Assessing the Indicator Properties of Species Assemblages for Natural Areas Monitoring Author(s): Claire Kremen Source: Ecological Applications, Vol. 2, No. 2 (May, 1992), pp. 203-217 Published by: Ecological Society of America Stable URL: http://www.jstor.org/stable/1941776 . Accessed: 07/02/2014 15:50 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 of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecological Applications. http://www.jstor.org This content downloaded from 128.32.85.74 on Fri, 7 Feb 2014 15:50:07 PM All use subject to JSTOR Terms and Conditions Ecological Applications,2(2), 1992, pp. 203-217 ? 1992 by the Ecological Society of America ASSESSING THE INDICATOR PROPERTIES OF SPECIES ASSEMBLAGES FOR NATURAL AREAS MONITORING' CLAIRE KREMEN Centerfor Conservation Biology, Stanford University, Stanford, California 94305 USA Abstract. The diversityof organismsand complexityof ecosystemsprevent thorough inventoryand monitoringof protectedareas, yet sound databases are needed to manage ecosystems for long-termpersistence. One strategyis thereforeto focus monitoringon indicatororganisms, but guidelinesare lackingfor selecting appropriate species or groups. This paper presentsa simple protocolbased on ordinationtechniques for establishing the indicatorproperties of a group of organismsand forselecting an indicatorspecies subset formore intensivemonitoring. Use of ordinationallows inclusionof many more taxa than have been traditionallyused fornatural areas monitoring,and need not relyon detailed knowledgeof species biology.As an example,I studiedthe indicator properties of a butterfly taxocene in a rain forestin Madagascar. Butterflieshave been suggestedas particularly good environmentalindicators due to their sensitivityto micro-climateand light level changes,and theirinteractions as larvae and adults with differentsets of host plants. The indicatorproperties of butterflyassemblages were evaluated in this studywith respectto a known patternof environmentalheterogeneity along topographic/moistureand distur- bance gradients.Butterfly assemblages were found to be excellentindicators of heterogeneity due to the topographic/moisturegradient, limited indicatorsof heterogeneitydue to an- thropogenicdisturbance, and poor indicatorsof plant diversity.The protocol definedin this studyis widely applicable to othergroups of organisms,spatial scales, and environ- mentalgradients. By examiningthe environmentalcorrelates of the distributionof species assemblages, this protocol can assess the indicatorproperties of targetspecies groups. Keywords: diversity;dominance; ecological monitoring; indicator species assemblage; Madagas- car; naturalareas conservation;ordination; rarity; Satyrinae; tropical butterflies. INTRODUCrION lation trendsor habitat quality (Landres et al. 1988). Most ecosystemstoday are subject to one or more Given the difficultiesinherent in using one or a few formsof anthropogenicdisturbance, especially pollu- species as indirectassays of complex ecosystemstruc- tion and acidification,habitat modificationand frag- tureand function(Ward 1978, Kimball and Levin 1985, mentation,and invasions by introducedspecies (Soule Cairns 1986, Soule 1987, Landres et al. 1988, Noss needed to establishand testcri- and Wilcox 1980, Burgessand Sharpe 1981, Petersand 1990), furtherwork is Darling 1985,Soule 1986, Schreiberand Newman 1988, teria forselecting indicators. Carleton 1989, Fajer 1989, Fajer et al. 1989, Klein Much previous workinvolving indicators has relied 1989). Given the pervasive spatial and rapid temporal on utilizingone or a few species (e.g., Management scale of currentanthropogenic environmental changes, Indicator Species of the Forest Service, Landres et al. methods are needed forchoosing appropriatespecies 1988). The failingof thisapproach is its narrowfocus, or species assemblages for establishingconservation which can resultin protectionof one organismat the prioritiesand monitoringbiotic responsesto local and expense of others(Kushlan 1979, Landres et al. 1988). global environmentalchange (Kimball and Levin 1985, By contrast,use of a greatervariety of indicatorspecies Soule 1990). could provide more fine-grainedinformation (Noss Outside of a substantialliterature on singleor multi- 1990): thedegree of detail gainedwould in turndepend species indicatorsof specificenvironmental contami- on variation in microhabitatuse, niche breadth,eco- nants (Cairns 1985, 1986), few practical guidelines logical function,and responseto environmentalchange currentlyexist forselecting indicators for monitoring among membersof the indicatorassemblage. By using naturalareas. A recentreview criticallyevaluated se- ordinationtechniques, one can easily examine the dis- lectionof vertebrate indicators, concluding that no sin- tributionsof many species simultaneouslyand their gle traditionalcriterion (e.g., highsensitivity to habitat relationship to environmental parameters (Gauch modification,large size, habitat specialization, low 1982a, Ter Braak 1987, Peet et al. 1988). These pow- population or species turnoverrates, or large area re- erfulmultivariate tools allow assessment of the indi- quirements)can be safelyused for monitoringpopu- cator propertiesof a much wider array of organisms, and could be used to broaden monitoringconcepts to I Manuscriptreceived 7 January1991; revised and accepted include detectionof environmentalpatterns based on 15 August1991. the response of a group of species. This content downloaded from 128.32.85.74 on Fri, 7 Feb 2014 15:50:07 PM All use subject to JSTOR Terms and Conditions 204 CLAIRE KREMEN Ecological Applications Vol. 2, No. 2 This paper presentsan analyticalmethod based on time for adult courtshipand oviposition, Watt et al. ordinationtechniques for assessing the indicatorprop- 1968, Kingsolver 1983a, b; severe climate and popu- ertiesof a given species assemblage (guild,taxon, tax- lation extinction,Ehrlich et al. 1972). Since butterfly ocene, or community).The method firsttests whether populations respondto habitatmodifications affecting the distributionaldata fromthe chosen species assem- local climates and light levels, it has been suggested blage indicateenvironmental patterns at thegeograph- that changes in butterflypopulations could serve to ic scale of interest.It then determineswhich environ- herald local or global climate change (Murphy et al. mental parametersthe species assemblage serves to 1990). indicate. Finally,it providesa frameworkfor selecting While studiesof butterflieshave contributedto con- the most importantindicator species fromwithin the servationbiology in both a populationand community originalspecies assemblage. context(e.g., Brown 1982, Ehrlichand Murphy 1987, Murphyet al. 1990, Singletonand Courtney1991), no Butterfliesas indicators studiesto date have evaluated the indicatorproperties The taxon Rhopalocera (butterfliesand skippers)was of butterflyspecies or assemblages. This studyexam- the group chosen forthis studyof a rain foresthabitat ines the abilityof butterflycommunity data to reveal in Madagascar. Littleecological informationexists on patternsof habitat heterogeneitydue to topography these species or theirhabitat, and some of the taxa are and anthropogenicdisturbance. Variation related to poorlydefined at the species level. This studytherefore thesetwo parametersstrongly influences micro-climate requireda method forchoosing indicatorspecies that and plant community composition (Swanson et al. did not depend on detailed knowledgeof theirbiology. 1988), and thusprovides one appropriateassay ofsome This propertyof the method developed below makes of the proposed indicatorproperties of butterflies. it particularlyimportant for use in testingand selecting METHODS indicatorsin regionswhere the ecological information- base is poor. Fieldsite In addition, the choice of the Rhopalocera allowed The fieldsite was located in the southeasternmon- a test of the claim, advanced by several authors,that tane rain forestof Madagascar, 7 km southwestof Ra- butterflieshave a particularvalue as ecological indi- nomafanaon route45 in the provinceof Fianarantsoa. cators (Gilbert 1980, 1984, Pyle 1980, Brown 1982, The area is topographicallydiverse, with steeply wood- Murphy et al. 1990). On a practical basis, butterflies ed hills, dissected by numerous streamsdraining into (in comparisonto otherinsect taxa) have a manageable the Namorona River. The site had a treespecies rich- level of diversity,are betterknown taxonomically, and ness on the order of 95 species/0.2 ha (D. Overdorff, can in many areas be reliably identifiedin the field unpublisheddata) includingFicus spp. (Moraceae), Eu- (Pollard 1977, Thomas 1983, Thomas and Mallorie genia spp. (Myrtaceae), Weinmannia spp. (Cunoni- 1985, Murphy and Wilcox 1986). On biological aceae), Symphonia spp. (Guttiferae),Ravensara and grounds,it has been suggestedthat butterflydiversity Ocotea spp. (Lauraceae), Pittosporumspp. (Pittospora- could be used as an index ofplant diversity (Pyle 1980), ceae), and many others. Common understoryplants