Conservation assessment of invertebrate assemblages: is there a place for global level taxon-focusing?

5 Pages·1994·0.89 MB·

by  T R New

CONSERVATION ASSESSMENTOFINVERTEBRATE ASSEMBLAGES:ISTHEREA
PLACEFORGLOBAL LEVELTAXON-FOCUSING?
NEW
IK.
New,T.R. I9940630:Conservationassessmentofinvertebrateassemblages:isthereaplace
for global level taxon-focusing? Memoirs ofthe Queensland Museum 36 (1): 153-157.
Brisbane, ISSN0079-88*S
Themassivediversityofinvertebrates,lackoftaxonomicandecologicalknowledgeofmost
groups,andthelow likelihoodofgreatly increasedlogisticcapability toacquirethis,ensure
that conventional 'inventory' approaches to assessing magnitude and patterns of species
diversityinnaturalassemblageswillremainunfulfilled.Inordertoincorporateinvciiebt
meaningfullyintoabroadrangeofconservationassessmentandmanagement,some formIof
'triage* seemsinevitable. Possiblegroundsforconcentratingonarestricted 'umbrellasuite'
ofecologically-importanttaxaarediscussed.[^Inventories, COttSemotionpriorities,keystone
taxa, indicatortaxa, umbrellataxa.flagshiptaxa.
W
T.R.New,DepartmentofZootomy, LaTrobe University, Bundoora\ revta Jfl&J, Australia.
30July 1993.
Many biologists now accept readily that im- tionol theecologicalimportanceofmvertebr
pendingmajorlossofbiodiversity, equated most and logistic support for their conservation, and
commonly to loss ofspecies, is the predominant (3) to apply that support in the best way(s) pos-
crisis facing our natural world in the next few sibletoincreasemanagementcapabilitybasedon
decades and that this mustbe countered with the sound science and ethics. But the constraints
best means at ourdisposal. The vast, and largely noted above are likely to increase, and there is
unheralded, proportion ofthis loss will comprise little realistic prospect of(forexample) doubling
invertebrate animals, whose central rules and ortripling the taxonomic workforce, 04 ofdivert-
values in contributingtosustainability ofnatural ing a significant proportion of the 'conservation
ecosystems are only now becoming appreciated, dollar' from vertebrate issues to the assessment
and for which our knowledge of diversity and of largely undocumented and non-charismatic
distribution is minimal. Documentation and taxa OT communiiies. We must, ofcourse, enn
quantification of invertebrate assemblages may tinue to emphasise the need for incre-ascd scien-
be regarded as a central theme in understanding tific and logistic capability (and urge massively
'biodiversity', and some people haveargued that greater funding for taxonomic work), and of the
such knowledge is a prerequisite for effective underpinning role of taxonomy and collection
conservation. However, the ideals espoused by management and interpretation as a vital tool lot
such a stance - of collecting and describing all conservation assessment - but, also, must not let
taxa of invertebrates in marine, terrestrial or this need prevent us from making progress.
fh vhwater assemblages as a basis fordetermin- It thus seems inevitable that our rationale in
ing patterns of distribution and abundance are seeking to document invertebrate assembl
Utopian forinvertebratesas a wholeand formost mustchange, and must be adapted toacceptsub-
taxonomic groups, not least because of the stantial constraints &nd 10 Advance our scientific
decline ofthe taxonomic workforce and ofsup- capability as effectively as possible. The inver-
portfor 'basic* ecological surveys atall levels. It tebrate conservation community must become
is indeed anachronistic thai, ac a time when the more positive, and (whilst WC must continue to
iu.ictieal need fordocumenting faunasadequate- bemoan lack ofoptimal capability seek tomake
I
y, asbasic information used in setting priorities rapid progress in selected areas rather than con-
for. and implementing, conservation manage- tinuing to Jostcr the dilute approach necessitated
ment is being espoused globally as a basis for by trying to document complex assemblages
assuringglobalsustainability,ourcapabilitytodo fully,orreasonably fully.Oneway toachieved^
this is being eroded. may be to focus our efforts more finely, and to
Theurgent needs fordocumenting invertebrate select the most 'rational* (that is. most informa-
assemblagesadequatelyare (1)tounderstand the tive) targets by some form of 'triage*, however
templateagainstwhichwecanappraiseeffectsof ethically difficult this might be. Indeed, in r
anthropogenic change, (2) to increase apprecia- invertebrate surveys some degreeoftriage i
MEMOIRSOF JHEQUEENSLAND MIJSF.UM
readyemployed:weusually selectonlypaxiicular jie Cnidaria, Porifera, Platyhclminthes (Turbcl-
taxoftomic groups for analysis, depending on laria), Mollusca, Annelida, Onyehophnra,
criteriasuchas ourowninterest m given groups. Arlhrnpoda (s.l,), Bryozoa, and Echinodcrmata.
ideasabout which might give us the lbest* infor- The principle of deliberately de-emphasising
mation or, simply, the capabilities of uur assis- mostinvertebratephylaor,atleast,omittingthem
tants or whether we have expertise oraccess to from quantitative asscssmeni for conservation is
expertiseinsystematicappraisalofthespecimens certainly a difficult one to espouse and this
collected- Such factors in practice already drive 'umbrella suite1 is a suggested one only, to
and restrict ecological interpretation, and our demonstrate the principle involved. It includes
ability toanalyse diverse natural assemblages in virtually all invertebrategroups which have been
terms of the taxa present and for comparative the subject of species-orientated conservation
ranking forconservation priority orimportanee. studies or used as indicator taxa; at that level,
However.thereareoftensubstantialdifficulties therefore, thisgroupingdoes little morethanfor-
in trying to compare surveys based on different malise thestatusquo. I alsoemphasisethatomis-
IftXa or habitats. There is a tntyOJ need 10 trans- sion of any group from this suite ot preferredtaxa
formwhat isatpresent little more thanaseriesof does noi demean its importance or relevance, or
ad hoc inteipitrtalions each depending to some suggcsl lhat il is any way expendable'- It is not,
extent on opportunism or local capability anil but many of the poorer known invertebrate
giving prominence to different taxonomic groupsare likely to be conserved more effective-
gnmps. into an effectively assembled and coor- ly by being placed under an ecologically com-
dinated dataaccumulation which can eventually prehensive umbrella than by being appraised
us great capability forcomparative assess- individually when this entails a massive "catch
mentofinvertebrateassemblages,andwhichcan Up1 operation or is logistically intensive to
help us overcome the various 'tuxotinmic achieve. By concentrating ourefforts on a suite
impediments' and 'ecological impediments' of laxa likely to yield 'high knowledge
whichhave temledin fosteranairofdefeatism in dividends', many (most) other groups may gain
recentyears. benefit.
The implicit priority is to augment capability
TAXON-FOCUSING for a number of ecologically informative invcr-
'L-hiitte groups which are already relatively well
Known, which have definable ecological values
ivoPteirldhabpestothfeocmuossttheefbfuelcktiovfeoauvrenreusetrtioctperdolgorgeiss-s andforwhichacoreofcapabilityisavailable.We
tic capability on a restricted suite ot major taxa, are clearly committed to levels of extrapolation
inverttoebdrealtiebegrraotueplsy.gOinvee aIpopwraoapcrhiotroittyhis[-i>(Nmeows,l oqruaonftigteanteirvaelliytybuitnnseeeekditnogsteoedkefbionteha'sdsiveemrbsliatygeisn
o1f99p3)hyDlOaillfdobreattotdeenltiimoint,;iflraorgme 'wuhmibcrhellsamasulilteer' gpehnaesriasliintgy'thaainadlt'hgoeungehrawleitdyesiinredtiovekrnsiotwy*,alletmh-e
segregates may be selected progressively in a animals present there is nopractical likelihood
range uf different habitau and ecological i:on thaiweshall everdosoatanyecologically p
ttehxatns.9Npehwylia19n9e3e)dscuogngseisdteerdattihoatnpienrOharpwsrntoomgoarien zinogolltoilgilsetvesl,haivneestsitelnecaer,nitnoverretderbersastethceonfseeelrivnagtsioonf
a sound comparative database on distribution, academic defeat ofnot being ahle to assess total
ittvarsity,andecologyrelevanttoconservationof assemblages completely, to move on from argu-
ing about numbers 61 species per se and to
all (or most) other invertebrate groups. Briefly,
thecriteria usedtodelimitsuchasuite(AppcmIix dgeavneilsomps]a bpiraocdtiivcearlsiFtryamoenwoprrkagtmoatsiacfegguraorudndosr.-
tIh)esekenkotwolecadpgietalainsedacsapeafbfielcittiyvelayvaaislpaoblses.ibTleheoyn Focussing on particular groups is more likely 10
emphasise (1) the relative knowledgewhich ex- enable assembly ofa broadly applicable data set
ists at present and (2) the groups' capability 10 within a foreseeable period, than continuing to
augment ecological understanding, so thai the pursue broader,moreacademicallysatisfyingbut
major 'values' adduced arc scientific ones. The less attainable, goals.
groupsarethosewhoseincidenceandabundance Other, alternative or complementary, ap-
canbeusedmosteffectivelytoassessthewcllbc- proaches are ol course possible. Rather than
ing of communities and ecosystems. The phyla primary delimitation ;H the phylum level, lower
suggested as particularly useful for (his exercise level ta.xa (orders, families) Irom a wider range
CONSERVATION ASSESSMENTOFINVERTEBRATE ASSEMBLAGES
ofphylacould beselectedforintensiveappraisal. i)to discuss the values of 'taXOfi triage' over any
This could indeed incorporate particularly more comprehensive approach;
relevant other groups of a wider spectrum of ii)to gain a broad consensus on the groups of
invertebrates whilst not diverting from the main invertebrates we need to assess, or which
thrust of focusing logistic capability. Either of merit priority, m assessing assemblages in
theseapproaches(oracombinationofthem)thus differenthabitats;
differsmarkedly from approaches such as 'guild iii)toderiveprotocolsforsamplingand assessing
analysis' ofassemblages, whereby itmay still be those taxa in standard comparable ways
necessary to systematically interpret all inver- (ranging from devising optimal sampling
tebrate groups and enhance the taxonomic sets to production of identification manuals
capability to doso, and sets ofvoucher material for distribution
A carefully-selected 'umbrella suite' oftax.i is touseis:. • nahlingtheir use: forvarious foims
likely to obviate the need forthis. ol ordination analysis, and the sound recog-
Tt could be suggested,, as has occurred in some nition anddelimitation of 'notable' species
past studies, that all invertebrates may be safely iv)to increase global capability tor interpreting
(.unserved in nuLura! communities by (he more the distribution of the priority groups and
'usual umbrellas' of vertebrates and vascular evaluating their rtssponses to hahitai change
plants, and that a logical extension may be to orotherdisturbance*and
ignore them completely in assrssmenf of as- v)to incorporate information on them into what
semblages. However, there is abundant evidence willeventuallyhecoroemorecomprehensive
thattheecologicalsensitivitiesofinvertebratesin databases useable forboth specificandcon>
allmajorecosystemsmaybeextraordinarilysub- paiativc assessment.
tleandthattheirpartitioningofresourcesmay be
undertaken in very intricate and sensitive ways DISCUSSION
Unless they are indeed incorporated in assess-
mentofthe'health'ofnaturalassemblages, much Optimal taxonomic groups (be they ai phylum
subtlety may be lost simply through ignoring the or low levels ofselectivity) in any such scheme
detailedneedsofthepredominantcomponentsof oftaxou-foLusnigtoenhanceinvcaebratccoi:
those assemblages and losing capability to vation should be selected in relation to the kinds
monitor the effects of anthropogenic intrusion. ofecosystembeingassessedandthe propertiesof
Simply, invertebrate assemblages cannot be as- \\\c species involved- Thesearc intci-ielated: ini-
sessed properly without assessing invertebrates tial appraisal ofmajorecosystem categories und
themselves in any context where broad com- Comparison between these in diffeient continent
parisons may be needed. andclimaticregimes (as suggestedbydi Castn el
Any particular ecological survey may neces- al.„ 1992) is likely to reveal the various suites of
sitate acquisition of a massive amount of data invertebrate taxa which will complement each
specifictothatstudy,itsvaluecouldbeenhanced other in general themes ofgathering information
dramatically ifthe main data were immediately and increasingly sophisticated use of indicator
relevantto. and available for, incorporating into taxa as well as the delineation ofcritical faunas
a issnationalorglobal comparativegceftfl based on criteria such as high diversity, high
DiCastrietal. (1992)emphasisedtheimportance endemism o* the presence of notable or rare
of rapid standardised methods for survey t> r species.Thebasis forsomesuchsurvey formany
rankingorassessingcommunities,andthistheme groups is already available in literature.
pervades other recent discussion (sec Speller- This approach i^ httl meant n> detri Speci&S
bcrg, 1993, forexamples). Di Castri and hiscol- orientatedconservationforthreatenedtaxaofany
leaguesnotedthatallmajortrophicgroupsshould invertebrate group; this is a different exercise
be included in the representative mxa used for from tavon-fivusmjt: foi defining and setting
assessment; that all main size groups, species- priorities in assemblages and, clearly, any espe-
nchandspecies-poorgroups,andgroupscontain- cially notablespeckshasthepotential tobecome
ing common and rare species should be an 'umbrella' or 'flagship* in ils own nghi
incorporated; and that, for example, Mfl-l.S Gene—rally, the phylum level is tooembracing for
familiesofinsects* should be included. this except, possibly, in the case of relatively
Important steps that might now l>e taken to small and notable groops such as the
recognise the need to increase our capability to Onychophora (New. 1994). Onychophora are
study natural assemblages include: group forwhichthe pencralappearance isunam-
1
l-r MEMOIRSOFTHEQUEENSLANDMUSEUM
biguous. Theirdetailed systematica are complex range of ecological considerations into taxon
but the mere preseiKe of any species may be delimitation, and that the habitat formation isthe
sufficienttomarkoutaforestorgrasslandsite,or background against which optimal groups must
a cave, as being of conservation significance. be decided.
They arc potentially useful flagships (and Atpresent the future forinvertebrateconserva-
umbrellas) forthe multitude ofless conspicuous tionisinthebalance,andprospectsfortheemerg-
invertebrates, mostly known even less well, ing science are critical. On the one hand we can
which also occur in wet forest habitats, for ex- continue as we are, largely uncoordinated ftfld
ample. By contrast, many arthropod groups having heated discussions about levels ofdiver-
manifest strongly all or most ofthe features on sity and the values of particular species, and—
Which Othftl phyla in their entirety have been perhaps-seeingourrestrictedresourcesdilutedto
excluded from the "umbrella suite': Small Size suboptimal ends through lack of focus. On the
(
general inaccessibility or difficulty of com- other hand, we can seekadifferentormorecoor-
prehensive sampling, lack of taxonomic dinatedfocus, involvinga level oftriageateither
knowledge and agreement, intangible diversity, the t3Xon level or the community (or major
little ecological knowledge or distributional in- habitat) level. My comments today arc directed
formation, or an entirely parasitic mode of life. to(lie first ofthesechanges, with the implication
These factors can guide usconstructively in our thai complementarity between the preferred
selection of fool orders or families within niusi groupswill indeedgiveusasound understanding
ofthe largerphyla. It may be profitable to select of broader aspects of invertebrate assemblages
'(axon sets' on aregional hasis. ratherthan and guide us effectively toward their manage-
globally, but there should be provision for the ment.
greatest amount ofcomparative assessment pos-
sible. Forexample, incorporationofgroups such ACKNOWLEDGEMENTS
as tardigrades and rotifers for assessing low
d(girUvoseuhrpessri&mtyaEydAnwhtaaarvrdecstl.eisc1s9r8te6el)rerievssatrnreciewaalerldscieownmhgmeurbuent.itthieesse CpoorMntsyefrrpvoaarmttitiohcneip'IaatwniaoPnsotitfnaecTrioFlwiotuaanrtdeddastbiByoinofdaiinnvadenrcLsiaiatlTyrsoaubnped-
asTshesestmweinntrmoaleysobfeisnuvietrmtieabrrivaetiels ainsc1o,1n)sdeirvveartsiiotyn tUhniisvepraspietry.f1roamppDrerciAa.tLe.cYoemnm,eanntdssoenvearadlraofttheorf
or presence/absence ofparticular taxa reflecting colleagues raised points at the meeting which
the complexity or "health" of natural com-
have helped toclarify particularuspecis
munities, and (2) monitoring the changes
wrought by changed conditions, perhaps more
LITERATURECITED
effectively than can be achieved by using other
organisms. 'Biologicalindicators*isaverybroad
leim. but there has been considerable recent in- DlCASTR1. F., VERNHES,J.K.& YOUNhN.T (edsj
terest in selecting groups ofinvertebrates whose A199p2r.opIonsvaelntfoorryainngintaenrdnamtoinoniatlornientgwobriko,diBvierosliotgyy.
presence or abundance can indeed indicate en- International. Special IssueNo27: 1-28.
viionmental health sensitively. For examples. NEW, T.R. 1993. Angels on a pin; dimensions of the
Spellerberg (1993) delimited five categories of crisis in invertebrate conservation. American
pollution indicators alone, and a recent volume Zoologist33:623-630.
on benthic invertebrates (Resh & Rosenberg, 1994. Onychophora in invertebrate conservation:
1993) demonstrates their wide indicator priorities, practice and prospects Zoological
relevance in freshwatercommunities j aroal ofuic-Linnean Society tin pre -
Any relatively well-known invertebrate group RESH, V.H & ROSENBERG, DM. (eds) 1493.
which can embrace values of traditional in- 'Freshwater biomonitoring and benthic
itic.iior, flagshipor umbrellaproperties probdbl) rracroinvertebrates*. IChapman &. Hall: New
York)
dmeelriimtist kheiygshtopnrieorgirtoyu.psIf(rietefp-rbouvielsdinpgocssoirbalKeartco SPB cLhCaRnBgEe'R.G,(Cia.Fmb(r9i9d3.ge'MUonniitvoerrisngiteycolPorgeiscsa:l
one example), this criterion would be especially Cambridge
important; however,themoregeneral perception USHER, MB. &).EDWARDS, M, 1986.The selection
of'keystones' atpresenttendstobeatthespecies ofconservation areas in Antarctica: an example
level, ratherthan the higher taxon. But 1 believe uving the arthropod fauna of antarctic islands-
that it is indeed possible to incorporate such a EnvironmentalConservation 13: 1 15-122.
CONSERVATIONASSESSMENTOFINVERTEBRATEASSEMBLAGES 157
APPENDIX
Criteriafordesignatingasuiteofinvertebratephylaforprioritystudy toconstructdatabasesforconservation
assessmentand toactas abroad umbrellasuiteforconservationofotnerinvertebrates (afterNew 1993).
1) Includemarine,freshwaterandterrestrial taxa, andgroupscrossingthesesystemsin variouscombinations;
all majorecosystemsrepresentedrepeatedly.
2) All feedingmodesandtrophic levels replicated, anddiverse waysofliferepresented;emphasison 'free-
living' taxa;allsignificantecologicalrolesand interactions, with indicatorgroupstomonitorthese,in-
corporated.
3) Mostgeographicallywidespread,butalsoincludelocalendemics,critical faunas,or 'hot-spots* ofdiversity
inselectedrangeofareas.
4) Mostdiverse,butwithestablishedtaxonomic frameworksforall,orsignificant, sections.
5) Substantialexistingecological information,suchas
i) taxapromoted/usedas indicators
ii)possssibilityofexpandingfromdocumentedexisting foci (such ascase-studies)
6) 'Values' definedordefinable, including rangeof'commodity' or 'applied' aspects likely toengenderpoliti-
calsupport.
7) Possibility ofincorporatingtaxa ineducational programmes, forexample tohelpovercomeprejudice
againstinvertebrates.
8) Amenable tocapture/sampling by standard orsimple techniques whichcan be replicatedeasily and com-
bined intosampling sets. Possibilities forlaboratory rearing to facilitateexsituconservation.
9) 'Critical mass' ofworkersongroupexists, with realistic potential forglobal/international cooperation and
complementarity.
10) Knowledgebase founded in museumandotherinstitutional collectionscan be used todocument thecriti-
cal nature anddefinedistributionsforselectedtaxa.