Population Biology of Checkerspot Butterflies and the Preservation of Global Biodiversity Author(S): Paul R

Nordic Society Oikos

Population Biology of Checkerspot Butterflies and the Preservation of Global Biodiversity Author(s): Paul R. Ehrlich Source: Oikos, Vol. 63, Fasc. 1 (Feb., 1992), pp. 6-12 Published by: Wiley on behalf of Nordic Society Oikos Stable URL: http://www.jstor.org/stable/3545510 . Accessed: 19/11/2014 10:03

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions OIKOS 63: 6-12. Copenhagen1992

Populationbiology of checkerspot butterflies and thepreservation ofglobal biodiversity

Paul R. Ehrlich

Ehrlich,P. R. 1992. Populationbiology of checkerspotbutterflies and the preservation of global biodiversity.- Oikos 63: 6-12.

Long-termresearch on Euphydryaspopulations has yielded much insightinto the requirementsfor conserving invertebrates. It also, however,has shownthat too much time is requiredto obtain such insightsspecies by species to preserveglobal biodiversity.Instead, quick samplingmethods must be devised to take inventoriesof the biota in prospectivereserves, planning use patternsin thosereserves, and monitoring the results.Conservation biologists have about a decade to develop and deploy such systemsif they are to play a significantrole in preventingthe loss of morethan half of terrestrialbiodiversity.

P. R. Ehrlich, Centerfor ConservationBiology, Dept of Biological Sci., Stanford Univ., Stanford,CA 94305, USA.

This paper addresses a series of points that have The species emergedfrom the combined work of our researchgroup approach to biodiversity in two seeminglydisparate areas: long-termfield and In the public mind,the biodiversitycrisis is one of loss laboratoryresearch on the populationbiology of butter- of species. This view is embodied in the lists of en- flies, especially of the checkerspotEuphydryas editha dangeredspecies producedby both governmentalbod- (Nymphalidae: Nymphalinae),and policy researchon ies and nongovernmentalorganizations, in the United the preservationof biodiversityand the maintenanceof States' Endangered Species Act, and in the publicity the ecosystemservices that depend upon it (Ehrlichand given to species on the brinkof extinctionsuch as the Ehrlich1981). Here I discusssome of the conclusionsI black rhinoand Californiacondor. This approachis also have drawn frommore than three decades of work in rootedin the scientificliterature, where the traditionof these two fields. My most importantconclusion is dis- focusingon species diversityas the measure of biodi- tressing.The sortof intensive,species-focused research versityis well entrenched(e.g., MacArthur1972; but that I and my colleagues have carried out on Euphy- see Hendricksonand Ehrlich1971). dryasappears to have a verylimited future in conserva- As usefulas a species-basedapproach to biodiversity tionbiology. Instead, ifa substantialportion of remain- has been, it suffersfrom numerous drawbacks. While it ing biodiversityis to be conserved,detailed studiesof is clear thatby farthe largestnumber of animalspecies singlespecies mustbe replaced with"quick and dirty" live in terrestrialhabitats, especially in tropicalmoist methodsof evaluatingentire ecosystems, designing re- forests(Wilson 1989), it is equally evidentthat propor- serves to protectthem, and determiningwhether those tionatelymuch greaterdiversity of phyla and classes is reservesare working. foundin the relativelyspecies-poor oceans (May 1989). I'll say no more about this aspect of diversityhere, except to point out that fromthe perspectiveof biologists,the worldwould be a muchpoorer place without

Accepted13 November1990 (D OIKOS

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions cephalopods, loriciferans,pycnogonids, ophiuroids, 1986, Murphyet al. 1990, Thomas et al. 1990). If pop- and the like. Whetheror not theycan provideus with ulationsare conserved,then species are conserved(but economic benefitsor play crucial roles in ecosystems, not necessarilyvice versa). Our group's long-termre- unusual organismsare fascinatingand help us to under- searchon checkerspotbutterflies (Euphydryas) has pro- stand the possible avenues thatcan be taken by evolu- vided considerableinsight into the causes and conse- tion. quences of populationextinction, and thereforeinto a wide arrayof global conservationissues.

The importanceof populationdiversity The need to conserveplants and Toward the other end of the scale, the importanceof populationdiversity is oftenoverlooked. First of all, the invertebrates genetic and ecological diversityamong populations Beforediscussing Euphydryas in more detail,I'd like to helps bufferspecies againstextinction. Geographically emphasize the great need to shiftthe emphasisin the circumscribedspecies withlittle population diversity- conservationcommunity from the protectionof "charis- especially island species - have proven highlyextinc- maticmegavertebrates" to the protectionof smalleror tion-prone.Population diversityis also extremelyim- less spectacular organisms.Everyone concerned with portantto the abilityof species to provide goods and conservationwants to see the panda survive,but from services needed by humanity.Substantial genetic di- the viewpointof both pandas and people the preserva- versityis required,for instance, in potentialcrop plants tion of more obscure organismsis crucial. Maintaining and theirrelatives in order to permitthem firstto be the diversityof plantsis, of course,the keyto the entire developed intosatisfactory crops and thento keep up in enterpriseof securingthe futureof the rest of organic the coevolutionaryraces theyrun withtheir predators diversityand of humansociety. Without bamboos there and parasites. And if the population of Engelmann would be no pandas; withoutthree kinds of grasses,Zea spruce trees (Picea engelmannii)in a watershedis de- mays,Oryza sativa,and Triticumspp. (whichhave been stroyed,with it will go the flood-controlservice of the developed into maize, rice, and wheat), therewould be subalpineecosystem. It will thenbe of littlecomfort to no civilizationas we know it. those drowned downstreamthat the species is in no Insects and otherterrestrial arthropods are also cru- dangerof extinction. cial componentsof the entireweb of life(Gilbert 1980, Our work with Euphydryasbutterflies has shown Wilson 1987). Withoutinsects and theirrelatives, the clearlythe significanceof populationdiversity to prob- livingworld would be unrecognizable.Loss of the polli- lems of conservation(Singer 1971, Gilbertand Singer nation and seed dispersalservices performed by insects 1973, Ehrlichet al. 1975, McKechnie et al. 1975, Ehr- and the absence of insectherbivory would dramatically lich and Murphy1987, Murphyand Weiss 1991a). Pop- alter (and pauperize) plant communitiesin ways that ulationsof Euphydryaseditha, for example, differfrom are difficultto imagine. The absence of insects and in one another genotypes,phenotypes, phenologies, use mites,which along withthe nematodescould comprise of resources, and flightbehavior (Singer 1971, 1972, more than 95% of species diversity(May 1989), would White and Singer 1974, Ehrlich et al. 1975). If this reverberatethrough food webs, changingsoil faunas of species herbivorousinsect is to be conserved,knowl- and fertility,exterminating most species of birds and edge of the biology of individualpopulations will be muchof the remainderof Earth's terrestrialvertebrate essential - since phenomena that threatenone pop- faunaas well as manyfreshwater fishes. The loss of ants ulation will not necessarilythreaten another. This was alone would completelyunravel tropical-rainforest eco- clearlydemonstrated the by varied responsesof groups systems(in which ants are key herbivoresand preda- of E. editha to populations the Californiadrought of tors) and cause untoldhavoc in most otherecosystems 1975-77 al. (Ehrlich et 1980). It should also be noted (Gilbert 1980, Holldobbler and Wilson 1990). that sort the of population diversitypresented by E. Insects and other terrestrialarthropods, after all, editha can be of considerablesignificance in questions comprisethe vast majorityof organicdiversity, with the related to of delivery ecosystemservices, control of possible addition of the still poorly-knownnematodes and of pests, harvesting economicallyimportant spe- (May 1989). Indeed, in termsof species diversity,all the cies. It is clear fromour for work, instance,that within a restcould almostbe considereda side issue. Also, most singlespecies some populationsmay have the capacity insectsare herbivorous(Erwin 1982); one could there- to be more effective crop pollinators(Murphy 1984) or foreview Euphydryasas representingthe verycore of more dangerouscrop pests, and thatsustainable yields biodiversity. may varygreatly between populations. Second, withtrivial exceptions, the processof species extinctionis actuallya complex process of progressive population extinction(Shaffer 1981, Gilpin and Souls

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions that appear vulnerableto inbreedingeffects, those ef- Euphydryasand the tacticsof fectshave not yetbeen detected.A transplantedcolony of E. gillettii(Holdren and Ehrlich1981) has persisted conservation withan Ne apparentlyless than 50 individualsfor thir- Perhaps the single most importanttactical conclusion teen generations;it may eventuallyprovide important for conservationiststhat can be drawn fromour long- informationon inbreedingresistance or susceptibilityin termresearch on these butterfliesis that the preserva- Euphydryas. tion of small invertebrateswill require a verydifferent Terrestrialinvertebrates normally do not have large approach fromthat developed on the basis of mega- home ranges or territories.Individuals of some trap- vertebrates.Think of the kinds of issues that pervade liningspecies in tropicalforests, such as euglossinebees the conservationof, say, rhinos,cheetahs, or condors. and heliconiinebutterflies (Ehrlich and Gilbert 1973), Whatis the minimumviable censussize thatwill sustain may require manyhectares of habitatto supportthem a populationof cheetahs?Are survivingindividuals too because of the dispersionof theirfood resources.But inbred? How much habitat is required to provide areal requirementsmeasured in square kilometers,seen enoughterritory space fora populationof black rhinos? in organismssuch as Californiacondors, grizzlybears, Should ex situconservation be attemptedfor California and Sumatran rhinos (Hutchinson and Ripley 1954) condors? How can deliberate killingof elephants by have rarelybeen ascertainedin insects,and individuals humanbeings be prevented? of even medium-sizebutterflies often are quite site- These are rarelyfirst-order kinds of questionsin in- tenacious and largelyconfine their activities to a few vertebrateconservation. For example, while establish- hectares(Daily et al. 1991). ing a minimumviable population size (MVP) (Soul6, Indeed forEuphydryas, and many(if not most) other 1987) - or, more likely,a minimumviable metapop- insectherbivores, the detailed qualityof the habitatis ulation(MVM) (Ehrlichand Murphy1987) - can be an much more importantthan its extent. Relatively re- interestingand usefulexercise with invertebrates, nor- strictedareas of the mostsuitable environment can sup- mallyendangerment is patentlong beforesuch a size is portreservoir populations that supply the long-distance even approached. The subspecies Euphydryaseditha dispersersthat maintain a species' metapopulationin a bayensisin the San FranciscoBay area is clearlyimper- largearea. Given enoughspace, grizzlybears, withtheir iled (and has been listedas "threatened"under the U.S. greatmobility and catholicdiets, can findfood. Further- EndangeredSpecies Act). Neverthelessthe large reser- more, they are able to persistin a wide range of cli- voir populationof the southernBay area metapopula- mates, from arctic tundra to semi-desert.Almost all tion (Ehrlich and Murphy1987) always numbersmore "generalist"insects, however, are specialistswhen com- than 104adults and oftenexceeds 10' individuals(Mur- pared to vertebrates.If the appropriate oviposition phy and Weiss 1988a). plantor plantsfor a populationof a Euphydryasspecies Indeed, a populationof 105E. edithamay existon a disappearsfrom a reserve,the butterflywill not persist, few dozen hectareswhen environmentalconditions are no matterhow largethe reserve.Furthermore, the den- optimal.In contrast,it is possible thatthere have never sityof the food plant usually must be high enough to been 105 grizzlybears at one time in the coterminous permitlarvae to move to a new plantwhen one has been UnitedStates. Few, ifany, vertebrates would be consid- devoured (few host plants are large enough to support ered endangered with populations of 104 adults. But the dozens of larvae froman egg mass fromhatch to thenfew vertebrate populations (and no populationsof diapause) (Singer1972). Grizzlybears can move tensof large vertebrates)typically go through2-5 fold annual kilometersin search of food, larvae at most tens of size fluctuations,as E. edithadoes often(Ehrlich et al. meters. 1975, Murphyand Weiss 1988a). For mostvertebrates, Also unlikemost vertebrates, Euphydryas are heavily again unlikeE. editha,population extinctions are not a dependenton appropriatemicroclimates for theirsur- normalpart of theirpopulation dynamics (Ehrlich et al. vival. In the mostintensively studied populations, those 1975, 1980). of E. editha bayensis,the eggs are laid in March and Endangered invertebratepopulations do not ordina- April, and the newlyhatched larvae immediatelyfind rilypersist with only a handfulof individualsover many themselvesin a race withthe senescence of theirfood generations(Murphy et al. 1990). Inbreedingdepres- plants(Singer 1972). If theyfail to reach the instarthat sion, therefore,has not oftenbeen a serious concern. can diapause throughthe dry summermonths before The standardthat populations should be maintainedat theplants senesce, they will not survive. Whether or not several hundredindividuals or more over manygener- the larvae can win the race dependson a complexphase ations to avoid inbreeding(Lande and Barrowclough relationshipbetween the phenologyof the host plant 1987) is rarelyviolated. Small demographicunits in E. and the insect populations(Singer and Ehrlich 1979). editha metapopulationsappear to receive immigrants That relationship,in turn,depends heavily on the inter- frequentlyenough to preventgenetic difficulties (Mur- actionsbetween topography of the habitatand its mac- phy et al. 1990), and that may be typical of insect roclimate that create diverse thermal microenviron- species. Furthermore,even in Euphydryaspopulations

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions ments or "topoclimates." (Geiger 1965, Murphyand establishthe extentof reserveswith an eye on the home Weiss 1988b, Weiss et al. 1988, 1990). ranges and resource needs of charismaticmegaverte- In habitatswith a singleexposure (say a gentlesouth- brates, the areal requirementsof "big thingsthat run facingslope) sequences of yearsmay occur with weather the world" (Terborgh1988), but to locate the reserves that makes the plant-Euphydryasphenologies incom- withattention to habitatdiversity required by the "little patiblein the singleavailable topoclimate,and the pop- thingsthat run the world" (Wilson 1987). ulation will be drivento extinction.But if the habitat containsa varietyof exposures,it willpossess areas with at least some favorabletopoclimates under nearly all weather conditions conceivable in the macroclimate, Euphydryasand strategiesfor and the populationwill probably persist even ifthe area conservation of habitatis relativelysmall. The Californiadrought of 1975-77 caused numerous extinctionsof component I believe that the most importantconclusion from our populationsof the Santa Clara County E. e. bayensis group's work on Euphydryasis strategicrather than metapopulationbecause of the veryearly senescence of tactical.Our researchhas made it crystalclear thatthe the host plants (Singer and Ehrlich1979, Ehrlichet al. sorts of detailed ecological and evolutionaryinforma- 1980, Ehrlichand Murphy1987, Harrisonet al. 1988). tion thatone would ideally like to have beforerecom- Larvae simplyhad too littletime to growto the size at mendingconservation programs for invertebrate species which they can enter diapause. The heavy rains that will almost never be available. Research on the Eu- accompaniedthe 1982-83 El Nifioalso resultedin large phydryassystem has provided a great many tactical population declines, in this case because a paucityof lessons about single-speciesconservation for inverte- wintersunshine delayed adult flight(and oviposition) brates- thatis, how to accomplishthe preservationof a longer than it delayed host plant senescence, again givenspecies. It has shownthe importanceof identify- shorteningthe timeavailable forlarval growth (Dobkin ingdemographic units, of differentiatingmigration from et al. 1987). gene flow, of recognizingsubtle key habitat quality Environmental-qualityfactors, especially those con- factorssuch as slope and exposure, and so on (Ehrlich nected withweather (Ehrlich et al. 1972) and human- and Murphy1987). caused disturbanceof habitats,also seem to governthe But thosetactical successes have shownus how to win persistenceof other temperate-zonebutterfly popula- battleswhile losing the war. More thanthree decades of tions(see summariesin Ehrlich1984 and Murphyet al. researchby dozens of investigatorshas been requiredto 1990). I suspectthe extinctiondynamics of manyother gain a reasonable understandingof the populationbiol- invertebrategroups are similarlycontrolled by thecom- ogyof Euphydryaseditha, to providesome notionof the bined effectsof habitatfragmentation and environment geographic scale upon which conservationplanning tal extremes(drought, deluge, wildfire,etc.) in temper- must proceed and the phenomena that must be ad- ate areas, while otherfactors such as demographicsto- dressed, and to be able to make sound recommenda- chasticity and overexploitation are much more tions forthe conservationof the best-knownmetapop- importantfor vertebrates. ulations. That work has shown that lessons learned Almost nothing,unfortunately, is known about the workingon one suiteof populationsof E. edithaare not factorsinfluencing population persistenceof inverte- necessarilyapplicable to co-occurringclose relatives brates in tropicalecosystems, although it is those sys- such as E. chalcedona (Brown and Ehrlich 1980, Mur- tems that are most endangered. Certainlyhost-plant phy et al. 1986) or to distantpopulations of E. editha relationshipsare criticalfor butterflies(Ehrlich 1984) itself(Ehrlich et al. 1975, 1980). The amountof effort and other herbivorousinsects, and for at least some thatwould be requiredto advance understandingof the butterflies,adult pollen sourcesare crucialas well (Ehr- biologyof just the 600 or so species of butterfliesthat lich and Gilbert1973). Herbivoresin generalare prob- live in NorthAmerica to the level of E. edithatoday is ably more specialized in the tropics;thus the massive mind-boggling;it mightbe done in a decade withthou- destructionof tropicalforest vegetation now occurring sands of investigatorsworking at it - if those investiga- (Myers 1989) is certainlyleading to losses of popula- torscould be trainedinstantly. tions and species of invertebratesunprecedented at And yet the fate of a substantialportion of Earth's least since the last ice age and possiblyin the 65 million terrestrialfauna, invertebratesas well as vertebrates, years since the extinctionsat the K-T boundary. A willbe determinedin the nextdecade or two (Vitousek special problemin the tropicsis the conversionof low et al. 1986, Myers 1989, Wilson 1989, Ehrlichand Wil- elevation habitat with warm exposures to agriculture son 1991). Conceivably,10 to 25 millionspecies could and otherforms of development.This removesan array go extinct,and withthem could go muchof the abilityof of niches with particularinsolation, temperature, and Earth's ecosystemsto supply humanitywith essential precipitationregimes along with the biota associated services(Ehrlich and Ehrlich1981, 1990). The destruc- withthem (Murphy and Weiss 1991a, b). tion of tropicalforests, for example, is already greatly Overall, the best tactic for conservationmay be to adding to the atmospheric build-up of greenhouse

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions gases, worseninga problemwith the potentialto bring One of the firsttasks of the conservationcommunity down civilization. is to decide on taxonomic groups to be used as in- In short,there is not remotelythe time,the person- dicatorsin inventoryingand monitoring,and settle on nel, nor the financialsupport available to study the appropriatetechniques to be used. I would suggestthat biology of most of the populations that must be pre- the major effortgo into three already well-known servedif the majorityof Earth's biologicaldiversity is to groups:vascular plants, birds, and large butterflies(Pa- be saved - and along withit the crucialfunctioning of pilionidae, Pieridae, Nymphalidae).The plants,form- ecosystems.Indeed, it has long been evidentthat even a ing the base of most food chains and the basic food rough catalogue of species diversityis unlikelyto be resourcefor almost all animals,are an obvious choice. completedbefore most of thatdiversity is gone (Ehrlich Indeed, withan effortfunded to the level of the cost of 1964). In some cases, conservationbiologists will be two useless B-2 bombers ($1300 million), the task of able to use theirgrowing understanding of population more or less completinga global surveyof plantscould viabilityanalysis (PVA) in aid of the preservationof be completed. Botanists,plant collections,and botan- targetpopulations and species. But most populations ical gardensare crucialto the futureof humanity,and and species almostcertainly will go extinctbefore they botanical resourcesneed rapid expansion and deploy- are even discovered,let alone investigated.The sortof mentto accomplishthe task of understandingand pro- intensiveshort-term effort that has recentlybeen ex- tectingEarth's flora. It is an indicationof misplaced pended on understandingthe conservationbiology of prioritieswithin the scientificcommunity that relatively the northernspotted owl (Strixoccidentalis caurina) in unimportantexercises such as the sequencing of the the United States (Thomas et al. 1990) could serve as a human genome can take priorityover the assessment model forresearch on the conservationbiology of ver- and preservationof Earth's irreplaceable botanical tebrates, as the work on Euphydryascan for inver- wealth. tebrates.But togetherthese techniquesare likelyto be In theory,plants alone, because of theirfundamental applied to less than 1/10000 of all species, and less than roles in ecosystems,could formthe basis of most in- 1/1000 000 of all geneticallydistinct populations or sub- ventorying/planning/monitoring activity. But the prob- species. A new strategyis requiredfor the overall goal lems of identifyingplants in the field(especially in the of savingecosystems, not species one at a time. tropics)can be substantial.Subtle changes in treefloras will oftenbe signalled by shiftsin recruitment(adult trees may persistfor a centuryor more in habitatsno longerable to supporta viable population),and saplings A new approach forconservation biology can be especially hard to identify.The shortage of skilled botanical taxonomistsand field workersthere- So conservationbiologists must take anotherapproach, fore makes supplementationwith animal groupsdesir- even as theycontinue honing their PVA skillsfor those able. rare occasions when theycan be put to good use. They The alpha taxonomyof the roughly9000 birdspecies mustdevelop cookbook responsesfor the preservation is largelycomplete, and in mostareas of theworld there of endangeredspecies to serve in the absence of exten- are ornithologistsand birdwatchers capable of identify- sive autecologicaldata. They mustlearn to do rapidand ing most species and trainingothers to do so as well. rough inventoriesof the biodiversityin entireecosys- Birds are indicatorsof vegetationalstructure and, in tems, plan the preservationand managementof those some situations,of thepresence or abundanceof certain ecosystems,and develop techniquesfor monitoring suc- floralcomponents (e.g., manyfruiting trees in tropical cess in preservingthe biota of those systems.This inevi- forests),and migratoryspecies carryinformation on the tably means using samples, both systematicand ge- conditionof distanthabitats. A great deal of work on ographic, to representthe entire taxonomicrange of monitoringtechniques has alreadybeen done, but more organismsand the entireextent of the ecosystems.Such willbe requiredto standardizeand simplifythem so that roughsampling is bound to lead to some seriouserrors they will be readily used by relativelyinexperienced that could resultin the loss of some populations and people. species, but this circumstancemust now be accepted. Butterfliesare also well known taxonomically,and Withoutsuch "quick and dirty"inventory, planning, people withoutextensive biological training can quickly and monitoringprocedures, future losses willinevitably learn to identifythe largerones. Butterfliesare more be far greater. It has, afterall, been a decade since tightlylinked to the taxonomicdiversity of the plant publicationof the landmarkreport "Research Priorities communitythan are birds,and should providea rather in Tropical Biology" (NRC 1980). That reporturged, sensitizeindicator of the stateof thatcommunity. They amongother things, establishment of crashprograms of are also verysensitive to pesticides,a major factorin samplingtropical diversityand greatlyincreased sup- the overall toxificationof the planet, and, as our work port for systematics.But littlehas been done on the on Euphydryashas shown,are responsiveto a varietyof former,and the status of systematicshas, if anything, other subtle aspects of habitat quality. Appropriate deteriorated. transect,malaise trapping,and baitingtechniques have

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This content downloaded from 149.119.156.187 on Wed, 19 Nov 2014 10:03:50 AM All use subject to JSTOR Terms and Conditions been worked out for butterfliesand should be easily Conclusions modifiableand standardizedfor monitoring. In tropicalareas, monitoringthe healthof ecosystems In sum,we have learneda greatdeal of value to conser- by samplingthe bird and butterflyfaunas may prove vation in more than three decades of intensivework simplerthan attempting to monitorthe floraat all. The withthe Euphydryassystem and otherbutterflies (Ehr- selection of aquatic organismsto monitorwill also be lichand Murphy1987). But the mostimportant lesson is required, with frogsperhaps being the easiest. Frogs that Earth's biota cannot now be saved by the sort of also are sufferingmysterious declines in manyareas of laborious dissectionof the biologyof populationsthat the world and should thereforebe watchedclosely and we have engaged in. Rather,it is criticalthat conserva- be the subjectsof investigationsto determinethe cause tion biologists build on what is already understood or causes. Monitoringof streamnutrients and siltloads about well-knownorganisms to develop tools that can could also provide a sensitiveindicator for evaluating be used to save biodiversityquickly and en masse. And ecosystemhealth (O'Neill et al. 1977); the techniques it is also criticalthat they be active politicallyto press for doing so are well developed, and sample analysis forthe resourcesrequired to allow themto apply their could be successfullydone in tropical countries.Our tools beforeit is too late. group is currentlysetting up a test inventorying/planning/monitoringsystem adjacent to La Amistad Na- Acknowledgements- I thank the many students and colleagues tionalPark on the Costa Rica - Panama borderwith the whohave worked with me overthe past three decades on the collaborationof Latin Americanbiologists. We plan to Euphydryassystem. G. C. Daily,A. H. Ehrlich,P. H. Raven, and P. Vitousekwere kind enough to criticisethe manuscript. evaluate various ideas and techniques and establish Specialappreciation goes to myfriend and coworker,D. D. joint programsfor training of para-ecologiststo employ Murphy,for his comments on thispaper and forcarrying so successfultechniques elsewhere in the neotropics. muchof the load in recent years. This work has been supported Simple, accurate,repeatable inventoryand monitor- bya longseries of grantsfrom the National Science Founda- tion,the most recent of whichis BSR 87-00102,grants from ingprograms of coastal and marinesystems need also be the Ford,Koret, Hewlett, W. AltonJones, and MacArthur developed. There is some evidence that shorebirds foundations,and byindividual donors. (waders) (Myerset al. 1987) and pelagicbirds (Boersma 1986) mightprove to be usefulindicator organisms for oil pollution. Indeed, shorebirdsand migratoryland birds are already providingcivilization with a general- ized warningabout the state of Earth's environment References (Terborgh1989, Ehrlich 1990). There is some move- menttoward developing such programs, but moreeffort Boersma, P. D. 1986. Ingestionof petroleumby seabirdscan serveas a monitorof waterquality. - Science 231: 373-376. (and funding)is clearlyneeded. Brown,I. L. and Ehrlich,P. R. 1980. Populationbiology of the While developingtechniques for samplingbiodiver- checkerspotbutterfly, Euphydryas chalcedona: structure of sitymust have highpriority, so mustdecisions on allo- the JasperRidge colony. - Oecologia (Berl.) 47: 239-251. cating effortto the understandingof Earth's diverse Daily, G. C., Ehrlich,P. R. and Wheye, D. 1991. Determi- nantsof spatialdistribution in a populationof the subalpine ecosystems. A balance of effort clearly must be butterflyOeneis chryxus,with a discussionof territorialand achieved between establishinginventorying/planning/ lek behavior.Submitted to Behavioral Ecology and Socio- monitoringsystems for establishedor prospectivere- biology. serves, quick surveysof futureextinction hotspots to Dobkin, D., Olivieri,I. and Ehrlich,P. R. 1987. Rainfalland the interactionof microclimatewith larval resourcesin the capturesome idea of the diversityabout to be lost (and population dynamicsof checkerspotbutterflies (Euphy- thusprovide stimulus for the establishmentof reserves), dryaseditha) inhabitingserpentine grassland. - Oecologia and in-depthstudies that will provide a pictureof the (Berl.) 71: 161-176. basic structureof diversity.The lattercould rangefrom Ehrlich,P. R. 1964. Some axioms of taxonomy.- Syst. Zool. 13: 109-123. listsof species of all organismsin hectareplots of trop- - 1984. The structureand dynamicsof butterflypopulations. ical forests(May 1989) to effortsto catalogue the biota - In: Vane-Wright,R. I. and Ackery, P. R. (eds), The of an entirenation (as now being attemptedby INBIO biologyof butterflies.Academic Press,London, pp. 25-40. in Costa Rica). I will not deal with the issue of the - 1990. People vs. birds.- Am. Birds 44: 193-196. - and Gilbert,L. E. 1973. Populationstructure and dynamics geographicallocation of effortin depth now, but only of the tropicalbutterfly Heliconius ethilla.- Biotropica5: emphasizethat sensible decisions on whereto studycan 69-82. only be made afterthose on how to studyhave been - and Ehrlich,A. H. 1981. Extinction:the causes and conse- made - and point out that every day the options of quences of the disappearanceof species. - Random House, New York. where to studyget fewer.It is hardlypossible to exag- - and Murphy,D. D. 1987. Conservationlessons fromlong- gerate the urgencywith which these issues should be term studies of checkerspotbutterflies. - Cons. Biol. 1: addressed (NRC 1980, Ehrlichand Ehrlich 1981, Ehr- 122-131. lich and Wilson 1991). - and Ehrlich,A. H. 1990. The populationexplosion. - Si- mon and Schuster,New York. - and Wilson,E. O., 1991. Biodiversitystudies: science and policy.- Science, in press.

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