icolls - Sustainable Tourism CRC

30.11.2012 Views
ECOLOGY, THREATS AND MANAGEMENT OPTIONS FOR SMALL ESTUARIES AND ICOLLS Analytical Methods Samples were analysed using a continuous flow-isotope ratio mass spectrometer (Micromass Isoprime EuroVector EA300, Manchester, UK) at Griffith University. Isotope ratios are expressed as either δ13C or δ 15 N and relate to the ratio of 13C:12C and 14N:15N respectively. Values were calculated according to the following equation: δ 13 C or δ 15 N = [(Rsample / Rstandard) – 1] x 1000 where Rsample is the isotopic ratio for the sample and Rstandard is the isotopic ratio of the standard (PeeDee belemnite carbonate for δ13C and atmospheric N for δ 15 N). Results A wide range of taxa was collected from the study ICOLLs. Notably, representatives from both freshwater and estuarine environments were commonly encountered, especially in systems that were closed at the time of sampling (Table 2). This pattern held across all major taxonomic divisions, including vertebrates (fish) and invertebrates (aquatic insects, crustaceans, polychaete worms and molluscs). 18 Table 2: Taxa collected from study ICOLLs Woolgoolga Jerusalem Ainsworth Taylor's Belongil Tallows Invertebrates Marphysa spp. Marphysa spp. Corixidae Marphysa spp. Marphysa spp. Marphysa spp. Amphipods Amphipods Anisoptera Corixidae Donax deltoides Corixidae Clibanarius spp. Ligia australiensis Dytisidae Notonectidae Uca vomeris Bivalvia Callianassa australiensis Callianassa australiensis Gerridae Metapenaeus bennettae Trichoptera Donax deltoides Mictyris longicarpus Trichoptera Callianassa australiensis Zygoptera Halicarcinus spp. Ephemeroptera Amphipods Saccostrea glomerata Zygoptera Ligia australiensis Metapenaeus bennettae Dytisidae Donax deltoides Pyrazus ebeninus Anisoptera Metapenaeus bennettae Mictyris longicarpus Gastropoda Halicarcinus spp Austrocochlea Ocypode Portunus porcata cordimana pelagicus Callianassa australiensis Caridina indistincta Scylla olivacea Fish Philypnodon grandiceps Gobiomorphus australis Pelates sexlineatus Ambassis marianus Centropogon australis Philypnodon grandiceps Platycephalus fuscus Arothron manilensis Rhadinocentrus ornatus Achlyopa nigra Hypseleotris galii Gambusia holbrooki Hypseleotris galii Gambusia holbrooki Mugil cephalus Mugil cephalus Ambassis marianus Favonigobius lateralis Centropogon australis Tetractenos hamiltoni Rhabdosargus sarba Platycephalus fuscus Philypnodon grandiceps Pseudomugil signifer Ambassis marianus

ECOLOGY, THREATS AND MANAGEMENT OPTIONS FOR SMALL ESTUARIES AND ICOLLS Woolgoolga Jerusalem Ainsworth Taylor's Belongil Tallows Favonigobius lateralis Gerres subfasciatus Platycephalus fuscus Sillago ciliata Mugil cephalus Acanthopagrus australis Other Verts Larus novaehollandiae Isotopic Analyses Sillago ciliata Achlyopa nigra Mugil cephalus Bufo marinus Larus novaehollandiae Platycephalus fuscus Hypseleotris galii Philypnodon grandiceps Anguilla anguilla Pelates sexlineatus Gerres subfasciatus Arothron manilensis Acanthopagrus australis Sillago ciliata Pelates sexlineatus Mugil cephalus Sillago ciliata Acanthopagrus australis Achlyopa nigra In all sites, isotopic discrimination between major principal carbon sources (namely riparian vegetation including mangroves, marine algae, filamentous green algae and BFPOM/seston) facilitated analyses of food web structure and consumer reliance on terrestrial, within-system and/or marine carbon subsidies. Wherever possible, replicate samples were pooled to attain mean (± S.E.) δ13C and δ 15 N isotope signatures. This approach enables a more rigorous examination of food web structure and function by facilitating greater understanding of isotopic variability within sites. There was considerable variability in carbon isotope signatures for some primary carbon sources among ICOLLs (Table 3). For example, the δ 13 C signatures of periphyton ranged from 18.98‰ in a site from Belongil Creek to 28.67‰ in a site in Lake Woolgoolga (Table 3). Despite this variability in algal carbon signatures, the δ 13 C signatures of riparian vegetation (including mangroves) were generally consistent both within and among sites (Table 3), ensuring a constant terrestrial end-member in the mixing model analyses. There was a very large range in δ 15 N isotope signatures of primary carbon sources (and consumers) among the study ICOLLs (Table 4). All components of the food web were heavily 15 N-enriched in Tallows Creek (relative to other ICOLLs sampled). For example, whiting (Sillago ciliata) isotopic signatures were typically around 30‰ in Tallows Creek, yet they rarely rose above 12‰ in the other ICOLLs from which they were collected. A more detailed appraisal of why Tallows Creek δ 15 N signatures are enriched and the implications of this enrichment are presented in Chapter 3 of this report. Table 3: Mean and S.E. δ13C values for all food web components sampled from all study ICOLLs. (Site Codes are as follows: WOO = Lake Woolgoolga, JER = Jerusalem Creek, AINS = Lake Ainsworth, TALL = Tallows Creek, BEL = Belongil Creek and TAY = Taylors Lagoon). WOO 1 WOO 2 WOO 3 JER 1 JER 2 AINS 1 TALL 1 TALL 2 TALL 3 BEL 1 BEL 2 BEL 3 TAY 1 Sample δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. δ 13 C s.e. BFPOM -26.03 0.00 -27.23 0.00 -18.40 0.00 -27.97 0.00 -22.87 0.00 -27.32 0.00 -22.32 0.00 -24.09 0.00 -26.86 0.00 -27.93 0.00 -27.51 0.00 -27.20 0.00 BCPOM -27.46 0.00 -29.10 0.00 -28.28 0.00 -29.22 0.00 -22.49 0.00 -27.32 0.00 -28.18 0.00 -29.60 0.00 -28.36 0.00 -27.44 0.00 -30.08 0.00 -28.90 0.00 -27.46 0.00 Periphyton -20.20 0.00 -21.80 0.40 -28.67 0.00 -27.83 0.00 -24.20 0.70 -23.60 1.90 -22.10 0.58 -18.98 1.76 -25.57 0.00 -25.70 0.00 Epilithon -21.63 0.00 -20.74 0.00 -22.70 0.00 -24.48 0.00 Epiphytes -18.89 0.00 Floating Algae -27.02 0.00 19

Page 1 and 2: ECOLOGY, THREATS AND MANAGEMENT OPT




Page 9 and 10: Chapter 1 ECOLOGY, THREATS AND MANA








Page 25: ECOLOGY, THREATS AND MANAGEMENT OPT


Page 31 and 32: Hypseleotris spp. Pseudomugil signi




Page 39 and 40: δ15 δ N (‰) 15N (‰) δ15 δ N























Page 85 and 86: Research Programs The Sustainable T

icolls

coastal

estuaries

management

fish

water

species

creek

marine

ecology

sustainable

tourism

www.crctourism.com.au

icolls - Sustainable Tourism CRC

icolls - Sustainable Tourism CRC ... View more icolls - Sustainable Tourism CRC

Delete template?

Save as template ?

icolls - Sustainable Tourism CRC icolls - Sustainable Tourism CRC