icolls - Sustainable Tourism CRC

ECOLOGY, THREATS AND MANAGEMENT OPTIONS FOR SMALL ESTUARIES AND ICOLLS
CONTENTS
ABSTRACT____________________________________________________________________________ VI
ACKNOWLEDGEMENTS _______________________________________________________________ VI
SUMMARY ___________________________________________________________________________ VII
CHAPTER 1 THREATS TO THE ECOLOGICAL HEALTH OF ICOLLS: A REVIEW WITH
EMPHASIS ON SMALL ICOLLS IN AUSTRALIA ___________________________________________ 1
ABSTRACT ____________________________________________________________________________ 1
INTRODUCTION ________________________________________________________________________ 1
PROCESSES THREATENING THE ECOLOGICAL HEALTH OF ICOLLS _________________________________ 4
Threatening Process 1: Eutrophication and Contamination_____________________________________ 4
Threatening Process 2: Fisheries _________________________________________________________ 6
Threatening Process 3: Artificial Berm Breaching and Modification of Flow Regimes _______________ 8
Threatening Process 4: Tourism and Recreational Use of ICOLLs______________________________ 11
Threatening Process 5: Coastal Development and Habitat Loss – Implications for Conservation ______ 12
KNOWLEDGE GAPS, RESEARCH PRIORITIES AND ECOLOGICALLY SUSTAINABLE MANAGEMENT PRACTICES
FOR ICOLLS _________________________________________________________________________ 13
CHAPTER 2 MARINE SUBSIDIES SUPPORT ICOLL FOOD WEBS: THE DEVELOPMENT OF A
MARINE PULSE CONCEPT _____________________________________________________________ 14
IMPLICATIONS OF CATCHMENT MODIFICATIONS ON ICOLL FOOD WEB STRUCTURE AND FUNCTION______ 14
CONCEPTUAL APPROACH TO CARBON FLOW IN ICOLL FOOD WEBS ______________________________ 14
MATERIALS AND METHODS ______________________________________________________________ 16
Site Selection_______________________________________________________________________ 16
Sampling Methods___________________________________________________________________ 17
Laboratory Sample Processing _________________________________________________________ 17
Analytical Methods __________________________________________________________________ 18
RESULTS ____________________________________________________________________________ 18
Isotopic Analyses ___________________________________________________________________ 19
DISCUSSION __________________________________________________________________________ 24
Biological Diversity and Conservation Value of ICOLLs_____________________________________ 24
Stable Isotope Signatures of Biota in ICOLLs _____________________________________________ 24
Opening Regimes and Carbon Flow in ICOLLs ____________________________________________ 24
Conclusions and Implications __________________________________________________________ 24
CHAPTER 3 SEWAGE EFFLUENT SIGNIFICANTLY INCREASES THE ∆ 15 N SIGNATURES OF
RESIDENT BIOTA IN AN INTERMITTENTLY OPEN ESTUARY ____________________________ 26
INTRODUCTION _______________________________________________________________________ 26
MATERIALS AND METHODS ______________________________________________________________ 27
Sampling Sites______________________________________________________________________ 27
Sampling Methods___________________________________________________________________ 27
Laboratory Sample Processing _________________________________________________________ 28
Analytical Methods __________________________________________________________________ 28
RESULTS ____________________________________________________________________________ 28
Community Composition _____________________________________________________________ 28
Stable Isotopes______________________________________________________________________ 29
Intraspecific Variation in δ 15 n Signatures in Tallows Creek ___________________________________ 30
DISCUSSION __________________________________________________________________________ 33
Sewage Effluent and δ 15 n Signatures of Biota in Tallows Creek _______________________________ 33
Food Web Structure and Function in Tallows and Belongil Creeks _____________________________ 33
Patterns of Fish Movement Inferred from Nitrogen Isotope Signatures __________________________ 34
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