Aquatic Bioassessment Laboratory

Fish and, California, United States

Aquatic Bioassessment Laboratory

Fish and, California, United States
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Ode P.R.,Aquatic Bioassessment Laboratory | Rehn A.C.,Aquatic Bioassessment Laboratory | Mazor R.D.,Aquatic Bioassessment Laboratory | Mazor R.D.,Southern California Coastal Water Research Project | And 8 more authors.
Freshwater Science | Year: 2016

Many advances in the field of bioassessment have focused on approaches for objectively selecting the pool of reference sites used to establish expectations for healthy waterbodies, but little emphasis has been placed on ways to evaluate the suitability of the reference-site pool for its intended applications (e.g., compliance assessment vs ambient monitoring). These evaluations are critical because an inadequately evaluated reference pool may bias assessments in some settings. We present an approach for evaluating the adequacy of a reference-site pool for supporting biotic-index development in environmentally heterogeneous and pervasively altered regions. We followed common approaches for selecting sites with low levels of anthropogenic stress to screen 1985 candidate stream reaches to create a pool of 590 reference sites for assessing the biological integrity of streams in California, USA. We assessed the resulting pool of reference sites against 2 performance criteria. First, we evaluated how well the reference-site pool represented the range of natural gradients present in the entire population of streams as estimated by sites sampled through probabilistic surveys. Second, we evaluated the degree to which we were successful in rejecting sites influenced by anthropogenic stress by comparing biological metric scores at reference sites with the most vs fewest potential sources of stress. Using this approach we established a reference-site pool with low levels of human-associated stress and broad coverage of environmental heterogeneity. This approach should be widely applicable and customizable to particular regional or programmatic needs. © 2016 by The Society for Freshwater Science.


Howard J.K.,Nature Conservancy | Klausmeyer K.R.,Nature Conservancy | Fesenmyer K.A.,Trout Unlimited | Furnish J.,U.S. Department of Agriculture | And 18 more authors.
PLoS ONE | Year: 2015

The ranges and abundances of species that depend on freshwater habitats are declining worldwide. Efforts to counteract those trends are often hampered by a lack of information about species distribution and conservation status and are often strongly biased toward a few well-studied groups.We identified the 3,906 vascular plants, macroinvertebrates, and vertebrates native to California, USA, that depend on fresh water for at least one stage of their life history. We evaluated the conservation status for these taxa using existing government and non-governmental organization assessments (e.g., endangered species act, NatureServe), created a spatial database of locality observations or distribution information from ∼400 data sources, and mapped patterns of richness, endemism, and vulnerability. Although nearly half of all taxa with conservation status (n = 1,939) are vulnerable to extinction, only 114 (6%) of those vulnerable taxa have a legal mandate for protection in the form of formal inclusion on a state or federal endangered species list. Endemic taxa are at greater risk than non-endemics, with 90% of the 927 endemic taxa vulnerable to extinction. Records with spatial data were available for a total of 2,276 species (61%). The patterns of species richness differ depending on the taxonomic group analyzed, but are similar across taxonomic level. No particular taxonomic group represents an umbrella for all species, but hotspots of high richness for listed species cover 40% of the hotspots for all other species and 58% of the hotspots for vulnerable freshwater species. By mapping freshwater species hotspots we show locations that represent the top priority for conservation action in the state. This study identifies opportunities to fill gaps in the evaluation of conservation status for freshwater taxa in California, to address the lack of occurrence information for nearly 40% of freshwater taxa and nearly 40% of watersheds in the state, and to implement adequate protections for freshwater taxa where they are currently lacking.


Marchetti M.P.,California State University, Chico | Esteban E.,California State University, Chico | Smith A.N.H.,NIWA - National Institute of Water and Atmospheric Research | Pickard D.,Aquatic Bioassessment Laboratory | And 2 more authors.
Journal of Freshwater Ecology | Year: 2011

The Feather River is a large flow-regulated river in the Central Valley of California. The Mediterranean climate of the area imposes a natural flow regime for the region that is characterized by predictable high flows in the winter and spring and low flows in the summer and fall. The Oroville Dam complex on the Feather River has created a permanent low-flow section of the river where a base flow is continuous year round but the natural annual variability of flow has been completely eliminated. We used this modified section of the river to examine the ecological impact that removing natural flow variability has on the macroinvertebrate assemblage and how we might measure such a change if it is present. Specifically, we examined whether biodiversity and community similarity differed between the low- and high-flow sections of the river for both benthic and drifting aquatic invertebrates. Using a modified Surber sampler we collected samples at three distinct time periods within a year (January, April, and July) for both drift and benthic fauna. Our results showed little difference between the low- and high-flow assemblages using common measures of diversity (i.e., species richness and Shannon diversity) and a measure of environmental tolerance (Hilsenhoff biotic index). Yet when we employed a multivariate measure of community similarity (i.e., non-metric multidimensional scaling) and associated statistical tests, we found significant assemblage differences between the low- and high-flow sections of the river. This study suggests that flow disturbance of this sort is likely to alter the macroinvertebrate community in ways that are not easily observed using common ecological metrics. © 2011 Taylor & Francis.


Miller S.,U.S. Department of Interior | Eldred P.,U.S. Department of Interior | Muldoon A.,Oregon State University | Anlauf-Dunn K.,State of Oregon | And 8 more authors.
Environmental Management | Year: 2016

Aquatic monitoring programs vary widely in objectives and design. However, each program faces the unifying challenge of assessing conditions and quantifying reasonable expectations for measured indicators. A common approach for setting resource expectations is to define reference conditions that represent areas of least human disturbance or most natural state of a resource characterized by the range of natural variability across a region of interest. Identification of reference sites often relies heavily on professional judgment, resulting in varying and unrepeatable methods. Standardized methods for data collection, site characterization, and reference site selection facilitate greater cooperation among assessment programs and development of assessment tools that are readily shareable and comparable. We illustrate an example that can serve the broader global monitoring community on how to create a consistent and transparent reference network for multiple stream resource agencies. We provide a case study that offers a simple example of how reference sites can be used, at the landscape level, to link upslope management practices to a specific in-channel response. We found management practices, particularly areas with high road densities, have more fine sediments than areas with fewer roads. While this example uses data from only one of the partner agencies, if data were collected in a similar manner they can be combined and create a larger, more robust dataset. We hope that this starts a dialog regarding more standardized ways through inter-agency collaborations to evaluate data. Creating more consistency in physical and biological field protocols will increase the ability to share data. © 2016 Springer Science+Business Media New York (outside the USA)


Brown L.R.,U.S. Geological Survey | May J.T.,U.S. Geological Survey | Rehn A.C.,Aquatic Bioassessment Laboratory | Ode P.R.,Aquatic Bioassessment Laboratory | And 2 more authors.
Landscape and Urban Planning | Year: 2012

As understanding of the complex relations among environmental stressors and biological responses improves, a logical next step is predictive modeling of biological condition at unsampled sites. We developed a boosted regression tree (BRT) model of biological condition, as measured by a benthic macroinvertebrate index of biotic integrity (BIBI), for streams in urbanized Southern Coastal California. We also developed a multiple linear regression (MLR) model as a benchmark for comparison with the BRT model. The BRT model explained 66% of the variance in B-IBI, identifying watershed population density and combined percentage agricultural and urban land cover in the riparian buffer as the most important predictors of B-IBI, but with watershed mean precipitation and watershed density of manmade channels also important. The MLR model explained 48% of the variance in B-IBI and included watershed population density and combined percentage agricultural and urban land cover in the riparian buffer. For a verification data set, the BRT model correctly classified 75% of impaired sites (B-IBI < 40) and 78% of unimpaired sites (B-IBI. ≥. 40). For the same verification data set, the MLR model correctly classified 69% of impaired sites and 87% of unimpaired sites. The BRT model should not be used to predict B-IBI for specific sites; however, the model can be useful for general applications such as identifying and prioritizing regions for monitoring, remediation or preservation, stratifying new bioassessments according to anticipated biological condition, or assessing the potential for change in stream biological condition based on anticipated changes in population density and development in stream buffers. © 2012.


Mazor R.D.,Southern California Coastal Water Research Project | Mazor R.D.,Aquatic Bioassessment Laboratory | Rehn A.C.,Aquatic Bioassessment Laboratory | Ode P.R.,Aquatic Bioassessment Laboratory | And 6 more authors.
Freshwater Science | Year: 2016

Regions with great natural environmental complexity present a challenge for attaining 2 key properties of an ideal bioassessment index: 1) index scores anchored to a benchmark of biological expectation that is appropriate for the range of natural environmental conditions at each assessment site, and 2) deviation from the reference benchmark measured equivalently in all settings so that a given index score has the same ecological meaning across the entire region of interest. These properties are particularly important for regulatory applications like biological criteria where errors or inconsistency in estimating site-specific reference condition or deviation from it can lead to management actions with significant financial and resource-protection consequences. We developed an index based on benthic macroinvertebrates for California, USA, a region with great environmental heterogeneity. We evaluated index performance (accuracy, precision, responsiveness, and sensitivity) throughout the region to determine if scores provide equivalent ecological meaning in different settings. Consistent performance across environmental settings was improved by 3 key elements of our approach: 1) use of a large reference data set that represents virtually all of the range of natural gradients in the region, 2) development of predictive models that account for the effects of natural gradients on biological assemblages, and 3) combination of 2 indices of biological condition (a ratio of observed-to-expected taxa [O/E] and a predictive multimetric index [pMMI]) into a single index (the California Stream Condition Index [CSCI]). Evaluation of index performance across broad environmental gradients provides essential information when assessing the suitability of the index for regulatory applications in diverse regions. © 2016 by The Society for Freshwater Science.


May J.T.,U.S. Geological Survey | Brown L.R.,U.S. Geological Survey | Rehn A.C.,Aquatic Bioassessment Laboratory | Waite I.R.,U.S. Geological Survey | And 3 more authors.
Environmental Monitoring and Assessment | Year: 2015

We used boosted regression trees (BRT) to model stream biological condition as measured by benthic macroinvertebrate taxonomic completeness, the ratio of observed to expected (O/E) taxa. Models were developed with and without exclusion of rare taxa at a site. BRT models are robust, requiring few assumptions compared with traditional modeling techniques such as multiple linear regression. The BRT models were constructed to provide baseline support to stressor delineation by identifying natural physiographic and human land use gradients affecting stream biological condition statewide and for eight ecological regions within the state, as part of the development of numerical biological objectives for California’s wadeable streams. Regions were defined on the basis of ecological, hydrologic, and jurisdictional factors and roughly corresponded with ecoregions. Physiographic and land use variables were derived from geographic information system coverages. The model for the entire state (n = 1,386) identified a composite measure of anthropogenic disturbance (the sum of urban, agricultural, and unmanaged roadside vegetation land cover) within the local watershed as the most important variable, explaining 56 % of the variance in O/E values. Models for individual regions explained between 51 and 84 % of the variance in O/E values. Measures of human disturbance were important in the three coastal regions. In the South Coast and Coastal Chaparral, local watershed measures of urbanization were the most important variables related to biological condition, while in the North Coast the composite measure of human disturbance at the watershed scale was most important. In the two mountain regions, natural gradients were most important, including slope, precipitation, and temperature. The remaining three regions had relatively small sample sizes (n ≤ 75 sites) and had models that gave mixed results. Understanding the spatial scale at which land use and land cover affect taxonomic completeness is imperative for sound management. Our results suggest that invertebrate taxonomic completeness is affected by human disturbance at the statewide and regional levels, with some differences among regions in the importance of natural gradients and types of human disturbance. The construction and application of models similar to the ones presented here could be useful in the planning and prioritization of actions for protection and conservation of biodiversity in California streams. © 2014, The Author(s).


Mazor R.D.,Southern California Coastal Water Research Project | Mazor R.D.,Aquatic Bioassessment Laboratory | Schiff K.,Southern California Coastal Water Research Project | Ritter K.,Southern California Coastal Water Research Project | And 2 more authors.
Environmental Monitoring and Assessment | Year: 2010

Biomonitoring programs are often required to assess streams for which assessment tools have not been developed. For example, low-gradient streams (slope ≤1%) comprise 20- 30% of stream miles in California and are of particular interest to watershed managers, yet most sampling methods and bioassessment indices in the state were developed in high-gradient systems. This study evaluated the performance of three sampling methods [targeted riffle com- posite (TRC), reach-wide benthos (RWB), and the margin-center-margin modification of RWB (MCM)] and two indices [the Southern California Index of Biotic Integrity (SCIBI) and the ratio of observed to expected taxa (O/E)] in low-gradient streams in California for application in this habitat type. Performance was evaluated in terms of efficacy (i.e., ability to collect enough individuals for index calculation), comparability (i.e., similarity of assemblages and index scores), sensitivity (i.e., responsiveness to disturbance), and precision (i.e., ability to detect small differences in index scores). The sampling methods varied in the degree to which they targeted macroinvertebraterich microhabitats, such as riffles and vegetated margins, which may be naturally scarce in lowgradient streams. The RWB method failed to collect sufficient numbers of individuals (i.e., ≥450) to calculate the SCIBI in 28 of 45 samples and often collected fewer than 100 individuals, suggesting it is inappropriate for low-gradient streams in California; failures for the other methods were less common (TRC, 16 samples; MCM, 11 samples). Within-site precision, measured as the minimum detectable difference (MDD) was poor but similar across methods for the SCIBI (ranging from 19 to 22). However, RWB had the lowest MDD for O/E scores (0.20 versus 0.24 and 0.28 for MCM and TRC, respectively). Mantel correlations showed that assemblages were more similar within sites among methods than within methods among sites, suggesting that the sampling methods were collecting similar assemblages of organisms. Statistically significant disagreements among methods were not detected, although O/E scores were higher for RWB samples than TRC. Index scores suggested impairment at all sites in the study. Although index scores did not respond strongly to several measurements of disturbance in the watershed, percent agriculture showed a significant, negative relationship with O/E scores. © Springer Science+Business Media B.V. 2010.


Mazor R.D.,Southern California Coastal Water Research Project | Mazor R.D.,Aquatic Bioassessment Laboratory | Stein E.D.,Southern California Coastal Water Research Project | Ode P.R.,Aquatic Bioassessment Laboratory | Schiff K.,Southern California Coastal Water Research Project
Freshwater Science | Year: 2014

Nonperennial streams are often excluded from biomonitoring programs because of inadequate knowledge about their biological and hydrological characteristics and variability. The ability to apply bioassessment indices to nonperennial streams would greatly expand the reach of biomonitoring programs. We sampled 12 nonperennial streams (3 of which were minimally stressed) in the San Diego hydrologic region multiple times to assess whether a benthic macroinvertebrate assessment index (the Southern California Index of Biotic Integrity [IBI]) developed for perennial streams could be used in nonperennial streams. We also sampled 3 minimally stressed perennial streams. Continuous water-level loggers and repeated site visits revealed that hydrologic regimes varied considerably among streams. Gradual drying was evident at some streams, and multiple drying/ rewetting events were evident at others. Moreover, streams that were nonperennial in one year were perennial in another. IBI scores from low-stress nonperennial streams were similar to those for low-stress perennial streams, and false indications of impairment (i.e., low IBI scores) were never observed. Furthermore, IBI scores declined as stress increased, suggesting that the IBI responded as expected in nonperennial streams. IBI scores were stable at most sites within and between years, but midsummer declines were observed at high-stress sites. These declines were associated with declines in discharge, fast-water habitat, and increases in sands and fines and macroalgae cover. These findings suggest that an assessment tool developed for perennial streams can be used to assess condition at certain nonperennial streams, and that biomonitoring programs can provide more comprehensive watershed assessments by including nonperennial streams in their surveys. © 2014 by The Society for Freshwater Science.

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