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This is a list of my publications, if you click on the title it will take you to the abstract.Connolly, R. M., Guest, M. A., Melville, A. J. and Oakes, J. M. (2004) Sulfur stable isotopes separate producers in marine foodweb analysis. Oecologia 138: 161-167. Melville, A. J. and Connolly, R. M. (2003) Spatial analysis of stable isotope data to determine primary sources of nutrition for fish. Oecologia 136: 499-507. Connolly, R. M., Melville, A. J. and Preston, K. M. (2002) Patterns of movement and habitat use by leafy seadragons tracked ultrasonically. Journal of Fish Biology 61: 684-695. Connolly, R. M., Melville, A. J. and Keesing, J. K. (2002) Abundance, movement and individual identification of leafy seadragons, Phycodurus eques (Pices : Syngnathidae). Marine and Freshwater Research 53: 777-780. Melville, A. J. and Connell, S. D. (2001) Effects of Ecklonia radiata on understorey species. Austal Ecology 26: 102-108. Stevenson J. and Melville A. (1999) Settlement and recruitment of the abalone Haliotis cyclobates Peron, 1816. Marine and Freshwater Research. 50(3):229-234 Cronin, E. R., Cheshire, A. C., Clarke, S. C. and Melville A. J. (1999) An investigation into the composition, biomass and oxygen budget of the fouling community on a tuna aquaculture farm . Biofouling 13: 279-299 Connolly, R. M., Guest, M. A., Melville, A. J. and Oakes, J. M. (in press) Sulfur stable isotopes separate producers in marine foodweb analysis. Oecologia Publish first. Ecological applications of stable isotope analysis rely on different producers having distinct isotopic ratios to trace energy and nutrient transfer to consumers. Carbon (C) and nitrogen (N) are the usual elements analysed. We tested the hypothesis that producers unable to be separated using C and N would be separated by sulphur (S), by reviewing estuarine and marine food web studies using all three elements (total of 836 pairwise comparisons between producers). S had a wider range of values across all producers than C and N (S: 34.4, C: 23.3, N: 18.7 ppt), and a higher mean difference among producers (S: 9.3, C: 6.5, N: 3.3 ppt). We varied from 1 to 10 ppt the distance producers must be apart to be considered separate. For each of these gap distances, S-separated producers tied on C and N in 40% or more of cases. Comparing the three elements individually, S had fewer tied pairs of producers for any gap distance than C or N. However, S also has higher within-producer variability. Statistical tests on simulated data showed that this higher variability caused S to be less effective than C for analysing differences among mean producer values, yet mixing models showed that S had the smallest confidence intervals around mean estimates of source contributions to consumers. We also examined the spatial and temporal scales over which S isotope signatures of the saltmarsh plant Spartina alterniflora varied. Differences between samples taken within tens of metres were smallest, but between samples hundreds of metres apart were as different as samples thousands of kilometres apart. The time between samples being taken did not influence S signatures. Overall, the use of S is recommended because it has a high probability of distinguishing the contribution of different producers to aquatic food webs. When two elements are employed, the combination of S and C separates more producers than any other combination. Melville, A. J. and Connolly, R. M. (2003) Spatial analysis of stable isotope data to determine primary sources of nutrition for fish. Oecologia 136: 499-507. Carbon and nitrogen stable isotopes were used to determine the ultimate autotrophic sources supporting production of three commercially important fish species over unvegetated mudflats in a subtropical estuary. Mean isotope values over the whole estuary for fish and autotroph sources were modeled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3–10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomization procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modeling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution from whole estuary modeling. Spatial analysis on sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves (up to 25%) and microalgae on the mudflats, considered unimportant based on whole estuary modeling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and demonstrated here that both in situ production of microalgae and organic matter from adjacent habitats were important to fish over mudflats. Connolly, R. M., Melville, A. J. and Preston, K. M. (2002) Patterns of movement and habitat use by leafy seadragons tracked ultrasonically. Journal of Fish Biology 61: 684-695. Nine adult leafy seadragons Phycodurus eques were tracked using ultrasonic telemetry for between 2 - 10 days around West Island, Australia. All fish except one moved within well-defined home ranges of up to 5 ha (using minimum convex polygon method). Short bursts of movement (at average veolocities of 2-17 m h-1) punctuated long periods (up to 68 h) without movement. The exceptional fish moved almost in a straight line away from its tagging location near the end of the tracking period, at a maximum velocity of 146 m h-1. There was no constant diel pattern in movements; some fish moved more at night, others during the day. The time leafy seadragons spent over particular habitats compared to the area of those havitats available at the study site was greater for Posidonia seagrass, about as expected for kelp-covered reefs and bare sand patches, and less than expected for Amphibolis seagrass and boulders covered with brown algae. In searching for tagging effects, a comparison of movement immediately after tagging showed no difference with subsequent movements for most fish. The lack of tagging effect may be because the transmitter can be attached to the bony appendages away from the body of the fish. There was no sign of damage to the fish upon removal of transmitters after tracking. Connolly, R. M., Melville, A. J. and Keesing, J. K. (2002) Abundance, movement and individual identification of leafy seadragons, Phycodurus eques (Pices : Syngnathidae) Marine and Freshwater Research 53: 777-780. The aim of this study was to estimate, for the first time, abundance and degree of movement of leafy seadragons, Phycodurus eques, at one location in southern Australia. The pattern of wear and damage to the leafy appendages was found to vary among individuals but was not a reliable method of identification of individual fish over long periods. Photographic evidence of individual facial markings for at least 11 months. We made 45 sightings in 47 dives over 14 months. Sightings were made in depths of 3-11 m over brown algae, seagrass, and sand covered with drift macroalgae. Nine individual fish were sighted and all except one were sighted at least twide (mean of five sightings, s.e. 1.2, range 1-12). Capture and recapture calculations (moment estimator algorithm) estimated 9.2 (+-0.3) seadragons in the study area (density 57 fish ha-1). resightings were made months apart, suggesting that the fish are remaining within a home range (range of 35-82 m, maximum distance between sighting for fish sighted >5 times). Information about patterns of movement of seadragons is directly relevant to management plans for this species and for marine protected areas designed to aid in their protection. Melville, A. J. and Connell, S. D. (2001) Effects of Ecklonia radiata on understorey species. Austal Ecology 26: 102-108. Plants are often grouped as canopy species or understorey species because it is thought that these sets of taxa interact in predictable ways. Mensurative experiments in southern Australia demonstrated that the percentage cover of encrusting corallin algae was greater, and articulated (branching) coralline algae less, on boulders under a conopy of dense kelp (>7 plants per m2), Ecklonia radiata, than on boulders without kelp. Experimental clearances of kelp and reciprocal transplants of boulders between patches of E. radiata and patches without kelp showed that canopies maintained and facilitated the growth of encrusting coralline algae and reduced the cover of articulated coralline algae. Potential artefacts associated with clearing kelp and transplanting boulders were not detected when tested with a series of translocation controls. These results reject the model that the co-occurrence of E. radiata and encrusting corallines is just and assemblage of plants caused by spatial and temporal coincidence. Instead, they suuort the model that kelp facilitates the growth and survival of understorey algae. Stevenson J. and Melville A. (1999) Settlement and recruitment of the abalone Haliotis cyclobates Peron, 1816. Marine and Freshwater Research. 50(3):229-234 The settlement preference, distribution and juvenile recruitment distribution of Haliotis cyclobates were investigated in a seagrass meadow in Gulf St Vincent, South Australia, in 1993 and 1994. Samples of hard substratum and seagrass were collected from seagrass patches and open areas and examined for newly settled and 0+ recruits. Hard substrata consisted of small rocks, large bivalve shells and bottles. Twelve newly settled recruits (<3 mm) were found: 11 on seagrass and one on hard substratum. Settlement onto seagrass blades is the first field example of an abalone species settling naturally onto soft substratum. 0+ recruits (4-9 mm) were found from March to October, indicating a single spawning and settlement season. 0+ recruits were found on small isolated patches of hard substratum in open and seagrass areas, suggesting that post-settlement migration may have some influence on recruitment patterns. The results indicate that the early life history of Haliotis cyclobates is adapted for enhancing recruitment into seagrass areas. Settlement onto seagrass blades is different from that observed for other species of abalone, and clarification of the specific settlement cue may contribute to the understanding of abalone settlement behaviour. Cronin, E. R., Cheshire, A. C., Clarke, S. C. and Melville A. J. (1999) An investigation into the composition, biomass and oxygen budget of the fouling community on a tuna aquaculture farm Biofouling 13: 279-299 The composition, distribution and oxygen dynamics of a net fouling community on a tuna sea cage farm were studied to determine the changes in community composition over time, and the effects of this fouling on the oxygen status of the water body in the cage. The oxygen exchange was quantified using an in-situ aquatic photosynthesis system in May and August 1995. Biofouling of the seacage was considerable, with a community consisting of a diverse collection of organisms dominated by detrital feeding animals. The community was a net consumer of oxygen despite the high productivity of algae in the system. Respiration of the entire community ranged from 155?330µmol O2g-1FWd-1. Production of the algal component (which predominated in the upper portion of the cage) was higher in August (335µmol O2g-1FWd-1) than in May (90µmol O2g-1FWd-1). In comparison to other oxygen sources and sinks in the cage system, the fouling community consumed <3% of the available oxygen. Whereas in a stressed system this may be sufficient to reduce oxygen levels below the critical values, it is probable that the restriction to mass water exchange (resulting from fouling) is more likely to lead to oxygen stresses in the cage system. |