Variability in stream macroinvertebrates at multiple spatial scales

SUMMARY 1. We intensively sampled 16 western Oregon streams to characterize: (1) the variability in macroinvertebrate assemblages at seven spatial scales; and (2) the change in taxon richness with increasing sampling effort. An analysis of variance (ANOVA) model calculated spatial variance components for taxon richness, total density, percent individuals of Ephemeroptera, Plecoptera and Trichoptera (EPT), percent dominance and Shannon diversity. 2. At the landscape level, ecoregion and among-streams components dominated variance for most metrics, accounting for 43‐72% of total variance. However, ecoregion accounted for very little variance in total density and 36% of the variance was attributable to differences between streams. For other metrics, variance components were more evenly divided between stream and ecoregion effects. 3. Within streams, approximately 70% of variance was associated with unstructured local spatial variation and not associated with habitat type or transect position. The remaining variance was typically split about evenly between habitat and transect. Sample position within a transect (left, centre or right) accounted for virtually none of the variance for any metric. 4. New taxa per stream increased rapidly with sampling effort with the first four to eight Surber samples (500 ‐1000 individuals counted), then increased more gradually. After counting more than 50 samples, new taxa continued to be added in stream reaches that were 80 times as long as their mean wetted width. Thus taxon richness was highly dependent on sampling effort, and comparisons between sites or streams must be normalized for sampling effort. 5. Characterization of spatial variance structure is fundamental to designing sampling programmes where spatial comparisons range from local to regional scales. Differences in metric responses across spatial scales demonstrate the importance of designing sampling strategies and analyses capable of discerning differences at the scale of interest.

[1]  A. Herlihy,et al.  Stream chemistry in the eastern United States: 1. Synoptic survey design, acid‐base status, and regional patterns , 1991 .

[2]  J. Meyer.  Stream Health: Incorporating the Human Dimension to Advance Stream Ecology , 1997, Journal of the North American Benthological Society.

[3]  M. Wiley,et al.  PATHOGEN OUTBREAKS REVEAL LARGE‐SCALE EFFECTS OF COMPETITION IN STREAM COMMUNITIES , 1997 .

[4]  V. Resh.  Sampling Variability and Life History Features: Basic Considerations in the Design of Aquatic Insect Studies , 1979 .

[5]  Richard H. Norris,et al.  Biological Monitoring: The Dilemma of Data Analysis , 1995, Journal of the North American Benthological Society.

[6]  Michael T. Barbour,et al.  Rapid bioassessment protocols for use in streams and rivers , 1989 .

[7]  R. Sparks,et al.  THE NATURAL FLOW REGIME. A PARADIGM FOR RIVER CONSERVATION AND RESTORATION , 1997 .

[8]  Hiram W. Li,et al.  Cumulative Effects of Riparian Disturbances along High Desert Trout Streams of the John Day Basin, Oregon , 1994 .

[9]  C. Frissell,et al.  A hierarchical framework for stream habitat classification: Viewing streams in a watershed context , 1986 .

[10]  F. W. Preston.  The Commonness, And Rarity, of Species , 1948 .

[11]  O. Arrhenius,et al.  Species and Area , 1921 .

[12]  Barbara J. Downes,et al.  Spatial variation in the distribution of stream invertebrates: implications of patchiness for models of community organization , 1993 .

[13]  V. Resh,et al.  Variability in Macroinvertebrate Rapid-Bioassessment Surveys and Habitat Assessments in a Northern California Stream , 1995, Journal of the North American Benthological Society.

[14]  James R. Karr,et al.  Assessing biological integrity in running waters : a method and its rationale , 1986 .

[15]  L. Johnson,et al.  Catchment and reach‐scale properties as indicators of macroinvertebrate species traits , 1997 .

[16]  P. McCullagh,et al.  Generalized Linear Models , 1992 .

[17]  G. Minshall,et al.  The River Continuum Concept , 1980 .

[18]  J. McAuliffe.  Competition for Space, Disturbance, and the Structure of a Benthic Stream Community , 1984 .

[19]  S. M. Glenn,et al.  EFFECTS OF ORGANISMAL AND DISTANCE SCALING ON ANALYSIS OF SPECIES DISTRIBUTION AND ABUNDANCE , 1997 .

[20]  A. Magurran.  Ecological Diversity and Its Measurement , 1988, Springer Netherlands.

[21]  D. Hart,et al.  Habitat diversity and the species—area relationship: alternative models and tests , 1991 .

[22]  C. Townsend,et al.  Scales and Causes of Patchiness in Stream Invertebrate Assemblages: Top-down Predator Effects? , 1997, Journal of the North American Benthological Society.

[23]  B. Downes,et al.  Different colonization patterns of two closely related stream insects (Austrosimulium spp.) following disturbance , 1991 .

[24]  Leska S. Fore,et al.  Statistical Properties of an Index of Biological Integrity Used to Evaluate Water Resources , 1994 .

[25]  R. May.  Patterns of species abundance and diversity , 1975 .

[26]  A. Hildrew.  Patchiness, species interactions and disturbance in the stream benthos , 1994 .

[27]  Y. Summar.  Reconciling landscape and local views of aquatic communities: lessons from Michigan trout streams , 1997 .

[28]  Charles P. Hawkins,et al.  Effects of Sampling Area and Subsampling Procedure on Comparisons of Taxa Richness among Streams , 1996, Journal of the North American Benthological Society.

[29]  Michael T. Barbour,et al.  Evaluation of EPA's rapid bioassessment benthic metrics: Metric redundancy and variability among reference stream sites , 1992 .

[30]  M. Keough,et al.  Scaling of colonization processes in streams: Parallels and lessons from marine hard substrata , 1998 .

[31]  S. Levin.  The problem of pattern and scale in ecology , 1992 .

[32]  Michael T. Barbour,et al.  Subsampling of Benthic Samples: A Defense of the Fixed-Count Method , 1996, Journal of the North American Benthological Society.

[33]  F. Swanson,et al.  An Ecosystem Perspective of Riparian ZonesFocus on links between land and water , 1991 .

[34]  R. Hughes,et al.  Correspondence Between Ecoregions and Spatial Patterns in Stream Ecosystems in Oregon , 1988 .

[35]  B. Kerans,et al.  Aquatic Invertebrate Assemblages: Spatial and Temporal Differences among Sampling Protocols , 1992, Journal of the North American Benthological Society.

[36]  P. S. Lake,et al.  Species richness of stream stones: an investigation of the mechanisms generating the species-area relationship , 1994 .

[37]  P. McCullagh,et al.  Generalized Linear Models , 1984 .

[38]  S. D. Cooper,et al.  Quantifying Spatial Heterogeneity in Streams , 1997, Journal of the North American Benthological Society.

[39]  Colin R. Townsend,et al.  Community structure in some southern English streams: the influence of physicochemical factors , 1983 .

[40]  A. Covich,et al.  Scales of observation of riparian forests and distributions of suspended detritus in a prairie river , 1997 .

[41]  S. D. Cooper,et al.  Implications of scale for patterns and processes in stream ecology , 1998 .

[42]  S. D. Cooper,et al.  Extrapolating from Individual Behavior to Populations and Communities in Streams , 1997, Journal of the North American Benthological Society.