Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches

Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events among species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune–beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilization. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: (1) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and (2) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores.

Limited functional redundancy in vertebrate scavenger guilds fails to compensate for the loss of raptors from urbanized sandy beaches

Aim: Globally, urbanization is one of the most widespread, intense and ecologically destructive forms of landscape transformation, and it is often concentrated in coastal areas. Theoretically, species losses attributable to urbanization are predicted not to alter overall ecosystem function if functional redundancy (i.e. replacement of function by alternative species) compensates for such losses. Here, we test this expectation by measuring how coastal urbanization affects scavenger guilds on sandy beaches and whether changes in guild composition result either in an overall loss of scavenging efficiency, or in functional compensation under alternative guild structures, maintaining net ecosystem functioning. Location: Fourteen beaches along the east coast of Australia with variable levels of urbanization. Methods: Scavenging communities and rates of carrion removal were determined using motion-triggered cameras at the beach-dune interface. Results: A substantial shift in the community structure of vertebrate scavengers was associated with gradients in urbanization. Iconic and functionally important raptors declined precipitously in abundance on urban beaches. Importantly, other vertebrates usually associated with urban settings (e.g. dogs, foxes, corvids) did not functionally replace raptors. In areas where < 15% of the abutting land had been developed into urban areas, carcass removal by scavengers was often complete, but always > 70%. Conversely, on beaches bordering coastal cities with < 40% of natural vegetation remaining, two-thirds of fish carcasses remained uneaten by scavengers. Raptors removed 70-100% of all deployed fish carcasses from beaches with < 8% urban land cover, but this number dropped significantly with greater levels of urbanization and was not compensated by other scavenger species in urban settings. Main conclusions: There is limited functional redundancy in vertebrate scavenger communities of sandy beach ecosystems, which impacts the system's capacity to mitigate the ecological consequences of detrimental landscape transformations.

A role for glutathione in the pathophysiology of bipolar disorder and schizophrenia? Animal models and relevance to clinical practice.

The tripeptide, glutathione (glutamylcysteinylglycine) is the primary endogenous free radical scavenger in the human body. When glutathione (GSH) levels are reduced there is an increased potential for cellular oxidative stress, characterised by an increase and accruement of reactive oxygen species (ROS). Oxidative stress has been implicated in the pathology of schizophrenia and bipolar disorder. This could partly be caused by alterations in dopaminergic and glutamatergic activity that are implicated in these illnesses. Glutamate and dopamine are highly redox reactive molecules and produce ROS during normal neurotransmission. Alterations to these neurotransmitter pathways may therefore increase the oxidative burden in the brain. Furthermore, mitochondrial dysfunction, as a source of oxidative stress, has been documented in both schizophrenia and bipolar disorder. The combination of altered neurotransmission and this mitochondrial dysfunction leading to oxidative damage may ultimately contribute to illness symptoms. Animal models have been established to investigate the involvement of glutathione depletion in aspects of schizophrenia and bipolar disorder to further characterise the role of oxidative stress in psychopathology. Stemming from preclinical evidence, clinical studies have recently shown antioxidant precursor treatment to be effective in schizophrenia and bipolar disorder, providing a novel clinical angle to augment often suboptimal conventional treatments.

Learning from sustainable landscapes of death in Bali : landscape planning and Tri Hita Karana

Landscape planning in many countries is predicated upon on fulfilling the functions for human living objectives. Many land use practices have been plotted for living, busines~, trading, industrial, farming as well as providing places for dead people primarily through cemeteries. Research in Palm Beach County, FL, has demonstrated the need to plan for 30 years of demand of land use functions to service death (Coutts, Basmaj ian et al. 20 I I). Coutts et al assert that planners are required and responsible for the planning of funeral necessities. Therefore, the protection of landscapes of death is an important consideration in the planning of landscapes. Bali is popular with its beautiful landscape, hospitality, and traditional architecture as demonstrating the integrity between human, environment and God, as expressed in the Balinese Tri Hita Karana concept. Balinese commemorate life from birth to death through their traditional ceremonies which informs their traditional cultural landscape. One of the most important landscapes, which cannot be separated fi·om Balinese life are graveyards which are used for deceased ceremonies. This landscape is an integral part of traditional village patterns across Bali. Culturally, Balinese people have their own traditional cremation ceremony which is call the Ngaben Ceremony. The Ceremony takes place in graveyards and thereupon ashes are placed in the sea waters surrounding Bali. An interesting point of planning in Bali is how to enable eco-friendly interment extensions to villages. This is occurring because of the increasing number of corpses that require cremation thus necessitating no accretions in land provision of graveyards. This research investigates the landscape of death in Bali expressed in its traditional values in the area of planning which implicate sustainable environments and land conservation topics. Other functions of graveyards, as noted by Strangstad ( 1988), include ceremonial and their role as educational tools for history lessons, art, sociology, geology, English lessons, as well as for scavenger hunts.

Viewpoints, creativity and embodied learning : developing perceptual and kinaesthetic skills in non-dancers studying undergraduate university drama

Viewpoints are a structural approach to training and directing for theatre. Originating from the innovative, inventive and exploratory approach of Mary Overlie and the self- confessed scavenger approach of Anne Bogart, Viewpoints offers a practical philosophy of working. As a training approach it begins with a disciplined engagement  of the body in space and time. The tangible elements of the Viewpoints provide a set of tasks on which the student can focus, thus freeing the imagination and spirit to  create. Yet at the same time the systematic logic of Viewpoints supports novice practitioners to begin to question their perception, invest in creative practice that demands action and exploration, and to deconstruct, re-organise and rebuild scores and sequences in the pursuit of theatre that is visceral and visual. This essay reports on undergraduate student experiences of learning Viewpoints. It interrogates the demands of embodied learning of the movement/structural system on non- ancers and examines student-actor experiences of embodied learning from multiple of subject positions – observer/participant/creator/reflector/actor.  

Neurobiology of schizophrenia spectrum disorders: The role of oxidative stress

Mitochondrial dysfunction and oxidative stress are increasingly implicated in the pathophysiology of schizophrenia. The brain is the body's highest energy consumer, and the glutathione system is the brain's dominant free radical scavenger. In the current paper, we review the evidence of central and peripheral nervous system anomalies in the oxidative defences of individuals with schizophrenia, principally involving the glutathione system. This is reflected by evidence of the manifold consequences of oxidative stress that include lipid peroxidation, protein carboxylation, DNA damage and apoptosis - all potentially part of the process of neuroprogression in the disorder. Importantly, oxidative stress is amenable to intervention. We consider the clinical potential of some possible interventions that help reduce oxidative stress, via augmentation of the glutathione system, particularly N-acetyl cysteine. We argue that a better understanding of the mechanisms and pathways underlying oxidative stress will assist in developing the therapeutic potential of this area.

Conservation gone to the dogs : when canids rule the beach in small coastal reserves

On most developed coastlines, dunes backing ocean beaches constitute an urbanised landscape mosaic containing remnant pockets of small conservation areas. Urbanised beaches are also prime sites for domestic dogs, known to be environmentally harmful in many other settings. It is unknown, however, whether small, protected parcels of dune are adequate for biological conservation and whether dogs compromise their functional conservation objectives. Here we examine, for two small (2 km ocean boundary) reserves in Eastern Australia abutting an urban area, whether such small reserves can continue to function as effective conservation instruments on ocean beaches, using scavenger community composition and efficiency to assess ecosystem function. Two non-native species of canids—domestic dogs (Canis lupus familiaris) and red foxes (Vulpes vulpes)—were ubiquitous and numerous inside conservation areas, to the point of having become the most abundant vertebrate scavengers at the beach-dune interface, outcompeting native scavengers for wave-cast carrion. Dogs and foxes have effectively supplanted raptors, normally abundant on non-urban beaches in the region, and other avian scavengers, as the principal consumers of animal carcasses both inside the declared reserves and at the urban beach. Whilst the ecological threats posed by foxes are widely and intensively addressed in Australia in the form of fox-control programs, dog controls are less common and stringent. Our data emphasize, however, that managing domestic dogs may be required to the same extent in order to maintain key forms and functions in coastal reserves situated close to urban areas.

Do the numbers and locations of road-killed anuran carcasses accurately reflect impacts of vehicular traffic?

Road-killed animals are easy and inexpensive to survey, and may provide information about species distributions, abundances, and mortality rates. As with any sampling method, however, we need to explore methodological biases in such data. First, how does an animal's behavior (e.g., use of the center vs. periphery of the road) influence its vulnerability to vehicular traffic? Second, how rapidly do post-mortem processes (scavenging by other animals, destruction or displacement by subsequent vehicles) change the numbers and locations of roadkills? Our surveys of anurans on a highway in tropical Australia show that different anuran species are distributed in different ways across the width of the road, and that locations of live versus dead animals sometimes differ within a species. Experimental trials show that location on the road affects the probability of being hit by a vehicle, with anurans in the middle of the road begin hit 35% more often than anurans on the edges; thus, center-using species are more likely to be hit than edge-using taxa. The magnitude of post-mortem displacement and destruction by subsequent vehicles depended on anuran species and body size. The mean parallel displacement distance was 122.7 cm, and carcasses of thin-skinned species exhibited greater post-mortem destruction. Scavenging raptors removed 73% of carcasses, most within a few hours of sunrise. Removal rates were biased with respect to size and species. Overall, our studies suggest that investigators should carefully evaluate potential biases before using roadkill counts to estimate underlying animal abundances or mortality rates.