Michael A. Weston

Climate change and its impact on Australia's avifauna

Abstract Relative to the northern hemisphere, little is known about the effect of climate change on southern hemisphere birds, although the impact could be significant. Here we review the effects of climate change on birds that have been documented or predicted, with particular reference to Australian species. Potential impacts include changes in geographic range, movement patterns, morphology, physiology, abundance, phenology and community composition. The evidence suggests that these changes are already happening, both overseas and in Australia, but more research is needed to determine the extent of these impacts and how to conserve birds in the face of climate change. Management options include promoting adaptation and resilience, intensive management of sensitive species, and improved planning for mitigation techniques and monitoring.

A review of flight-initiation distances and their application to managing disturbance to Australian birds

Abstract Disturbance—the response of birds to a stimulus such as the presence of a person—is considered a conservation threat for some Australian birds. The distance at which a bird flees from perceived danger is defined as the flight-initiation distance (FID), and could be used to designate separation distances between birds and stimuli that might cause disturbance. We review the known FIDs for Australian birds, and report FIDs for 250 species. Most FIDs are from south-eastern Australia, and almost all refer to a single walker as the stimulus. Several prominent factors correlated with FID are discussed (e.g. body mass and the distance at which an approach begins). FIDs have not been used extensively in the management of disturbance, for a variety of reasons including lack and inaccessibility of available data. We call for standardised data collection and greater application of available data to the management of disturbance.

Conflict between genetic and phenotypic differentiation: the evolutionary history of a 'lost and rediscovered' shorebird.

Understanding and resolving conflicts between phenotypic and genetic differentiation is central to evolutionary research. While phenotypically monomorphic species may exhibit deep genetic divergences, some morphologically distinct taxa lack notable genetic differentiation. Here we conduct a molecular investigation of an enigmatic shorebird with a convoluted taxonomic history, the White-faced Plover (Charadrius alexandrinus dealbatus), widely regarded as a subspecies of the Kentish Plover (C. alexandrinus). Described as distinct in 1863, its name was consistently misapplied in subsequent decades until taxonomic clarification ensued in 2008. Using a recently proposed test of species delimitation, we reconfirm the phenotypic distinctness of dealbatus. We then compare three mitochondrial and seven nuclear DNA markers among 278 samples of dealbatus and alexandrinus from across their breeding range and four other closely related plovers. We fail to find any population genetic differentiation between dealbatus and alexandrinus, whereas the other species are deeply diverged at the study loci. Kentish Plovers join a small but growing list of species for which low levels of genetic differentiation are accompanied by the presence of strong phenotypic divergence, suggesting that diagnostic phenotypic characters may be encoded by few genes that are difficult to detect. Alternatively, gene expression differences may be crucial in producing different phenotypes whereas neutral differentiation may be lagging behind.

Responses of Incubating Hooded Plovers (Thinornis rubricollis) to Disturbance

Abstract Hooded Plovers (Thinornis rubricollis) and recreationists co-occur on the ocean beaches of southern Australia, and it has been suggested that disturbance of the breeding birds by humans constitutes a conservation problem. This study examines whether humans disturb incubating Hooded Plovers and places that disturbance in context with naturally occurring disturbances. Incubating Hooded Plovers encountered and responded to a variety of human and natural stimuli. The most common response involved leaving the nest for a period of time (an “absence”), and humans were responsible for 33.1% of time spent off nests. The response rates of incubating birds varied with the type of stimulus, with higher than expected response rates to two species of potentially predatory birds. About 17% of encounters with potential causes of disturbance occurred while birds were already responding to other disturbance, and this prolonged the return to the nest. Absences from the nest that were not apparently caused by disturbance were shorter and less frequent than those caused by external disturbance stimuli. Nest habitat influenced the response to encounters with humans, and on average foredune nests suffered the greatest decrease in attendance per encounter. This study has confirmed that human disturbance is more frequent than natural disturbances, and that humans decrease nest attendance substantially and more than any other source of disturbance.

Disturbance to brood-rearing hooded plover Thinornis rubricollis: responses and consequences

We examined the causes and consequences of disturbance to the chicks of Hooded Plover Thinornis rubricollis in central southern Victoria, Australia. Humans were the most frequent source of encounters, and response rates to a variety of stimuli were high. Three possible mechanisms by which disturbance could reduce chick survival were evaluated. (1) Disturbance might cause thermal stress to chicks. An encounter with a human often caused brooding to cease, but it is not clear whether overall levels of brooding were compromised. Chicks found themselves un-brooded due to disturbance for up to 290 min, and in ambient temperatures of 10–46°C. (2) Disturbance might cause energetic stress to chicks. Encounters with humans usually caused chick foraging to stop. Higher levels of disturbance were associated with less chick foraging. There was a tendency for broods to forage in lower and potentially more profitable levels of the habitat in less-disturbed conditions. However, the overall pattern of habitat use was similar during disturbed and less-disturbed conditions. (3) Adult defence of broods could be compromised by disturbance. However, no brood predation occurred in disturbed circumstances, and adults stayed close to their broods even in disturbed conditions. These data suggest that defence of chicks was not compromised by disturbance.

A review of terrestrial bird atlases of the world and their application

Abstract We reviewed 272 bird atlases (standardised surveys intended to document the distribution of birds) from around the world. Atlases we located were conducted in 50 countries from six continents with most (82.4%) from Europe and North America. Atlases were mostly run by ornithological societies (67.1%), had amassed at least 27.9 million records of birds over an area roughly 31.4% of the land area of the Earth, and had involved at least 108 000 contributors. They had a modal data collection period of 4 years (some ran over several decades) and varied greatly in scale, covering local areas to entire continents (21 km2—10390000 km2); atlases that covered larger areas involved more observers and generated more records. Most atlases (88.3%) were constrained to particular seasons, and most of these focussed on the main local breeding period (81.0%). Spatial sampling units ranged from 0.02 km2 (2 ha) to 3092 km2, temporal units of sampling varied from 20 minutes to several years. Little information is available on the application of data generated by atlases. We focussed on five major atlases for which information was available. We located 97 scientific publications drawing on data from these five major atlases; papers most frequently focussed on bird distribution (26.8%), ecology (20.6%) and land-use planning (17.5%). Atlas books were cited often, 7–31 times per year. Provision of data to third parties from two major atlases (one from Australia and one from Britain and Ireland) was frequent and remarkably similar. Data were requested mostly for environmental impact studies (almost half of all requests), conservation policy and planning (~20%), research (~20%) and other mapping (~13%). Despite the uses we describe, atlas data seem under-utilised.

Managing a breeding population of the Hooded Plover Thinornis rubricollis in a high-use recreational environment

Summary Mornington Peninsula National Park, Victoria, Australia, is heavily used by recreationists. It also holds a breeding population of the Hooded Plover Thinornis rubricollis , a rare endemic shorebird. We monitored the population of plovers over seven breeding seasons, 1991–1998. Mortality of nests (about 60%), and of chicks (over 70%) was high, but preliminary data suggests mortality was low in juveniles. The major cause of mortality of nests was trampling by people. The causes of mortality in chicks is unknown, but mortality was age dependent, and was highest in the youngest chicks. A combination of management techniques that have been phased into operation over the seven years of the study appear to be increasing the reproductive success of the population.

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.

Buses, cars, bicycles and walkers: The influence of the type of human transport on the flight responses of waterbirds

One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus) selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases), motor vehicles always evoked shorter flight-initiation distances (FID) than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles) may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people) and vary in their capacity to travel around important habitat.

Birds and Beaches, Dogs and Leashes: Dog Owners' Sense of Obligation to Leash Dogs on Beaches in Victoria, Australia

Domesticated dogs threaten the conservation of beach-nesting birds in Australia through disturbance, and destruction of eggs and chicks. Leashing of dogs can improve conservation outcomes, but few dogs are leashed on beaches. We surveyed dog owners to explore their sense of obligation to leash dogs on beaches. Dog owners were more likely to feel obliged to leash their dog when they believed other people expected dogs to be leashed, and when they believed their dog was a threat to wildlife or people. Dog owners were less likely to feel obliged to leash their dog if they considered unleashed dog recreation to be important. Improved compliance may be achieved through community-based approaches to foster social norms for dog control, tailoring information products to emphasize the risk that all unleashed dogs may pose to beach-nesting birds and raising awareness of designated off-leash exercise dog recreation areas.