Scale, pattern and process in biological invasions

217 Pages·1997·7.7 MB·English

by  Allen, Craig R.

SCALE,PATTERN,ANDPROCESSINBIOLOGICALINVASIONS
By
CRAIGR.ALLEN
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL
OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT
OFTHEREQUIREMENTSFORTHEDEGREEOF
DOCTOROFPHILOSOPHY
UNIVERSITYOFFLORIDA
1997
Copyright1997
by
CraigR.Allen
ACKNOWLEDGEMENTS
Theworkpresentedinthisdissertationwouldnothavebeenpossible
withoutthecooperationandencouragementofmany. Foremostistheunderstanding
ofmyimmediatefamily,thatismywifePattyandnowthree-year-oldson,Reece.
Reece,whilegenerallyconfusedaboutwhatIwasdoing,nonethelesssupportedmy
effortto"writeabook"inordertobecomea"doctor." Conflictsaroseonlywhenhe
neededmycomputerfordinosaurgames. Myco-advisors,W.M.KitchensandC.S.
Holling,encouragedmyinvestigationsandprovidedmewithintellectualsupportand
opportunity. Forthesamereasons,Iextendmyappreciationtomycommittee
members,S.Humphrey,M.MoultonandD.Wojcik. Numerousfriendsand
colleaguesprovidedmewithintellectualsupportandactedasasoundingboardfor
ideas. ForemostareE.A.Forys,G.PetersonM.P.MoultonandJ.Sendzemiraswell
astheentire"gang"oftheArthurMarshalEcologyLaboratory. Iwishtothankallfor
theirsupportandfriendship.
II!
TABLEOFCONTENTS
page
ACKNOWLEDGEMENTS
iii
ABSTRACT viii
INTRODUCTION
1
CHAPTERS
1. TRADITIONALHYPOTHESES: INVASIONSAND
EXTINCTIONSINTHEEVERGLADESECOREGION 5
Introduction 5
Body-massdifferencehypothesis 6
Dietdifferencehypothesis 7
Speciesreplacementhypothesis 7
Phylogenetichypothesis 8
Methods 8
Results 11
Discussion 14
2. LUMPYPATTERNSOFBODYMASSPREDICTINVASIONS
ANDEXTINCTIONSINTRANSFORMINGLANDSCAPES 18
Introduction 18
Methodsandanalysis 21
Specieslists 21
Analysis 22
Results 26
Discussion 31
3. UNSUCCESSFULNON-INDIGENOUSAVIFAUNAIN
SOUTHFLORIDA 37
Introduction 37
Community-levelvariables 41
iv
Landscape-levelvariables 43
Methods 45
Data 45
Analysis 46
Results 47
Discussion 49
4. THESOUTHFLORIDAVERTEBRATECOMMUNITY
THROUGHTIME 54
Introduction 54
Methods 56
Changesovertime 56
Annualchanges 57
Results 58
Changesovertime 58
Annualchanges 61
Discussion 62
5. PATTERNSINSTRUCTUREANDINVASIONIN
MEDITERRANEAN-CLIMATEECOSYSTEMS 64
Introduction 64
Methods 66
Datasources 66
Bodymassestimates 68
Analysisofmediterranean-climatevertebratecommunitystructure....69
Invasionsinmediterranean-climateecosystems 70
Results 71
Analysisofmediterranean-climatevertebratecommunitystructure....71
Invasionsinmediterranean-climateecosystems 76
Discussion 77
6. RARITY,ABUNDANCEANDNOMADISMINRELATION
TOSCALEBREAKSINMEDITERRANEAN-CLIMATE
ECOSYSTEMS 81
Introduction 81
Methods 83
Data 83
Rareanddecliningspeciesanalysis 84
Analysisofabundance 84
Analysisofnomadicbirds 84
Results 85
Rareanddecliningspecies 85
Analysisofabundance 86
Analysisofnomadicbirds 86
Discussion 87
7. VERTEBRATECOMMUNITYSTRUCTUREWITHINRANGES
OFSCALE 89
Introduction -. 89
Methods 93
Sourcesofbiologicaldata 93
Descriptionofstudysites 93
Statisticalanalyses 96
Simulationswithanullmodel 97
Meta-analysis 98
Community-levelsimulations 99
Results 99
Simulatedandobservedtrendsinsegmentlengthvariance 100
Binomialtestforover-dispersionofsegmentlengths 101
Testsforpotentialbiasorartifact 102
Community-levelsimulations 102
Discussion 105
8. CONCLUSIONS ANDSYNTHESIS:AHIERARCHICAL
MODELOFCOMMUNITYASSEMBLY 108
Introduction 108
Rulesimposedbythelandscapetemplate 109
Rulespartitioningspecieswithinfeedingguilds 110
Rulesformorphologicaloverdispersion Ill
Ahierarchicalmodel 112
Invasionsandextinctions 115
APPENDICES
A. DIET,FORAGINGSTRATA,ANDBODYMASSOFVERTEBRATE
SPECIESINSOUTHFLORIDA 117
B. BODYMASSANDLUMPSTRUCTUREOFVERTEBRATESIN
SOUTHFLORIDA 128
C. SUCCESSFULANDUNSUCCSESSFULAVIANINTRODUCTIONS
INSOUTHFLORIDA 139
D. AVIFAUNAINTRODUCEDINTOSOUTHFLORIDAWITHAN
INADEQUATEPROPAGULE 144
VI
E. BIRDSOFMEDITERRANEAN-CLIMATEECOSYSTEMS 145
F. MAMMALSOFMEDITERRANEAN-CLIMATEECOSYSTEMS 172
G. ABUNDANCE,DECLINEANDNOMADISMINTHEFAUNAOF
MEDITERRANEAN-CLIMATEECOSYSTEMS 184
LITERATURECITED 193
BIOGRAPHICALSKETCH 206
Vll
AbstractofDissertationPresentedtotheGraduateSchool
oftheUniversityofFloridainPartialFulfillmentofthe
RequirementsfortheDegreeofDoctorofPhilosophy
SCALE,PATTERN,ANDPROCESSINBIOLOGICALINVASIONS
By
CraigR.Allen
December1997
Chairman:W.M.Kitchens
CoChair:C.S.Holling
MajorDepartment:WildlifeEcologyandConservation
Thephenomenonofbiologicalinvasionandextinctionarecentralfociofthe
fieldofconservationbiology. Extinctionsdecreasediversity,andthelossofecological
functionfollowingextinctionsjeopardizesotherspeciesandthecontinuedfunctionof
ecosystems,aswellastheservicesthattheyprovide. Invasionsmayincreaselocal
diversity,butthisisatthelossofglobaldiversity.
Muchefforthasbeenmadetodeterminetheprocessesunderlyinginvasions
andextinctions. Thishasprimarilyresultedinlonglistsofcharacteristicsofinvasive
anddecliningspecies. Theselistsareusuallygeneratedbysinglespeciesstudiesor
studiesofisolatedcommunities,andhavelittlepredictivevalue. Similarly,the
associationbetweeninvasionsand"disturbance"issovagueastobeoflittlevalue.
Disturbanceisascale-boundmeasure,andassociationmadebetweeninvasionsand
disturbanceisoflittlevalueaslongasitremainsscaleinvariant.
viii
Landscapepatternisscaledependentanddifferentsizedanimalslivingupon
thesamelandscapeperceivetheirenvironmentatdifferentscales. Increasingevidence
suggeststhatecosystemsarestructuredbyrelativelyfewkeyprocessesoperatingat
specifictemporalandspatialscales. Thedistincttemporalfrequenciesandspatialscale
characterizingthesekeyprocessescreateshierarchicallandscapestructureswithscale
specificpattern. Thescale-specificeffectofkeyprocessesleadstoadiscontinuous
distributionofecologicalstructureandpatternwhichinturnentrainsattributesof
animalsresidingonthelandscape. Thisentrainmentreflectsadaptationstoa
discontinuouspatternofresourcedistributionactingonanimalcommunityassembly
andevolutionbothbysortingspeciesandbyprovidingaspecificsetofevolutionary
opportunitiesandconstraintsandleadstoadiscontinuousdistributionofanimalbody
masses.
Itestedseveraltraditionalhypothesesconcerninginvasionsandextinctions.
Thesehypotheseswerebasedonbodysize,nicheandphylogeny,andallwere
rejected. However,invasionsandextinctionswerepredictableinthecontextofscale-
specificcommunitystructure,andtendedtooccuratscalebreaks. Additional
biologicalvariabilityatscalebreakswasdocumented,includinganassociationwith
abundanceandnomadism. Anunderstandingofthescale-specificnatureofanimals,
ecologicalprocesses,andstructureledtoahierarchicalmodelofvertebrate
communityassembly.
INTRODUCTION
SeveralyearsagoIwasrequestedtofindten200to400-hectarestudyareas
thatconsistedofasinglehabitat-typeandsupportedrelativelyhomogenous
populationsofredimportedfireants(Solenopsisinvicta),NorthernBobwhite
(Colinusvirginianus)andwhite-taileddeer(Odocoileusvirginianus). Ittookbutfew
tripstothelandscapeinquestion,coveringtensofthousandsofsquarekilometers,to
reachtheconclusionthatsuchataskwasnotpossible. Althoughthedesiredstudy
areasizewassmallandthebroadlandformextensive,tensitessupporting
homogenouspopulationsofthosespeciescouldnotbefound. Theeventualsolution
wastopairstudysitestoremovetheinherentvariabilityamongsites.
Althoughnowseeminglyobvious,thereasonformydifficultieswerenot
apparentatthetime.Afireantcolonymayexploitanareaofnomorethan2,500m2
whileadeermayoperateinanareaintheorderof1,000,000m\ Fireants,bobwhite,
anddeerallexploittheirenvironmentatgrosslydifferentscales. Whatmaybe
relativelyhomogenoushabitatforbobwhite,andthussupportcomparablepopulations
on200-hastudyareas,istoosmalltocapturetherepeatedpatternsindeerdensity,
andtoolargeforfireants. Becausethesespeciesdiffergreatlyinbodysize,their
environmentalperceptionalsoisgrosslydifferent. Thehabitatstructurethateach
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