Bodega Marine Laboratory/Reserve
March 2-4, 2012 |
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Participant Abstracts
Believing is Seeing: A photographic index of the University of California Natural Reserve System
Christopher Woodcock, Department of Art (Studio)
University of California, Davis
The University of California Natural Reserve System (NRS) is the largest university-administered system dedicated to providing and protecting the natural landscapes of California for research. Education is often thought of as an endeavor that occurs within the confines of a classroom, but the 37 NRS sites provide a unique opportunity to study and conduct research in habitats unavailable in a classroom setting. Located throughout California, the forty-five-year-old NRS consists of a mosaic of native ecological and topographical diversity endemic to the state. At a time when every resource at the University of California is being questioned and critiqued for its particular value, I sought to use landscape photography to visually index the scale and importance of the NRS. My Mathias Grant is the culmination of over 6 weeks of field research and more than 4,000 miles traversing the state of California with a 5x7-inch field camera. The resulting body of work is a series of four 5x7-inch images captured at each reserve. Standing alone, the images are meant to summarize the reserves' various ecotones. Taken at dawn or dusk, the exposures last from seconds to minutes in the rapidly changing crepuscular light. During the presentation I will discuss the virtues of conducting such a large and extensive project, describe my first-hand research while showing a selection of images, and elaborate on the tools and techniques that I employed. The resulting body of work is a photographic portrait of the University of California Natural Reserve System.
Chelsea Arnold
School of Engineering, University of California, Merced
Meadow degradation is a critical problem facing a variety of environments, including high elevation ecosystems of the Sierra Nevada, California, and has become a focus of major research and restoration efforts. A meadow experiences degradation when the hydrologic regime is altered by lowering of the water table due to incision of stream channels. Consequently, pivotal to the restoration efforts in degraded meadows has been returning a high water table to the meadows. While this approach creates conditions conducive to the re-establishment of traditional meadow vegetation, it does not take into account the long and short-term impacts of aerobic decomposition of soil organic matter (SOM) and consolidation of meadow soils that occur when the water level is low. Within the historic range of water level in a meadow, it is hypothesized that a meadow will retain its water holding capacity and resiliency. However, if the water table drops below a historic level, the processes of soil consolidation and aerobic decomposition will influence the resiliency of the meadow through a) irreversible plastic deformation of the soil pores and b) changes in SOM chemistry and distribution. The subsequent change in soil structure results in decreased porosity, increased bulk density, and a reduction in permeability of the meadow. Such changes can adversely impact the overall water holding capacity of the meadow. The research presented here utilizes a modified triaxial system to quantify the historic limit of dryness experienced in a high elevation meadow and degree of consolidation the meadow would experience if that limit was exceeded.
Christopher Kopp
Department of Biology, University of California, San Diego
Shifting range distributions observed worldwide provide some of the best evidence of species responses to increasing global temperatures over the past century. Many predictions of species range shifts are based on the climate envelope approach, with the null prediction that species ranges will shift poleward and upward in elevation to track suitable climate. However, observed rates of range alteration vary widely among species, potentially due to both differential dispersal rates and species interactions. In 2010 we conducted a re-survey of plant species distribution and abundance in eastern-California’s White Mountains, in areas originally surveyed by Harold Mooney in 1961. Species presence and abundance data were collected along line transects between elevations of 2,900 m and 4,000 m. We found that A. arbuscula increased its elevational range margin on granitic soils as much as 150 m from the original 1961 survey, and this upward range expansion coincided with significant declines in abundances of three alpine cushion plants: Trifolium andersonii, Phlox condensata, and Eriogonum ovalifolium. There were, however, smaller but significant declines in these species at higher elevations and on soil types where A. arbuscula had already become abundant. Together these results suggest that rising temperatures may be negatively impacting these alpine plant communities via both direct and indirect mechanisms, increasing the likelihood of local extinctions as compared with predictions from a simple climate envelope approach. Based on these results we have established an experiment that tests the effects of shading, warming, and presence of A. arbuscula on alpine plant species in the White Mountains.
Carla J. Essenberg
Department of Biology, University of California, Riverside
Many studies have found effects of flower or plant density on pollinator visitation rates at local scales. Much less is known about effects at larger scales, in spite of the potential importance of those effects for plant population and community dynamics. Here I present data from an observational study in which I measured the effects of floral resource density on per-flower visitation rates and visitor species composition at both local (4 m2) and large (12.5 ha) spatial scales, using the annual plant Holocarpha virgata at the UC McLaughlin Reserve. Responses were scale-dependent. Both the total per-flowerhead visitation rate and visitation by the most common visitor, the eucerine bee Melissodes lupina, were positively correlated with large-scale floral resource density as it changed through the season. However, local flowerhead density had no effect on total visitation rates and had a negative effect on visitation by M. lupina. In addition, the species composition of visitors changed with local flowerhead density: visitation by M. lupina declined and visitation by honeybees increased with local density. Because of variation in pollinator quality, shifts in species composition such as those I observed could lead to unexpected changes in pollination success with flower density. The scale-dependence of the effects of floral resource density means that data collected at local scales cannot safely be applied to larger-scale contexts.
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