ORCID Profile
0000-0002-9793-6619
Current Organisation
Southern Cross University
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Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/MF10259
Abstract: Gastropods play an important ecological role in kelp forests however, this role is dependent on where exactly in such communities these animals are located. We assessed the spatial and temporal patterns in the utilisation of available reef and macroalgal substrates by three gastropods in a north-eastern New Zealand kelp (Ecklonia radiata (C. Agardh) J. Agardh, 1848) forest, focusing on predation as a factor influencing these patterns. Although kelp provided a large habitable surface area for gastropods, much of this area was under-utilised. During the day, gastropods on E. radiata were largely confined to the primary laminae. At night, gastropods on the reef migrated into the algal canopy where they occupied regions of the kelp that were not occupied during the day. Over a 36-day period, 93% of the gastropods tethered to the reef were consumed by predators, whereas none tethered in the algal canopy was consumed. We consider that night-time vertical migration and dispersion through the algal canopy may be primarily a response to predation by diurnally feeding fish and nocturnal benthic predators such as lobsters. Our research highlights the importance of considering diel changes in epifaunal distribution and abundance when assessing their ecological role.
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1007/S10661-006-0359-3
Abstract: An investigation of the impacts from elevated intertidal Pacific oyster culture in a New Zealand estuary showed enhanced sedimentation beneath culture racks compared with other sites. Seabed elevation beneath racks was generally lower than between them, suggesting that topographic patterns more likely result from a local effect of rack structures on hydrodynamic processes than from enhanced deposition. Compared with control sites, seabed sediments within the farm had a greater silt/clay and organic content, and a lower redox potential and shear strength. While a marked trend in macrofaunal species richness was not evident, species composition and dominance patterns were consistent with a disturbance gradient, with farm effects not evident 35 m from the perimeter of the racks. Of the environmental variables measured, sediment shear strength was most closely associated with the distribution and density of macrofauna, suggesting that human-induced disturbance from farming operations may have contributed to the biological patterns. To evaluate the taxonomic sufficiency needed to document impacts, aggregation to the family level based on Linnean classification was compared with an aggregation scheme based on general groups' identifiable with limited taxonomic expertise. Compared with species-level analyses, spatial patterns of impact were equally discernible at both aggregation levels used, provided density rather than presence/absence data were used. Once baseline conditions are established and the efficacy of taxonomic aggregation demonstrated, a general group' scheme provides an appropriate and increasingly relevant tool for routine monitoring.
Publisher: Informa UK Limited
Date: 06-1996
Publisher: CSIRO Publishing
Date: 1980
DOI: 10.1071/MF9800037
Abstract: The reproductive cycles of Siphonaria denticulata and S. virgulata were determined by measuring the length or weight of the spawn of each species. S. denticulara lays a typical. coiled, gelatinous egg ribbon, cemented to the rocky substratum. S. virgulata lays a globular egg mass which is released directly into the water. This latter form of spawning is apparently unique amongst pulmonate molluscs. S. denticulata has a long breeding season, extending from November-December to the following April-May. Spawning usually occurs every 2 weeks for large adults, but smaller (i.e. younger) limpets spawn less frequently. Periods of spawning correspond to periods of full or new moons. The exact length of the breeding season of S. virgulata is unknown. Estimates of fecundity were obtained from counts of eggs within egg masses. There were differences in the fecundity of S. denticulata between localities, but S. denticulata and S. virgulata from the same locality had similar fecundities for similar-sized animals. Egg ribbons of S. denticulata experimentally placed high on the shore were found to suffer higher mortality from desiccation than those lower on the shore. This may explain why S. virgulata, which generally lives higher on the shore than its congener, has pelagic egg masses.
Publisher: Informa UK Limited
Date: 1987
Publisher: Elsevier BV
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 1982
DOI: 10.1007/BF00349015
Publisher: CSIRO Publishing
Date: 1995
DOI: 10.1071/MF9950617
Abstract: An examination of the reproductive condition of a population of paua, H. iris, at Leigh in north-eastern New Zealand during 1986-87 revealed a long breeding season extending from late summer through autumn and winter and into early spring. Within this period, a sharp decrease of over 60% in the gonad index for both males and females indicated major spawning events in July and October. A smaller decrease in the gonad index in March suggested a third, minor spawning. These spawning events were confirmed by regular examination of histological sections of gonadal material. This breeding pattern is different from that previously described for southern localities in New Zealand, where spawning activity is limited to a four-month period from late summer into autumn. Paua in this northern population had a sex ratio slightly biased towards males (1 female to every 1.3 males) and achieved reproductive maturity between the sizes of 48 and 60 mm shell length. These features are also different from those described for southern populations of H. iris. These findings highlight the need to take regional differences in reproductive pattern into account when describing the population dynamics of marine gastropods.
Publisher: Wiley
Date: 08-10-2015
DOI: 10.1002/AQC.2600
Publisher: Informa UK Limited
Date: 06-1980
Publisher: Springer Science and Business Media LLC
Date: 06-1982
DOI: 10.1007/BF00389010
Publisher: Informa UK Limited
Date: 1986
Publisher: Springer Science and Business Media LLC
Date: 05-1985
DOI: 10.1007/BF00346466
Publisher: Inter-Research Science Center
Date: 14-10-0010
DOI: 10.3354/MEPS11469
Publisher: Wiley
Date: 26-10-2012
Publisher: Informa UK Limited
Date: 09-2003
Publisher: Elsevier BV
Date: 10-1996
Publisher: Springer Science and Business Media LLC
Date: 10-1990
DOI: 10.1007/BF01314345
Publisher: Informa UK Limited
Date: 09-2006
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/PC15048
Abstract: Bio ersity conservation is a major issue in ports and harbours as scientists, managers and the public become increasingly aware of the importance of healthy ecosystems to the wellbeing of urban populations. Sydney’s Harbour provides essential environmental, social and economic values to community, government and industry. Recent systematic reviews of the biological and physical characteristics of Sydney Harbour revealed high environmental and conservation value, especially considering the large numbers of people using its resources. However, like many coastal areas, the harbour has been subject to stressors such as habitat loss, metal, organic and nutrient pollution, the introduction of non-indigenous species, foreshore construction and commercial and recreational fishing. Here we outline the environmental assets of the harbour and the major threats, and report on current and developing conservation strategies. By learning about the progress of environmental management in Sydney Harbour, the difficulties faced and new planning strategies implemented, coastal and harbour environmental managers within the region can be better prepared when faced with similar challenges.
Publisher: Informa UK Limited
Date: 03-2001
Publisher: Coastal Education and Research Foundation
Date: 03-03-2016
DOI: 10.2112/SI75-129.1
Publisher: Elsevier BV
Date: 02-1983
Publisher: Informa UK Limited
Date: 09-1988
Publisher: Informa UK Limited
Date: 03-2000
Publisher: Wiley
Date: 28-03-2011
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/MF07054
Abstract: Spatial and temporal patterns of variability in ascidian assemblages were investigated on horizontal subtidal rocky reefs at Port Stephens, New South Wales (NSW). The study was designed to provide a baseline dataset on ascidian ersity and distribution patterns for an area destined to become a marine park (the Port Stephens–Great Lakes Marine Park: PSGLMP). Differences in ascidian assemblages between exposed oceanic island reefs and sheltered reefs within Port Stephens, and between two depth zones within each subtidal reef, were quantified using non-parametric multivariate techniques coupled with analysis of variance (ANOVA). Ascidian assemblages were highly variable between reef sites, reef exposures and particularly between depth zones within each reef surveyed. However, temporal variation was only observed for a few ascidian species. These highly variable spatial patterns in ersity indicate that numerous subtidal reefs may need to be protected within PSGLMP if the aim of the marine park is to adequately represent the entire array of marine bio ersity in the area.
Publisher: Elsevier BV
Date: 04-1981
Publisher: Elsevier BV
Date: 09-1976
Publisher: CSIRO Publishing
Date: 1980
DOI: 10.1071/MF9800049
Abstract: Reproductive cycles of four species of limpets were determined using quantitative analyses of counts of eggs and weights of gonads. Montfortula rugosa has a breeding season extending for 8-9 months, but does not show marked peaks of reproductive activity. It spawns small numbers of eggs over a long period, and never has a very large gonad. Notoacmea petterdi has a very short spawning season in May or June. Prior to spawning the gonad may account for over half the wet weight of an in idual. After spawning there is a long resting period, after which the size of the gonad and the number and proportion of mature eggs increases gradually over the next 7-8 months. Patelloida alticostata and P. latistrigata have strategies which are intermediate between the other two species. Spawning may occur over a 4-6 month period during which time there are two peaks of spawning activity. The production of mature oocytes recommences soon after spawning has ceased in July, and the gonad rapidly increases in size during the following 4 months. Estimates of fecundity are given for the three species of acmaeid limpet. In these species, fecundity increases with increasing size yet in iduals are capable of producing and spawning mature eggs at the end of their first year on the shore. The adaptive significance of such a strategy is discussed.
Publisher: Elsevier BV
Date: 09-1976
Publisher: Elsevier BV
Date: 04-2005
Publisher: Inter-Research Science Center
Date: 1984
DOI: 10.3354/MEPS017085
Publisher: Informa UK Limited
Date: 06-1980
Publisher: Springer Science and Business Media LLC
Date: 05-1985
DOI: 10.1007/BF00399025
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF15159
Abstract: Sydney Harbour is a global hotspot for marine and estuarine ersity. Despite its social, economic and biological value, the available knowledge has not previously been reviewed or synthesised. We systematically reviewed the published literature and consulted experts to establish our current understanding of the Harbour’s natural systems, identify knowledge gaps, and compare Sydney Harbour to other major estuaries worldwide. Of the 110 studies in our review, 81 focussed on ecology or biology, six on the chemistry, 10 on geology and 11 on oceanography. Subtidal rocky reef habitats were the most studied, with a focus on habitat forming macroalgae. In total 586 fish species have been recorded from the Harbour, which is high relative to other major estuaries worldwide. There has been a lack of process studies, and an almost complete absence of substantial time series that constrains our capacity to identify trends, environmental thresholds or major drivers of biotic interactions. We also highlight a lack of knowledge on the ecological functioning of Sydney Harbour, including studies on microbial communities. A sound understanding of the complexity, connectivity and dynamics underlying ecosystem functioning will allow further advances in management for the Harbour and for similarly modified estuaries around the world.
Publisher: Informa UK Limited
Date: 1997
Publisher: Informa UK Limited
Date: 06-2001
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: Informa UK Limited
Date: 06-1990
Publisher: Informa UK Limited
Date: 06-1997
Publisher: Informa UK Limited
Date: 12-1997
Publisher: Elsevier BV
Date: 10-2002
Publisher: Elsevier BV
Date: 11-2004
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF15157
Abstract: Sydney Harbour is a hotspot for ersity. However, as with estuaries worldwide, its ersity and functioning faces increasing threats from urbanisation. This is the first synthesis of threats and impacts in Sydney Harbour. In total 200 studies were reviewed: 109 focussed on contamination, 58 on habitat modification, 11 addressed non-indigenous species (NIS) and eight investigated fisheries. Metal concentrations in sediments and seaweeds are among the highest recorded worldwide and organic contamination can also be high. Contamination is associated with increased abundances of opportunistic species, and changes in benthic community structure. The Harbour is also heavily invaded, but invaders’ ecological and economic impacts are poorly quantified. Communities within Sydney Harbour are significantly affected by extensive physical modification, with artificial structures supporting more NIS and lower ersity than their natural equivalents. We know little about the effects of fishing on the Harbour’s ecology, and although ocean warming along Sydney is among the fastest in the world, we know little about how the ecosystem will respond to warming. The interactive and cumulative effects of stressors on ecosystem functioning and services in the Harbour are largely unknown. Sustainable management of this iconic natural system requires that knowledge gaps are addressed and translated into coherent environmental plans.
Publisher: Annual Reviews
Date: 11-2000
DOI: 10.1146/ANNUREV.ECOLSYS.31.1.61
Abstract: ▪ Abstract Conservation in New Zealand is failing to halt an ongoing decline in bio ersity. Classical problems of ecosystem loss and fragmentation have largely been countered in some regions by reservation of 30% of total land area. Unsustainable harvesting of native bio ersity has stopped indeed harvesting of terrestrial species is rare. In contrast, marine reserves do not cover even 1% of the managed area, and harvest of native species, some of it unsustainable, are a major industry. Introduced pests, especially mammals, are the overwhelming conservation problem. Legislation, management, and considerable public opinion is based on preservationist ideals that demand the sanctity of native land bio ersity. Considerable success in threatened species management, island eradications, and mainland control of pests is increasing opportunities for restoration. New legislation is increasingly built on concepts of sustainability and offers the opportunity for integrating conservation, use, and development. Realization of these opportunities requires greater understanding of the relative merits of preservation versus sustainability, the dynamics and costs of pest control, the need for ecosystem processes in addition to in idual species, and the involvement of people, especially the rights of indigenous Maori. Understanding marine environments and linking attitudes to land and sea is also a challenge.
No related grants have been discovered for Bob Creese.