GRASSLANDS

Cremers,Bart  (bcremers@calpoly.edu),
 Mike Hall (mhall@calpoly.edu),
 and Brent Hallock (bhallock@calpoly.edu)
 Effects of high intensity-short duration and open cattle grazing on oak woodland/savanna rangeland. The objective of this project is to quantitatively assess the effects of high intensity-short duration grazing on natural ecosystems, particularly the oak woodland/savanna rangelands that are so important to the cattle industry in California. The research will consist of quantitative comparisons in grazed and un-grazed areas and will include detailed measurements of the following: (1) beef production; (2) forage productivity and quality; (3) soil quality, erodeability, and soil nutrient content; (4) pasture cover and species diversity; and (5) natural oak recruitment. The overall goal is to test if high intensity-short duration grazing is a viable tool for rangeland improvement. The working hypothesis of the research is that the correct grazing practices will enhance the productivity of the forage production and quality, therefore increasing beef productivity.

Harpole, W. Stanley (harpole@lter.umn.edu), David Tilman (tilman@swan.lter.umn.edu, Eric Seabloom, and O. J. Reichman. 
Relationships between soil resources and plant invasion in California grassland. Resource competition as it relates to invasions by non-native species has received little attention. Plants compete for limited resources, and for a plant species to invade a community it must either compete successfully for those resources or avoid competition by exploiting an unused spatial or temporal niche. Increasing resource supply through fertilization can favor invasive species. These four studies are an attempt to explain why, in terms of resource competition, exotic annual species continue to dominate California grasslands even after grazing has ended.

Hufford, Kristina M. (huffard@lifesci.ucsb.edu) and Susan Mazer (mazer@lifesci.ucsb.edu) 
Gene flow and hybridization between introduced and local populations of native perennial bunchgrasses; the potential for hybrid breakdown and its implications for restoration efforts.
Hybridization between plants native to restoration sites and individuals from distant populations may cause reduced vigor in subsequent generations due to "hybrid breakdown" - the loss of locally adapted gene combinations through the process of genetic recombination. We propose to examine the genetic consequences of recent introductions of California native grass seeds from distant populations to Sedgwick Reserve of the U.C. Natural Reserve System. In this study, we will conduct a reciprocal transplant experiment of three native grass species at Sedgwick Reserve and Vandenberg Air Force Base to investigate levels of local adaptation between sites and the potential for hybrid breakdown.

Mazer, Susan J. (mazer@lifesci.ucsb.edu) and Elizabeth Mason
Cultivation of native perennial grass species from Vandenberg Air Force Base for use as a seed source for restoration efforts: detecting hybridization, ecotypic differentiation, and genetic differentiation between Vandenberg and Sedgwick genotypes.
See below.

Mazer, Susan J. (mazer@lifesci.ucsb.edu) 
Gene flow and hybridization between introduced and endemic populations of three native perennial grass species. A 60m x 1000m parcel of land was made available at Sedgwick to be used as an outdoor nursery for the cultivation of perennial grass species derived from seeds collected from natural populations at Vandenberg Air Force Base. The seeds could then be used for restoration efforts among the grasslands of Vandenberg Air Force Base. One issue that has generated concern is whether the genotypes of seeds used in restoration efforts are genetically and ecologically distinguishable from the seeds that would normally grow in a given habitat. If seeds from one area are planted in a different environment, the long-term survivorship of these seeds may be at risk. Additionally, the potential for hybridization poses an additional risk when distinct genotypes are introduced to and hybridize with locally adapted populations. The current nursery situation is therefore an opportunity to examine a potential hybridization event at its onset, and to suggest guidelines and cautions for future restoration efforts.

Reichman, O. J., Eric Seabloom, Dave Tilman, and Stan Harpole 
Multiple stable equilibra or competitive superiority in grassland communities. The major focus of this research is to determine environmental factors that can precipitate a switch from annual to perennial and perennial to annual dominated communities. 136 plots which range in size from 9 to 25 square meters are being subjected to a variety of treatments including seed additions, burning, nitrogen addition, watering, and pocket gopher exclusion to determine the conditions under which both annual and perennial dominated systems can persist.

Reichman, O. J., Eric Seabloom, Stephanie Romanach, Elise Stephens, Sean Watts, and Andrew Borcher
Dynamic interactions between plant distributions and animal-generated disturbances: trajectories of restored communities. The role of animal-generated disturbance in restoration is a conundrum, because the disturbances are essential for the persistence of native annual species but they also increase the potential of invasion by exotic species. The researchers will use the central California grassland system to study the effects of the preexisting disturbance regime on the persistence of species in the restored community, and on the subsequent disturbance pattern, i.e. gopher activity. The main component of this experiment takes place in 36 gopher enclosures in experimentally planted perennial grassland. The plots will be subjected to a combination of different burning regimes and varying densities of pocket gophers.

Schultz, Cheryl B. (schultz@bren.ucsb.edu), Eric Seabloom, and Sean Watts
Restoring wildflowers in California's native grasslands. An important component of restoring native grasslands is restoring native wildflower diversity. The researchers propose to investigate ecological processes that influence wildflower establishment. This experiment will also be used to teach ecological field methods in a Restoration Ecology course. Students will be involved in monitoring the results of the experiment and in surveying the insect community. Forb (wildflower) seeds will be added to already-established perennial grass plots. Newly turned soil from gopher mounds will be added to the experimental area to simulate gopher disturbances. The nectivorous insect community at Sedgwick will also be surveyed to provide baseline information and their associated resource needs.

Ward, Theresa (taward@ucdavis.edu) Riparian grazing practices and water quality of California rangelands There is significant concern about grazing impacts on rangeland riparian resources. The scientific literature shows that improper, and often undefined, grazing leads to negative impacts on rangeland riparian resources. Unfortunately, the literature does not provide a tool-box of field-tested, practical, and economically-feasible grazing management recommendations to safeguard riparian resources. The researchers are conducting a survey of 300 rangeland riparian areas across California to collect a consistent data set allowing identification of site by management combinations correlated with high and low riparian health scores. They will report preliminary results based upon the 150 sites currently enrolled in the study. Preliminary analysis across sites indicates that some simple management practices are associated with increased riparian health scores. A manager can expect to improve riparian health (as measured by the NRCS method) by spending time on some simple measures, with the greatest improvement coming from time invested in off-site feeding. They will continue to enroll sites in this project over the next year. 

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Koenig, Walter D. and Jean Knops California acorn survey. The goal of this study is to understand the patterns of variable acorn production by California oaks. Acorn production by 51 trees at Sedgwick is visually surveyed as part of a statewide project. This is the 7th year of this survey.

Kuhn, Bill (kuhn@geog.ucsb.edu) and Frank Davis (fd@geog.ucsb.edu) 
Valley oak ecology: water stress and acorn production. By taking field measurements of valley oak adults and seedlings, the researchers hope to determine two relationships: 1) the relationship between tree age (size), depth to water table, and water stress; and 2) the relationship between tree density and acorn production related to water stress environment. It is hoped that results of the study will further the understanding of valley oaks and provide essential information for the management of valley oak woodlands and savannas.

Mahall, Bruce (mahall@lifesci.ucsb.edu), Frank Davis, Claudia Tyler (tyler@lifesci.ucsb.edu), and Mike Hall
Santa Barbara County Oak Restoration Program. The researchers are conducting a long-term oak regeneration program to improve the understanding of the role of cattle and other ecological factors in limiting or promoting recruitment by valley oak, blue oak, and coast live oak. The specific goals of this research are to: 1) conduct large-scale grazing and related experiments that will determine the factors affecting the establishment of valley, live and blue oaks in ecosystems represented on Sedgwick Ranch; 2) develop a prescription for actively promoting oak regeneration in such ecosystems; 3) disseminate the findings in the form of presentations, onsite demonstration projects, and literature that is directed towards local landowners and resource managers interested in the management and restoration of oak woodlands. The researchers are in the seventh year of a ten-year project that entails collecting and sowing valley oak and coast live oak acorns in grazed and un-grazed areas with or without rodents, and monitoring patterns of seedling and sapling survivorship under the different treatments.

Mata, Catarina (mata@lifesci.ucsb.edu)
The role of water stress (drought) in oak seedling and sapling survival and performance in Sedgwick Reserve. The aim of this project is to determine the importance of summer drought and water stress on oak seedling establishment. It is hypothesized that water stress is the major stress factor for these plants. The researchers will try to assess the water status of the field seedlings and evaluate the resistance to water stress of both coast live oak and valley oak species in a pot experiment on campus.

Sage, Richard D. (rdsage@silcom.com) 
Investigations of the evolutionary ecology of valley oaks (Quercus lobata Nee). Valley oaks are good subjects for studying the evolutionary ecology of seeds. Acorns made good study subjects, and the seedlings are absolutely dependent on the endosperm energy for growth during the initial post-germination period. The researcher's investigations are aimed at learning how the mother tree packages her energy into acorns, and how these provisions affect the survival of the seedling. To this end he is observing the year-to-year patterns of acorn size and shape in about 100 individually marked adult oaks at the Sedgwick Reserve. Experimental alteration of the endosperm reserves of acorns and measurements of the resulting effects on seedling performance are planned, as well as observing the preferences of wild scrub jays for acorns of different size and shape. The results of these studies will provide a deeper insight into how acorn biology influences the evolutionary success of a valley oak tree.

Sork, Victoria L. (sork@unsl.edu), Peter E. Smouse, and Frank W. Davis 
Landscape patterns of propagule flow and genetic structure in declining populations of California valley oak, Quercus lobata. Excessive reproduction isolation can result in increased genetic drift, reduced genetic variation, inbreeding depression, and even reproductive collapse. This project represents a case study of the evolutionary dynamics of gene flow on a landscape scale. The conditions under which valley oaks are at risk of reproductive collapse due to genetic fragmentation resulting from progressive population decimation will be investigated. This project will contribute significantly to the discussions of conservation of valley oak and the development of policy concerning its future management.

Romanach, Stephanie (romanach@lifesci.ucsb.edu)
The influence of social behavior, resource abundance, and the physical environment on the use of space. See below.

Romanach, Stephanie, O. J. Reichman, Eric Seabloom, Elise Stephens, and Sean Watts
How the presence of conspecific neighbors affects the home range structure or territorial animals. This is part of a larger project using the agricultural fields on the west side of Figueroa Creek, near the main building complex. The researchers hope to determine how the disturbance created by pocket gophers impacts the restoration of a California grassland. They will be looking at the initial distribution of the plants and how that affects the gophers' movement/disturbance, and in turn, how the gophers affect the plant community composition and distribution. They also plan to look at the interactions of the gophers on each other and that of the plants on each other. There are a total of 56-20m x 20m pens, each with a different combination of fire and gopher density, as well as control and long-term study pens.

Sanver, Dilek (dsanver@uci.edu) 
The effect of cynipid gall structure on the diversity of parasitoids on Quercus lobata and Quercus douglasii. There have been several studies that have tested the relationship between gall size and the parasitoid species that can attack those galls. Galls are areas of active tissue growth in a plant in response to the feeding activities of an insect on that plant, and are thought to protect the gall maker from parasitoid attack by forming a physical barrier. There have been no large-scale studies done using several different species of gall makers that share the same group of parasitoids. The different oak species at Sedgwick support numerous cynipid gall maker species, and these cynipid galls show remarkable variation in size and structure. This research project will include the collecting of cynipid galls from oak trees and the identification of the gall maker species for each gall type. Each gall type will be quantified by taking measurements and then the gall makers and parasitoids from those galls will be cut to determine whether parasitoid diversity is correlated with gall structure.

Montalvo, Arlee (montalvo@citrus.ucr.edu), James D. Bever, Victor P. Claasen, Norman C. Ellstrand, John B. Skillman, Tracy Tennant, and Van Stout
Adaptation of California poppy (eschscholzia californica) to extreme soil differences: exploring physiological and symbiotic mechanisms. It is known that root-inhabiting fungi have favorable symbiotic relationships with plants such that both the fungus and the plant benefit. The fungus benefits by deriving a carbon energy source from the plant, and the plant benefits because the fungus increases plant access to soil resources, especially phosphorus, which would otherwise be unavailable. The researchers predict that the arbuscular mycorrhizal, a type of beneficial root fungus, play an important role in helping plants to adapt to their environments. The researchers will test this prediction through experiments using native plant species (e.g. California poppy) that grow off and on serpentine soils and which are known to form an association with arbuscular mycorrhizal fungi. They will survey for differences in fungal species associated with plants in contrasting soil environments and perform experiments on plants grown from seeds collected from these environments and grown in reciprocal soil treatments.

Schueller, Sheila K. (schuel@umich.edu)
California mainland and Channel Islands pollination ecology of an invasive plant, Nicotiana glauca (Solanacea): interactions and comparisons with native hummingbird-pollinated plants. There are few studies that use mainland-island comparisons to investigate the effects of a change in pollinator composition or activity on plant reproductive biology and floral trait evolution. Island groups such as the Channel Islands, which are less isolated and closer to the mainland, are ideal for intraspecific studies of the ecological and evolutionary consequences of island colonization. Comparing the ability of an introduced species with that of a native species to reproduce in the 'pollinator-challenging' setting of an island will give us a better understanding of the reasons for invasives' success and of the attributes allowing for success in fragmented habitats. This research thus centers on the response of a native plant (California fuschia) and an introduced hummingbird-visited plant (tree tobacco) to pollinator conditions on two of the Channel Islands (Santa Cruz and Santa Catalina). The Sedgwick Reserve will serve the role as one of the mainland comparison sites.

Carson, John W. (900 Calle de los Amigos, N38, Santa Barbara, CA 93105, 805-563-9573) 
Insect-Spider Survey of the Sedgwick Reserve Main plant communities will be studied to increase our knowledge of the diversity and relative abundance of spiders and insects on the Reserve. The two main collecting methods will be small pitfall trips that have the tops level with the surface of the soil to catch ground arthropods, and malaise traps (the size of a small pup tent) to catch flying insects. The larger more common insects will be identified to family (genus/species where feasible), and spiders will be identified to family initially, with a later attempt at genus identification.

LaBonte, John P. (labonte@lifesci.ucsb.edu)
A survey of the reptiles and amphibians of the University of California Sedgwick Reserve, Santa Barbara County. The purpose of this three-year project is to assemble an inventory of the reptiles and amphibians of the Sedgwick Reserve and to examine the spatial arrangement of these species in relation to the diverse habitats that are included within the reserve. 200 4' x 4' plywood boards, called 'cover boards' will be placed at locations along an elevation gradient of over 1,000 feet to act as artificial refuges. Each board will be lifted, and all reptiles and amphibians underneath will be captured and inventoried. This project will also serve as a preliminary study for research focusing on the foraging behavior, habitat use, and movement patterns of the western rattlesnake.

Chamran, Faraneh (faraneh@geog.ucsb.edu) and Oliver Chadwick (oac@geog.ucsb.edu)
An explicit treatment of topography in modeling ecosystem processes on small hillslopes. In this study I am using computer-generated landscape models to provide a representation of hydro-ecological patterns on a hill slope in the California grasslands. I use data from the El Niño (1997-1998) and La Niña (1998-1999) cycles to understand topography and hydro-ecological patterns. The results suggest that differences in net primary productivity, soil organic carbon, and soil respiration parallel differences in available water. Soil water in turn is modified by topography. These differences are even more pronounced in the La Niña water year due to lateral water re-distribution. A soil-water balance model is used to map variation of available soil-water based on daily rainfall and evapotranspiration values. This map coupled with maps from other locations presents a powerful tool for hypothesizing the spatial distribution of fine-hillslope ecosystem processes.

Cloud, John (cloud9@geog.ucsb.edu), Oliver Chadwick, Helmut Ehrenspech, and Lansing Duncan Mulam
Project: Small stream course stabilization by bioengineering and experimental treatments. A badly eroding first order stream course immediately adjacent to and below Figueroa Mountain Road will be observed, and an attempt will be made to stabilize and re-vegetate the stream course. Experimental treatments used include wooden and rock check dams; various types of biodegradable erosion cloth blankets; the planting of a variety of native grasses and shrubs; and the removal of exotic annual and perennial plants.

Dornelles, Douglas (dornelle@lifesci.ucsb.edu) 
Soil biogeochemical and physical characterizations under different types of common California vegetation; and impact of El Niño on soil characteristics. The intent of this project is to characterize the biological, chemical and physical soil properties in three vegetation types: oak woodland, coastal sage scrub, and California grassland. The researchers will also be characterizing the biological, physical and chemical properties of El Niño caused landslides in grassland and coastal sage scrub as compared to undisturbed, adjacent plots located in the Lisque watershed.

Fierer, Noah (fierer@lifesci.ucsb.edu) 
The effects of periodic rainfall events on soil microbial processes and microbial community structure at Sedgwick Reserve. The purpose of the proposed research is to examine the effects of periodic wetting and drying events on soil microbial processes within the Sedgwick Reserve. The researchers will assess the impact of these wetting/drying events on the rates and properties of carbon mineralization, nitrogen mineralization, and nitrification in the soil. They will attempt to correlate any of these changes with changes in soil microbial community composition. There is some evidence that soil may have a differential response to stress depending on present moisture status, duration of drought, and exposure to previous stress. A rainfall simulator will be used to mimic natural rainfall events on plots throughout Sedgwick. The collected data will then be used to build a model describing the short-term and long-term impacts of rainfall events on carbon and nitrogen cycling within the Sedgwick Reserve.

Gabet, Emmanuel (egabet@bren.ucsb.edu), and Tom Dunne (tdunne@bren.ucsb.edu) 
A stochastic sediment supply model for a mountainous, semi-arid landscape. Cattle-grazing has often been identified as the cause of erosion and soil stability problems, including soil erosion, bullying, and siltation. With the use of a rainfall simulator, the researchers propose to investigate the effects of grazing on surface runoff and sediment transport. By understanding the process of the effects of grazing and rangeland conversion, they hope to identify areas that are vulnerable to erosion, thus helping land managers to protect these areas prone to erosion.

Garcia, Antonio F. (afg@magic.geol.ucsb.edu) and Oliver Chadwick Geological mapping of the Sedgwick ranch area. The work conducted in this study includes detailed characterization and mapping of geologic materials that are present in the Sedgwick Ranch area. The ultimate goal of this study is to understand the formation and evolution of the landscape of this area. The data generated by this work is "primary data", in that it will provide an inventory of the character and distribution of surficial geologic materials in the Sedgwick Reserve. The resulting GIS map will be made available so others may see the information.

Schimel, Josh (schimel@lifesci.ucsb.edu) and Patricia Holden (holden@bren.ucsb.edu) Linking resource and stress gradients to microbial community composition and function through the soil profile of a California annual grassland at the Sedgwick Reserve. Our understanding of the factors that control microbial community composition and dynamics, and of the links between community composition and functioning, is limited. The central hypothesis of this proposal is that the gradients of resources and stress are the primary drivers of the size, diversity, dynamics, activity, and growth strategies of the microbial community throughout the soil profile. Work will be performed at two sites on the Reserve where monitoring of soil climate, chemistry and microbial communities down to at least 4m will take place.

Seabloom, Eric (seabloom@nceas.ucsb.edu), O. J. Reichman (reichman@nceas.ucsb.edu), Sean Watts, and Stan Harpole  
An analysis of biotic and physical factors in El Niño induced landslides. The researchers selected eight landslides in 1998 for use in a long-term study of succession (the evolution of a habitat). Four of the landslides are located in coastal sage scrub, and four are in annual grassland communities. Vegetation and soil samples were taken in 1999 and 2000 for analysis.

Trumbore, Susan (setrumbo@lifesci.ucsb.edu), Julia Gaudinski, and Edward A. Schuur 
Carbon isotopes in soil organic matter and soil respiration along a hillslope. In collaboration with Oliver Chadwick, the researchers are studying the relationships between water and carbon dynamics in soils on a hillslope on the Sedgwick Reserve. Isotope samples are taken of carbon dioxide in soil, air and in the carbon dioxide flux from the soil surface to the atmosphere. Radiocarbon and beryllium-10 isotopes are also measured in the soil profile. The carbon isotopes, particularly radiocarbon, tell us the major source of respired CO2, whether it is plant metabolism or decomposition of stored soil organic matter.

Safford, Hugh (hdsafford@ucdavis.edu)
Regional and local diversity in an insular environment: serpentine plants in California. As part of a larger study involving serpentine outcrops throughout the state of California, the Sedgwick Reserve will be sampled for regional and local patterns of plant species diversity. It is hypothesized that the richness of endemic species at a regional scale will be positively associated with the total area and measure of the patchiness of serpentine within a region. It is also hypothesized that local diversity is influenced by habitat geometry, as well as by regional diversity and local environmental factors.

Arntz, Michael 
Landscape images of the Natural Reserve System. As part of a series involving all of the reserves in the U.C. Natural Reserve System, the Sedgwick Reserve will play host to the artist in his development of landscape images.