Potential for delineating indicator-defined regions for streams in Victoria, Australia

Potential for delineating indicator-defined regions for streams in Victoria, AustraliaAuthor(s): P. Newall and F. WellsSource: Journal of the North American Benthological Society, Vol. 19, No. 3 (September2000), pp. 557-571Published by: Society for Freshwater ScienceStable URL: http://www.jstor.org/stable/1468114 .

Accessed: 11/05/2014 16:37

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Society for Freshwater Science is collaborating with JSTOR to digitize, preserve and extend access to Journalof the North American Benthological Society.

http://www.jstor.org

This content downloaded from 83.99.209.143 on Sun, 11 May 2014 16:37:55 PMAll use subject to JSTOR Terms and Conditions

http://www.jstor.org/action/showPublisher?publisherCode=nabs

http://www.jstor.org/stable/1468114?origin=JSTOR-pdf

http://www.jstor.org/page/info/about/policies/terms.jsp


557

J. N. Am. Benthol. Soc., 2000, 19(3):557–571q 2000 by The North American Benthological Society

BRIDGES

BRIDGES is a recurring feature of J-NABS intended to provide a forum for the interchange of ideas andinformation between basic and applied researchers in benthic science. Articles in this series will focus on topicalresearch areas and linkages between basic and applied aspects of research, monitoring policy, and education.Readers with ideas for topics should contact Associate Editors, Nick Aumen and Marty Gurtz.

Aquatic resource managers often group landscapes into regions defined by general similarities of environ-mental attributes, such as physical features, biota, and climate. These regionalizations may be defined prior totheir incorporation and use in monitoring efforts or other resource management programs. Unfortunately, someregionalizations defined a priori are poorly related to patterns of specific biota. Newall and Wells have illustratedthe potential benefits of an a posteriori approach to regionalization, using site-specific data already collected.They argue that this approach is preferable because it is based on data most commonly used by managers, thatlarge indicator data sets may exist already, and that it can be used to set management objectives specificallydesigned for the range of conditions encountered within each separate region.

Nick Aumen, [email protected] Gurtz, [email protected]

Potential for delineating indicator-defined regions for streams inVictoria, Australia

P. NEWALL1

Cooperative Research Centre for Freshwater Ecology, Environment Protection Authority of Victoria,GPO Box 4395QQ, Melbourne, Victoria 3001, Australia

F. WELLS

Department of Land Information, Royal Melbourne Institute of Technology University, GPO Box 2476V,Melbourne, Victoria 3001, Australia

Regionalizations designed to assist in themanagement of aquatic ecosystems have beendefined (Omernik 1987) and incorporated intobiomonitoring programs (Barbour et al. 1997)across the United States. Similar delineationshave been used within Victoria, Australia (Tillerand Newall 1995, Wells and Newall 1997). Eachof these regionalizations has been developed apriori, using a set of regional environmental fea-tures (such as landform, climate, vegetation,land use, and soil type) to identify and separateareas of relatively homogeneous ecological char-acter.

Aquatic resource management agencies typi-cally focus on 1 or 2 indicator methods in iso-lation (e.g., physicochemical analyses, macroin-vertebrates, fish, or benthic algae) for determin-ing aquatic ecosystem health and potential im-pacts to that health. The diverse nature ofaquatic ecosystems suggests that the accuracy ofthese methods may be increased through

1 E-mail address: [email protected]

grouping of similar sites, such as that per-formed by regionalization. However, recentcomparisons between a priori regionalizationsand benthic macroinvertebrate groupings inVictoria (Marchant et al. 2000) and fish distri-butions in Wisconsin (Newall and Magnuson1999) have shown poor relationships. Thesepoor relationships may be a result of insufficientknowledge about the effects of environmentalfeatures used in these regionalizations for ade-quate a priori characterization of aquatic ecosys-tems. Also, these a priori regionalizations pro-vide a general description of ecosystem char-acter rather than a specific tool for ecologicalassessment using 1 or 2 indicators. An a pos-teriori method of regionalization may have po-tential benefit as an alternative to delineating ana priori set of regions and subsequently com-paring it to an aquatic ecosystem classification.An a posteriori method uses existing, site-spe-cific indicator data to classify site groups, andsubsequently delineate regions. An advantage



558 [Volume 19P. NEWALL AND F. WELLS

of a posteriori regionalizations is that they canbe based upon the indicator (or tool) most com-monly used by the relevant natural resourcemanagement agency. A condition of the methodis that it requires a data set with a large numberof sites of suitable quality for the managementgoals. The resulting regionalizations could beused to set objectives specifically designed forthe range of conditions encountered within eachseparate region, thereby potentially increasingthe precision of objectives.

The objective of this study is to determine ifdata collected from extant monitoring programscan be separated into general regional groups,using data sets from the state of Victoria, Aus-tralia. Although some attempts will be made torelate any defined regions to other regional en-vironmental features, our primary focus is onwhether the data have an intrinsic regional pat-terning. Because this is a preliminary attempt todistinguish regions using an alternative methodto a priori regionalization, the regions herein arepresented only for evaluating the potential ofthe method. Neither the regions nor their namesin this paper are being proposed as permanenttools.

Methods

General overview

We used large data sets that had been gath-ered for state and national water-quality moni-toring programs. The data were classified hier-archically into groups and those groups werethen visually assessed for regional tendencies.We used 2 indicator types—physicochemicalmeasures and macroinvertebrates. Both indica-tors provide a good measure of aquatic ecosys-tem health (Hellawell 1986, Plafkin et al. 1989,ANZECC 1992, Barbour et al. 1997) and areused commonly in Victoria with readily acces-sible data sets. The sites from each data set areindependent. The 2 data sets were analyzed sep-arately to produce a physicochemical regionali-zation and a macroinvertebrate regionalization.

Physicochemical data and site selection

The physicochemical data set used in this studywas obtained from the Environment ProtectionAuthority (EPA) Fixed Site Network and the Vic-torian Water Quality Monitoring Network

(VWQMN) (Hunter 1993, Hunter and Zampatti1994, Hunter and Hedger 1995, Hunter and Loone1996). The sites in these networks were sampledmonthly. Criteria for site selection included: con-tinuity of data between the years 1990 to 1995 in-clusive (sites with missing data for a season ormore were omitted); no known major impacts;and a restriction to river and stream sites. Thisprocess resulted in 9 sites being selected from theEPA network and 82 sites from the VWQMN, to-taling 91 sites across Victoria.

The physicochemical indicators chosen for anal-ysis included color (Pt/Co units), electrical con-ductivity (EC) at 258C (mS/cm), turbidity (NTU),nitrates and nitrites (mg/L), total Kjeldahl N(mg/L), total N (mg/L), and total P (mg/L). Sol-uble reactive P (mg/L) was measured at theVWQMN sites, but not at the 9 EPA sites.

Macroinvertebrate data and site selection

The macroinvertebrate data set was obtainedfrom the Victorian component of the MonitoringRiver Health Initiative (MRHI) (Davies 1994).The data were from edge habitat samples, col-lected and live sorted (Tiller and Metzeling1998) from 199 relatively unimpacted referencesites across the State. Sites generally were sam-pled on 4 occasions between 1990 and 1996 andincluded at least 1 spring and 1 fall sample.

The macroinvertebrates collected for theMRHI in Victoria were identified to species lev-el. Exceptions were identifications that stoppedat Oligochaeta, Turbellaria, Nematomorpha,Hirudinea, and Acarina. Chironomids wereidentified to genus. The total number of taxarecorded from the 199 sites was 1025.

Numerical analyses

Classifications were performed separately oneach data set using the flexible unweighted pair-group method using arithmetic mean averages(UPGMA), a hierarchical classification programwithin the PATN statistical package (L. Belbin.1993. PATN pattern analysis package, a techni-cal reference. Division of Wildlife and Ecology,CSIRO, Canberra, Australia). The associationmatrix was created using the Bray–Curtis dis-similarity measure. The output therefore includ-ed a physicochemical-based dendrogram ofsites and a macroinvertebrate-based dendro-gram of sites. Median values over 5 y were used



2000] 559BRIDGES

for the physicochemical data set to assess thecentral tendencies of the data (Larsen et al.1988). Species occurrences in the macroinverte-brate data set were converted to presence/ab-sence because binary data perform as well asquantitative data in exploring trends in aquaticecosystems (Marchant et al. 1995), particularlyat the species level (Marchant 1990).

Regionalization process

The dendrogram of sites from each data setwas used to establish a series of sequential sitegroups (i.e., the sites were initially divided into2 site groups, then into 3 site groups, then 4,and so on). The hierarchical nature of theUPGMA classification program meant that eachsuccessive division occurred through the split-ting of a single site group from the previous setof groups.

The sequentially delineated site groups werethen plotted on a map of Victoria and visuallyassessed for regional tendencies. That is, the 1stdivision (into 2 groups) was plotted, then thenext division (3 groups) was plotted on a newmap, and so forth. The method was largely sub-jective, requiring a decision as to whether eachnew site group was geographically distinct orwhether it intermingled spatially with other sitegroups to the extent that it could not be region-ally defined. When the next new group couldnot be regionally defined, the process was halt-ed. The process did not require regions to becontiguous. A geographically discontiguousgroup was accepted if it occupied areas withsimilar regional environmental features.

The distributions of the site groups from eachdata set were then compared with maps of re-gional environmental features to facilitate thedrawing of regional boundaries around the sitegroups. Final boundary placement methodswere similar to those described by Omernik(1987) and required the use of best professionaljudgement (Hughes 1995). The method involveddelineations based on coincidence of categoryboundaries (e.g., contours, isohyets, vegetationchanges) for the selected environmental fea-tures. Where changes in a single feature causeda clearly different landscape, boundaries weredelineated using that feature. Maps of regionalenvironmental features used included physiog-raphy (Jenkin 1982, NRS 1996a), relief (Duncan1982), mean annual rainfall (Lee 1982, NRS un-

published map), median annual runoff (Holmes1982), current vegetation (Paine 1982, NRS un-published map, NRS 1994), land use (NRS 1994,1996b), and geology (Douglas 1982). Althoughthese environmental features were used in finalboundary placements, we emphasize that the re-gions were delineated primarily using the sitegroupings.

Regional descriptions and characterizations

For the physicochemical analysis, each indi-cator was plotted on a map of Victoria and vi-sually assessed for spatial trends. For the ma-croinvertebrate data set, constancy and fidelityscores were calculated for each species in eachregion as used by Newall and Magnuson (1999).Constancy is the proportion of sites at which aparticular species is present. A constancy of 1means that the species is present at every site inthe region, and a constancy of 0.1 means thatthe species is present at 10% of the sites in theregion. Fidelity is a measure of a species’ pref-erence for a region and is calculated as the ratioof the species constancy for a selected region toits constancy across all sites in the data set. Afidelity .1 indicates a preference for the select-ed region, whereas a fidelity ,1 indicates apreference against the region. The farther the fi-delity score is from 1, the stronger the prefer-ence, whereas a fidelity near 1 suggests no pref-erence. A fidelity .2 suggests a strong prefer-ence for the region. In this study, species withfidelity scores .1.5 suggested a preference fora region and were therefore included in its char-acterization.

The regional delineations presented in thispaper are preliminary and a detailed descrip-tion of their regional features and ecology is notwithin the scope of the study. Consequently,only general descriptions of these features arepresented.

Results

Interpretation of the results is assisted bycomparison with a map of Victoria showing re-lief and major land features (Fig. 1).

Physicochemical regions

The 1st division in the physicochemical clas-sification produced 2 site groups that displayed




FIG. 1. Major relief features of Victoria, Australia.

a distinct regional pattern. There was a westernlowlands site group containing 35 sites and amore eastern upland site group containing 56sites (Fig. 2A). Outliers from the eastern uplandgroup included several sites in the Otway Rang-es and 1 in the Grampian Ranges. There was 1outlier from the western lowland group, nearthe southeast coast.

The western lowlands group was split by the2nd division (Fig. 2B), forming a group of 14sites that were generally close to foothills of theOtway Ranges and the central Great DividingRange (western lowlands, foothills-influenced) andthe remaining 21 sites (western, true lowland). Incontrast, the 3rd division split the eastern up-land group into 2 groups, of 27 and 29 sites (Fig.2C). The group containing 27 sites (the easternfoothills group) was concentrated in the lowersections of the Great Dividing Range, and alsohad several sites in the isolated uplands of theGrampians, Otway, and Strzelecki Ranges. The2nd of the eastern uplands groups (the easternhighlands) typically was concentrated in thehigher reaches of the Great Dividing Range.

At the next level of division (Fig. 2D), therewere 2 simultaneous divisions, 1 that split theeastern foothills into 2 groups of 17 and 10 sites,and 1 that split the western, true lowland into2 groups of 7 and 14 sites. Neither of these di-visions resulted in groupings that were geo-graphically distinct or able to be regionalized.The regionalization process was thereforestopped at 4 physicochemical groups.

Characterization of the physicochemical regions

In general, there was little relationship be-tween the physicochemical regions and the in-dividual physicochemical components. Electri-cal conductivity, however, displayed a strong re-lationship with the delineated regions (Fig. 3,Table 1).

The regional environmental features thatwere most useful in describing and distinguish-ing between the physicochemical regions werephysiography, vegetation structure, and rainfall.Using these features, regional boundaries weredelineated for the 4 physicochemical groups



2000] 561BRIDGES

TABLE 1. Environmental descriptions (physiography, vegetation structure, rainfall) and electrical conductiv-ity (EC, median and SD) for the 4 physicochemical-based regions.

Region Environmental description

EC (mS/cm@258C)

median SD

Western, true lowland Within the lowland plains of western Victoria;mostly used for cropping and grazing withpatches of open woodland and shrubland; pre-cipitation typically 200 to 700 mm per annum

3333 1786

Western lowlands,foothills-influenced

In lowlands of western Victoria, typically imme-diately downstream of foothills; much of thearea is irrigated and non-irrigated croplandsand grazing lands; remnant native vegetationis often dry, very open woodland; precipitationis typically 300 to 1000 mm per annum

824 176

Eastern foothills Within the foothills and proximal lowlands ofthe Great Dividing, Strzelecki, Otway, andGrampians Ranges; vegetation is moderatelywet, very open woodland to tall forests; muchof the region is also cropped, grazed, or usedfor forestry activities; precipitation is generally500 to 1400 mm per annum

187 106

Eastern highlands Generally within or near the mountains of theGreat Dividing Range; very wet, open, andlow to very tall forests, with patches of wood-land, grassland, and herbfield; precipitationgenerally 700 to 1400 mm per annum

53 16

(Fig. 4). Regional features are described in Table1. Although the regional boundaries weredrawn attempting to accommodate the sitegroupings, not all sites from a site group werenecessarily included within a single region. Forexample, Fig. 4 shows that the western, truelowlands are based on UPGMA group 4, yet 1UPGMA group 4 site is situated within thewestern lowlands, foothills-influenced region.Figure 4 also shows, however, that this situationwas rare.

Macroinvertebrate regions

Using the steps detailed in the previous sec-tion, 4 macroinvertebrate regions were delineat-ed (Fig. 5): the alpine region (6 sites), the upperfoothills region (71 sites), the lower foothills andadjacent plains region (60 sites), and the lowlandplains region (62 sites). These 4 site groups dis-played clear regional patterns, although less dis-tinctly than the 4 physicochemical regions (Fig.4 cf. Fig. 5).

Characterization of the macroinvertebrate regions

The most useful regional descriptors for char-acterizing the 4 macroinvertebrate-based re-gions were physiography, rainfall, altitude, andvegetation structure. Regional features and mostcharacteristic taxa for each of the regions are de-scribed in Table 2.

The 2 taxa most characteristic of the alpineregion sites were the mayfly Nousia spp. and theblackfly Austrosimulium montanum. Both hadvery high fidelities for the alpine sites (.5) andrelatively high constancies. The blackfly isknown to occur in swift, cold, upland streams(Mackerras and Mackerras 1952), which typifythis region. In contrast, it is difficult to charac-terize the ecology of the unidentified Nousia spp.because there are several species in the genusand they may cover a wide range of habitats (J.Dean, EPA, Victoria, personal communication).

Nousia sp. AV1 was the species most charac-teristic of the upper foothills sites. This speciesis common in foothill streams in general (J.Dean, personal communication) and therefore




FIG. 2. Distribution across Victoria, Australia, of physicochemical site groups separated by the unweightedpair groups with mean averaging (UPGMA) classification program. A.—2 UPGMA groups. B.—3 UPGMAgroups. C.—4 UPGMA groups. D.—6 UPGMA groups.



2000] 563BRIDGES

FIG. 2. Continued.




FIG. 3. Distribution of median electrical conductivity (mS/cm@258C) measurements across Victoria, Austra-lia, with boundaries of physicochemical regions overlain.

its high constancy and moderately high fidelityare consistent with expectations for this region.The true bug Microvelia spp. (constancy 0.70)was the next most representative taxon for theregion. This taxon had a relatively low fidelity(1.32), however, suggesting that although it waswell represented in the region, it also was com-mon in other regions.

In the lower foothills and adjacent plains re-gion, the most characteristic taxa were the chi-ronomid Ablabesmyia sp., the mayfly Koorrnongasp. 1, the mayfly Centroptilum spp., the caddisflyNotalina bifaria, the caddisfly Hellyethira spp.,and the stonefly Dinotoperla serricauda/thwaitesi.The unidentified species of Hellyethira spp. hada high constancy (0.82) and a high fidelity (1.96)for this region. Without further resolution, how-ever, this taxon is of limited value in character-izing the region (J. Dean, personal communica-tion). Dinotoperla serricauda/thwaitesi also had ahigh constancy (0.82) and a high fidelity (1.73),but difficulty in separating D. serricauda from D.thwaitesi meant that little ecological informationcould be gleaned from this taxon.

Ablabesmyia sp. also had a high constancy and

fidelity, and Koorrnonga sp. 1, Centroptilum spp.,and N. bifaria had high constancies and moder-ately high fidelities. All these taxa tend to preferflowing waters at medium and low altitudes(Suter 1986, St. Clair 1991, Cranston 1997), andthis habitat preference is consistent with thegeneral condition of the streams in this region.

The caddisfly N. spira, the amphipod Austro-chiltonia spp., and the dragonfly, Ischnura heter-osticta had high constancy and fidelity scores forthe lowland plains macroinvertebrate region.All these taxa typically are found in slow-flow-ing, warm-water streams at low altitudes (Wil-liams 1967, St. Clair 1991, Hawking and Theis-chinger 1999), which typifies the general con-dition of the streams in this region.

Comparison between the physicochemical andmacroinvertebrate regionalizations

The physicochemical regionalization and themacroinvertebrate regionalization contained somesimilarities and several broad discrepancies (Fig.6). Both regionalizations distinguished some of thehigh-altitude areas of the state, including the east-



2000] 565BRIDGES

FIG. 4. Regionalization of Victoria, Australia, based on selected physicochemical indicators.

FIG. 5. Regionalization of Victoria, Australia, based on macroinvertebrate data.




TABLE 2. Environmental descriptions (physiography, rainfall, altitude, vegetation structure) and most char-acteristic macroinvertebrate species for sites used for the macroinvertebrate-based regions. asl 5 above sea level.C 5 constancy, F 5 fidelity (see text for explanation of these terms).

Region Environmental descriptions Characteristic taxa

Alpine Alpine and subalpine areas of the Great Divid-ing Range; typically in wet to very wet areaswith rainfall . 1400 mm per annum on aver-age; site altitudes averaged 1346 m asl; vegeta-tion was typically grassland, herbfield, andwoodland

Nousia spp. (C 5 0.83, F 55.02), Austrosimulium mon-tanum (C 5 0.67, F 5 5.10)

Upper foothills Mountains and foothills; a wet region with aver-age annual precipitation typically between 700and 1400 mm; mean altitude of the sites was325 m asl; the area is mostly characterized bytall to very tall open forest

Nousia sp. AV1 (C 5 0.87, F5 1.50)

Lower foothills andadjacent plains

Low foothills and plains immediately down-stream of foothills; average annual precipita-tion generally ranges from 500 to 1400 mm;mean site altitude was 215 m asl; vegetation isa mix of woodland, low to tall open forest,and land cleared for cropping, grazing, andforestry

Ablabesmyia sp. (C 5 0.72, F5 1.88), Koorrnonga sp. 1(C 5 0.88, F 5 1.52), Cen-troptilum spp. (C 5 0.80, F5 1.5), Notalina bifaria (C5 0.80, F 5 1.55)

Lowland plains Low, often flat plains; contains the drier parts ofthe state with rainfalls averaging ;200 to 1000mm per annum; average site altitude is 203 masl; the land is largely cleared for grazing andcropping

Notalina spira (C 5 0.94, F 52.07), Austrochiltonia spp.(C 5 0.87, F 5 2.31), Isch-nura heterostricta (C 5 0.81,F 5 2.51)

ern part of the Great Dividing Range and theGrampians and Otway Ranges (Fig. 1).

The macroinvertebrate-based alpine and up-per foothills regions largely overlapped with thephysicochemical-based eastern highlands regionin the eastern part of the state (Fig. 6). This over-lap did not occur in the western half of the state,however, where the macroinvertebrate upperfoothills region occurred in 2 separate areas,and where the physicochemical eastern high-lands region did not occur at all. Another dis-crepancy was the center and west of the state,which was encompassed largely by a single ma-croinvertebrate-based region, the lowland plains(Fig. 5), with the remaining regions being con-centrated in the east of the state. In contrast, thephysicochemical regions were distributed moreevenly across the state (Fig. 4).

Discussion

Classification of the physicochemical sites andmacroinvertebrate sites into groups with broadregional patterns demonstrates the potential forusing a posteriori indicator-based regionaliza-

tions in the assessment and management ofaquatic resources. Successful regionalization us-ing extant monitoring and assessment sites,rather than sites specifically selected for region-alizations, indicates that the method may be eas-ily instituted and adapted within currently op-erating water-quality programs.

We were able to use regional environmentalfeatures to finalize boundary placement and de-lineate regions that encompassed most siteswithin each individual classification groupwhile also separating the different site groups.The usefulness of regional environmental fea-tures, such as landform, vegetation structure,and rainfall, in defining regional boundariessuggests that these features can be related toaquatic ecosystems, as assumed in a priori re-gionalizations. These boundary placements,however, are yet to be tested. Further, theboundaries were drawn by searching for chang-es in regional environmental features that laybetween the site groups already defined by theselected indicators, which is the inverse of usingan a priori selection of features and boundariesto predict variations in biotic assemblages.



2000] 567BRIDGES

FIG. 6. Comparison of the physicochemical regionalization with the macroinvertebrate regionalization ofVictoria, Australia. Macroinvertebrate regions: A 5 alpine, LP 5 lowland plains, LF/AP 5 lower foothills andadjacent plains, UF 5 upper foothills.

Macroinvertebrate regionalization

Regionalization is a form of classification, andimplicit in classification is an acceptance of dis-continuity in composition of the phenomena be-ing classified. This approach contrasts with theconcept of continuous change along relevantcausal gradients. Similarly, the delineation of aregion implies an expected level of homogeneitywithin that region, generally overriding localsite variation. Potential applications for a pos-teriori macroinvertebrate regionalizations thatmay be of most benefit are those used in com-bination with models that accommodate grada-tional changes and local site variations. Appli-cations of this type include the derivation of re-gional objectives using biotic indices (e.g.,Stream Invertebrate Grade Number—AverageLevel [SIGNAL], Chessman 1995); predictionand classification systems such as the River In-vertebrate Prediction And Classification System(RIVPACS) (Wright et al. 1993) and the Austra-lian River Assessment Scheme (AUSRIVAS)(Simpson et al. 1997); and taxonomic checklistssuch as Key Invertebrate Family scores (Govern-ment of Victoria 1999).

SIGNAL is a biotic index-based method of as-sessing water quality. It uses predeterminedpollution sensitivity scores for all macroinver-tebrate families found at a site to derive an over-all score for that site. The score then is convertedinto a rating of the water quality (e.g., scores .65 clean water). A concern with the method,however, is that it may be weighted against low-land regions, providing lower values for the nat-ural macroinvertebrate fauna of these regions(DNRE 1997). Interpretations of the index maytherefore be enhanced if natural regional differ-ences are incorporated into the method, facili-tating the development of regional assessmentsand criteria. This approach may include usingbest attainable quality sites to both delineate andestablish acceptable values as an assessment cri-terion. RIVPACS and AUSRIVAS models predictfaunal assemblages based on a suite of environ-mental conditions measured at a site (Wright etal. 1993, Simpson et al. 1997). An assemblagepredicted by AUSRIVAS is likely to be more pre-cise if it is from a model based on sites withinthe same region rather than on the current mod-el, which uses sites across the state (L. Metzel-




ing, EPA, Victoria, personal communication).Our regionalization is based on grouping siteswith similar assemblages, offering potential forimproved precision of site assessments. The der-ivation of Key Invertebrate Families, as used bythe Government of Victoria (1999), inherentlyfocuses on the regional nature of macroinver-tebrate distributions. The a posteriori regionali-zation process presented in our study should as-sist in the development and extension of the useof Key Invertebrate Families within Victoria andelsewhere.

A potential refinement to the macroinverte-brate regionalization method presented in ourstudy may be the inclusion of riffle sample data.Our preference for maximizing consistency be-tween all sites led to the omission of riffle datain our analysis because not all sites had rifflesto sample. Counterarguments to this omissionmay be that inclusion of riffle data maximizesinformation and that riffle samples are morerepresentative than edge habitat samples of in-stream conditions. It may be useful, therefore,to compare edge habitat results with riffle hab-itat results and also combined edge/riffle re-sults in future studies.

Physicochemical regionalization

The physicochemical regions produced bythis study were strongly influenced by the ECdata. The regions defined in Fig. 3 displayedstrong similarities with existing maps ofgroundwater and surface water salinity (Holmes1982, Lawrence 1982). The high ranges in valuesfor EC probably caused this patterning, sug-gesting that future regionalizations with physi-cochemical data should be range standardizedor log transformed to ensure a more equal rep-resentation of each indicator. A potential prob-lem with this, however, is that the attempt toaccommodate many physicochemical indicatorsin a general water-quality regionalization mayreduce its utility because the boundaries appli-cable for any indicator may be far removed fromthe boundaries applicable to all other indicators.This problem may be overcome through explor-atory data analysis aimed at identifying the crit-ical variables to use in the classification.

Comparison of macroinvertebrate andphysicochemical regionalizations

The similarity in the 2 regionalizations wasexpected because physicochemical indicators

(Rohm et al. 1987, Larsen et al. 1988) and ma-croinvertebrate assemblages (Hughes et al.1994) both vary with regional features. Also,physicochemical conditions themselves clearlyinfluence the macroinvertebrate assemblages(Plafkin et al. 1989). However, macroinverte-brate distributions are influenced by a range offactors beyond those used for the physicochem-ical regionalization in this study. Consequently,the 2 regionalizations provided here also wereexpected to display differences. Our study wasdeveloped on the basic tenet that each specificindicator type used for water-quality assess-ment (e.g., physicochemical indicators, macroin-vertebrates) will produce a different regionali-zation. A corollary is that each regionalizationcan contribute towards the setting of more pre-cise objectives for that indicator by basing theobjectives on directly comparable sites.

Another factor expected to contribute to dif-ferences between the 2 regionalizations was theuse of median physicochemical values. Al-though median values are useful for character-izing central tendencies of the physicochemicaldata, extreme values, ranges, or measures ofvariation may also be influential in macroinver-tebrate distribution.

The differences between the 2 regionaliza-tions emphasize the importance of using region-alizations designed to accommodate the specificindicator (or group of indicators) being used inan assessment. The key feature of the study,however, was the demonstration of regional pat-terns in both data sets. Use of intrinsic regionalpatterning displayed by chosen indicators clear-ly has the potential to increase the precision ofwater-quality objectives based on these indica-tors within Victoria and elsewhere.

ACKNOWLEDGEMENTS

This study evolved from Trust Fund Project92/7, funded by the Australian and New Zea-land Environment and Conservation Council(ANZECC). The views expressed herein, how-ever, are the authors’ own. The authors thankthe staff of Freshwater Sciences, EnvironmentProtection Authority, Victoria, for macroinver-tebrate counting and identification and for com-ments on an early draft of the paper. Leon Metz-eling and Richard Marchant provided detailedcomments on later drafts. Rebecca Hewlett andJohn Dean provided advice on macroinverte-



2000] 569BRIDGES

brate ecology. We also thank Chuck Hawkinsand an anonymous reviewer for their valuablecomments on the manuscript.

Literature Cited

ANZECC (AUSTRALIAN AND NEW ZEALAND ENVIRON-MENT AND CONSERVATION COUNCIL). 1992. Aus-tralian water-quality guidelines for fresh and ma-rine waters. Australian and New Zealand Envi-ronment and Conservation Council, Canberra,ACT, Australia. (Available from: ANZECC Sec-retariat, P.O. Box 787, Canberra, Australian Cap-ital Territory 2601, Australia.)

BARBOUR, M. T., J. GERRITSEN, B. D. SNYDER, AND J. B.STRIBLING. 1997. Revision to rapid bioassessmentprotocols for use in streams and rivers: periphy-ton, benthic macroinvertebrates and fish. EPA-841-D-97-002. Office of Wetlands, Oceans andWatersheds, US Environmental Protection Agen-cy, Washington, DC.

CHESSMAN, B. 1995. Rapid assessment of rivers usingmacroinvertebrates: a procedure based on habi-tat-specific sampling, family level identificationand a biotic index. Australian Journal of Ecology20:122–129.

CRANSTON, P. 1997. Identification guide to the chiron-omidae of New South Wales. AWT EnSight Iden-tification Guide No. 1. Australian Water Technol-ogies Pty. Ltd., West Ryde, NSW, Australia.(Available from: Australian Water TechnologiesPty. Ltd., EnSight, 51 Hermitage Rd, West Ryde,New South Wales 2114, Australia.)

DAVIES, P. 1994. River bioassessment manual. NationalRiver Processes and Management Program, Mon-itoring River Health Initiative. CommonwealthEnvironment Protection Agency, Land and WaterResearch and Development Corporation and theDepartment of Environment, Sport and Territo-ries, Sandy Bay, Tasmania, Australia. (Availablefrom: Program Coordinator, National River Pro-cesses and Management Program, FreshwaterSystems, 82 Waimea Ave., Sandy Bay, Tasmania7005, Australia.)

DNRE (DEPARTMENT OF NATURAL RESOURCES AND

ENVIRONMENT). 1997. Index of stream condition:reference manual. Department of Natural Re-sources and Environment, East Melbourne, Vic-toria, Australia. (Available from: Department ofNatural Resources and Environment, P.O. Box500, East Melbourne, Victoria 3002, Australia.)

DOUGLAS, J. G. 1982. Geology. Pages 11–16 in J. S.Duncan (editor). Atlas of Victoria. Victorian Gov-ernment Printing Office, Melbourne, Australia.

DUNCAN, J. S. 1982. Relief. Pages 3–5 in J. S. Duncan(editor). Atlas of Victoria. Victorian GovernmentPrinting Office, Melbourne, Australia.

GOVERNMENT OF VICTORIA. 1999. State environment

protection policy (Waters of Victoria): schedule F7(Waters of the Yarra catchment). EnvironmentProtection Authority (EPA), Melbourne, Victoria,Australia. (Available from: EPA, P.O. Box 4395QQ,Melbourne, Victoria 3001, Australia.)

HAWKING, J., AND G. THEISCHINGER. 1999. Dragonflylarvae (Odonata), a guide to the identification oflarvae of Australian families and identificationand ecology of larvae from New South Wales. Co-operative Research Centre for Freshwater Ecolo-gy, Identification Guide Series No. 24. Murray-Darling Freshwater Research Centre, Albury,New South Wales, Australia.

HELLAWELL, J. M. 1986. Biological indicators of fresh-water pollution and environmental management.Elsevier Applied Science Publishers, London, UK.

HOLMES, R. E. 1982. Water resources. Pages 32–35 inJ. S. Duncan (editor). Atlas of Victoria. VictorianGovernment Printing Office, Melbourne, Austra-lia.

HUGHES, R. M. 1995. Defining acceptable biologicalstatus by comparing with reference condition.Pages 31–48 in W. Davis and T. Simon (editors).Biological assessment and criteria. Tools for waterresource planning and decision making. LewisPublishers, Boca Raton, Florida.

HUGHES, R. M., S. A. HEISKARY, W. J. MATTHEWS, AND

C. O. YODER. 1994. Use of ecoregions in biologicalmonitoring. Pages 125–150 in S. Loeb and A. Spa-cie (editors). Biological monitoring of aquatic sys-tems. Lewis Publishers, Boca Raton, Florida.

HUNTER, K. 1993. Victorian water quality monitoringnetwork, August 1990–December 1992. ReportNo. 110. State Water Laboratory of Victoria,Mount Waverley, Victoria, Australia. (Availablefrom: Water Ecoscience Pty. Ltd., 68 RickettsRoad, Mount Waverley, Victoria 3149, Australia.)

HUNTER, K., AND M. HEDGER. 1995. Victorian waterquality monitoring network annual report 1994.Report No. 29/95. Department of Conservationand Natural Resources, Melbourne, Victoria, Aus-tralia. (Available from: Water Ecoscience Pty. Ltd.,68 Ricketts Road, Mount Waverley, Victoria 3149,Australia.)

HUNTER, K., AND J. LOONE. 1996. State water qualitymonitoring annual report: Victoria 1995. ReportNo. 70/96. Department of Natural Resources andEnvironment, Melbourne, Victoria, Australia.(Available from: Water Ecoscience Pty. Ltd., 68Ricketts Road, Mount Waverley, Victoria 3149,Australia.)

HUNTER, K., AND B. ZAMPATTI. 1994. Victorian waterquality monitoring network annual report 1993.Report No. 112. State Water Laboratory of Victo-ria, Mount Waverley, Victoria, Australia. (Avail-able from: Water Ecoscience Pty. Ltd., 68 RickettsRoad, Mount Waverley, Victoria 3149, Australia.)

JENKIN, J. J. 1982. Physiography. Pages 20–25 in J. S.




Duncan (editor). Atlas of Victoria. Victorian Gov-ernment Printing Office, Melbourne, Australia.

LARSEN, D. P., D. R. DUDLEY, AND R. M. HUGHES. 1988.A regional approach for assessing attainable sur-face water quality: an Ohio case study. Journal ofSoil and Water Conservation 43:171–176.

LAWRENCE, C. R. 1982. Groundwater resources. Pages36–38 in J. S. Duncan (editor). Atlas of Victoria.Victorian Government Printing Office, Melbourne,Australia.

LEE, D. M. 1982. Climate. Pages 26–31 in J. S. Duncan(editor). Atlas of Victoria. Victorian GovernmentPrinting Office, Melbourne, Australia.

MACKERRAS, I. M., AND M. J. MACKERRAS. 1952. Noteson Australasian Simuliidae (Diptera) III. Proceed-ings of the Linnaean Society of New South Wales77:104–113.

MARCHANT, R. 1990. Robustness of classification andordination techniques applied to macroinverte-brate communities from the La Trobe River, Vic-toria. Australian Journal of Marine and Fresh-water Research 41:493–504.

MARCHANT, R., L. A. BARMUTA, AND B. CHESSMAN.1995. Influence of sample quantification and tax-onomic resolution on the ordination of macroin-vertebrate communities from running waters inVictoria, Australia. Marine and Freshwater Re-search 46:501–506.

MARCHANT, R., F. WELLS, AND P. NEWALL. 2000. As-sessment of an ecoregion approach for classifyingmacroinvertebrate assemblages from streams inVictoria, Australia. Journal of the North AmericanBenthological Society 19:497–500.

NEWALL, P., AND J. J. MAGNUSON. 1999. The impor-tance of ecoregion versus drainage area on fishdistributions in the St. Croix River and its Wis-consin tributaries. Environmental Biology of Fish-es 55:245–254.

NRS (NATURAL RESOURCE SYSTEMS). 1994. Victoria: asatellite image (map), 1:1,000,000. Department ofNatural Resources and Environment (DNRE),Melbourne, Victoria, Australia. (Available from:NRS, Level 2, 121 William St., Melbourne, Victoria3000, Australia.)

NRS (NATURAL RESOURCE SYSTEMS). 1996a. Broadlandform types, Victoria (map), 1:1,000,000. De-partment of Natural Resources and Environment,Melbourne, Victoria, Australia. (Available from:NRS, Level 2, 121 William St., Melbourne, Victoria3000, Australia.)

NRS (NATURAL RESOURCE SYSTEMS). 1996b. Agricul-tural landuse, Victoria (map), 1:1,000,000. De-partment of Natural Resources and Environment,Melbourne, Victoria, Australia. (Available from:NRS, Level 2, 121 William St., Melbourne, Victoria3000, Australia.)

NRS (NATURAL RESOURCE SYSTEMS). Unpublished.Untitled maps of rainfall and vegetation across

Victoria. (Available from: NRS, Level 2, 121 Wil-liam St., Melbourne, Victoria 3000, Australia.)

OMERNIK, J. 1987. Ecoregions of the conterminousUnited States. Annals of the Association of Amer-ican Geographers 77:118–125.

PAINE, D. 1982. Vegetation. Pages 49–56 in J. S. Duncan(editor). Atlas of Victoria. Victorian GovernmentPrinting Office, Melbourne, Australia.

PLAFKIN, J. L., M. T. BARBOUR, K. D. PORTER, S. K.GROSS, AND R. M. HUGHES. 1989. Rapid bioas-sessment protocols for use in streams and rivers:benthic macroinvertebrates and fish. EPA 440-4-89-001. Office of Water Regulations and Stan-dards, US Environmental Protection Agency,Washington, DC.

ROHM, C. M., J. W. GIESE, AND C. C. BENNETT. 1987.Evaluation of an aquatic ecoregion classificationof streams in Arkansas. Journal of FreshwaterEcology 4:127–140.

SIMPSON, J. C., R. H. NORRIS, L. BARMUTA, AND P.BLACKMAN. 1997. Australian River AssessmentSystem. National River Health Program predic-tive model manual. Cooperative Research Centrefor Freshwater Ecology, University of Canberra,Belconnen, ACT, Australia (http://ausrivas.canberra.edu.au/ausrivas/manual). AusRivASweb page: http://ausrivas.canberra.edu.au/aus-rivas.

ST. CLAIR, R. 1991. The genus Notalina (Trichoptera:Leptoceridae: Triplectidinae) in southeastern Aus-tralia, with descriptions of the larvae and pupae.Invertebrate Taxonomy 4:895–893.

SUTER, P. J. 1986. The Ephemeroptera (mayflies) ofSouth Australia. Records of the South AustralianMuseum 19:339–397.

TILLER, D., AND L. METZELING. 1998. Rapid bioassess-ment methods used by the Environment Protec-tion Authority in Victoria. Publication No. 604.Environment Protection Authority (EPA), Mel-bourne, Victoria, Australia. (Available from: EPA,P.O. Box 4395QQ, Melbourne, Victoria 3001, Aus-tralia.)

TILLER, D., AND P. NEWALL. 1995. Preliminary nutrientguidelines for Victorian inland streams. Publica-tion No. 478. Environment Protection Authority(EPA), Melbourne, Victoria, Australia. (Availablefrom: EPA, P.O. Box 4395QQ, Melbourne, Victoria3001, Australia.)

WELLS, F., AND P. NEWALL. 1997. An examination ofan aquatic ecoregion protocol for Australia. Aus-tralia and New Zealand Environment and Con-servation Council (ANZECC), Canberra, ACT,Australia. (Available from: ANZECC Secretariat,P.O. Box 787, Canberra, Australian Capital Terri-tory 2601, Australia.)

WILLIAMS, W. D. 1967. Amphipoda. Pages 17–21 in I.A. E. Bayly, J. A. Bishop, and I. D. Hiscock (edi-tors). An illustrated key to the genera of the Crus-



2000] 571BRIDGES

tacea of Australian inland waters. Australian So-ciety for Limnology, Melbourne, Victoria, Austra-lia.

WRIGHT, J. F., M. T. FURSE, AND P. D. ARMITAGE. 1993.RIVPACS—a technique for evaluating the biolog-ical quality of rivers in the U.K. European WaterPollution Control 3:15–25.

About the Authors

Peter Newall is an aquatic ecologist with researchinterests in the use of regionalizations, particularlyin relation to the use of biological objectives for themanagement and protection of aquatic ecosystems.Other research interests include the use of diatoms asbiological indicators and the use of biota in the deri-

vation of physicochemical water-quality guidelines.He received his PhD from the University of Wiscon-sin-Madison, studying the relationships between fishfauna, ecoregions, and local site variables. Fiona Wellsis a research officer in the Department of Land In-formation at the Royal Melbourne Institute of Tech-nology University, Victoria, Australia. She has beenconsulting to the Victorian Environment ProtectionAuthority for the past 4 y, focussing on the region-alization of Victorian streams for the development ofbiological objectives to enhance the protection ofaquatic ecosystems.

Received: 10 September 1999Accepted: 30 March 2000



NOTES



Documents

Potential for delineating indicator-defined regions for streams in Victoria, Australia