Human threats to sandy beaches: a meta-analysis of ghost crabs illustrates global anthropogenic impacts

Beach and coastal dune systems are increasingly subjected to a broad range of anthropogenic pressures that on many shorelines require significant conservation and mitigation interventions. But these interventions require reliable data on the severity and frequency of adverse ecological impacts. Such evidence is often obtained by measuring the response of 'indicator species'.Ghost crabs are the largest invertebrates inhabiting tropical and subtropical sandy shores and are frequently used to assess human impacts on ocean beaches. Here we present the first global meta-analysis of these impacts, and analyse the design properties and metrics of studies using ghost-crabs in their assessment. This was complemented by a gap analysis to identify thematic areas of anthropogenic pressures on sandy beach ecosystems that are under-represented in the published literature.Our meta-analysis demonstrates a broad geographic reach, encompassing studies on shores of the Pacific, Indian, and Atlantic Oceans, as well as the South China Sea. It also reveals what are, arguably, two major limitations: i) the near-universal use of proxies (i.e. burrow counts to estimate abundance) at the cost of directly measuring biological traits and bio-markers in the organism itself; and ii) descriptive or correlative study designs that rarely extend beyond a simple 'compare and contrast approach', and hence fail to identify the mechanistic cause(s) of observed contrasts.Evidence for a historically narrow range of assessed pressures (i.e., chiefly urbanisation, vehicles, beach nourishment, and recreation) is juxtaposed with rich opportunities for the broader integration of ghost crabs as a model taxon in studies of disturbance and impact assessments on ocean beaches. Tangible advances will most likely occur where ghost crabs provide foci for experiments that test specific hypotheses associated with effects of chemical, light and acoustic pollution, as well as the consequences of climate change (e.g. species range shifts).

Massive loggerhead nest predation by ghost crabs in Boavista Island (Cape Verde): implications of the absence of large predators.

[EN] The impact of nest predators on sea turtle hatching success is highly variable depending on predator abundance and also on interactions among different predators. Food web connectivity usually makes it difficult to understand predator-prey interactions and develop efficient conservation strategies. In the Cape Verde archipelago there is an important nesting area for loggerheads where ghost crabs are the only described nest predator. We have studied the impact of ghost crabs on loggerhead nests on this threatened population as well as the efficiency of several management practices to reduce this impact.

Vertical distribution by demographic groups of ghost crab Ocypode quadrata (Crustacea: Brachyura)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metrics to assess ecological condition, change, and impacts in sandy beach ecosystems

Complexity is increasingly the hallmark in environmental management practices of sandy shorelines. This arises primarily from meeting growing public demands (e.g., real estate, recreation) whilst reconciling economic demands with expectations of coastal users who have modern conservation ethics. Ideally, shoreline management is underpinned by empirical data, but selecting ecologically-meaningful metrics to accurately measure the condition of systems, and the ecological effects of human activities, is a complex task. Here we construct a framework for metric selection, considering six categories of issues that authorities commonly address: erosion; habitat loss; recreation; fishing; pollution (litter and chemical contaminants); and wildlife conservation. Possible metrics were scored in terms of their ability to reflect environmental change, and against criteria that are widely used for judging the performance of ecological indicators (i.e., sensitivity, practicability, costs, and public appeal). From this analysis, four types of broadly applicable metrics that also performed very well against the indicator criteria emerged: 1.) traits of bird populations and assemblages (e.g., abundance, diversity, distributions, habitat use); 2.) breeding/reproductive performance sensu lato (especially relevant for birds and turtles nesting on beaches and in dunes, but equally applicable to invertebrates and plants); 3.) population parameters and distributions of vertebrates associated primarily with dunes and the supralittoral beach zone (traditionally focused on birds and turtles, but expandable to mammals); 4.) compound measurements of the abundance/cover/biomass of biota (plants, invertebrates, vertebrates) at both the population and assemblage level. Local constraints (i.e., the absence of birds in highly degraded urban settings or lack of dunes on bluff-backed beaches) and particular issues may require alternatives. Metrics - if selected and applied correctly - provide empirical evidence of environmental condition and change, but often do not reflect deeper environmental values per se. Yet, values remain poorly articulated for many beach systems; this calls for a comprehensive identification of environmental values and the development of targeted programs to conserve these values on sandy shorelines globally.

The early shorebird will catch fewer invertebrates on trampled sandy beaches

Many species of birds breeding on ocean beaches and in coastal dunes are of global conservation concern. Most of these species rely on invertebrates (e.g. insects, small crustaceans) as an irreplaceable food source, foraging primarily around the strandline on the upper beach near the dunes. Sandy beaches are also prime sites for human recreation, which impacts these food resources via negative trampling effects. We quantified acute trampling impacts on assemblages of upper shore invertebrates in a controlled experiment over a range of foot traffic intensities (up to 56 steps per square metre) on a temperate beach in Victoria, Australia. Trampling significantly altered assemblage structure (species composition and density) and was correlated with significant declines in invertebrate abundance and species richness. Trampling effects were strongest for rare species. In heavily trafficked plots the abundance of sand hoppers (Amphipoda), a principal prey item of threatened Hooded Plovers breeding on this beach, was halved. In contrast to the consistently strong effects of trampling, natural habitat attributes (e.g. sediment grain size, compactness) were much less influential predictors. If acute suppression of invertebrates caused by trampling, as demonstrated here, is more widespread on beaches it may constitute a significant threat to endangered vertebrates reliant on these invertebrates. This calls for a re-thinking of conservation actions by considering active management of food resources, possibly through enhancement of wrack or direct augmentation of prey items to breeding territories.

Ghost fishing in the pot fishery for blue swimmer crabs Portunus pelagicus in Queensland, Australia

Blue swimmer crabs (Portunus pelagicus) are an economically important crab caught in baited traps throughout the Indo-west Pacific and Mediterranean. In Australia they are traditionally caught using rigid wire traps (approximate to pots) but there has been a recent increase in the use of collapsible pots constructed from polyethylene trawl mesh. Two experiments were conducted in Moreton Bay, Queensland, to determine the ghost fishing potential of lost crab pots on both target and bycatch species and to evaluate the differences between traditional and contemporary pot designs. A lost contemporary, collapsible trawl mesh pot will catch between 3 and 223 R pelagicus per year after the bait has been exhausted, while a traditional wire mesh pot would catch 11-74 crabs peryear. As most fishers now use the collapsible trawl mesh pots, ghost fishing mortality could be as high as 111,811-670,866 crabs per year. Bycatch retention was also higher in contemporary designs. Periods of strong winds appeared to increase the ghost fishing potential of lost pots. The use of escape gaps, larger mesh sizes and construction options that allow for the deterioration of entrance funnels to minimise ghost fishing are recommended to reduce environmental impacts.

Effects of harvesting callianassid (ghost) shrimps on subtropical benthic communities

The effects of harvesting of callianassid shrimp (Trypaea australiensis) on the abundance and composition of macrobenthic assemblages in unvegetated sediments of a subtropical coastal embayment in Queensland, Australia were examined using a combination of sampling and manipulative experiments. First, the abundance and composition of the benthic infauna in an area regularly used for the collection of shrimp for bait by recreational anglers was compared with multiple reference areas. Second, a BACI design, with multiple reference areas, was used to examine the short-term effects of harvesting on the benthic assemblages from an intensive commercialised fishing competition. Third, a large-scale, controlled manipulative experiment, where shrimp were harvested from 10,000 m(2) plots at intensities commensurate with those from recreational and commercial operators, was done to determine the impacts on different components of the infaunal assemblage. Only a few benthic taxa showed significant declines in abundance in response to the removal of ghost shrimp from the unvegetated sediments. There was evidence, however, of more subtle effects with changes in the degree of spatial variation (patchiness) of several taxa as a result of harvesting.. Groups such as capitellid polychaetes, gammarid amphipods and some bivalves were significantly more patchy in their distribution in areas subjected to harvesting than reference areas, at a scale of tens of metres. This scale corresponds to the patterns of movement and activity of recreational harvesters working in these areas. In contrast, patchiness in the abundance of ghost shrimp decreased significantly under harvesting at scales of hundreds of metres, in response to harvesters focussing their efforts on areas with greater numbers of burrow entrances, leading to a more even distribution of the animals. Controlled experimental harvesting caused declines in the abundance of soldier crabs (Mictyris longicarpus), polychaetes and amphipods and an increase in the spatial patchiness of polychaetes. Populations of ghost shrimp were, however, resilient to harvesting over extended periods of time. In conclusion, harvesting of ghost shrimp for bait by recreational and commercial fishers causes significant but localised impacts on a limited range of benthic fauna in unvegetated sediments, including changes in the degree of spatial patchiness in their distribution. (c) 2005 Elsevier B.V. All rights reserved.

Speaking to each other at last? the ghost of tv past, present and to come...

John Hartley discusses TV past, present and future and concludes that 'This brave new world does have a couple of dystopian elements. One is that no-one knows how to fund non-universal TV production. Another is that any future 'imagined community' will have to get used to the fact that most people aren't inside it.

Teaching crabs to walk straight : is there a place for ethics education in Malaysian accountancy courses?

Recent releases from the International Federation of Accountants (IFAC) highlight the importance of ethics education. Academic institutions employ varying methods of teaching ethics and place varying levels of emphasis on ethics teaching during a business/accounting degree. This paper attempts to evaluate whether teaching ethics to final year accountancy students is beneficial. At the commencement of a semester 85 final year accounting students were given five ethical scenarios on which to make an ethical decision. During the semester they were subject to two different methods of teaching ethics, a traditional lecture/tutorial process and a group assignment. ----- After a significant gap, students were re-presented with the ethical scenarios and asked what action they now considered appropriate. In all five instances students offered a more ethical response the second time. When asked to evaluate the methodologies the students considered both training methods to have a positive effect on their ethical thinking. The results suggest it is beneficial to include ethics teaching in accountancy courses, if the profession’s goal of ethical practitioners is to be achieved.

Melbourne on film dossier: 'Ghost Rider'

Despite being set in an unnamed Texan city, Ghost Rider (Mark Steven Johnson, 2007) was a landmark film for Melbourne. It was the first international production to be made at the Central City (now Docklands) Studios, much to the relief of the heavily-invested state government. And it demonstrated to the world (or more importantly, to producers resident in a small part of southern California), that the city was willing and available to be made over and made up to fit even (especially!) the most stupid filmmaking fantasies. Announcing the imminent arrival of the production in October 2004, the Herald Sun boldly predicted that '[c]ity lanes, Telstra Dome and the Yarra River will be the stars of the new action film'. In fact Melbourne is, as the filmmakers intended, (virtually) unidentifiable onscreen. For the Victorian State government, Ausfilm, Film Victoria and the Melbourne Film Office, this lack of specificity was something to be celebrated; a few months before Ghost Rider went in to production, the then State Minister for Innovation, John Brumby, declared that 'it's almost inconceivable that [Ghost Rider] won't put Melbourne on the map internationally'.

Ghost Wash

‘Ghost Wash’ unveils the past in a contemporary context. It is a blending of video projection, sound, music and performance that reconstructs the anger, the angularity, and the angst of Brisbane music from the late 70s through the 80s. The music is contained within an ongoing story about Brisbane music history.

Ghost hunting with lollies, chess and Lego : appreciating the ‘messy’ complexity (and costs) of doing difficult research in education

This paper contributes to conversations about the funding and quality of education research. The paper proceeds in two parts. Part I sets the context by presenting an historical analysis of funding allocations made to Education research through the ARC’s Discovery projects scheme between the years 2002 and 2014, and compares these trends to allocations made to another field within the Social, Behavioural and Economic Sciences assessment panel: Psychology and Cognitive Science. Part II highlights the consequences of underfunding education research by presenting evidence from an Australian Research Council Discovery project that is tracking the experiences of disaffected students who are referred to behaviour schools. The re-scoping decisions that became necessary and the incidental costs that accrue from complications that occur in the field are illustrated and discussed through vignettes of research with “ghosts” who don’t like school but who do like lollies, chess and Lego.

Broken gates and leaky graves : spectral language and Australia's ghost stories

Ghost stories are unusual amongst supernatural literatures in their modelling of a recognisable, mimetic reality interrupted or infiltrated by immaterial forces. In its discussion of Australian ghost stories, this thesis advances a new approach to ghost narratives which seeks to model and articulate the mechanics of ghosts and hauntings as something reliant on and engaged with the material and the mundane.

The rise and fall of the international law of maritime terrorism : the ghost of piracy is still hunting!

Maritime terrorism is a serious threat to global security. A major debate in this regard is the treating of acts of maritime terrorism as piracy by some scholars and a rejection of this view by others. Moreover, the international law of maritime terrorism suffers from fundamental definitional issues, much like the international law of terrorism. This article examines the current international law of maritime terrorism with a particular emphasis on the debate regarding the applicability of the international law of piracy in the case of maritime terrorism. It argues that the international law of piracy is not applicable in the enforcement and prosecution of maritime terrorists on the high seas. International treaties on terrorism and the post-September 11 developments relating to international laws on terrorism have created a workable international legal framework for combating maritime terrorism, despite some bottlenecks.

The ghost in the machine: Legal challenges of neural interface devices

Neural interface devices and the melding of mind and machine, challenge the law in determining where civil liability for injury, damage or loss should lie. The ability of the human mind to instruct and control these devices means that in a negligence action against a person with a neural interface device, determining the standard of care owed by him or her will be of paramount importance. This article considers some of the factors that may influence the court’s determination of the appropriate standard of care to be applied in this situation, leading to the conclusion that a new standard of care might evolve.