A subproject completed during the study compared periodicity of streamflow in previously urbanized and non-urbanized watersheds in the Berkeley Hills. Two daily discharge peaks which lagged 1.5 hours behind two daily peaks in lawn irrigation were observed. Peak daily streamflow on the urbanized watershed was 10 times that of a similar non-urbanized watershed. The stream from the urbanized watershed flowed continuously throughout the year while the stream from the non-urbanized watershed ceased flowing from late July until mid-October.

Bees are one of the key groups of anthophilies that make use of the floral resources present within urban landscapes. The ecological patterns of bees in cities are under further investigation in this dissertation work in an effort to build knowledge capacity that can be applied to management and conservation.

Seasonal occurrence patterns are common among bees and their floral resources in wildland habitats. To investigate the nature of these phenological interactions in cities, bee visitation to a constructed floral resource base in Berkeley, California was monitored in the first year of garden development. The constructed habitat was used by nearly one-third of the locally known bee species. Bees visiting this urban resource displayed distinct patterns of seasonality paralleling those of wildland bees, with some species exhibiting extended seasons.

Differential bee visitation patterns are common between individual floral resources. The effective monitoring of bee populations requires an understanding of this variability. To investigate the patterns and trends in urban resource usage, the foraging of the community of bees visiting Tecoma stans resources in three tropical dry forest cities in Costa Rica was studied. Substantial variability was noted between individual T. stans resources in each of the three populations. The observed variability is driven by the quality of the food resource as measured by the number of individual flowers available. Additionally, the regional landscape plays a role in general species occurrence patterns at a resource.

The urban landscape presents a heterogeneous mosaic patchwork of habitat resources. To investigate the influence of this local variability on resource usage, the foraging patterns of bees in tropical and temperate landscapes were examined. In the dry forest of Costa Rica, bee foraging on T. stans was studied in the cities of Bagaces, Cañas, and Liberia. In the coastal grassland region of California, bee foraging on California poppy (Eschscholzia californica) was studied in the cities of Berkeley, Emeryville, and Oakland. In both regions, resource abundance and spatial distribution were the main drivers of bee visitation in all taxon groups. Land use and uniquely urban landscape variables influenced the occurrence of certain bee taxa.

A study of the effects of streamflow regulation on riparian vegetation focused on seedling establishment along 30 low-gradient, alluvial streams throughout central California. Initial establishment densities were generally lower on regulated streams than along non-regulated ones. However, prolific establishment occurred on the recently regulated streams as the vegetation adjusts to new stream conditions. Seedling survival was slightly greater on regulated streams than non-regulated ones following the 1985-1986 flooding. Survival was much higher on both regulated and non-regulated streams during the year of low discharges (1986-1987).

Seedling survival and growth were monitored in a controlled experiment simulating regulated and non-regulated conditions. Survival did not vary considerably among species. Growth was less in the fluctuating water level treatment than under simulated non-regulated conditions. Growth was higher for all four common species under the fluctuating treatment in a gravelly substrate but lower for cottonwood and sandbar willow in a sandy substrate.

Quantifying the impacts of climate change on flora is of interest to many watershed and land managers, but has been challenging to study and distinguish from other disturbances that can reshape the landscape. This dissertation has found new tools to assist watershed managers in modeling the impacts of climate change by utilizing large comprehensive spatial datasets derived from remote sensing technology. To understand the recent expansion of the Douglas-fir (Pseudotsuga menziesii) forest within the San Francisco Peninsula Watershed across spatial-temporal scales with respect to increased precipitation over the past century, GIS models were developed using Light Detection And Ranging (LiDAR). The Douglas-fir was selected to be studied within the San Francisco Peninsula Watershed primarily because of its impact on replacing oak woodland, chaparral and grassland vegetation types. Secondly, Douglas-fir has a minimum mean annual precipitation requirement of around 34 inches, which allows it to be more competitive in formerly drier parts of the watershed. Extensive daily precipitation records spanning the last 100 years were recorded by the Spring Valley Water Company and later by the San Francisco Public Utilities Commission (SFPUC), which has provided a unique opportunity to study the Douglas-fir spread pattern influenced by increased rainfall.

The SFPUC rain gauges showed an increase in mean annual precipitation of approximately 15 cm over the past century, which is consistent with independent data on climate research for the central California coast. Using LiDAR, over 12,000 individual overstory Douglas-fir trees were identified and their heights measured. Tree cores were taken of Douglas-fir inhabiting different microclimates to determine their age and rate of growth in the study area of the San Francisco Peninsula Watershed, allowing a species distribution model (SDM) of Douglas-fir to be devised. The high density of rain gauge stations encompassing the Douglas-fir forest spanning the last 100 years provided a unique opportunity to model the advancement pattern of the Douglas-fir forest with respect to historical and future climate scenarios. The results show the Douglas-fir advances more quickly with increased annual precipitation across the entire study area.

An anthropological study on cultural values of heritage trees in urban landscapes focuses on symbolic functions of old and big trees in temple gardens in Bangkok. In this study, I discuss significance of urban forests on temple grounds in both cultural aspects and how they contribute to ecological aspects in the urban context. For the cultural aspects of the trees in the selected temple gardens, I discuss scholastic doctrines of Buddhist materials and their impact on local culture, then examine the roles of trees as material objects in the Buddhist aspects from the point of view of an insider, as a practitioner, an outsider, and as a scholar. The study consists of two parts, qualitative and quantitative components. In the qualitative part, using an ethnographic approach, I examine the relationship between Buddhism doctrine with ecological approaches that have been influenced by preexisting local culture. The study reveals how cultural values of trees are perceived in the religious realm and the change of religious structure in today society. I conduct ethnographic field work on the cultural perceptions of cultural and ecological services of temple trees and address the historical and cultural significance of trees in Sangha, the Buddhist monk community. I explore the Buddhist monks’ attitudes toward trees in the temples, comparing the Buddhist doctrines, rituals, and their actual experiences in order to answer the question how the Sangha perceives cultural values and religious symbolic of trees on temple grounds. I examine influential factors that make trees sacred. Does location matter? If the same tree species with similar size and age grow outside temples, do they still convey the same symbolic significances? From preexisting local culture to religious doctrines, I question how Buddhist monks and their influences on society, culture, and environment assign cultural values and powerful status of sacred symbols to the trees. I question whether temple trees are preserved with these cultural constructions of assigned values.

For the quantitative part, I address the roles of temple gardens as green infrastructure in the city. I examine the green coverage in temple gardens at two scales, the site scale and citywide. Combining the conventional method of Line Transect at the site scale with data from Landsat 8 and the recent Object-based Image Analysis method at the citywide scale with the high-resolution satellite imagery, the percentage of green canopy coverage of religious land uses is compared with other land uses to address the questions on how cultural values of the trees contribute to the green infrastructures of the city. Qualitative analysis of cultural and ecological perceptions toward the trees are put in parallel to this quantitative analysis of the green coverage ratio to examine how monks, the managers of this monastic landscape, understand and appreciate their habitat and the values of these urban heritage trees. I analyze the patterns and locations of heritages trees in temple gardens and develop an inventory of species of heritage large trees from selected study sites. There are 184 trees of 61 species mentioned as significant trees in temple gardens. Then I conclude from in-depth interviews and my observations the ways temples can maintain species diversity and the ways in which heritage trees in temple gardens can have suitable cares, maintain species diversity, and be a healthy ecological component in urban spheres.

Urban forests have aesthetic, environmental, human health, and economic benefits that motivate tree planting programs. Realizing these benefits depends on tree survival. Cost-benefit analyses for urban forest ecosystem services are sensitive to mortality rate assumptions and associated population projections. However, long-term mortality data is needed to assess the accuracy of these assumptions. Analytical tools from demography, such as life tables, mortality curves, and survival analysis, can improve our understanding of urban tree mortality. Demographic approaches have been widely used in forest ecology to quantify population dynamics and project future changes in wildland systems. However, to apply demographic techniques to urban forests, longitudinal data is needed, with repeated mortality observations on individual trees. In this dissertation, I analyzed five years of longitudinal data from two Northern California studies: street trees in Oakland and yard trees in Sacramento. These field projects are complemented by a conceptual overview of demographic approaches to urban tree mortality (Chapter 1), and an investigation of practitioner-based tree monitoring programs.

For the Oakland study (Chapter 2), I documented tree mortality and planting rates, net population growth, and assessed selected risk factors for survival. I monitored the entire street tree population in a small plot for five years after an initial inventory (2006). I adapted the classic demographic balancing equation to quantify annual inputs and outputs to the system, tracking pools of live and standing dead trees. There was a 17.2% net increase in live tree counts during the study period, with 3.7% overall annual mortality. However, population growth was constrained by high mortality of small/young trees. Size-based mortality rates followed a Type III curve, with highest mortality for small trees, and lower for mid-size and large trees. I used multivariate logistic regression to evaluate the relationship between 2011 survival outcomes and inventory data from 2006. Significant associations were found for size class, foliage condition, planting location, and a multiplicative interaction term for size and foliage condition.

For the Sacramento study (Chapter 3), I assessed tree losses during the establishment phase for a residential tree give-away program. A cohort of young trees distributed in 2007 was monitored for five years. I used Random Forests to identify the most important risk factors at different life history stages, and survival analysis to evaluate post-planting survivorship. Analysis included socioeconomic, biophysical, and maintenance characteristics. In addition to field observations of tree planting status, survival, and maintenance, I also collected property ownership information (renter vs. owner-occupancy, homeowner change, and foreclosure) through the Multiple Listing Service and neighborhood socioeconomic characteristics from the U.S. Census. I found that 84.9% of trees were planted, with 70.9% survivorship at five years post-planting. Planting rates were higher in neighborhoods with higher educational attainment, and on owner-occupied properties with stable residential ownership. Five-year survival was also higher for properties with stable homeownership, as well as for tree species with low water use demand. When I incorporated maintenance characteristics from the first year of field observations, factors related to tree care were important to survival. Many residents did not adhere to recommended maintenance practices. These results illustrate the critical role of stewardship and consistent homeownership to young tree mortality on residential properties, and suggest that survival assumptions in urban forest cost-benefit models may be overly optimistic.

To learn more about practitioner-driven monitoring efforts, I surveyed 32 local urban forestry organizations across the United States about the goals, challenges, methods, and uses of their monitoring programs (Chapter 4). Non-profit organizations, municipal agencies, state agencies, and utilities participated. Common goals for monitoring included evaluating the success of tree planting and management, taking a proactive approach towards tree care, and engaging communities. Challenges included limited staff and funding, difficulties with data management and technology, and field crew training. Programs used monitoring results to inform tree planting and maintenance practices, provide feedback to individuals responsible for tree care, and manage hazard trees. Participants emphasized the importance of planning ahead: carefully considering what data to collect, setting clear goals, developing an appropriate database, and planning for funding and staff time. Urban tree monitoring partnerships between researchers and local organizations should be developed, with standardized protocols and clear research questions. Such partnerships would provide urban forestry professionals with improved mortality information to evaluate the success of planting programs, while expanding the data sets available to researchers. The Oakland and Sacramento studies (Chapters 2 and 3) offer examples of demographic approaches to urban tree mortality that can be replicated and expanded as more longitudinal data becomes available from both researchers and practitioners.

Found in nearly all terrestrial ecosystems, small in size and able to occupy a variety of hunting niches, spiders' consumptive effects on other arthropods can have important impacts for ecosystems. This dissertation describes research into spider populations and their interactions with potential arthropod prey in California's native and non-native grasslands. In meadows found in northern California, native and non-native grassland patches support different functional groups of arthropod predators, sap-feeders, pollinators, and scavengers and arthropod diversity is linked to native plant diversity.

Wandering spiders' ability to forage within the meadow's interior is linked to the distance from the shaded woodland boundary. Native grasses offer a cooler conduit into the meadow interior than non-native annual grasses during midsummer heat. Juvenile spiders in particular, are more abundant in the more structurally complex native dominated areas of the grassland. Potential prey species and abundance differ along the trajectory from woodland boundary to meadow interior and may have consequences for the survival of juvenile spiders that reside primarily near the woodland boundary.

Spiders' ability to influence the eating habits of potential prey species is regulated by temperature and grassland characteristics. In experimental wolf spider enclosures, cooler habitats in which spiders were present evidenced lower herbivory by large chewing invertebrates. Herbivory differed across a gradient of temperature and sunlight but newly restored plants in exposed and warmer soil faced higher rates of herbivory than established plants; herbivory may be better mediated by spider activity in cooler environments.

In California, the common native shrub, Baccharis pilularis DC. (coyote brush, Asteraceae) readily invades grasslands in the absence of fire and grazing. Research shows that water availability is important in regulating B. pilularis seedling establishment in grasslands, with late spring rainfall providing a timely source of moisture that helps B. pilularis roots compete with neighboring grassland plants. The ecohydrology of B. pilularis, particularly during invasion into grasslands, remains largely unexplored. For this research I investigated 1) intraspecific variation in water relations between the prostrate B. pilularis ssp. pilularis and erect B. pilularis ssp. consanguinea (herein B. pilularis) in a mature common garden, 2) seasonal water relations and use of experimentally planted B. pilularis seedlings with and without neighboring plants in cool, fog-prone, perennial-dominated and warm, dry annual-dominated coastal grasslands, and 3) seasonal water relations between experimental B. pilularis seedlings and naturally-occurring adults in the two contrasting grassland types. For these studies I measured a suite of water relations traits including stomatal conductance, stem water potentials, leaf stable carbon isotope composition, tissue-level parameters that reflect cell hydration, stable isotope composition of xylem water, and whole stem hydraulic conductance. First, I found that despite the decreasing water availability during the rainless summer, both B. pilularis morphotypes increased rates of stomatal conductance and photosynthesis. These increases are likely a strategy to meet increased carbon demands before B. pilularis’ fall blooming period, so the plants can produce adequate numbers of wind-pollinated and wind-dispersed flowers to ensure successful dispersal and establishment into neighboring grasslands. Second, a manipulative neighbor removal treatment demonstrated that grassland neighbors harvest fog for use by B. pilularis seedlings when fog water is present but not in the warm, dry annual grassland with very little fog where seedlings grew significantly better. Third, as expected, adults showed greater tolerance for water deficit and seedlings readily used fog water when fog was present. As in Chapter One, plants in both age classes show the same increased demand for carbon before the onset of the blooming period as demonstrated by increased stomatal conductance, osmotic adjustment, bulk leaf δ13C during the rainless summer. These results provide evidence that B. pilularis is well adapted to withstand water deficits yet plant water status can benefit from neighbors in fog-prone areas. In a warmer and drier climate, this shrub will likely become an increasingly dominant presence throughout the California Floristic Province.

Roadkill data have been analyzed in a 25.6 mile-long highway stretch in the Californian central coast, in search of distribution patterns. The highway stretch was broken up into 1/10 mile sections. Roadkill data were collected along the road, mapped, and analyzed together with surrounding landscape units and landscape features defined at three different scales, namely micro-, meso-, and macro-landscape scales.

Landscape and roadkill data were arranged in such a way as to allow numerous comparisons between them at each scale. Most analyses were done by analyzing the line of best fit in X-Y plots. Linear and logarithmic comparisons were made, and t-scores (<0.05) were used to determine statistical significance.

Trends in roadkill distribution along roads have been found at different scales. Roadkill distribution patterns related to landscape features have been identified through statistical analysis even where geographical cluster does not exist.

In addition the statistical analysis, new roadkill evidence found during the underpass inventory suggested the existence of an important deer pathway, operating at a larger scale than the one used in this study. Should the pathway be confirmed as such by future specific monitoring, efficient corrective measures could be successfully determined and implemented.