Grantee Research Project Results
2006 Progress Report: Quantifying Stream Ecosystem Resilence To Identify Thresholds For Salmon Recovery
EPA Grant Number: R832439Title: Quantifying Stream Ecosystem Resilence To Identify Thresholds For Salmon Recovery
Investigators: Merenlender, Adina , Kondolf, Matt , Resh, Vincent
Current Investigators: Merenlender, Adina , Kondolf, Matt , Moyle, Peter , Resh, Vincent
Institution: University of California - Berkeley
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2006 through June 30, 2007 (Extended to August 31, 2008)
Project Period Covered by this Report: July 1, 2006 through June 30, 2007
Project Amount: $299,922
RFA: Exploratory Research: Understanding Ecological Thresholds In Aquatic Systems Through Retrospective Analysis (2004) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water
Objective:
The objective of this research project is to increase our understanding of stream resilience and identify flow thresholds beyond which changes in macroinvertebrate community structure and decline in salmonid survivorship may result. To do this we proposed to use retrospective data to develop models based on the relationship among physical and biological variables that interact on different temporal and spatial scales in California’s North Coast Mediterranean-climate watersheds.
Our research will provide the preliminary evaluations necessary for identifying how and where ecosystems could be recovered by reducing the stress human systems place on stream flow, and where restoration practices are likely to achieve desired results. Working with stakeholders, we are using this information to help develop best management guidelines so that vineyard managers can minimize the impacts of pumping stream water during the dry season. Because increasing water storage during the winter is often the only alternative to removing stream water during the dry season, we are also examining the potential consequences of appropriating additional winter storage on winter flows that can impact the ability for salmonids to move up to their spawning grounds.
Our methods involve: (1) creating models of natural flow regime on a daily scale by using historical stream flow and rainfall data; (2) creating spatially explicit estimates of water demand in each stream in the study region over time; (3) identifying reaches where stream flow may be adversely affected by human water extraction; and (4) exploring the potential impacts that spring and summer stream flow dynamics have had on stream biota, evaluated using long-term fish and macroinvertebrate monitoring data. The data available for quantifying the variables described above are not perfect, but sufficient data do exist for estimating when human demand may lower resilience thresholds, leading to alternative states of biotic interactions in small coastal California streams.
Progress Summary:
During Year 1 of this research, we have made progress on all four tasks listed above for several upstream tributaries in North Coast California. We examined a 20-year data set of fish and macroinvertebrate abundance records from two streams in Lake and Napa Counties to explore the influence of long-term natural variability in stream flow on the aquatic biota there. The pattern of precipitation, and thus flow conditions, observed during the study period allowed for the examination of the effects of drought and drought-recovery on both fish and macroinvertebrate populations. Although there were differences in response-times to interannual flow variability, both macroinvertebrate communities and fish populations exhibited similar responses to changes in flow based on their life history and functional characteristics. Furthermore, interannual variability in fish populations is also linked to year-to-year changes in macroinvertebrate community composition. Furthermore, these studies underscore the role of stochastic processes and the importance of understanding the underlying causes of natural variability when designing and implementing long-term monitoring programs or any multiyear ecological studies.
In Sonoma County, we are exploring the relationship between anadromous salmonid populations, natural stream flow variability, and agricultural water use in five upland tributaries of the Russian River where 12 years of salmonid survivorship data are available. We have begun to estimate the flow regime for these streams so that we can ultimately examine the role that flow conditions during the summer may have had on survivorship. To do this we used precipitation records at nearby weather stations to derive regression models to predict mean daily flow as a function of rainfall over various antecedent periods. Data indicate that the models created a reliable estimate of flows in both spring and summer.
To provide an initial characterization of water demand for these streams, we used a GIS to arrange water rights records by catchment on a daily scale. We used these data to compare daily-scale expressions of surface water demand to median-year flow regime representations (derived from flow records of median annual discharge years at historical U.S. Geological Survey gauges) for dry, average, and wet watersheds. We found that during the summer, approved water rights exceeded the estimated stream flow in the tributaries that we are studying during low, average, and sometimes high rainfall years.
The progress we have made to date has established the framework to build models that will quantify the tradeoffs for both the wine grape growers and salmonid recovery efforts between storing more water in the winter and pumping on demand year round to meet agricultural and residential water needs.
Future Activities:
Our future efforts will focus on merging existing biological data describing salmonid populations with stream hydrology and expressions of surface water demand. The hydrology components described above will be adjusted to predict stream flow in the primary study region over the 10-year period during which salmonid survivorship surveys were conducted, and offer more detailed descriptions of how human water demand influences stream hydrology through the wine grape growing season.
We will then be able to use regression analysis to explore if the stream location, habitat type, stream flow, number of days that required irrigation for vineyard heat protection, and riparian cover can explain juvenile steelhead survivorship and possibly recruitment in the spring for the 10-year period that data exists.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 7 publications | 5 publications in selected types | All 5 journal articles |
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Beche LA, McElravy EP, Resh VH. Long-term seasonal variation in the biological traits of benthic-macroinvertebrates in two Mediterranean-climate streams in California, U.S.A. Freshwater Biology 2006;51(1):56-75. |
R832439 (2006) R832439 (2008) |
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Supplemental Keywords:
environmental flow, ecological resilience, anadromous salmonids, threshold, surface water abstraction, inter-annual variability, benthic macroinvertebrate, water management, nonlinear ecosystem dynamics, aquatic ecology, coupled human and natural systems, cumulative watershed effects,, RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Aquatic Ecosystem, Aquatic Ecosystems & Estuarine Research, Ecological Risk Assessment, Ecology and Ecosystems, Environmental Monitoring, environmental history, species interaction, water quality, aquatic ecosystem restoration, anthropogenic impact, estuarine research, ecological thresholds, stream habitat, ecosystem indicators, modeling ecosystem change, salmon recovery, ecosystem response, ecosystem stress, riverine ecosystems, trophic interactions, aquatic ecosystemsRelevant Websites:
http://nature.berkeley.edu/ihrmp Exit
http://www.russianriverwatershed.net/ Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.