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
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 support@jstor.org.
.
Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Oikos.
http://www.jstor.org
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
1992
OIKOS 63: 6-12. Copenhagen
and thepreservation
butterflies
biologyofcheckerspot
Population
ofglobalbiodiversity
Paul R. Ehrlich
and the preservaEhrlich,P. R. 1992. Populationbiologyof checkerspotbutterflies
- Oikos 63: 6-12.
tion of global biodiversity.
Long-termresearchon Euphydryaspopulationshas yielded much insightinto the
It also, however,has shownthattoo much
forconservinginvertebrates.
requirements
timeis requiredto obtain such insightsspecies by species to preserveglobal biodiversity.Instead, quick samplingmethodsmustbe devised to take inventoriesof the
biota in prospectivereserves,planninguse patternsin thosereserves,and monitoring
the results.Conservationbiologistshave about a decade to develop and deploysuch
role in preventing
theloss of morethanhalfof
systemsiftheyare to playa significant
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
emergedfromthecombinedworkofour researchgroup
in two seeminglydisparate areas: long-termfield and
laboratoryresearchon thepopulationbiologyof butterflies,especially of the checkerspotEuphydryaseditha
(Nymphalidae: Nymphalinae),and policy researchon
and the maintenanceof
thepreservationof biodiversity
theecosystemservicesthatdepend upon it (Ehrlichand
Ehrlich1981). Here I discusssome of the conclusionsI
have drawnfrommore than threedecades of work in
these two fields.My most importantconclusionis distressing.The sortof intensive,species-focusedresearch
that I and my colleagues have carriedout on Euphydryasappears to have a verylimitedfuturein conservationbiology.Instead,ifa substantialportionof remaining biodiversityis to be conserved,detailed studiesof
singlespecies mustbe replaced with"quick and dirty"
methodsof evaluatingentireecosystems,designingreservesto protectthem,and determining
whetherthose
reservesare working.
The speciesapproach to biodiversity
In the public mind,the biodiversity
crisisis one of loss
of species. This view is embodied in the lists of endangeredspecies producedby both governmentalbodies and nongovernmental
organizations,in the United
States' Endangered Species Act, and in the publicity
givento species on the brinkof extinctionsuch as the
black rhinoand Californiacondor.This approachis also
rootedin the scientific
literature,wherethe traditionof
focusingon species diversityas the measure of biodiversityis well entrenched(e.g., MacArthur1972; but
see Hendricksonand Ehrlich1971).
As usefulas a species-basedapproachto biodiversity
has been, it suffersfromnumerousdrawbacks.While it
is clear thatby farthe largestnumberof animalspecies
live in terrestrialhabitats,especiallyin tropicalmoist
forests(Wilson 1989), it is equally evidentthatproportionatelymuchgreaterdiversityof phyla and classes is
foundin the relativelyspecies-pooroceans (May 1989).
I'll say no more about this aspect of diversityhere,
except to point out that fromthe perspectiveof biologists,theworldwould be a muchpoorerplace without
Accepted13 November
1990
(D OIKOS
6
OIKOS 63:1 (1992)
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,
and the like. Whetheror not theycan provideus with
economic benefitsor play crucial roles in ecosystems,
unusualorganismsare fascinatingand help us to understand the possible avenues thatcan be taken by evolution.
The importanceof populationdiversity
Toward the other end of the scale, the importanceof
is oftenoverlooked.Firstof all, the
populationdiversity
genetic and ecological diversityamong populations
helps bufferspecies againstextinction.Geographically
circumscribedspecies withlittlepopulationdiversityespecially island species - have proven highlyextinction-prone.Population diversityis also extremelyimportantto the abilityof species to provide goods and
services needed by humanity.Substantialgenetic diversityis required,forinstance,in potentialcrop plants
and theirrelativesin order to permitthemfirstto be
developed intosatisfactory
cropsand thento keep up in
the coevolutionaryraces theyrun withtheirpredators
and parasites. And if the population of Engelmann
spruce trees (Picea engelmannii)in a watershedis destroyed,withit will go the flood-controlserviceof the
subalpineecosystem.It will thenbe of littlecomfortto
those drowned downstreamthat the species is in no
dangerof extinction.
Our work with Euphydryasbutterflieshas shown
clearlythe significanceof populationdiversityto problems of conservation(Singer 1971, Gilbertand Singer
1973, Ehrlichet al. 1975, McKechnie et al. 1975, Ehrlich and Murphy1987, Murphyand Weiss 1991a). Populationsof Euphydryaseditha,forexample,differfrom
one anotherin genotypes,phenotypes,phenologies,use
of resources, and flightbehavior (Singer 1971, 1972,
White and Singer 1974, Ehrlich et al. 1975). If this
species of herbivorousinsectis to be conserved,knowledge of the biology of individualpopulationswill be
essential - since phenomena that threatenone populationwill not necessarilythreatenanother.This was
clearlydemonstratedby the variedresponsesof groups
of E. editha populationsto the Californiadroughtof
1975-77 (Ehrlich et al. 1980). It should also be noted
that the sort of population diversitypresentedby E.
edithacan be of considerablesignificancein questions
related to deliveryof ecosystemservices, control of
pests, and harvestingof economicallyimportantspecies. It is clear fromour work,forinstance,thatwithina
singlespecies some populationsmay have the capacity
to be more effectivecrop pollinators(Murphy1984) or
more dangerouscrop pests, and thatsustainableyields
may varygreatlybetweenpopulations.
Second, withtrivialexceptions,theprocessof species
extinctionis actuallya complex process of progressive
populationextinction(Shaffer1981, Gilpin and Souls
1986, Murphyet al. 1990, Thomas et al. 1990). If populationsare conserved,thenspecies are conserved(but
not necessarilyvice versa). Our group's long-termresearchon checkerspotbutterflies
(Euphydryas)has provided considerableinsightinto the causes and consequences of populationextinction,and thereforeinto a
wide arrayof global conservationissues.
The need to conserveplantsand
invertebrates
BeforediscussingEuphydryasin moredetail,I'd like to
emphasize the great need to shiftthe emphasisin the
conservationcommunity
fromthe protectionof "charismaticmegavertebrates"
to the protectionof smalleror
less spectacularorganisms.Everyone concerned with
conservationwantsto see the panda survive,but from
the viewpointof both pandas and people the preservation of more obscure organismsis crucial.Maintaining
thediversity
of plantsis, of course,the keyto theentire
enterpriseof securingthe futureof the restof organic
and of humansociety.Withoutbamboos there
diversity
wouldbe no pandas; withoutthreekindsofgrasses,Zea
mays,Oryza sativa,and Triticum
spp. (whichhave been
developed intomaize, rice,and wheat), therewould be
no civilizationas we know it.
Insectsand otherterrestrial
arthropodsare also crucial componentsof the entireweb of life(Gilbert1980,
Wilson 1987). Withoutinsectsand theirrelatives,the
livingworldwould be unrecognizable.Loss of the pollinationand seed dispersalservicesperformedby insects
and the absence of insectherbivorywould dramatically
alter (and pauperize) plant communitiesin ways that
are difficultto imagine. The absence of insects and
mites,whichalong withthe nematodescould comprise
more than95% of species diversity(May 1989), would
reverberatethroughfood webs, changingsoil faunas
and fertility,
most species of birds and
exterminating
muchof the remainderof Earth's terrestrial
vertebrate
faunaas well as manyfreshwater
fishes.The loss of ants
alone would completelyunraveltropical-rainforest
ecosystems(in whichants are key herbivoresand predators) and cause untoldhavoc in mostotherecosystems
(Gilbert1980, Holldobblerand Wilson 1990).
Insects and other terrestrialarthropods,after all,
comprisethevastmajorityof organicdiversity,
withthe
possible additionof the stillpoorly-knownnematodes
(May 1989). Indeed, in termsofspeciesdiversity,
all the
restcould almostbe considereda side issue. Also, most
insectsare herbivorous(Erwin 1982); one could thereforeview Euphydryasas representing
the verycore of
biodiversity.
7
OIKOS 63:1 (1992)
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
Euphydryasand the tacticsof
conservation
Perhaps the single most importanttacticalconclusion
that can be drawn fromour longfor conservationists
is thatthe preservatermresearchon these butterflies
will requirea verydifferent
tion of small invertebrates
approach fromthat developed on the basis of megavertebrates.Think of the kinds of issues that pervade
the conservationof, say, rhinos,cheetahs,or condors.
Whatis the minimumviable censussize thatwillsustain
a populationof cheetahs?Are survivingindividualstoo
inbred? How much habitat is required to provide
space fora populationof black rhinos?
enoughterritory
Should ex situconservationbe attemptedforCalifornia
condors? How can deliberate killingof elephants by
humanbeingsbe prevented?
kindsof questionsin inThese are rarelyfirst-order
vertebrateconservation.For example, while establishing a minimumviable population size (MVP) (Soul6,
1987) - or, more likely,a minimumviable metapopulation(MVM) (Ehrlichand Murphy1987) - can be an
norand usefulexercisewithinvertebrates,
interesting
mallyendangermentis patentlong beforesuch a size is
even approached. The subspecies Euphydryaseditha
bayensisin the San FranciscoBay area is clearlyimperiled (and has been listedas "threatened"undertheU.S.
EndangeredSpecies Act). Neverthelessthe largereservoir populationof the southernBay area metapopulation (Ehrlichand Murphy1987) always numbersmore
than 104adultsand oftenexceeds 10' individuals(Murphyand Weiss 1988a).
Indeed, a populationof 105E. edithamay existon a
conditionsare
fewdozen hectareswhen environmental
optimal.In contrast,it is possible thattherehave never
been 105 grizzlybears at one time in the coterminous
UnitedStates. Few, ifany,vertebrateswouldbe considered endangered with populations of 104 adults. But
thenfewvertebratepopulations(and no populationsof
large vertebrates)typicallygo through2-5 fold annual
size fluctuations,
as E. edithadoes often(Ehrlichet al.
1975, Murphyand Weiss 1988a). For mostvertebrates,
again unlikeE. editha,populationextinctionsare not a
normalpartof theirpopulationdynamics(Ehrlichet al.
1975, 1980).
Endangeredinvertebratepopulationsdo not ordinarilypersistwithonlya handfulof individualsover many
generations(Murphyet al. 1990). Inbreedingdepression, therefore,has not oftenbeen a serious concern.
The standardthatpopulationsshould be maintainedat
several hundredindividualsor more over manygenerations to avoid inbreeding(Lande and Barrowclough
1987) is rarelyviolated. Small demographicunitsin E.
editha metapopulationsappear to receive immigrants
(Murenough to preventgeneticdifficulties
frequently
phy et al. 1990), and that may be typical of insect
even in Euphydryaspopulations
species. Furthermore,
that appear vulnerableto inbreedingeffects,those effectshave notyetbeen detected.A transplantedcolony
of E. gillettii(Holdren and Ehrlich1981) has persisted
withan Ne apparentlyless than 50 individualsforthirteen generations;it may eventuallyprovide important
on inbreedingresistanceor susceptibility
information
in
Euphydryas.
Terrestrialinvertebratesnormallydo not have large
home ranges or territories.Individualsof some trapliningspecies in tropicalforests,such as euglossinebees
and heliconiinebutterflies(Ehrlich and Gilbert1973),
may requiremanyhectaresof habitatto supportthem
because of the dispersionof theirfood resources.But
measuredin square kilometers,seen
areal requirements
in organismssuch as Californiacondors,grizzlybears,
and Sumatran rhinos (Hutchinson and Ripley 1954)
have rarelybeen ascertainedin insects,and individuals
of even medium-sizebutterfliesoften are quite sitetenacious and largelyconfinetheiractivitiesto a few
hectares(Daily et al. 1991).
Indeed forEuphydryas,and many(ifnotmost)other
insectherbivores,the detailed qualityof the habitatis
much more importantthan its extent. Relativelyrestrictedareas of the mostsuitableenvironment
can supportreservoirpopulationsthatsupplythe long-distance
dispersersthatmaintaina species' metapopulationin a
largearea. Given enoughspace, grizzlybears,withtheir
greatmobilityand catholicdiets,can findfood. Furthermore, theyare able to persistin a wide range of climates, fromarctic tundra to semi-desert.Almost all
"generalist"insects,however,are specialistswhencompared to vertebrates.If the appropriate oviposition
plantor plantsfora populationof a Euphydryasspecies
disappearsfroma reserve,the butterfly
willnot persist,
no matterhow largethe reserve.Furthermore,
the densityof the food plant usuallymustbe highenough to
permitlarvaeto move to a newplantwhenone has been
devoured (few host plantsare large enough to support
the dozens of larvae froman egg mass fromhatch to
diapause) (Singer1972). Grizzlybears can move tensof
kilometersin search of food, larvae at most tens of
meters.
Also unlikemostvertebrates,Euphydryasare heavily
dependenton appropriatemicroclimatesfortheirsurvival. In themostintensively
studiedpopulations,those
of E. edithabayensis,the eggs are laid in March and
April, and the newlyhatchedlarvae immediatelyfind
themselvesin a race withthe senescence of theirfood
plants(Singer1972). If theyfailto reach theinstarthat
can diapause throughthe dry summermonthsbefore
theplantssenesce,theywillnotsurvive.Whetheror not
thelarvae can wintherace dependson a complexphase
relationshipbetween the phenologyof the host plant
and the insectpopulations(Singer and Ehrlich 1979).
That relationship,in turn,dependsheavilyon theinteractionsbetweentopographyof the habitatand itsmacroclimate that create diverse thermal microenviron-
8
OIKOS 63:1 (1992)
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
Weiss 1988b, Weiss et al. 1988, 1990).
In habitatswitha singleexposure(say a gentlesouthfacingslope) sequences ofyearsmayoccurwithweather
that makes the plant-Euphydryas
phenologies incompatiblein the singleavailable topoclimate,and thepopulation will be drivento extinction.But if the habitat
containsa varietyof exposures,itwillpossess areas with
at least some favorabletopoclimatesunder nearlyall
weather conditionsconceivable in the macroclimate,
and thepopulationwillprobablypersisteven ifthe area
of habitatis relativelysmall. The Californiadroughtof
1975-77 caused numerous extinctionsof component
populationsof the Santa Clara CountyE. e. bayensis
metapopulationbecause of the veryearlysenescenceof
the host plants(Singer and Ehrlich1979, Ehrlichet al.
1980, Ehrlichand Murphy1987, Harrisonet al. 1988).
Larvae simplyhad too littletimeto growto the size at
which they can enter diapause. The heavy rains that
accompaniedthe 1982-83El Nifioalso resultedin large
population declines, in this case because a paucityof
wintersunshinedelayed adult flight(and oviposition)
longer than it delayed host plant senescence, again
shorteningthe timeavailable forlarvalgrowth(Dobkin
et al. 1987).
Environmental-quality
factors,especiallythose connected withweather(Ehrlich et al. 1972) and humancaused disturbanceof habitats,also seem to governthe
persistenceof other temperate-zonebutterfly
populations(see summariesin Ehrlich1984 and Murphyet al.
1990). I suspectthe extinctiondynamicsof manyother
invertebrate
groupsare similarlycontrolledby thecombined effectsof habitatfragmentation
and environment
tal extremes(drought,deluge, wildfire,etc.) in temperate areas, while otherfactorssuch as demographicstochasticity and overexploitation are much more
importantforvertebrates.
Almost nothing,unfortunately,
is known about the
factorsinfluencingpopulation persistenceof invertebrates in tropicalecosystems,althoughit is those systems that are most endangered. Certainlyhost-plant
relationshipsare criticalfor butterflies(Ehrlich 1984)
and other herbivorousinsects, and for at least some
adultpollen sourcesare crucialas well (Ehrbutterflies,
lich and Gilbert1973). Herbivoresin generalare probably more specialized in the tropics;thus the massive
destructionof tropicalforestvegetationnow occurring
(Myers 1989) is certainlyleading to losses of populations and species of invertebratesunprecedentedat
least since the last ice age and possiblyin the 65 million
years since the extinctionsat the K-T boundary. A
special problemin the tropicsis the conversionof low
elevation habitat with warm exposures to agriculture
and otherformsof development.This removesan array
of niches withparticularinsolation,temperature,and
precipitationregimes along with the biota associated
withthem(Murphyand Weiss 1991a, b).
Overall, the best tactic for conservationmay be to
establishtheextentof reserveswithan eye on thehome
ranges and resource needs of charismaticmegavertebrates, the areal requirementsof "big thingsthat run
the world" (Terborgh1988), but to locate the reserves
withattentionto habitatdiversity
requiredbythe "little
thingsthatrun the world" (Wilson 1987).
Euphydryasand strategiesfor
conservation
I believe thatthe most importantconclusionfromour
group's work on Euphydryasis strategicratherthan
tactical.Our researchhas made it crystalclear thatthe
sortsof detailed ecological and evolutionaryinformation thatone would ideallylike to have beforerecommendingconservationprogramsforinvertebrate
species
will almost never be available. Research on the Euphydryassystemhas provided a great many tactical
lessons about single-speciesconservationfor invertebrates- thatis, how to accomplishthe preservationof a
givenspecies. It has shownthe importanceof identifyingdemographicunits,ofdifferentiating
migrationfrom
gene flow, of recognizingsubtle key habitat quality
factorssuch as slope and exposure,and so on (Ehrlich
and Murphy1987).
But thosetacticalsuccesseshave shownus how to win
battleswhilelosingthewar. More thanthreedecades of
researchbydozens of investigators
has been requiredto
gain a reasonableunderstanding
of the populationbiologyofEuphydryaseditha,to providesome notionofthe
geographic scale upon which conservationplanning
must proceed and the phenomena that must be addressed, and to be able to make sound recommendationsforthe conservationof the best-knownmetapopulations. That work has shown that lessons learned
workingon one suiteof populationsof E. edithaare not
necessarilyapplicable to co-occurringclose relatives
such as E. chalcedona (Brown and Ehrlich1980, Murphy et al. 1986) or to distantpopulationsof E. editha
itself(Ehrlichet al. 1975, 1980). The amountof effort
thatwould be requiredto advance understanding
of the
biologyof just the 600 or so species of butterflies
that
live in NorthAmerica to the level of E. edithatodayis
it mightbe done in a decade withthoumind-boggling;
sands of investigators
workingat it - if those investigatorscould be trainedinstantly.
And yet the fate of a substantialportionof Earth's
terrestrialfauna, invertebratesas well as vertebrates,
willbe determinedin the nextdecade or two (Vitousek
et al. 1986, Myers 1989, Wilson 1989, Ehrlichand Wilson 1991). Conceivably,10 to 25 millionspecies could
go extinct,and withthemcould go muchoftheabilityof
Earth's ecosystemsto supply humanitywith essential
services(Ehrlichand Ehrlich1981, 1990). The destruction of tropicalforests,forexample, is alreadygreatly
adding to the atmosphericbuild-up of greenhouse
9
OIKOS 63:1 (1992)
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 problemwiththe potentialto bring
down civilization.
In short,thereis not remotelythe time,the personnel, nor the financialsupport available to study the
biologyof most of the populationsthat must be preis to
servedifthemajorityof Earth'sbiologicaldiversity
be saved - and along withit the crucialfunctioning
of
ecosystems.Indeed, it has longbeen evidentthateven a
rough catalogue of species diversityis unlikelyto be
completedbeforemostof thatdiversity
is gone (Ehrlich
1964). In some cases, conservationbiologistswill be
able to use theirgrowingunderstandingof population
viabilityanalysis (PVA) in aid of the preservationof
targetpopulations and species. But most populations
and species almostcertainlywill go extinctbeforethey
are even discovered,let alone investigated.The sortof
intensiveshort-term
effortthat has recentlybeen expended on understandingthe conservationbiology of
the northernspottedowl (Strixoccidentaliscaurina) in
the United States (Thomas et al. 1990) could serveas a
model forresearchon the conservationbiologyof vertebrates, as the work on Euphydryascan for invertebrates.But togetherthese techniquesare likelyto be
applied to less than1/10000 of all species, and less than
1/1000000 of all geneticallydistinctpopulationsor subspecies. A new strategyis requiredforthe overall goal
of savingecosystems,not species one at a time.
A new approach forconservationbiology
So conservationbiologistsmusttake anotherapproach,
even as theycontinuehoningtheirPVA skillsforthose
rare occasions when theycan be put to good use. They
mustdevelop cookbook responsesforthe preservation
of endangeredspecies to serve in the absence of extensive autecologicaldata. They mustlearnto do rapidand
roughinventoriesof the biodiversityin entireecosystems,plan the preservationand managementof those
ecosystems,and develop techniquesformonitoring
success in preservingthebiota of thosesystems.This inevitably means using samples, both systematicand geographic,to representthe entire taxonomicrange of
organismsand theentireextentof theecosystems.Such
roughsamplingis bound to lead to some seriouserrors
that could resultin the loss of some populationsand
species, but this circumstancemust now be accepted.
Withoutsuch "quick and dirty"inventory,planning,
and monitoring
procedures,futurelosses willinevitably
be far greater. It has, afterall, been a decade since
publicationof the landmarkreport"Research Priorities
in Tropical Biology" (NRC 1980). That reporturged,
amongotherthings,establishment
of crashprogramsof
samplingtropical diversityand greatlyincreased support for systematics.But littlehas been done on the
former,and the statusof systematicshas, if anything,
deteriorated.
One of the firsttasksof the conservationcommunity
is to decide on taxonomic groups to be used as indicatorsin inventorying
and monitoring,and settleon
appropriatetechniquesto be used. I would suggestthat
the major effortgo into three already well-known
groups:vascularplants,birds,and largebutterflies
(Papilionidae, Pieridae, Nymphalidae).The plants,forming the base of most food chains and the basic food
resourceforalmostall animals,are an obvious choice.
Indeed, withan effortfundedto the level of the cost of
two useless B-2 bombers ($1300 million), the task of
more or less completinga global surveyof plantscould
be completed.Botanists,plant collections,and botanical gardensare crucialto the futureof humanity,and
botanical resourcesneed rapid expansion and deploymentto accomplishthe task of understanding
and protectingEarth's flora. It is an indicationof misplaced
prioritieswithinthe scientific
thatrelatively
community
unimportantexercises such as the sequencing of the
human genome can take priorityover the assessment
and preservationof Earth's irreplaceable botanical
wealth.
In theory,plantsalone, because of theirfundamental
roles in ecosystems,could formthe basis of most inventorying/
planning/monitoring
activity.But the problems of identifying
plantsin the field(especiallyin the
tropics)can be substantial.Subtlechangesin treefloras
will oftenbe signalledby shiftsin recruitment(adult
trees may persistfora centuryor more in habitatsno
longerable to supporta viablepopulation),and saplings
can be especially hard to identify.The shortage of
skilled botanical taxonomistsand field workersthereforemakes supplementationwithanimal groupsdesirable.
The alpha taxonomyof the roughly9000 birdspecies
is largelycomplete,and in mostareas of theworldthere
are ornithologists
and birdwatcherscapable of identifying most species and trainingothersto do so as well.
Birds are indicatorsof vegetationalstructureand, in
some situations,ofthepresenceor abundanceofcertain
floralcomponents(e.g., manyfruiting
treesin tropical
forests),and migratory
speciescarryinformation
on the
conditionof distanthabitats.A great deal of work on
monitoring
techniqueshas alreadybeen done, but more
willbe requiredto standardizeand simplify
themso that
they will be readily used by relativelyinexperienced
people.
Butterfliesare also well known taxonomically,and
people withoutextensivebiologicaltrainingcan quickly
learn to identifythe largerones. Butterfliesare more
tightlylinked to the taxonomicdiversityof the plant
thanare birds,and should providea rather
community
sensitizeindicatorof the stateof thatcommunity.
They
are also verysensitiveto pesticides,a major factorin
the overall toxification
of the planet, and, as our work
on Euphydryashas shown,are responsiveto a varietyof
other subtle aspects of habitat quality. Appropriate
transect,malaise trapping,and baitingtechniqueshave
10
OIKOS 63:1 (1992)
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 standardizedformonitoring.
In tropicalareas, monitoring
thehealthof ecosystems In sum,we have learneda greatdeal ofvalue to conserfaunas may prove vation in more than three decades of intensivework
by samplingthe bird and butterfly
to monitorthe floraat all. The withthe Euphydryassystemand otherbutterflies
simplerthanattempting
(Ehrselectionof aquatic organismsto monitorwill also be lichand Murphy1987). But themostimportantlessonis
required, with frogsperhaps being the easiest. Frogs thatEarth's biota cannot now be saved by the sort of
also are suffering
mysteriousdeclinesin manyareas of laborious dissectionof the biologyof populationsthat
the worldand should thereforebe watchedcloselyand we have engagedin. Rather,it is criticalthatconservabe the subjectsof investigations
to determinethe cause tion biologists build on what is already understood
or causes. Monitoringof streamnutrientsand siltloads about well-knownorganismsto develop tools thatcan
could also provide a sensitiveindicatorfor evaluating be used to save biodiversity
quicklyand en masse. And
ecosystemhealth (O'Neill et al. 1977); the techniques it is also criticalthattheybe active politicallyto press
for doing so are well developed, and sample analysis forthe resourcesrequiredto allow themto applytheir
could be successfullydone in tropical countries.Our tools beforeit is too late.
group is currentlysettingup a test inventorying/planning/monitoring
systemadjacent to La Amistad Na- Acknowledgements
- I thankthemanystudents
andcolleagues
tionalPark on the Costa Rica - Panama borderwiththe whohaveworkedwithmeoverthepastthreedecadeson the
G. C. Daily,A. H. Ehrlich,
system.
P. H. Raven,
collaborationof Latin Americanbiologists.We plan to Euphydryas
andP. Vitousekwerekindenoughto criticise
themanuscript.
evaluate various ideas and techniques and establish Specialappreciation
and coworker,
goesto myfriend
D. D.
joint programsfortrainingof para-ecologiststo employ Murphy,
forhiscomments
on thispaperand forcarrying
so
muchoftheloadinrecent
years.Thisworkhasbeensupported
successfultechniqueselsewherein the neotropics.
fromtheNationalScienceFoundaSimple, accurate,repeatableinventoryand monitor- bya longseriesofgrants
tion,themostrecentofwhichis BSR 87-00102,grantsfrom
ingprogramsofcoastal and marinesystemsneed also be theFord,Koret,Hewlett,W. AltonJones,and MacArthur
developed. There is some evidence that shorebirds foundations,
andbyindividual
donors.
(waders) (Myerset al. 1987) and pelagicbirds(Boersma
1986) mightprove to be usefulindicatororganismsfor
oil pollution. Indeed, shorebirdsand migratoryland
birdsare alreadyprovidingcivilizationwitha generalized warningabout the state of Earth's environment References
(Terborgh1989, Ehrlich 1990). There is some movementtowarddevelopingsuchprograms,butmoreeffort Boersma, P. D. 1986. Ingestionof petroleumby seabirdscan
serveas a monitorofwaterquality.- Science 231: 373-376.
(and funding)is clearlyneeded.
Brown,I. L. and Ehrlich,P. R. 1980. Populationbiologyof the
While developingtechniquesfor samplingbiodivercheckerspotbutterfly,
Euphydryaschalcedona:structure
of
the JasperRidge colony. - Oecologia (Berl.) 47: 239-251.
sitymusthave highpriority,so mustdecisionson allocating effortto the understandingof Earth's diverse Daily, G. C., Ehrlich,P. R. and Wheye, D. 1991. Determinantsof spatialdistribution
in a populationofthesubalpine
ecosystems. A balance of effort clearly must be
butterfly
Oeneischryxus,witha discussionofterritorial
and
achieved between establishinginventorying/planning/ lek behavior.Submittedto Behavioral Ecology and Sociobiology.
monitoringsystemsfor establishedor prospectivereserves, quick surveysof futureextinctionhotspotsto Dobkin, D., Olivieri,I. and Ehrlich,P. R. 1987. Rainfalland
the interactionof microclimatewithlarvalresourcesin the
capturesome idea of the diversityabout to be lost (and
population dynamicsof checkerspotbutterflies(Euphythusprovidestimulusfortheestablishment
ofreserves),
dryaseditha) inhabitingserpentinegrassland.- Oecologia
(Berl.) 71: 161-176.
and in-depthstudiesthat will provide a pictureof the
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 butterfly
populations.
ical forests(May 1989) to effortsto catalogue the biota
- In: Vane-Wright,R. I. and Ackery, P. R. (eds), The
biologyof butterflies.
Academic Press,London, pp. 25-40.
of an entirenation (as now beingattemptedby INBIO
- 1990. People vs. birds.- Am. Birds 44: 193-196.
in Costa Rica). I will not deal with the issue of the
- and Gilbert,L. E. 1973. Populationstructure
and dynamics
geographicallocation of effortin depth now, but only
of the tropicalbutterfly
Heliconiusethilla.- Biotropica5:
emphasizethatsensibledecisionson whereto studycan
69-82.
- and Ehrlich,A. H. 1981. Extinction:the causes and conseonly be made afterthose on how to studyhave been
quences of the disappearanceof species. - Random House,
made - and point out that every day the options of
New York.
whereto studyget fewer.It is hardlypossible to exag- and Murphy,D. D. 1987. Conservationlessonsfromlonggerate the urgencywith which these issues should be
term studies of checkerspotbutterflies.- Cons. Biol. 1:
122-131.
addressed (NRC 1980, Ehrlichand Ehrlich1981, Ehr- and Ehrlich,A. H. 1990. The populationexplosion. - Silich and Wilson 1991).
mon and Schuster,New York.
- and Wilson,E. O., 1991. Biodiversitystudies:science and
policy.- Science, in press.
OIKOS 63:1 (1992)
11
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
Breedlove, D. E., Brussard,P. F. and Sharp,M. A. 1972.
Weatherand the "regulation"of subalpine butterfly
populations.- Ecology 53: 243-247.
-, White, R. R., Singer, M. C., McKechnie, S. W. and
Gilbert,L. E. 1975. Checkerspotbutterflies:a historical
perspective.- Science 188: 221-228.
-, Murphy,D. D., Singer,M. C., Sherwood,C. B., White,
R. R. and Brown,I. L. 1980. Extinction,reduction,stabilityand increase:the responseof checkerspotbutterfly
(Euphydryas)populationsto the Californiadrought.- Oecologia (Berl.) 46: 101-105.
Erwin,T. L. 1982. Tropicalforests:theirrichnessin Coleoptera and other arthropodspecies. - Coleopt. Bull. 36:
74-75.
Geiger, R. 1965. The climate near the ground. - Harvard
Univ. Press, Cambridge,MA.
Gilbert,L. E. 1980. Food web organizationand the conserva- In: Soul6, M. E. and Wilcox,
tionofneotropicaldiversity.
B. A. (eds), Conservationbiology. Sinauer, Sunderland,
MA, pp. 11-33.
- and Singer,M. C. 1973. Dispersal and gene flowin a butterflyspecies. - Am. Nat. 107: 58-72.
Gilpin, M. E. and Sould, M. E. 1986. Minimumviable populations:processesof species extinction.- In: Soul6, M. E.
(ed.), Conservationbiology: the science of scarcityand
diversity.Sinauer, Sunderland,MA, pp. 13-34.
Harrison,S., Murphy,D. D. and Ehrlich,P. R. 1988. Distribution of the Bay checkerspotbutterfly,
Euphydryaseditha
bayensis:evidencefora metapopulationmodel. - Am. Nat.
132: 360-382.
Hendrickson,J. A. and Ehrlich, P. R. 1971. An expanded
conceptof "species diversity."- Notulae Naturae No. 439:
1-6, Oct. 12.
Holdren, C. E. and Ehrlich,P. R. 1981. Long-rangedispersal
in checkerspotbutterflies:
transplantexperimentswithEuphydryasgillettii.- Oecologia (Berl.) 50: 125-129.
Holldobler, B. and Wilson, E. 0. 1990. The ants. - Harvard
Univ. Press, Cambridge,MA.
Hutchinson,G. E. and Ripley,S. D. 1954. Gene dispersaland
the ethologyof the Rhinocerotidae.- Evolution 8: 178179.
Lande, R. and Barrowclough,G. F. 1987. Effectivepopulation
size, geneticvariation,and theiruse in populationmanagement. - In: Soul6, M. E. (ed.), Viable populations for
conservation.CambridgeUniv. Press, Cambridge,pp. 87123.
MacArthur,R. H. 1972. Geographicalecology.- Harper and
Row, New York.
May, R. 1989. How manyspecies are thereon Earth?- Science
241: 1441-1449.
McKechnie,S. W., Ehrlich,P. R. and White,R. R. 1975. Populationgeneticsof Euphydryasbutterflies.I. Genetic variation and the neutralityhypothesis.- Genetics 81: 571594.
Murphy,D. D. 1984. Butterfliesand theirnectarplants: the
role of the checkerspotbutterfly
Euphydryaseditha as a
pollen vector.- Oikos 43: 113-117.
- and Weiss, S. B. 1988a. A long-termmonitoring
plan fora
- Cons. Biol. 2: 367-374.
threatenedbutterfly.
- and Weiss, S. B. 1988b. Ecological studiesand the conservationof the Bay checkerspotbutterfly,
Euphydryaseditha
bayensis.- Biol. Cons. 46: 183-200.
- and Weiss, S. B. 1991a. The effectsof climatechange on
-,
biological diversityin western North America: species
losses and mechanisms.- In: Peters, R. and Lovejoy, T.
(eds), Consequences of the greenhouseeffectforbiological
diversity.Yale Univ. Press, New Haven, CT. (In press).
- and Weiss, S. B. 1991b.Warmslopes and cool: topographic
criteriain conservationplanning.- Endangered Species
Update (In press).
-, Menninger,M. S., Ehrlich,P. R. and Wilcox,B. A. 1986.
Local populationdynamicsof adultbutterflies
and theconservationstatusoftwocloselyrelatedspecies.- Biol. Cons.
37: 201-223.
-, Freas, K. E. and Weiss, S. B. 1990. An environmentmetapopulationapproach to population viabilityanalysis
fora threatenedinvertebrate.- Cons. Biol. 4: 41-51.
Myers, N. 1989. Deforestationrates in tropical forestsand
theirclimaticimplications.- Friendsof theEarth,London.
Myers,P., Morrison,R., Antas, P., Harrington,T., Lovejoy,
T., Sallaberry,S., Senner,S. and Tarak, A. 1987. Conservationstrategyformigratory
species. - Am. Sci. 75: 19-26.
NRC (National Research Council). 1980. Research priorities
in tropicalbiology.- NationalAcademyof Sciences,Washington,D.C.
O'Neill, R. V., Ausmus,B. S., Jackson,D. R., Van Hook, R.
I., Van Voris, P., Washburn,C. and Watson,A. P. 1977.
Monitoringterrestrialecosystemsby analysis of nutrient
export.- Water,Air Soil Poll. 8: 271-277.
Shaffer,M. L. 1981. Minimumviable population sizes for
conservation.- BioScience 31: 131-134.
Singer,M. C. 1971. Evolutionof foodplantpreferencesin the
butterfly
Euphydryaseditha.- Evolution35: 383-389.
- 1972. Complex componentsof habitatsuitabilitywithina
butterfly
colony.- Science 176: 75-77.
- and Ehrlich,P. R. 1979. Populationdynamicsof thecheckerspot butterfly
Euphydryaseditha.- Fortschr.Zool. 25:
53-60.
SouI6, M. E., 1987. Viable populations for conservation.CambridgeUniv. Press, Cambridge.
Terborgh,J. 1988. The big thingsthatruntheworld- a sequel
to E. 0. Wilson. - Cons. Biol. 2: 402-403.
- 1989. Where have all the birds gone? - PrincetonUniv.
Press, Princeton,NJ.
Thomas, J. W., Forsman,E. D., Lint, J. B., Meslow, E. C.,
Noon, B. R. and Verner,J. 1990. A conservationstrategy
forthenorthernspottedowl. - InteragencyScientificCommitteeto Address the Conservationof the NorthernSpotted Owl. Portland,OR.
Vitousek,P. M., Ehrlich,P. R., Ehrlich,A. H. and Matson,P.
M. 1986. Human appropriationof the productsof photosynthesis.- BioScience 36: 368-373.
Weiss, S. B., Murphy,D. D. and White, R. R. 1988. Sun,
slope, and butterflies:
topographicdeterminants
of habitat
qualityforEuphydryaseditha.- Ecology 69: 1486-1496.
-, Murphy,D. D., Ehrlich,P. R. and Metzler,C. F. 1990.
Complex determinantsof emergence phenology in Bay
checkerspotpopulations.- Submittedto Ecology.
White, R. R. and Singer,M. C. 1974. Geographicaldistribution of hostplantchoice in Euphydryaseditha.- J. Lepid.
Soc. 28: 103-107.
Wilson, E. 0. 1987. The littlethingsthatrun the world (the
importanceand conservationof invertebrates).- Cons.
Biol. 1: 344-346.
- 1989. Threatsto biodiversity.
- Sci. Am. 261 (3): 108-116
(September).
12
OIKOS 63:1 (1992)
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