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1.
Alan T. Herlihy Jean Sifneos Chris Bason Amy Jacobs Mary E. Kentula M. Siobhan Fennessy 《Environmental management》2009,44(2):369-377
We sampled 92 wetlands from four different basins in the United States to quantify observer repeatability in rapid wetland
condition assessment using the Delaware Rapid Assessment Protocol (DERAP). In the Inland Bays basin of Delaware, 58 wetland
sites were sampled by multiple observers with varying levels of experience (novice to expert) following a thorough training
workshop. In the Nanticoke (Delaware/Maryland), Cuyahoga (Ohio), and John Day (Oregon) basins, 34 wetlands were sampled by
two expert teams of observers with minimal protocol training. The variance in observer to observer scoring at each site was
used to calculate pooled standard deviations (SDpool), coefficients of variation, and signal-to-noise ratios for each survey. The results showed that the experience level of
the observer had little impact on the repeatability of the final rapid assessment score. Training, however, had a large impact
on observer to observer repeatability. The SDpool in the Inland Bay survey with training (2.2 points out of a 0–30 score) was about half that observed in the other three basins
where observers had minimal training (SDpool = 4.2 points). Using the results from the survey with training, we would expect that two sites assessed by different, trained
observers who obtain DERAP scores differing by more than 4 points are highly likely to differ in ecological condition, and
that sites with scores that differ by 2 or fewer points are within variability that can be attributed to observer differences. 相似文献
2.
Graphical models (alternatively, Bayesian belief networks, path analysis models) are increasingly used for modeling complex
ecological systems (e.g., Lee, In: Ferson S, Burgman M(eds) Quantative methods for conservation biology. Springer, Berlin
Heilin Heideslperk New York, pp.127–147, 2000; Borsuk et al., J Water Res Plann Manage 129:271–282, 2003). Their implementation
in this context leverages their utility in modeling interrelationships in multivariate systems, and in a Bayesian implementation,
their intuitive appeal of yielding easily interpretable posterior probability estimates. However, methods for incorporating
correlational structure to account for observations collected through time and/or space—features of most ecological data—have
not been widely studied; Haas et al. (AI Appl 8:15–27, 1994) is one exception. In this paper, an “isomorphic” chain graph
(ICG) model is introduced to account for correlation between samples by linking site-specific Bayes network models. Several
results show that the ICG preserves many of the Markov properties (conditional and marginal dependencies) of the site-specific
models. The ICG model is compared with a model that does not account for spatial correlation. Data from several stream networks
in the Willamette River valley, Oregon (USA) are used. Significant correlation between sites within the same stream network
is shown with an ICG model. 相似文献
3.
Methods development and use of macroinvertebrates as indicators of ecological conditions for streams in the Mid-Atlantic Highlands Region 总被引:2,自引:0,他引:2
Klemm DJ Blocksom KA Thoeny WT Fulk FA Herlihy AT Kaufmann PR Cormier SM 《Environmental monitoring and assessment》2002,78(2):169-212
The Mid-Atlantic Highlands Assessment (MAHA) included the sampling of macroinvertebrates from 424 wadeable stream sites to determine status and trends, biological conditions, and water quality in first through third order streams in the Mid-Atlantic Highlands Region (MAHR) of the United States in 1993–1995. We identified reference and impaired sites using water chemistry and habitat criteria and evaluated a set of candidate macroinvertebrate metrics using a stepwise process. This process examined several metric characteristics, including ability of metrics to discriminate reference and impaired sites, relative scope of impairment, correlations with chemical and habitat indicators of stream disturbance, redundancy with other metrics, and within-year variability. Metrics that performed well were compared with metrics currently being used by three states in the region: Pennsylvania, Virginia, and West Virginia. Some of the metrics used by these states did not perform well when evaluated using regional data, while other metrics used by all three states in some form, specifically number of taxa, number of EPT taxa, and Hilsenhoff Biotic Index, performed well overall. Reasons for discrepancies between state and regional evaluations of metrics are explored. We also provide a set of metrics that, when used in combination, may provide a useful assessment of stream conditions in the MAHR. 相似文献
4.
R.P.O. Schulte A.R. Melland O. Fenton M. Herlihy K. Richards P. Jordan 《Environmental Science & Policy》2010,13(6):472-484
Depletion of plant-available soil phosphorus (P) from excessive to agronomically optimum levels is a measure being implemented in Ireland to reduce the risk of diffuse P transfer from land to water. Within the Nitrates and Water Framework Directive regulations the policy tool is designed to help achieve good status by 2015 in water bodies at risk from eutrophication. To guide expectation, this study used soil plot data from eight common soil associations to develop a model of Soil Test P (STP) (Morgan's extract) decline following periods of zero P amendment. This was used to predict the time required to move from excessive (Index 4) to the upper boundary of the optimum (Index 3) soil P concentration range. The relative P balance (P balance : Total soil P) best described an exponential decline (R2 = 63%) of STP according to a backwards step-wise regression of a range of soil parameters. Using annual field P balance scenarios (?30 kg P ha?1, ?15 kg P ha?1, ?7 kg P ha?1), average time to the optimum soil P boundary condition was estimated from a range of realistic Total P and STP starting points. For worst case scenarios of high Total P and STP starting points, average time to the boundary was estimated at 7–15 years depending on the field P balance. However, uncertainty analysis of the regression parameter showed that variation can be from 3 to >20 years. Combined with variation in how soil P source changes translate to resulting P delivery to water bodies, water policy regulators are advised to note this inherent uncertainty from P source to receptor with regard to expectations of Water Framework Directive water quality targets and deadlines. 相似文献
5.
6.
Robert M. Hughes Alan T. Herlihy Philip R. Kaufmann 《Journal of the American Water Resources Association》2010,46(4):792-806
Hughes, Robert M., Alan T. Herlihy, and Philip R. Kaufmann, 2010. An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States. Journal of the American Water Resources Association (JAWRA) 46(4): 792-806. DOI: 10.1111/j.1752-1688.2010.00455.x Abstract: Assessment of stream physical habitat condition is important for evaluating stream quality globally. However, the diversity of metrics and methods for assessing physical habitat condition confounds comparisons among practitioners. We surveyed 51 previously sampled stream sites (0.0-6.3 m wide) located in regions of row-crop agriculture in Oregon, California, North Dakota, South Dakota, Nebraska, Iowa, Minnesota, Pennsylvania, Maryland, and West Virginia to evaluate the comparability of four indexes of physical habitat condition relative to each other. We also compared the indexes to previously calculated indexes of fish and macroinvertebrate condition. The physical habitat indexes included the Stream Visual Assessment Protocol Version 2 of the Natural Resources Conservation Service, the qualitative habitat evaluation index of the Ohio Environmental Protection Agency, the rapid bioassessment protocol of the United States Environmental Protection Agency (USEPA), and a qualitative physical habitat index based on USEPA quantitative physical habitat measurements. All four indexes were highly correlated with each other, but low-to-moderately correlated with biotic index scores for fish and macroinvertebrate assemblages. Moderately high correlations occurred between some macroinvertebrate biotic index scores and quantitative metrics. We conclude that additional research is needed to increase the predictive and diagnostic capabilities of qualitative physical habitat indexes. 相似文献
7.
Designing a Spatially Balanced, Randomized Site Selection Process for Regional Stream Surveys: The EMAP Mid-Atlantic Pilot Study 总被引:8,自引:0,他引:8
Alan T. Herlihy David P. Larsen Steven G. Paulsen N. Scott Urquhart Barbara J. Rosenbaum 《Environmental monitoring and assessment》2000,63(1):95-113
In 1993, the U.S. Environmental Protection Agency (EPA), as part of the Environmental Monitoring and Assessment Program (EMAP), initiated a sample survey of streams in the mid-Atlantic. A major objective of the survey was to quantify ecological condition in wadeable streams across the region. To accomplish this goal, we selected 615 stream sites using a randomized sampling design with some restrictions. The design utilized the digitized stream network taken from 1:100,000-scale USGS topographic maps as the sample frame. Using a GIS, first- through third-order (wadeable) stream segments in the sample frame were randomly laid out in a line and sampled at fixed intervals after a random start. We used a variable probability approach so that roughly equal numbers of first-, second-, and third-order stream sites would appear in the sample. The sample design allows inference from the sample data to the status of the entire 230,400 km of wadeable stream length in the mid-Atlantic study area. Of this mapped stream length, 10% was not in the target population because no stream channel existed (4%), the stream channel was dry (5%), or the stream was not wadeable (1%). We were unable to collect field data from another 10% of the mapped stream length due to lack of access (mostly landowner denials). Thus, the field data we collected at 509 sites allows inference to the ecological condition for 184,600 km of the mapped stream length in the region. 相似文献
8.
Development and evaluation of a Macroinvertebrate Biotic Integrity Index (MBII) for regionally assessing Mid-Atlantic Highlands Streams 总被引:5,自引:0,他引:5
Klemm DJ Blocksom KA Fulk FA Herlihy AT Hughes RM Kaufmann PR Peck DV Stoddard JL Thoeny WT Griffith MB Davis WS 《Environmental management》2003,31(5):0656-0669
The Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the
Mid-Atlantic Highlands region (MAHR) by the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment
Program (EMAP). Over 100 candidate metrics were evaluated for range, precision, responsiveness to various disturbances, relationship
to catchment area, and redundancy. Seven metrics were selected, representing taxa richness (Ephemeroptera richness, Plecoptera
richness, Trichoptera richness), assemblage composition (percent non-insect individuals, percent 5 dominant taxa), pollution
tolerance [Macroinvertebrate Tolerance Index (MTI)], and one functional feeding group (collector-filterer richness). We scored
metrics and summed them, then ranked the resulting index through use of independently evaluated reference stream reaches.
Although sites were classified into lowland and upland ecoregional groups, we did not need to develop separate scoring criteria
for each ecoregional group. We were able to use the same metrics for pool and riffle composite samples, but we had to score
them differently. Using the EMAP probability design, we inferred the results, with known confidence bounds, to the 167,797
kilometers of wadeable streams in the Mid-Atlantic Highlands. We classified 17% of the target stream length in the MAHR as
good, 57% as fair, and 26% as poor. Pool-dominated reaches were relatively rare in the MAHR, and the usefulness of the MBII
was more difficult to assess in these reaches. The process used for developing the MBII is widely applicable and resulted
in an index effective in evaluating region-wide conditions and distinguishing good and impaired reaches among both upland
and lowland streams dominated by riffle habitat. 相似文献
9.
The number of sites sampled must be considered when determining the effort necessary for adequately assessing taxa richness
in an ecosystem for bioassessment purposes; however, there have been few studies concerning the number of sites necessary
for bioassessment of large rivers. We evaluated the effect of sample size (i.e., number of sites) necessary to collect vertebrate
(fish and aquatic amphibians), macroinvertebrate, and diatom taxa from seven large rivers in Oregon and Washington, USA during
the summers of 2006–2008. We used Monte Carlo simulation to determine the number of sites needed to collect 90–95% of the
taxa 75–95% of the time from 20 randomly located sites on each river. The river wetted widths varied from 27.8 to 126.0 m,
mean substrate size varied from 1 to 10 cm, and mainstem distances sampled varied from 87 to 254 km. We sampled vertebrates
at each site (i.e., 50 times the mean wetted channel width) by nearshore-raft electrofishing. We sampled benthic macroinvertebrates
nearshore through the use of a 500-μm mesh kick net at 11 systematic stations. From each site composite sample, we identified
a target of 500 macroinvertebrate individuals to the lowest possible taxon, usually genus. We sampled benthic diatoms nearshore
at the same 11 stations from a 12-cm2 area. At each station, we sucked diatoms from soft substrate into a 60-ml syringe or brushed them off a rock and rinsed them
with river water into the same jar. We counted a minimum of 600 valves at 1,000× magnification for each site. We collected
120–211 diatom taxa, 98–128 macroinvertebrate taxa, and 14–33 vertebrate species per river. To collect 90-95% of the taxa
75-95% of the time that were collected at 20 sites, it was necessary to sample 11–16 randomly distributed sites for vertebrates,
13–17 sites for macroinvertebrates, and 16–18 sites for diatoms. We conclude that 12–16 randomly distributed sites are needed
for cost-efficient sampling of vertebrate richness in the main stems of our study rivers, but 20 sites markedly underestimates
the species richness of benthic macroinvertebrates and diatoms in those rivers. 相似文献
10.
Keith N. Eshleman Robert H. Gardner Steven W. Seagle Nancy M. Castro Daniel A. Fiscus James R. Webb James N. Galloway Frank A. Deviney Alan T. Herlihy 《Environmental monitoring and assessment》2000,63(1):187-197
The objective of this research project is to develop, test, validate, and demonstrate an analytical framework for assessing regional-scale forest disturbance in the mid-Atlantic region by linking forest disturbance and forest nitrogen export to surface waters at multiple spatial scales. It is hypothesized that excessive nitrogen (N) leakage (export) from forested watersheds is a potentially useful, integrative "indicator" of a negative change in forest function which occurs in synchrony with changes in forest structure and species composition. Our research focuses mainly on forest disturbance associated with recent defoliations by the gypsy moth larva (Lymantria dispar) at spatial scales ranging from small watersheds to the entire Chesapeake Bay watershed. An approach for assessing the magnitude of forest disturbance and its impact on surface water quality will be based on an empirical model relating forest N leakage and gypsy moth defoliation that will be calibrated using data from 25 intensively-monitored forested watersheds in the region and tested using data from more than 60 other forested watersheds in Virginia. Ultimately, the model will be extended to the region using spatially-extensive data describing: 1) the spatial distribution of dominant forest types in the mid-Atlantic region based on both remote sensing imagery and plot-scale vegetation data; 2) the spatial pattern of gypsy moth defoliation of forested areas from aerial mapping; and 3) measurements of dissolved N concentrations in streams from synoptic water quality surveys. 相似文献