Ross Coleman | The University of Sydney (original) (raw)

Papers by Ross Coleman

Marine and Freshwater Research

Although small starfish may exert significant grazing effects on hard substrata, quantification o... more Although small starfish may exert significant grazing effects on hard substrata, quantification of these effects has been difficult because of methodological limitations. Previously, caging small starfish for field experiments has failed because animals can escape through cage meshes and confounding effects may arise as the starfish can feed on organisms growing on the fences themselves, rather than the surface under investigation. Here, we investigated the efficiency of alternative barrier methods, such as antifouling paint and sticky barriers, for shorter-term experimental manipulation of the herbivorous starfish Parvulastra exigua. Laboratory and field manipulations tested the hypotheses that barriers are efficient in retaining starfish within plots and that the chemical repellent of the barriers does not affect the normal functioning of starfish. The results showed that the sticky barrier did not deter P. exigua, but antifouling paint retained greater numbers of individuals with...

Marine environmental research, Jan 20, 2018

Community ecology has traditionally assumed that the distribution of species is mainly influenced... more Community ecology has traditionally assumed that the distribution of species is mainly influenced by environmental processes. There is, however, growing evidence that environmental (habitat characteristics and biotic interactions) and spatial processes (factors that affect a local assemblage regardless of environmental conditions - typically related to dispersal and movement of species) interactively shape biological assemblages. A metacommunity, which is a set of local assemblages connected by dispersal of individuals, is spatial in nature and can be used as a straightforward approach for investigating the interactive and independent effects of both environmental and spatial processes. Here, we examined (i) how environmental and spatial processes affect the metacommunity organization of marine macroinvertebrates inhabiting the intertidal sediments of a biodiverse coastal ecosystem; (ii) whether the influence of these processes is constant through time or is affected by extreme weat...

Marine Pollution Bulletin

Journal of Experimental Marine Biology and Ecology

It is well known that grazing gastropods, notably limpets, have a structuring effect on rocky sho... more It is well known that grazing gastropods, notably limpets, have a structuring effect on rocky shore ecology. The findings to establish this knowledge came from exclusion experiments, often using fences necessitating complex procedural controls. Barriers of anti-fouling copper paint (AP) have been shown to be an effective way to control densities of species in intertidal rocky shores. This method may produce fewer confounding effects than traditional methods of exclosure such as fences/cages and, consequently, is seen as a better solution for excluding grazing molluscs. Nevertheless, the potential artefacts arising from AP as a barrier system are not fully quantified. To better understand the biological impacts of AP and also determine its applicability in field studies, we first determined if using AP as a fence to enclose limpets led to elevated copper levels in test animals. Then, we tested short-term effects of AP on the tenacity, foraging behaviour, grazing pressure and body mass of the limpet Cellana tramoserica in its natural environment over a representative experimental period. AP barriers increased copper concentrations tenfold in C. tramoserica, but this did not affect any of the response variables measured under natural conditions. Overall, our results showed that AP is not as deleterious to limpets as reported from laboratory studies and this supports its use as an effective cageless method to manipulate densities of species on rocky shores in a short time scale.

The Journal of animal ecology, Jul 25, 2017

1.Understanding site fidelity is important in animal ecology, but evidence is lacking that this b... more 1.Understanding site fidelity is important in animal ecology, but evidence is lacking that this behaviour is due to an animal choosing a specific location. To discern site selection behaviour it is necessary to consider the spatial distribution of habitats that animals can occupy within a landscape. Tracking animals and defining clear habitat boundaries, however, is often difficult. 2.We use in situ habitat distribution data and animal movement simulations to investigate behavioural choice in site fidelity patterns. We resolved the difficulty of gathering data by working with intertidal rock pool systems, which are of manageable size and where boundaries are easy to define. Movements of the intertidal starfish Parvulastra exigua were quantified to test the hypotheses that (1) this species displays fidelity to a particular rock pool and that (2) rock pool fidelity is due to site selection behaviour. Observed patterns of individuals (n=10 starfish) returning to a previously occupied r...

Marine Biology, 2016

Although the ecology of molluscan grazers on intertidal rocky shores is very well documented, the... more Although the ecology of molluscan grazers on intertidal rocky shores is very well documented, there are other abundant grazers, such as herbivorous starfish, that can modify the structure of benthic assemblages yet whose behaviour is poorly understood. The feeding habits of asteroids suggest that they are opportunistic feeders foraging on a broad range of available resources. The reasons for the variation in the food types consumed are not clear. We investigated the feeding habits of the intertidal herbivorous starfish Parvulastra exigua with respect to the temporal and spatial distribution of food and tidal cycles in two populations. We predicted that food choice by P. exigua would be a function of food abundance and that foraging would be independent of tidal cycle. The results showed that this starfish forages on a narrow range of algal food resources, with an apparent selection for microalgae. Foraging during high and low tide was variable across locations; however, most individuals from both populations foraged during any tidal period. These results indicate that P. exigua forages on the same food consumed by many other intertidal grazers, indicating the potential for competition for resources. Grazing on biofilm by P. exigua may play an important role in modifying the structure of algal assemblages on rocky shores by potentially preventing the growth of macroalgae.

Marine Pollution Bulletin, 2013

Background/Question/Methods Copper is an essential micro-nutrient for plants, though at higher co... more Background/Question/Methods Copper is an essential micro-nutrient for plants, though at higher concentrations it causes chloroplast dysfunction and inhibits photosynthesis. Due to their close contact with their environment, unicellular algae are thought to be particularly sensitive to Cu exposure. While brown algae tend to dominate heavy-metal contaminated habitats, little is known about the effect of copper on micro-algal community structure. Additionally, despite it being widely acknowledged that historical contingencies such as land-use legacies and species arrival order affect biodiversity assessment, the effect of disturbance history remains underexplored. This project had two objectives: (1) understand how copper contamination affects micro-algae type and abundance and (2) determine how historical contaminations may interact with other factors. For the first objective, micro-algal assemblages were developed on PVC settlement plates surrounded by copper anti-fouling paint. For ...

Oecologia, 1996

This paper presents tests of a model of wound-induced defence in herbaceous plants. Many studies ... more This paper presents tests of a model of wound-induced defence in herbaceous plants. Many studies have reported both chemical changes in leaves and changes in the behaviour and/or physiology of herbivores as a result of wounding leaves. These studies and others have led to the development of various models to explain wound-induced effects both in terms of plant response and

Marine environmental research, Jan 13, 2018

The field of eco-engineering has burgeoned in recent years in response to the proliferation of ar... more The field of eco-engineering has burgeoned in recent years in response to the proliferation of artificial structures. Adding water-retaining features to seawalls has been successful in increasing biodiversity relative to the surrounding structure. Artificial rock pools may not, however, completely mimic natural rock pools. Here, we compared natural colonisation, through dispersal and recruitment, of intertidal mobile species to water-retaining flowerpots on seawalls with that into rock pools. This represents the more usual 'passive' approach to eco-engineering where features are built to enhance biodiversity and are allowed to colonise naturally, as opposed to seeding or transplanting organisms to features. While flowerpots supported some mobile species not found on the seawall, other species common on natural shores did not recruit to flowerpots. Thus, in a second experiment we tested the effectiveness of an 'active' approach through transplanting mobile organisms t...

Biofouling, 2017

AbstractCopper based paints are used to prevent fouling on the hulls of ships. The widely documen... more AbstractCopper based paints are used to prevent fouling on the hulls of ships. The widely documented effect of copper on hull assemblages may be primarily due to direct effects on the invertebrates themselves or indirect effects from copper absorbed into the microbial biofilm before settlement has commenced. Artificial units of habitat were exposed to varied regimes of copper to examine (1) the photosynthetic efficiency and pigments of early-colonising biofilms, and (2) subsequent macroinvertebrate assemblage change in response to the different regimes of copper. Macroinvertebrate assemblages were found to be less sensitive to the direct effects of copper than indirect effects as delivered through biofilms that have been historically exposed to copper, with some species more tolerant than others. This raises further concern for the efficacy of copper as a universal antifoulant on the hulls of ships, which may continue to assist the invasion of copper-tolerant invertebrate species.

Herbivory is an important ecological process controlling community structure and function in almo... more Herbivory is an important ecological process controlling community structure and function in almost all ecosystems. The effects of herbivores on algal assemblages depend primarily on consumer and algal traits, but the strength of this interaction is contingent on physical and biological processes. Marine herbivory is particularly intense, where grazers can remove around 70% of primary production. Present understanding of marine herbivory is largely based on well-studied groups including herbivorous fishes, gastropods, crustaceans and sea urchins. Herbivory in other marine taxa is poorly understood, but nonetheless important. For instance, grazing by starfish has the potential to strongly affect algal assemblages. Most starfish feed by extruding their stomach and digesting their food externally. This feeding mechanism is distinctive and complex, and evolutionarily advantageous as it allows individuals to explore many different food sources. Variation in the feeding habits of herbivorous starfish is intriguing because some species are very specialised whereas others are more generalist, and the reasons for those variations are not well understood. Some herbivorous starfish are obligate herbivores while others vary from herbivory to carnivory between life stages or between populations within the same species. The question that then arises is how well we are able to predict grazing pressure from complex feeding habits on benthic systems? This review provides a synthesis of herbivory in starfish showing that: the majority of species forage on microalgae and soft tissue macroalgae; fidelity to an algal diet appears to be related to the size of individuals; and, feeding habits are likely to change with variation in food availability. Directions for future studies on the biology and ecology of herbivorous starfish are suggested to better understand variation in species feeding behaviour. Elucidating the mechanisms that contribute to variation in the behaviour of herbivorous starfish is crucial to predict the effects that these species exert on the structure of marine benthic communities. The influence of omnivorous species also warrants more detailed study. Such investigations are important in the context of climate change, given the potential for species invasions associated with range expansions.

The construction of artificial structures in the marine environment is increasing globally. Eco-e... more The construction of artificial structures in the marine environment is increasing globally. Eco-engineering aims to mitigate the negative ecological impacts of built infrastructure through designing structures to be multifunctional, benefiting both humans and nature. To date, the focus of eco-engineering has largely been on benefits for benthic invertebrates and algae. Here, the potential effect of eco-engineered habitats designed for benthic species on fish was investigated. Eco-engineered habitats (" flowerpots ") were added to an intertidal seawall in Sydney Harbour, Australia. Responses of fish assemblages to the added habitats were quantified at two spatial scales; large (among seawalls) and small (within a seawall). Data were collected during high tide using cameras attached to the seawall to observe pelagic and benthic fish. At the larger spatial scale, herbivores, planktivores, and invertebrate predators were generally more abundant at the seawall with the added flowerpots, although results were temporally variable. At the smaller spatial scale, certain benthic species were more abundant around flowerpots than at the adjacent control areas of seawall, although there was no general pattern of differences in species density and trophic group abundance of pelagic fish between areas of the seawall with or without added habitats. Although we did not find consistent, statistically significant findings throughout our study, the field of research to improve fish habitat within human-use constraints is promising and important, although it is in its early stages (it is experimental and requires a lot of trial and error).

Copper based paints are used to prevent fouling on the hulls of ships. The widely documented effe... more Copper based paints are used to prevent fouling on the hulls of ships. The widely documented effect of copper on hull assemblages may be primarily due to direct effects on the invertebrates themselves or indirect effects from copper absorbed into the microbial biofilm before settlement has commenced. Artificial units of habitat were exposed to varied regimes of copper to examine (1) the photosynthetic efficiency and pigments of early-colonising biofilms, and (2) subsequent macroinvertebrate assemblage change in response to the different regimes of copper. Macroinvertebrate assemblages were found to be less sensitive to the direct effects of copper than indirect effects as delivered through biofilms that have been historically exposed to copper, with some species more tolerant than others. This raises further concern for the efficacy of copper as a universal antifoulant on the hulls of ships, which may continue to assist the invasion of copper-tolerant invertebrate species.