Southwestern riparian-stream ecosystems: research design, complexity, and opportunity

14 Pages·1991·0.8 MB·English

by  Rinne, J.N

Historic, Archive Document
Do not assume content reflects current
scientific knowledge, policies, or practices.

/rf7. 7
United States Southwestern
y. Departmentof
Agriculture Riparian-Stream Ecosystems:
Forest Service
RockyMountain Research Design, Complexity, and Opportunity
Forest and Range
Experiment Station
p
Fort Collins, John N. Rinne and Russell AcrLaFayette
Colorado80526
ResearchPaper
RM-299 to
CP
o
USDA Forest Service October 1991
Research PaperRM-299
Southwestern Riparian-Stream Ecosystems:
Research Design, Complexity, and Opportunity
John N. Rinne, Research Fisheries Biologist
Rocky Mountain Forest and Range Experiment Station1
Russell A. LaFayette, Hydrologist
USDA Forest Service, Southwestern Region2
ABSTRACT
Two basic approaches to research design in riparian areas—
—
intrastreamandinterstream andtheirmeritsareevaluatedbasedon
physical, chemicalandbiological datafromstreams incentralAri-
zona and northern New Mexico. Interactionbetween research and
managementpersonnelmustbeconstantandclosetoidentifyresearch
opportunity. Suchapartnership operatingwithintheframeworkof
dailyforestlandmanagementactivitywillbeeffectiveingenerating
valid,defendable,andapplicableinformationforfuturemanagement
offorest lands.
Conducting viable research on the effects ofthe combination of
natural- and land management-induced factors on stream environ-
mentsandbiotainsouthwesternNational Forests iscomplex. Fac-
torscontributingtocomplexityare: (1)interactionsofmultipleland
uses, (2) spatial-temporal relationships, (3) inability to establish a
frameofreference, (4)inabilitytoreplicatestudyareas, (5)jurisdic-
tioninhabitatandspeciesmanagement,and(6)frequentchangesin
landmanagementobjectivesanddirection.Combined,thesefactors
renderitdifficulttoeffectivelystudylandmanagementimpacts on
riparian ecosystems.
1HeadquartersisinFortCollins,incooperationwithColoradoStateUniversity.JohnN.Rinneis
withtheStation'sResearchWorkUnitinTempe,Arizona.
2RussellA. LaFayetteiswiththeWatershedandAirManagementDivision,Albuquerque, New
Mexico.
Southwestern Riparian-Stream Ecosystems:
Research Design, Complexity, and Opportunity
John N. Rinne and Russell A. LaFayette
INTRODUCTION tiveofthestudywastodetermineifadecadeofgrazing
exclusionwasbeneficialtoriparianstreamhabitatand
NationalForestlandscovermorethan21millionacres fishes. This riparian area was previously (1973-75)
in Arizona and New Mexico. Topographically, these fenced to eliminate livestock grazing. Fencing design
landsaretypicallyupperelevation(>1,500m)andare precluded unequivocable conclusions from research
thecoolestandbest-wateredareasinthepredominant- (Rinne1988a).Becauseofapparentshortcomings,acur-
lyaridandsemiaridSouthwest.Becauseoftherelatively sory, interstream study was also initiated onthe Rios
greaterannualprecipitation(>31cmannually),exten- CapulinandNambe andthe SantaFeRivernorthand
sive harvestable stands of conifer forests flourish. eastofSantaFe,NewMexico.Finally,in1985another
Livestock graze on herbaceous forage over more than interstreamstudywasinitiatedonsixstreamsdraining
75% ofall National Forest lands inthe Southwest. In theMogollonRimintheTontoNationalForesttoestab-
addition,theselandshavesustainedtimberharvestfor lish baseline data to examine the effects ofproposed
overthreequartersofacentury.Intheseupland, more changesingrazingmanagement.Datawerecollectedon
mesicareas,streamssupportbothwildandput-and-take fishes,theirhabitats,andtheirfoodsource(macroinver-
populations oftrout and otherwild, native fishes. tebrates)instreamsdrainingwatershedseithersubjected
Montanestreamsandsurroundingriparianecosystems toorrestrictedfromgeneralmultipleuses,suchasgraz-
compriselessthan1%oftheforestlandscape.Research ing,timberharvest,andrecreationalactivityandfishing.
onthestructureandfunctioningofthesevaluablenatur- Results of research on these riparian-stream
alresourceareasinmontaneareasinthe Southwestis ecosystemswerenotalwayswhathadbeenanticipated.
bothcomplexand inits infancy (Rinne 1985). Forex- Study results demonstrated (1) that land managers
ample,untilrecently,moststudiesrelatingtheinterac- should not expect quick, broad-scale solutions to
tions of grazing and fisheries have been descriptive, resourceproblems, and(2)thatresearchersinteracting
popularized, and have lacked scientific approach and with personnel from all forest disciplines must be
proper study design (Platts 1982; Rinne 1988a, 1989; vigilantofresearchopportunitiesandexceedinglyper-
SzaroandRinne1988).Further,theeffectsoflivestock ceptiveinstudydesigntoprovidemeaningfulinforma-
grazingonriparianecosystems,waterquantityandqual- tionforeffectivelandmanagement.Thispaper(1)points
ity, stream dynamics, and fish populations havebeen outthecomplexityoftherelationshipsthatmustbecon-
sparselyquantifiedanddocumented.Thecombinedef- sidered when selecting and designing studies ofthe
fectsoflandusepracticesandnaturaleventsonstream functioning of and interactions within riparian
habitatandfisheriesinteractionshavebecomethetopic ecosystems, (2) discussesthe merits ofthetwo poten-
ofincreasedresearchinthelastdecade.However,most tialapproachestostudydesignforriparianecosystems,
research effort on the effects of grazing on riparian and (3) emphasizestheneedforresearchandmanage-
ecosystems,forexample,hasbeeninthenorthernRocky mentpersonneltointeractcloselyandcontinuallytodis-
Mountain and Great Basin Provinces (Kauffman and cernopportunityforstudiesthatwillprovideanswers
Krueger 1984). forland management problems.
Between 1982 and 1985, researchwasinitiatedona
single and two locally contiguous groups ofmontane
streams incentralArizonaandinnorthernNewMexi- STUDY AREAS
co(fig. 1). In1982,researchcommencedontheRiode
lasVacas,SantaFeNationalForest.Theprimaryobjec- Threeseparatestudyareaswereexamined(fig. 1).The
firstwasasinglestream, theRio delasVacas, athird-
order montane stream draining the San Pedro Parks
«» WildernessArea, SantaFeNationalForest,NewMexi-
1 2 co.Studyareadescriptionsandlivestockgrazinghisto-
ry are in Szaro et al. (1985) and Rinne (1988a). The
secondareaincludedthreestreams.TheSantaFeRiver
New isasecond-orderstreamintheSangredeCristoMoun-
tainsofnorthernNewMexicoservingasaprimarywater
Arizona Mexico supply forthe city ofSanta Fe. To ensure highwater
quality,thewatershedhasbeenclosedtonormalmulti-
pleusessincethe1930's.TheRioNambeandRioCapu-
lin are first-order streams having their source on the
Figure1.—LocatioMnogooflRlioondeRilmas(V3)acsatsud(y1),arSeaanst.aFeRiver(2),and nsoarmtehwmeosutnotnaiintsaospptohseitSeanstidae.FeBoRtihvewra,tbeurtshderdasinarneorstuhb--
1
jectto normalNational Forestlanduses. Steep mixed
coniferslopes border all three streams.
The lastarea, agroup ofsixstreams, liesbelowthe
Mogollon Rim in central Arizona. Six perennial first-
orderstreams(Pine,Dude,Bonita,Ellison,Christopher,
andHortoncreeks)issuefromamajorfaultblock(Rinne
andMedina1988).Historically,thesewatershedshave
beensubjectedtovariedgrazingandtimbermanagement
practices. PineCreek, atoneend oftheuse spectrum,
hasnotbeengrazedorloggedfor25years. Incontrast,
theHortonCreekwatershedhasbeengrazedseason-long
andcontinuously(May-October), andtimberhasbeen
harvested on the watershed for years. The other
watersheds are within grazing allotments and timber
managementareasthatfallbetweenthesetwoextremes.
Studieswereinitiatedtoestablishbaselineinformation
toevaluateproposedchangesingrazingmanagement.
InJune 1990, a10,000-hanaturalwildfire (theDude
Fire)dramaticallyalteredthreeofthesixwatershedsin
this area. This natural event combined with eventful
pretreatmentdataprovidedanexcellentopportunityto
evaluatenaturalandartificialeffectsonthestructureand
functioning ofriparian areas.
TheRiodelasVacassupportsthreenativeandatleast
twointroducedspeciesoffishes(Rinne1988a).Because
rainbow and the native cutthroat trout hybridize, the
SantaFeRiverandRiosNambeandCapulincontainboth
nativecutthroatandintroducedrainbowtroutandtheir
hybrids. AllstreamsbuttheSantaFeRiveraresubject
tosportfishing.TheMogollonRimstreamscontainonly
introducedsalmonidsinvariedassemblages(Rinneand
Medina 1988).
Figure2.—Streambankvegetationalongreachesofstreaminun-
METHODS grazed(upper)andgrazed(lower)areasoftheRiodelasVacas.
tyvariedfrom20%to100%ingrazedareas;bankswere
Fishnumbersandbiomasseswereestimatedbyelec- totally stable in the exclosed areas. Stream substrate
trofishingblocked 50-msectionsofstreamthreetimes permeability and flow were less in the grazed areas
(Rinne 1978). Waterqualitywasanalyzedbystandard (Rinne 1988a).
fieldwaterqualitykit,streambankdeteriorationwases- Initially, the intrastreamapproachontheRio delas
timatedfollowedmethodsofBinns(1982),andstream- Vacas appeared tobe desirable to control variation in
bank vegetation and overhanging vegetation were dataestimates. However, althoughastreamanditsas-
measuredwithametertape.Aquaticmacroinvertebrates sociated riparian habitat are usually a well-defined
werecollectedbySurbersampler,sorted,andidentified narrowbandofhabitatwithintheforestlandscape,func-
inthelab;BioticConditionIndiceswerethencalculat- tionallythe converse istrue. Streams are dynamically
ed using methods ofWinget and Mangum (1979). interrelatedwithandaffectedalongtheirentirelength
bytheirwatersheds(Hynes1975,Platts1979,Triskaet
al. 1982).Accordingly,agivenreachofstreamsuchas
Research Design thatexclosedintheVacasisnotfunctioning indepen-
dently, butratherisaffectedcumulativelybynotonly
Intrastream Approach upstreamanddownstreamreaches(Vannoteetal. 1980),
butby land uses onthe watershed.
Thisresearchapproachwastakentostudytheeffects Forexample,watersamplescollectedinsummer1984
ofgrazingonfishpopulationsandtheirhabitatsinthe inanupperungrazedreach(samplesection3;fig.3)in-
Rio de las Vacas. Rinne (1988a) reported findings on dicated the presence of significantly higher nutrient
fishes, andresultswillonlybereferredtohere. Physi- (phosphates,nitrates,andsulfates)contentthaninsam-
calhabitatstructureintheRiodelasVacaswasdramat- plesfromadownstreamreach (sectionD) sampledthe
icallydifferentbetweengrazedandungrazedreachesof next day (table 1). Because ofthese differences, addi-
stream(Rinne1985;fig.2).Streambankvegetationand tional samples were analyzedtwo days laterfromthe
overhanging vegetation were much greater inthe un- same upstream locality (sample section 3). Nutrients
grazedcomparedtothegrazedreaches. Bankinstabili- werenolongerdetectable,buthardnesshadincreased
2
Numbers offish among study sections in the Vacas
were likewise highly variable in 1982 (Rinne 1985,
1988a). Inungrazed reaches ofstream, 86-95% ofthe
fish and 51-75% oftotal biomass were comprised of
suckersandchubs. Bycomparison,thesenonsalmonid
taxacontributed95% ormoreoftotalnumberandbio-
mass inthe grazed area. Numbers offishwere greater
inthegrazedarea,butsimilarbiomassesinthetwoareas
reflected the larger mean size offish inthe ungrazed
reaches.
Conceivably, the obvious benefits accrued to fish
habitat in the reaches of stream within nongrazed
reaches were dampened by the negative effects up-
stream. Incontextoftherivercontinuumconcept, the
lengthofstreambenefited (2 km)wasnotsufficientto
produceasignificantlypositiveeffectonsalmonidpopu-
lationsintheVacas. PlattsandNelson(1985)reported
this same spatial-linear influence in a Utah stream.
Aquaticmacroinvertebrateanalysesindicatedmarked
differencesbetweenexclosed and grazed areas (Rinne
1988b). However, because of lack of background
pretreatmentdata, these differences couldbeas easily
attributedtonatural,linearchangesinstreammorphol-
ogy,waterquality, andtoincreasedsolarradiationbe-
cause ofless streamside vegetation. Although several
toleranttaxaweremoreabundantingrazedareasthan
inungrazed areas, relative densities andbiomasses of
macroinvertebratesandBCIdidnotconsistentlyfitwhat
wouldbeexpectedinthetwodifferentlytreatedareas.
Interstream Approach
Inkeepingwiththeideathatwatershedmanagement
impactsastream(Hynes1975),dataonfishpopulations
were collected from streams situated within paired
watershedsthathavebeenmanageddifferentlyforacon-
1 Km Flow soridweartaeblreshpeedriaopdproofatcihmwea(statbalkeesn2t-o3)d.etTehrimsinienttehresfteraesaim-
Figure3.—AdetailedmapoftheRiodelasVacasstudyareain- bilityofsuch adesignin discerning land use impacts
dicating50-mstudysectionsintheupstreamgrazed(F-l)andun- onstreamhabitatandfishes.Twoareaswereexamined
siggrnaizfeidca(n1t-6l)y.arHeaesaavnydtrheecrdeoawtnisotnraelamusgerazaebdovareeath(Ae-E)s.tudy inNNeewwMMexeixcioc.o—aFnidshopnoepuilnaAtriioznonnuamb(feirg.s1i)n.studysec-
area involving several hundred campers on a holiday tion 1 intheSantaFeRiverwerecomparablebetween
weekendwasapparentlyresponsiblefortheshort-term, 1982and1983,butincreased43%innumbersand96%
highly variable nutrient concentrations. inbiomassbetweenyears insection 2 (table 2). Study
Table1.—Selectedwaterqualityestimates(allinmg/L)intheRiodelasVacas,June1984. Rangesareinparentheses.
t-Valuesandsignificance(*0.05, **0.01)betweenSunday(6/24)andTuesday(6/26)measurementsareshown.
Study Nutrients Hardness
Date Time section n P04 N03 so4 Alkalinity CA MG Total
6/24/84 1245 3 10 0.18 1.26 2.7 112.8 85.6 97.5 183.1
(0.14-0.21) (0.95-1.65) (1.0-6.0) (110-120) (80- 90) ( 91-100) (179-190)
6/25/84 1100 D 10 0.007 0.15 1.8 131.3 96.4 109.7 206.1
(0.003-0.13) (0.05-0.25) (1.0-3.0) (121-140) (92-100) (103-116) (190-211)
6/26/84 1200 3 10 0 0 0 110.2 94.2 106.4 200.6
(104-115) (91-100) (100-112) (194-210)
f-Statistic 8.19** 13.04** 1.24** 2.69 1.13 3.6** 11.53**
3
Table2.—ComparativefishnumbersandbiomassesintheSantaFeRiver,and RiosNambeand
Capulin, 1982-1984.
Numberper Biomass
Stream Year Section 50m km g/50m kg/km
SantaFeRiver 1982 1 40 800 1,052 21.0
2 40 800 1^423 28.5
1983 1 36 720 1,110 22.2
2 57 1,140 2,786 55.7
Mean 865 1,593 31.9
RioCapulin 1983 50 1,000 1,092 21.8
1984 38 760 1,340 26.8
2 35 700 1,165 23.3
3 19 380 801 16.0
Mean 710 1,100 22.0
RioNambe 1983 1 37 740 1,117 22.3
1984 1 23 460 1,626 32.5
2 8 160 394 7.9
Mean 453 1,046 20.9
Table3.—PreliminaryfishstatisticsinMogollonRimstreamsbasedonsamplesof50-msectionsof
stream. Relativeranksfromhighesttolowestareshown inparenthesesafterstatistics.
Numberof Biomass Fishdensity Meanlength Meanweight
Stream(n)1 Summer fish/km (kg/km) n/m2 g/m2 offish(cm) offish(g)
Pine(5) 1985 1,500(2) 54.8(2) 0.53(1) 15.0(2) 14.6(3) 36.5(4)
1986 1,396(2) 38.9(4)
Horton(7) 1985 680(3) 46.2(3) 0.12(5) 11.8(3) 16.2(1) 70.0(1)
1986 350(4) 39.0(3)
Christopher(2) 1985 2,780(1) 66.4(1) 0.46(2) 15.2(1) 11.6(5) 23.9(5)
1986 1,853(1) 60.3(1)
Ellison(2) 1985 290(4) 6.0(6) 0.27(3) 6.9(4) 10.8(6) 11.1 (6)
1986 533(3) 13.8(4)
Dude(2) 1985 200(6) 10.6(4) 0.16(4) 6.2(5) 15.9(2) 48.0(2)
1986 302(5) 12.0(4)
Bonita(2) 1985 210(5) 8.5(5) 0.08(6) 5.1 (6) 14.3(4) 40.6(3)
1986 152(6) 10.7(2)
1Numberof50-msections.
section1intheRioCapulindecreased25%infishnum- numbersandbiomassintheSantaFeRiverwerehigher
bers between 1983 and 1984, but biomass increased thanintheothertwostreams(table2),naturalvariation
23%.Numberoffishinstudysection1decreasedalmost (seePlattsandNelson1988)andsportfishingeffectscan-
40%from1983to 1984intheRioNambe,butbiomass notbeadequatelydefinedbysuchbriefsampling(Platts
increased 46%. 1981).
Fish populations in the "quasi-pristine" Santa Fe Arizona.—Based on mean widths and summer low
watershedwerenotsignificantlygreaterthanintheRios flows, the sixMogollonRimstreams are grouped into
NambeandCapulin—watershedsundernormalmulti- three larger (Pine, Horton, andChristopher) andthree
ple use management. In an interstream analysis ap- smaller(Bonita,Ellison,andDude)creeks(table4).Sum-
proach, the question of comparability of watersheds merwatertemperatureswereslightlywarmerintwoof
immediatelyarises. Thethree streams arecontiguous; thestreams(DudeandBonita).Chemically,allstreams
they head on the same mountain. However, geologic are similar except Pine Creek, which displayed the
strata,watershedexposure,andvegetationmaybediffer- highestspecificconductance,alkalinity,hardness,and
ent.Themostobviousdifferenceisthatsportfishingis dissolved oxygen.
prohibitedontheSantaFeRiverbutoccursontheRios Overall, fishnumberandbiomassperkilometerfol-
NambeandCapulin. Indeed, onemightexpectgreater lowedstreamsize (table3). However, Christopherand
fishpopulationsintheSantaFe.Althoughaveragefish PineCreeksrankedaheadofthelargerHortonCreekin
4
Table4.—PhysicochemicalcharacteristicsofMogollonRimstreamsinsummer1985.Temperature,pH,dissolvedoxygen,andspecificconductance
arebasedon24-hrdata(rangesinparentheses);theremainderofparameterscomprise5sampleseach.Meanwidthsarederivedfrom10
measurementsandflowsfrom5estimates.
Dissolved Specific Mean Total Total
Stream Date Tempe(rC)sture pH o(xmygg/Lo)n co(nmdmuchtossn)c6 wi(dm)th PNu0t4rienNt0s3(mgS/L0)4 m3/min di(rvmdgii/iLii)iy hs(rmdg/nLG)ss
Pine 6/27 13.8 7.8 8.6 278 2.6 0.19 1.01 4.2 1.66 132 171
(11.2-16.4) (7.7-8.0) (8.0-9.8) (269-285)
Horton 6/24 14.6 7.9 8.1 237 3.1 0.36 1.04 14.6 5.65 129 165
(10.9-19.4) (7.6-8.3) (7.4-9.0) (234-240)
Christopher 6/26 11.5 7.7 8.6 231 4.0 0.38 1.03 17.8 2.39 88 149
(9.3-15.2) (7.6-8.0) (8.1-9.1) (229-232)
Ellison 7/23 14.6 7.5 7.6 211 2.0 0.16 0.66 2.6 0.28 87 140
(13.1-16.1) (7.4-7.6) (7.2-8.0) (209-217)
Dude 7/20 16.9 7.8 7.7 251 2.0 0.24 0.83 3.4 0.37 105 158
(14.6-20.1) (7.7-8.1) (7.0-8.0) (245-254)
Bonita 8/6 15.0 7.8 8.4 239 2.1 0.39 0.70 1.2 1.12 120 149
(13.0-17.7) (7.7-7.9) (7.7-9.5) (234-250)
thesestatisticsandintroutdensity(numberandgrams replication ofexperiments, and avalid research area.
persquaremeter).Basedonmeanlengthandweightof The Rio de las Vacas study findings allude to the
fish,HortonCreeklackedsmallerindividuals,perhaps difficultyinachievingcontrolandreplicationonNation-
reflecting reduced spawning success inthatstream. al Forest lands, even on a single stream system. A
AverageCalculatedBioticConditionIndicesforaquat- researcher's inabilitytocontrolthevarying degreesof
icmacroinvertebrateswerehighest(83)inChristopher; landusesprecludesdeterminingthedifferentialimpacts
identicalinPine,Horton,andBonitacreeks(74-75);and ofthese respective uses. Independent management of
leastinDude(66)andEllison(57)creeks.Awaterpen- habitatbythe Forest Service andthe sport fishery (or
ny (genus Psephenus) that may be an indicator of hunting)bystatenaturalresourcedepartmentsfurther
reducedsubstratefinesediments(Usinger1956:365)was complicates the situation (Rinne 1988a).
collected only in Pine Creek. The presence of water Land use planning is an essential and functioning
penny, greatertroutdensityandbiomassinPinecom- componentoftheNationalForestPlanningActof1976.
paredto Horton, andapparent lackoftroutreproduc- However,well-designedstudiesconductedbythescien-
tioninHortonmayindicateincreasedsubstratefinesin tificmethodunderonemanagementplancaneasilybe-
Horton.Nevertheless,streamsizebasedonmeanwidth comeinvalidatedbyachangeinmanagement.Further,
andflowappearstolargelyinfluencefishnumbersand changesinlandmanagementplansbytheForestServ-
size (RinneandMedina 1988). SimilartoboththeRio icecanbeappealedbypermittees.Forexample,recent
de las Vacas and the Santa Fe area streams, both fish effortsweremadetocooperatewithoneforestinRegion
numbersandbiomassgenerallydecreasedintheMogol- 3 to studythe effects ofgrazing managementchanges
lonRim streamsbetween 1985 and 1986 (table 3). on one allotment that encompasses three contiguous
Theutilityofusingcontiguous,orpaired,watersheds montaneriparian-streamecosystems. Limitedpretreat-
to delineate land management effects on riparian ment data onfishes were available and plans were in
ecosystemsisnotabsolute.Severalyearsofdatacollec- progresstominimallymodifyspatialaspectsofthere-
tionareprerequisitetoestablisha"referencepoint"for vised grazing planby addition ofone fence. The pro-
individualstreams.Differential,historic,cumulativeef- posedplanandtheoveralldesignwouldhaveprovided
fectsofthevaryingmultipleusespotentiallyrendereven ample time for collection of additional pretreatment
"across the divide" riparian areas to be in different information. Itwas an excellent opportunity forvalid
states.Thepresenceof"nearpristine"watersheds,such researchthatpotentiallywouldproducemuchneeded
asPineCreek,providesanindexorreferenceofpoten- information for land managers. The permittee subse-
tialnaturalconditionandisinvaluableforestablishing quently appealed the proposed changes and litigation
researchdesignedto determinethe effects ofmanage- becameimminent.Aresearcherisalwaysatriskinsuch
mentactivity onthewatershed. asituation.Unfortunately,suchlitigationdelaysmuch
needed research and management opportunity.
Moreover, future management may be based on the
ResearchComplexity resultsofthecourt'sdecision,whichwillbeeconomi-
cally, socially, orfinanciallybased(BormanandJohn-
Basicrequirementsofscientificfieldresearcharecon- son1990)ratherthanbeingbasedonecology,biology,
trol ofvariables in time and space, adequate design, hydrology, or known best management practices for
5
riparian and fisheries resources. Ultimately, in such instream morphology and sedimenttransportwillbe
cases,thelandmanager,theresearcher, andthenatur- determined.Thedynamicsofwoodyorganicdebrisdis-
al resources all lose. positionandmovementthroughthesesystemsandtheir
effects on fish and theirhabitat will continue. Future
grazingstrategiesconceivablywillbedesignedtopro-
Natural Disturbance, Forest Management, videasettingforresearch(Rinne1989,SzaroandRinne
and Research Opportunity 1988).
Opportunities forcooperativeresearchand manage-
Often,naturaldisturbanceeventseffectchangesinthe mentefforts,suchasthoseoutlinedaboveandinprocess
landscape thatprovide opportunities forthe research- ofbeinginitiatedonthewatershedsandintheriparian
er. TheDudeFireisanexampleofsuchanopportuni- areas affectedbythe Dude Fire, conceptuallywill ad-
ty. The Dude Fire resultedfromlightning onJune 25, dresssomeoftheabovesuggestedshortcomingstovalid
1990. More than 10,000 ha of forest burned in the fieldresearchefforts,ifmanagementdirectiondoesnot
watershedsofDude,Bonita,andEllisoncreeks.Amul- change.Multiyearpretreatmentdataareavailable.Tim-
tidisciplinary rehabilitationteam was formed and im- berharvestformanyyearsto comehasbeenremoved
mediatewatershedrehabilitationwasinstitutedthrough forall practical purposes by the fire, and grazing has
aerial seeding. Several small salvage timber contracts beensuspendedforseveralyearsbydecree.Removalof
havebeenlet. Atwo-yearmoratoriumhasbeenplaced thesehuman-inducedimpactsforseveralyearsallows
on grazing. forevaluationoftheresponseofboththewatershedand
One ofthe team's charges was to draftalong-range riparian areas to natural events such as meteorology,
planforwatershedrehabilitationandmanagementinthe geology, botany, andhydrology. Further, there is am-
aftermathofthefire.Thelong-termscopeoftherehabili- ple opportunity to later induce grazing design over a
tationeffortanditsmultidisciplinaryphilosophy,com- longtermthatwouldalloweffectiveevaluationthrough
bined with more than three years of serendipitous separation of previous natural versus subsequently
pretreatment information onfish populations, aquatic human-induced impacts on riparian areas.
macroinvertebrates, substrate fine content, and water Replication in most grazing studies has been done
quality,providedanunprecedentedopportunitytoex- linearly in treatments (pastures) on the same stream
aminetheresponseoftheriparianhabitatandbiotato (Rinne 1988a). Althoughsuchadesignremoves inter-
wildfire and future land uses. streamvariability,itisdeficientincontextofthefunc-
Fishpopulationnumbersandspeciesweredetermined tioning ofstream ecosystems (Rinne 1989; Rinne and
withinaweekafterthefireandpriortothesummerrainy Medina,inpress).Thatis,althoughtheterrestrialcom-
season.Nosignificantdifferenceinfishpopulationsoc- ponentsoftreatments(pastures)arerelativelyconfined
curred among the three streams immediately afterthe anddefinable,theaquaticcomponentsareverydynam-
fire (table 5). Spotsampling inlateJuly afterflooding ic.Water,itsquantityandqualityandstreambiotacan
revealednofish. Subsequentsamplingthroughoutthe changefrequentlyandquicklyandarenotdelimitedby
stream courses in October 1990 and February 1991 strandsofbarbwire.Thiswaswelldemonstratedinthe
documentedonlyoneadult(300mm)brooktroutinthe Vacas study. Theinfluencesofspatialrelationshipsof
headwaters ofDude Creek; effectively, fishhavebeen grazed stream reaches versus contiguous ungrazed
eliminatedfromthethreestreams.Becausetroutareab- reaches must be considered in designing research
sent,re-introductionsoffishesareproposedto(1)evalu- studies. Ifan interstreamapproach is necessary, graz-
ate elevated water temperatures in June 1991, (2) ing must be conducted only in downstream reaches.
determinefloodingeffectsonfishes,(3)delineateflood- Fencing and ultimate grazing strategies based on
ing effects on fish food sources (aquatic macroinver- watershedboundariesandinthemoredesirableinter-
tebrates), and (4) determine if immediate (July 1990) streamapproach areboth achievable objectives onthe
postfirequantityorqualityofwaterwasresponsiblefor watersheds affectedbythe Dude Fire.
loss offishes. Otherpossiblesolutionstothe dilemmaofconduct-
Analysesofwaterquantityandquality,andofaquat- ingviable, defendableresearchwouldbe (1)toutilize
icmacroinvertebrateswillcontinueinthesub-Mogollon existingexperimentalforests, or(2)designatelanduse
Rimstreamsaffectedandunaffectedbythefire.Changes management with research priority. Arizona contains
Table5.—Comparisonoftheeffectsoffireonthreetroutpopulations(numberfish/km),MogollonRim,
centralArizona.
Trout(number/km)
Date Dude Bonita Ellison
Prefire(1985-86) 360 440 400
Immediatelypostfire(7/9/90) 260 360 160
Threeweekslater(7/25-26/90) 0 0 0
Autumn(10/23/90) 0 0 0
Winter(2/26/91) 1 0 0
(S