Since the Reserve came under management by the University of California Natural Reserve System and the Berkeley campus, an active program of university level research has produced over 135 publications, including 11 Ph.D. dissertations (see http://angelo.berkeley.edu/publications.htm for a nearly complete list). Currently, 22 faculty from 12 universities or colleges are engaged in research at the Angelo Reserve, along with about 40 graduate and 25 undergraduate students.
In addition to a number of ongoing individual projects, three collaborative programs support current research. These are complementary and synergistic, as findings from any one of these areas of inquiry will strengthen research in the others. The three programs are the Keck Hydrowatch, the Desktop Watershed Integrative Project of the National Center for Earth Surface Dynamics (NCED), and a multi-university NSF project investigating landscape, food web, and stoichiometric effects on nutrient spiraling down channel networks.
In 2002, the National Center for Earth Surface Dynamics (NCED), an NSF Science and Technology Center, chose the Angelo Reserve as its first collaborative field site. Since that time, earth scientists, engineers, and ecologists have been collaborating in studies that begin with high resolution LiDar digital elevation data, and attempt to link ecology and landscapes to forecast responses by both to change. This effort (one of three large integrated projects at NCED) has been designated “Desktop Watersheds”, and is under the leadership of Bill Dietrich. Other faculty involved are Jill Banfield and Mary Power ( Berkeley), and Miki Hondzo, Jacques Finlay, Efi Foufoula-Georgiou, and Chris Paola (Univ. of Minnesota). We have been mapping ecosystem processes (e.g. denitrification, stream metabolism), as well as distributions, abundances, performances, and interactions of key organisms through the drainage network, and investigating environmental controls of these patterns and processes. We are attempting prediction through two routes. One is empirical, to use engineering approaches (e.g., statistical upscaling and dimensionless analysis) to discover scale-free predictors of biomass or process intensity that can be read or inferred from topographic maps. The other approach uses targeted experiments to determine why changes in ecological regimes or ecosystem processes occur along environmental gradients (e.g. down drainage networks or across valleys), then combines process-based understanding with modeling to predict how thresholds between these regimes would shift with land use, climate, or biotic change.
Former NCED postdocs John Schade and Jill Welter (now faculty at St. Olaf’s and St. Catherine’s Colleges, respectively), with Steve Thomas (U. Nebraska), Jacques Finlay (U. Minnesota) and Mary Power (Berkeley) were awarded a grant from the NSF Ecosystems Panel “Coupling consumer-resource interactions and stream spiraling in a stream network.” This funds faculty, graduate and undergraduate research examining how trophic interactions (food chain length and the degree of stoichiometric imbalance between consumers and resources) combine with environmental factors mediated by drainage network position to affect stream spiraling. Spiraling is the model framework used to investigate nutrient fluxes and retention in watersheds. Short spiral lengths correspond to rapid nutrient uptake and assimilation for biological productivity, and decreased rates of export of nutrients from catchments. Both outcomes are generally favorable for watershed and water quality management.
Keck Hydrowatch, Elder Creek watershed. With funding from the Keck Foundation, Berkeley professors Inez Fung, Todd Dawson, Bill Dietrich, Jim Kirchner, Ron Cohen, and David Culler are using the 17 km2 Elder Creek watershed as a testbed to develop instrumentation and methods for tracing the life cycle of water, as it moves inland from the ocean as fog or precipitation, is intercepted by vegetation and land surfaces, and travels by various surface and subsurface paths to emerge as river runoff and travel back to the ocean. The details, scales and rates of the processes mediating this journey are now needed for Global Circulation Models, and for downscaling to anticipate effects of climate change on watershed ecosystems. Todd Dawson is instrumenting trees in various landscape position to develop their use as indicators of changing soil moisture, a critical variable that proves extremely challenging to monitor, particularly in landscapes with deeply fractured bedrock.
Future research directions (hopes and dreams)
“Desktop watersheds” Predict the Future of the Eel River (or similar basins) by linking landscapes and ecosystems, using rapid interation between map-based predictions about the status of the environment or ecosystems at specified sites, and field work motivated by such hypotheses.
“Towards predictive mapping”. Develop a tool for ecological forecasting by analyzing why ecological regimes change across certain landscape thresholds (e.g., down drainage networks), then using dem models to forecast how these boundaries would shift spatially with climate, land use, or biotic change.
Coordinating with TNC and USFS watershed studies and monitoring programs throughout the California North Coast (subject of discussion).
Research projects roughly categorized by landscape position
Upland Terraces and Hillslopes.
Strath terrace formation. Theodore Fuller and Leslie Perg (University of Minnesota) are studying the elevation of the bedrock strath surface and the internal stratigraphyof deposits overlying the strath surface in order to develop a qualitative analysis of terraces in the basin and to refine a model of terrace formation.
Conifer-Endophyte Investigation. Fungal endophytes are present in the foliar tissues of all studied conifers and yet their influence of leaf physiology is virtually unknown. Emily Limm (UC Berkeley) is investigating the influence fungal endophytes have on leaf function in redwood and Douglas fir trees, and the influence of leaf age on endophyte assemblages.
Long term erosion rates from different sub-basins in the South Fork Eel network. Jane Staiger and Leslie Perg (U. Minnesota) have used cosmogenic isotope data to estimate erosion rates from catchments draining into the South Fork Eel, and will relate these to topography, aspect, vegetation cover, and land use.
Longitudinal gradients down the channel network
Whole stream ecosystem metabolism. Camille McNeely (Eastern Washington State University), Jacques Finlay, Miki Hondzo (U. Minnesota) and Mary Power (UC Berkeley) are measuring instream metabolism at reaches distributed over the drainage network to provide a foundation for other studies relating food web structure or ecosystem fluxes to longitudinal environmental gradients.
Carbon sources to river food webs. Jacques Finlay, Camille McNeely, Sandra Clinton (Univ. North Carolina, Charlotte), Mike Limm, Wendy Palen, and Mary Power are using carbon and hydrogen stable isotopes to determine the relative contributions of terrestrial and aquatic primary production to food web members down the river network. Peter Weber (Lawrence Berkeley Laboratories) has collaborated with this group to analyze carbon isotopes in steelhead otoliths from various network positions.
Grazer carbon sources and impacts on algal accrual down drainage networks. Camille McNeely, Jacques Finlay, and Mary Power have studied how changing carbon sources down drainage networks affect food web interactions among armored caddisflies, midges and mayflies that are more vulnerable to predators, and invertebrate and vertebrate predators at different drainage network positions. McNeely discovered a drainage area threshold (2 km2) below which caddisflies limit algal accrual. At higher network positions, caddisflies do not limit algae, even though they continue to derive their carbon entirely from algal sources. (McNeely et al. in press, McNeely and Power, in press).
Channel environmental predictors of hot spots of denitrification down the river network. Ben O’Connor, Miki Hondzo, Jacques Finlay (Univ. Minnesota) and collaborators have documented considerable fine scale (within reach) heterogeneity in denitrification potential related to the abundance-activity of microbial nirK genes that encode for nitrite reductase. Hot spots of denitrification in the field were predictable from scaled dimensionless groupings of stream hydraulic parameters, benthic organic matter, nitrate, and dissolved oxygen flux (O’Connor et al. 2006).
Periphyton distribution, radiation, hydraulics, and nutrient fluxes. Miki Hondzo, Tanya Warnaars, (University of Minnesota) and Mary Power surveyed periphyton accrual and nutrient fluxes at various network positions to develop dimensionless scaling relationships between environmental conditions mediated by hydraulic geometry and fundamental niche requirements of algae. (Warnaars et al., in revision).
Effects of landscape position, food webs, and nutrient stoichiometry on stream nutrient spiraling. John Schade (St. Olaf’s University), Jill Welter (St. Catherine’s University), Steve Thomas (Univ. of Nebraska), Mary Power and Power lab grad students Mike Limm and Maria Goodrich (UC Berkeley), and Jacques Finlay, and former post doc Camille McNeely and lab grad student Jim Hood, (Univ. of Minnesota) are studying how nutrient uptake dynamics (‘spiral length’) responds to landscape and food web controls, particularly the stoichiometric composition of consumers and resources, down the South Fork Eel drainage.
Effects of resource quality on stream consumer stoichiometry
Jim Hood and Jacques Finlay (University of Minnesota), John Schade (St. Olaf’s University), Camille McNeely (EWU) and others are investigating how consumer identity, ontongeny, and resource quality influence the nutrient ratios of aquatic invertebrates. Variation in surface vs. groundwater sources in streams, and strong effects on N fixers lower in the watershed are emerging as primary influences on biogeochemical composition of nutrients in stream networks. Cailin Orr is examining the effect of periphyton and detrital organic matter on water and nutrient exchange with the streambed experiments designed to test hypotheses generated in recent flume studies in Minnesota.
Bacterial-Algal Interactions in Epilithic Biofilms Maria Goodrich (UC Berkeley) is manipulating factors (nutrients, carbon supply) influencing the interactions between biofilm-associated algae and heterotrophic bacteria down river drainage networks in the Angelo Coast Range Reserve.
Water flowpaths, channel morphology and stream ecosystem processes as controls of nutrient sources and sinks in stream networks. Jacques Finlay and Cailin Orr (University of Minnesota), John Schade (St. Olaf’s University), Steve Thomas (Univ. of Nebraska), and others are examining the factors that determine concentrations and flux of nutrients in streams.
Terrace meadow studies
South Meadow precipitation manipulations For the past 6 years, Blake Suttle (U.C. Berkeley) has manipulated the amount and timing of rainfall to match predictions pf leading global circulation models for the California North Coast. His experiments in large grassland plots test predictions about the responses of food webs in these grasslands to alternative predictive climate change scenarios. Blake and colleagues find that the direct responses by grassland species to climate change are reversed within a few years by feedbacks mediated through community and ecosystem level interactions (Suttle et al., Science 2007). Collaborators: Meredith Thomsen, Univ. Wisconsin, LaCrosse, Mary Power, U.C. Berkeley.
Food quality of plants for grasshoppers. Blake Suttle and Joe Sapp have studied the growth rates of grasshoppers, the dominant meadow herbivore, on mixed and single species of various common meadow forbs. In contrast to most diet studies, plants were left to grow in their natural environments, and hand thinned and weeded to establish different diet treatments, eliminating artifactual effects of clipping stress on plant food quality.
Solutes, soil production, and biota. In mountainous western landscapes, such as in the Angelo Coast Range Reserve (ACCR), nitrogen is the major nutrient limiting primary and secondary production in both watershed and channel ecosystems. genomics (Jill Banfield lab in EPS at Berkeley: Karelyn Cruz (UC Berkeley) is carrying out a survey of nitrogen fixing microbial diversity. Anna Rosling is studying fungal responses to rainfall manipulations and phosphorus availability, sampling at the South Meadow to isolate fungi from deep soil and weathered bedrock (Rosling et al. 2007).
Lizard population dynamics and distributions among riparian versus meadow habitats. John Sabo (Arizona State University) is comparing the abundance of western fence lizards (Sceloporus occidentalis) and western sagebrush lizards (S. graciosus) on cobble bar and meadow "island" habitats within the SF Eel watershed.
Are the Acroceridae pollinators or nectar scavengers? Christopher J Borkent (Royal British Columbia Museum) is assessing what flower visiting behaviors of Eulonchus species (Acroceridae, small-headed flies) show under natural conditions and how effectively they pollinate compared to other pollinators.
Main channel studies
Long term monitoring of Rana boylii. Sarah J Kupferberg, with Wendy Palen, Mary Power, and others, is carrying out a long term monitoring study, now in its 16th year, of Foothill Yellow Legged frogs (Rana boylii) on the Angelo Reserve. Her spring census of R. boylii egg masses over a 5 km reach of the South Fork Eel River and 1 km of Ten Mile Creek is closely related to the number of breeding females within that habitat.
Long term monitoring of exotic and native fishes. Since 1994, Angelo researchers have snorkel censused 14-16 large pools over a 7 km reach of river, from 1 km below Hunter’s Pool to Kraal’s pool upstream of the Angelo Reserve. We roughly estimate size distributions and abundances of native and exotic fish, bullfrog tadpoles, and native turtles.
Effects of flood versus drought on food web reassembly in Mediterranean rivers. Mary Power, Bill Dietrich, and Michael Parker have analyzed 18 years of hydrologic and algal data and results from 5 seasons of experiments examining hydrologic and food web controls of summer algal accrual in the South Fork Eel River. Flood scour resets food webs with earlier successional grazers that can be controlled by fish and other predators. In the absence of scouring floods, predator resistant grazers eliminate dynamic linkages between predators and algal accrual, and curtail energy flow to fish and other consumers at higher food web positions (Power et al., in revision).
Sediment dynamics in managed ecosystems: linking physical processes to biological consequences. Bret C Harvey, (USFS, Redwood Sciences Lab, Arcata) is collecting aquatic invertebrate samples (including evening drift) and physical data for hydraulic modeling of food availability for salmonids in the South Fork Eel River above Elder Creek. These data will contribute to his parameterization of Individual Based models of salmonid performance in various types of habitat.
Effects of fine bed sediments on juvenile steelhead and food webs supporting them
Mary Power, Blake Suttle, Camille McNeely, and Jonathan Levine investigated the impacts of deposited fine sediment in experiments in which juvenile steelhead reared with increasing levels of embeddedness (from zero to 100%). Steelhead growth decreased linearly and survival decreased in an accelerated nonlinear fashion with increasing sediment, due to decreased food availability coupled with increasing metabolic costs of increased activity and intraspecific aggression. The invertebrate community changed from one of more available prey to one of unavailable burrowing taxa with higher levels of deposited fine sediment. Steelhead in more heavily embedded channels showed more continuous movement and aggression and higher incidence of injury. (Suttle et al. 2004).
Effects of fine bed sediments on Pacific lamprey larvae Mike Limm and Wendy Palen have carried out similar experiments, and found that juvenile lamprey growth increases linearly with the concentration of fine deposited sediments—the opposite result from that found for juvenile steelhead.
Carbon sources and ecosystem effects of Pacific lamprey larvae. Mike Limm (UC Berkeley) is investigating the role of Pacific lamprey in the South Fork Eel river food web to shed light on their roles in benthic detrital dynamics, and their interactions with other benthic organisms. He is also carrying out diet and isotope analyses to examine longitudinal variation in their carbon sources.
Channel geomorphic response to White Alder recruitment. Christopher DiVittorio (UC Berkeley), with Mary Power, Bill Dietrich, Chris Paola (Univ. Minnesota), Jesse DeWolf and Shayla Workman (Branscomb, CA) have surveyed ridge-to-ridge cross sections across the river through reaches where a dense cohort of White Alders (Alnus rhombifolia) recruited in 2000, and through control reaches without alders, to investigate the effects of alder recruitment on channel morphological change and food web structure in the South Fork Eel River.
Riparian studies and River-Forest Exchange
Biogeochemical effects of alders in a stream network. Jill R. Welter (St. Catherine’s College) is exploring linkages between the spatial distribution of alders in the South Fork Eel River watershed, foliar and phloem quality, terrestrial herbivore performance, and in-stream respiration and decomposition of alder leaves.
Import and export of arthropods from watershed streams. Camille McNeely (University of Minnesota) is measuring the biomass of arthropods, plant material, and other biomass entering streams in the South Fork Eel River watershed, and the biomass and abundance of aquatic insects emerging from the streams.
Carbon flux into tributaries of the South Fork of the Eel River. Mike Limm (UC Berkeley), Camille McNeely, Jim Hood and Jacques Finlay (University of Minnesota) are investigating organic carbon flux into the tributaries of the South Fork of the Eel River, and the fate of terrestrial organic matter introduced to streams. Organic matter inputs to streams have been measured for ~2 years. Measurements of fluxes and retention of fine particulate organic matter and leaves are ongoing using routine sampling and estimation of distance traveled downstream by marker leaves introduced experimentally to different network positions. The fate of terrestrial organic matter is examined through whole stream respiration measurements (see “Longitudinal gradients”), decomposition experiments, and stable isotope tracing
Importance of emerging aquatic insects to terrestrial consumers. Mary Power, Bill Rainey, John Sabo, Michael Parker, and Jonna Smythe have studied the responses to “bug flux” from the river corridor by bats, lizards, filmy dome spiders, wolf spiders, and tetragnathid spiders. (Power et al. 2004, Power and Rainey 2000, Sabo and Power, 2004a,b).
Angelo and beyond….
Phytophthora ramorum distribution in coastal California watersheds.
The Angelo reserve is part of Shannon Murphy's (UC Davis) network of sampling locations that will monitor Phytophthora ramorum infestation, causal agent of Sudden Oak Death.
Phylogeography of banana slugs (Ariolimax spp.) John S Pearse (UC Santa Cruz) is studying the distribution of banana slugs on the west coast of North America to determine the species boundaries, which reflect vicariant events.
Chytridiomycosis infection status of Rana boylii and R. catesbeiana. A fungal pathogen, Batrachochytrium dendrobatidis, causing the disease chytridiomycosis, has been found in association with mass die-offs of frogs. Vance Vredenburg (UC Berkeley) will test the infection status of amphibian species at the Angelo reserve.
Runoff and suspended sediment export in Northern California rivers. Tom Lisle, Bret Harvey, and Rand Ead have added the South Fork Eel River at our Branscomb gage site to their network of sites where they are monitoring suspended sediments in rivers as a function of flow discharge.
