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Migratory animals are threatened by human-induced global change. However, little is known about how stopover habitat, essential for refuelling during migration, affects the population dynamics of migratory species. Using 20 years of continent-wide citizen science data, we assess population trends of ten shorebird taxa that refuel on Yellow Sea tidal mudflats, a threatened ecosystem that has shrunk by >65% in recent decades. Seven of the taxa declined at rates of up to 8% per year. Taxa with the greatest reliance on the Yellow Sea as a stopover site showed the greatest declines, whereas those that stop primarily in other regions had slowly declining or stable populations. Decline rate was unaffected by shared evolutionary history among taxa and was not predicted by migration distance, breeding range size, non-breeding location, generation time or body size. These results suggest that changes in stopover habitat can severely limit migratory populations.

Tasmania (including offshore islands) has the largest breeding population of little penguins (Eudyptula minor) in Australia, but coastal development around nesting areas has led to habitat loss, often resulting in smaller, fragmented colonies. Colonies have also been subject to predation by introduced domestic species. This study assessed whether historical levels of domestic dog predation could threaten the viability of penguin populations.Data collected since the 1980s detailing little penguin kills by domestic dogs were used to inform the extent of individual mortality events. The potential impact of dog attacks on the viability of little penguin colonies of the sizes typically found on mainland Tasmania was explored using an age‐based population model. Simulation was conducted over decadal timescales to assess the impact of attacks at varying frequencies and intensities on small (100 birds), medium (300 birds) and large (500 birds) colonies that were stable, growing or decreasing.Results suggested that frequent and intense dog attacks markedly increased the probability of colony decline, regardless of colony size. Even large, growing penguin colonies were at risk of decline. The risk of extinction was <10% for medium and large stable colonies if no more than 15–25 penguins were killed per attack and there were no more than 20 attacks per 50 years. For small‐sized colonies, the risk of extinction was <10% if fewer than 10 attacks occurred per 50‐year period and no more than 15 birds were killed per attack.Importantly, results suggested that for small colonies especially, even low levels of predator attack could lead to colony collapse in 10–15 years. For large colonies that were already decreasing, the average time to extinction was markedly increased with additional mortalities from dogs, highlighting the need for ongoing management measures that reduce or eliminate dog attacks to help conserve this iconic species. [ABSTRACT FROM AUTHOR]

An ecological risk assessment, based on life‐history and behavioural attributes of 273 bird taxa, was used to identify which of those taxa are at high risk from negative interactions with offshore wind farms in Australia. The marine area of Australia was divided by state/territory boundaries perpendicular to the coast into eight regions, with Western Australia further divided into north and south, and a Bass Strait region bounded by the Victoria coast and the north coast of Tasmania. These regions were subdivided into coastal, inshore and offshore sub‐regions and a risk summary for all bird taxa occurring in each of these sub‐regions produced. In coastal and inshore sub‐regions of Bass Strait, South Australia and Tasmania, the species with the highest risk scores were Orange‐bellied Parrot Neophema chrysogaster, Furneaux White‐fronted Tern Sterna striata incerta, Swift Parrot Lathamus discolor, Shy Albatross Thalassarche cauta, Far Eastern Curlew Numenius madagascariensis and Anadyr Bar‐tailed Godwit Limosa lapponica anadyrensis. In offshore sub‐regions in southern Australia, the highest risk species were all albatrosses, comprising Northern Royal Diomedea sanfordi, Eastern Antipodean D. antipodensis antipodensis, Gibson's D. antipodensis gibsoni, Wandering D. exulans, Amsterdam D. amsterdamensis and Grey‐headed Albatross T. chrysostoma. Compared to onshore installations, there are logistical challenges to quantifying the potential and realized impacts of offshore wind farms that require different approaches to data collection and analyses. The extensive development of offshore wind farms in the Northern Hemisphere provides examples of best and emerging approaches to quantify and mitigate negative impacts of offshore wind farms that can be applied in an Australian context. Despite differences in the species involved, the same approaches to identifying high‐risk species and to the monitoring and mitigation of negative impacts should be applied in a coordinated, regional‐scale approach to the development of offshore wind farms in Australia. [ABSTRACT FROM AUTHOR]

Many long-term studies have reported changes in seabird abundance and distribution in response to climate change and various anthropogenic activities. However, a greater understanding of how species are responding to change over large spatial and temporal scales are required—particularly at high latitudes such as the Southern Ocean. We examined black-browed Thalassarche melanophris (BBAL) and light-mantled sooty Phoebetria palpebrata albatross (LMSA) observations spanning over 50 years. Both species have a wide-ranging distribution in a rapidly changing Southern Ocean. We used generalized additive models (GAMs) to investigate environmental drivers of their abundance and occurrence. Our results show that climate indices, sea surface temperature and sea surface height are the main drivers influencing the distribution and abundance of both species. The abundance of BBAL southeast of Australia was observed to be decreased substantially whereas no significant change was observed in the abundance of LMSA. Both species demonstrated contrasting distributions along their latitudinal gradient with BBAL showing early stages of a southward range shift. Our analyses suggest that responses to climate change are species-specific. These rare, long-term data have provided an understanding of species' responses to past changes in the marine environment and can provide critical information for future conservation and management. [ABSTRACT FROM AUTHOR]

Population estimates are widely used to underpin conservation decisions. However, determining accurate population estimates for migratory species is especially challenging, as they are often widespread and it is rarely possible to survey them throughout their full distribution. In the East Asian–Australasian Flyway (EAAF), this problem is compounded by its size (85 million square kilometres) and the number of migratory species it supports (nearly 500). Here, we provide analytical approaches for addressing this problem, presenting a revision of the EAAF population estimates for 37 migratory shorebird species protected under Australian national environmental legislation. Population estimates were generated by (1) summarizing existing count data in the non‐breeding range, (2) spatially extrapolating across uncounted areas, and (3) modelling abundance on the basis of estimates of breeding range and density. Expert review was used to adjust modelled estimates, particularly in under‐counted areas. There were many gaps in shorebird monitoring data, necessitating substantial use of extrapolation and expert review, the extent of which varied among species. Spatial extrapolation to under‐counted areas often produced estimates that were much higher than the observed data, and expert review was used to cross‐check and adjust these where necessary. Estimates of population size obtained through analyses of breeding ranges and density indicated that 18 species were poorly represented by counts in the non‐breeding season. It was difficult to determine independently the robustness of these estimates, but these breeding ground estimates were considered the best available data for 10 species that mostly use poorly surveyed freshwater or pelagic habitats in the non‐breeding season. We discuss the rationale and limitations of these approaches to population estimation, and how they could be modified for other applications. Data available for population estimates will vary in quality and extent among species, regions and migration stage, and approaches need to be flexible enough to provide useful information for conservation policy and planning. [ABSTRACT FROM AUTHOR]

There is an absence of quantitative criteria and definitions for unusual or anomalous mortality events involving birds, often referred to as "wrecks". These events most commonly involve seabirds, although terrestrial bird wrecks have also been documented. Typically, the peer-reviewed literature investigating wreck events lacks the details necessary to further our understanding of the circumstances and potential causes of these events. This study reviewed the peer-reviewed literature for wrecks involving Ardenna seabirds (shearwaters), and included grey literature and data collected by citizen science (community) groups. Our results showed a significant time-lag between wreck events and when the data was published in the peer-reviewed literature, which did not occur in the grey literature. Both the grey and peer-reviewed literature were often skewed towards reporting larger wreck events, with only the citizen science dataset capturing smaller wrecks. We outline a proposed framework for reporting mortality events, including the use of quantitative categories to document the numbers of birds involved and taxon-specific thresholds. In doing so, we aim to establish a framework to aid in the quantitative reporting and analyses of future seabird wrecks. [ABSTRACT FROM AUTHOR]

Migratory shorebirds are primarily found at five locations in south-east Tasmania. Analysis of annual summer and winter shorebird counts indicated that species-specific changes have occurred in the distribution of shorebirds among the five locations. Overall, Holarctic breeding migratory shorebirds have decreased in south-east Tasmania during the last 55 years. Examples include the Curlew Sandpiper Calidris ferruginea and Eastern Curlew Numenius madagascariensis, both listed as Critically Endangered. Curlew Sandpipers, formerly the second most numerous species with numbers exceeding 1000, have become rare visitors to the region. Similarly, the number of Eastern Curlew has decreased by more than 90% compared with around 300 in the 1960s. As their numbers decreased larger species consolidated into a single flock and favoured locations with least disturbed roosts. Smaller species continued to exploit all suitable habitat. At all five locations, there is evidence of deterioration in habitat quality. The decreases in migratory shorebird numbers in south-east Tasmania are consistent with those experienced throughout the East Asian-Australasian Flyway, but exaggerated by its position at southern extremity of the Flyway. While the causes of these decreases at flyway scale may lie primarily outside south-east Tasmania, it is uncertain whether its shorebird habitats remain capable of supporting the peak population levels recorded in the earlier decades of this study. This is of concern if the Flyway's migratory shorebird populations recover and predicted changes in climatic conditions occur shift shorebird distributions towards the southern limits of their range. [ABSTRACT FROM AUTHOR]

Elucidating the factors underlying the origin and maintenance of genetic variation among populations is crucial for our understanding of their ecology and evolution, and also to help identify conservation priorities. While intrinsic movement has been hypothesized as the major determinant of population genetic structuring in abundant vagile species, growing evidence indicates that vagility does not always predict genetic differentiation. However, identifying the determinants of genetic structuring can be challenging, and these are largely unknown for most vagile species. Although, in principle, levels of gene flow can be inferred from neutral allele frequency divergence among populations, underlying assumptions may be unrealistic. Moreover, molecular studies have suggested that contemporary gene flow has often not overridden historical influences on population genetic structure, which indicates potential inadequacies of any interpretations that fail to consider the influence of history in shaping that structure. This exhaustive review of the theoretical and empirical literature investigates the determinants of population genetic differentiation using seabirds as a model system for vagile taxa. Seabirds provide a tractable group within which to identify the determinants of genetic differentiation, given their widespread distribution in marine habitats and an abundance of ecological and genetic studies conducted on this group. Herein we evaluate mitochondrial DNA (mtDNA) variation in 73 seabird species. Lack of mutation–drift equilibrium observed in 19% of species coincided with lower estimates of genetic differentiation, suggesting that dynamic demographic histories can often lead to erroneous interpretations of contemporary gene flow, even in vagile species. Presence of land across the species sampling range, or sampling of breeding colonies representing ice‐free Pleistocene refuge zones, appear to be associated with genetic differentiation in Tropical and Southern Temperate species, respectively, indicating that long‐term barriers and persistence of populations are important for their genetic structuring. Conversely, biotic factors commonly considered to influence population genetic structure, such as spatial segregation during foraging, were inconsistently associated with population genetic differentiation. In light of these results, we recommend that genetic studies should consider potential historical events when identifying determinants of genetic differentiation among populations to avoid overestimating the role of contemporary factors, even for highly vagile taxa. [ABSTRACT FROM AUTHOR]

Temperate Australian saltmarshes, including those in the southern island state of Tasmania, are considered to be a threatened ecological community under Australian federal legislation. There is a need to improve our understanding of the ecological components, functional relationships and threatening processes of Tasmanian coastal saltmarshes and distil research priorities that could assist recovery actions. A semisystematic review of the literature on Tasmanian coastal saltmarshes supported by expert local knowledge identified 75 studies from 1947 to 2019. Existing understanding pertains to saltmarsh plants, soils, invertebrates and human impacts with ongoing studies currently adding to this knowledge base. Several knowledge gaps remain, and the present review recommends six key priority areas for research: (1) citizen science–organised inventory of (initially) saltmarsh birds, plants and human impacts with the potential for expansion of datasets; (2) use of saltmarsh by marine transient species including fish and decapods; (3) use of saltmarsh by, and interactions with, native and introduced mammals; (4) invertebrates and their interactions with predators (e.g. birds, fish) and prey (e.g. insects, plants, detritus); (5) historic saltmarsh loss and priority areas for conservation; (6) monitoring changes to saltmarsh due to both localised human impacts (e.g. grazing, eutrophication, destruction) and global change factors (e.g. climate change, sea-level rise). Addressing these research priorities will help in developing a better understanding of the ecological character of Tasmanian coastal saltmarshes and improve their conservation management. A semisystematic literature review supported by expert local knowledge documents existing knowledge on the ecological components, functional relationships and threatening processes of Tasmanian coastal saltmarshes. Research gaps and priorities are identified to assist saltmarsh recovery actions and improve its conservation status. [ABSTRACT FROM AUTHOR]

Migratory species can travel tens of thousands of kilometers each year, spending different parts of their annual cycle in geographically distinct locations. Understanding the drivers of population change is vital for conserving migratory species, yet the challenge of collecting data over entire geographic ranges has hindered attempts to identify the processes leading to observed population changes. Here, we use remotely sensed environmental data and bird count data to investigate the factors driving variability in abundance in two subspecies of a long‐distance migratory shorebird, the bar‐tailed godwit Limosa lapponica. We compiled a spatially and temporally explicit dataset of three environmental variables to identify the conditions experienced by each subspecies in each stage of their annual cycle (breeding, non‐breeding and staging). We used a Bayesian N‐mixture model to analyze 18 years of monthly count data from 21 sites across Australia and New Zealand in relation to the remote sensing data. We found that the abundance of one subspecies L. l. menzbieri in their non‐breeding range was related to climate conditions in breeding grounds, and detected sustained population declines between 1995 and 2012 in both subspecies (L. l. menzbieri, –6.7% and L. l. baueri, –2.1% year–1). To investigate the possible causes of the declines, we quantified changes in habitat extent at 22 migratory staging sites in the Yellow Sea, East Asia, over a 25‐year period and found –1.7% and –1.2% year–1 loss of habitat at staging sites used by L. l. menzbieri and L. l baueri, respectively. Our results highlight the need to identify environmental and anthropogenic drivers of population change across all stages of migration to allow the formulation of effective conservation strategies across entire migratory ranges. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests foraging segregation as a key mechanism promoting genetic divergence within seabird species. However, testing for a relationship between population genetic structure and foraging movements among seabird colonies can be challenging. Telemetry studies suggest that Flesh-footed Shearwater Ardenna carneipes that breed at Lord Howe Island or New Zealand, versus southwestern Australia or Saint-Paul Island in the Indian Ocean, migrate to different regions (North Pacific Ocean and northern Indian Ocean, respectively) during the non-breeding season, which may inhibit gene flow among colonies. In this study, we sequenced a 858-base pair mitochondrial region and seven nuclear DNA fragments (352-654 bp) for 148 individuals to test genetic differentiation among colonies of Flesh-footed Shearwaters. Strong genetic divergence was detected between Pacific colonies relative to those further West. Molecular analysis of fisheries' bycatch individuals sampled in the Sea of Japan indicated that individuals from both western and eastern colonies were migrating through this area, and hence the apparent segregation of the non-breeding distribution based on telemetry is invalid and cannot contribute to the population genetic structure among colonies. The genetic divergence among colonies is better explained by philopatry and evidence of differences in foraging strategies during the breeding season, as supported by the observed genetic divergence between Lord Howe Island and New Zealand colonies. We suggest molecular analysis of fisheries' bycatch individuals as a rigorous method to identify foraging segregation, and we recommend the eastern and western A. carneipes colonies be regarded as different Management Units. [ABSTRACT FROM AUTHOR]

A recent field observation of a colour-banded Australian Pied Oystercatcher Haematopus longirostris in its 33rd year is remarkable, not only for its age, but also for the resilience of its bands. This bird was banded as a pullus and thus its exact age is known. The chronology of the sightings of this and a second, even older, oystercatcher is discussed in terms of the demography of the species in southeast Tasmania. Monitoring the survival of banded oystercatchers at their breeding territories is an effective means of determining the longevity of oystercatchers. It is particularly advantageous with respect to addressing issues associated with the deterioration of the colour bands used to identify individual birds and of the probability that breeding birds are under-represented at communal roosts. However, small sample sizes and the study of anomalous populations may generate results that are not representative of the species. While the Australian Pied Oystercatcher is undoubtedly long-lived, the published generation time of 39 years is probably excessive. [ABSTRACT FROM AUTHOR]

Decreases in shorebird populations are increasingly evident worldwide, especially in the East Asian–Australasian Flyway (EAAF). To arrest these declines, it is important to understand the scale of both the problem and the solutions. We analysed an expansive Australian citizen-science dataset, spanning the period 1973 to 2014, to explore factors related to differences in trends among shorebird populations in wetlands throughout Australia. Of seven resident Australian shorebird species, the four inland species exhibited continental decreases, whereas the three coastal species did not. Decreases in inland resident shorebirds were related to changes in availability of water at non-tidal wetlands, suggesting that degradation of wetlands in Australia’s interior is playing a role in these declines. For migratory shorebirds, the analyses revealed continental decreases in abundance in 12 of 19 species, and decreases in 17 of 19 in the southern half of Australia over the past 15 years. Many trends were strongly associated with continental gradients in latitude or longitude, suggesting some large-scale patterns in the decreases, with steeper declines often evident in southern Australia. After accounting for this effect, local variables did not explain variation in migratory shorebird trends between sites. Our results are consistent with other studies indicating that decreases in migratory shorebird populations in the EAAF are most likely being driven primarily by factors outside Australia. This reinforces the need for urgent overseas conservation actions. However, substantially heterogeneous trends within Australia, combined with declines of inland resident shorebirds indicate effective management of Australian shorebird habitat remains important. [ABSTRACT FROM AUTHOR]