Description: In this chapter a variety of field and laboratory techniques to assess biofouling assemblages are described. The first part, focusing on traditional methods, also includes methods of using image analysis, functional groups and several mathematical and theoretical models to estimate species diversity. The second part is applied and deals with the assessment of biofouling on in-service vessels in order to determine their biosecurity risk. The third part gives an overview of the methods required to undertake field experiments with biofouling assemblages on a global scale. Assessing fouling assemblages: This chapter focuses on traditional methods, also includes methods of using image analysis, functional groups and several mathematical and theoretical models to estimate species diversity. In ecology, manipulative experiments of living organisms are often carried out in the field, providing a real assessment of the community in question. As a precursor to these experiments a baseline survey of the natural community is essential to provide the wider context for change. The chapter gives some of the more popular methods used to assess fouling communities. The protocols necessary for carrying out these methods along with appropriate statistical techniques are discussed. Finally, a critique of the problems associated with each method is provided, and suggestions made for how to address these problems. Both field methods and digital methods are discussed in the chapter. Assessment of in-service vessels for biosecurity risk: Biofouling organisms, including sessile and mobile species, are encountered on all vessel types, including commercial vessels of all categories, naval ships, and recreational vessels. Criteria used to determine the biosecurity risk posed by hull fouling of in-service vessels are often specific to the requirements of environmental management agencies and result in the use of different sampling approaches. The biosecurity risk of vessels can also be estimated using abundance, biomass or richness of biofouling as the metrics of interest. This chapter provides guidance on approaches to determining the biosecurity risk of in-service vessels in situ or in dry-dock. It focuses on surveys designed to create biological inventories of vessel hulls and associated estimates of biofouling abundance. An absence of biofouling can only be guaranteed for inspections that have been designed using a statistical framework that provides a level of confidence of "freedom of infestation". Experiments on a global scale: The international research and student training program-Global Approach by Modular Experiments (GAME)-is one of a few initiatives worldwide that implements the scaling up of ecological studies from the regional to the global scale. Moreover, the innovative coupling of teaching and research and the propagation of a modular approach in experimental research makes it unique in marine sciences. Modularity means the simultaneous execution of identical experiments at multiple study sites that cover several biogeographic regions and climate zones. Marine epibiotic communities have repeatedly been recognized as suitable model systems for studies in community ecology and biodiversity research and such consortia of sessile metazoans and macroalgae have properties that make them for experimental studies. The chapter also presents chronology of a GAME project in seven major steps.

Description: 1 Several theoretical models predict under what conditions maximum species diversity can be maintained, and they are often used to develop effective ecosystem management plans. 2 Two models that are currently used to predict patterns of species diversity were empirically tested in marine subtidal benthic communities of different successional stages. 3 The two models were: the interactive effects of nutrient availability and disturbance frequency proposed by Kondoh (2001; Proceedings of the Royal Society London B, 268, 269–271), and the intermediate disturbance hypothesis (IDH) proposed by Connell (1978; Science, 199, 1302–1310). 4 Interactive effects were found to be transient and only occurred in the older communities, while the unimodal pattern suggested by the IDH was not supported in either successional stage. 5 It is concluded that these models are very general and thus lack sufficient explanatory power. Both models require a number of specific prerequisites for maximum diversity to be found, and though applicable in many different ecosystems they need to be refined as tools in order that they can be effectively used in habitat management plans.

Description: Natural communities are constantly changing due to a variety of interacting external processes and the temporal occurrence and intensity of these processes can have important implications for the diversity and structure of marine sessile assemblages. In this study, we investigated the effects of temporal variation in a disturbance regime, as well as the specific timing of events within different regimes, on the composition and diversity of marine subtidal fouling assemblages. We did this in a multi-factorial experiment using artificial settlement tiles deployed at two sites on the North East coast of England. We found that although there were significant effects of disturbances on the composition of assemblages, there were no effects of either the variation in the disturbance regime or the specific timing of events on the diversity or assemblage composition at either site. In contrast to recent implications we conclude that in marine fouling assemblages, the variability in disturbance regimes (as a driving force) is unimportant, while disturbance itself is an important force for structuring robust ecosystems.