scholarly journals Preliminary survival and movement data for a declining population of Flesh-footed Shearwater Ardenna carneipes in Western Australia provides insights into marine threats

2018 ◽  
Vol 29 (2) ◽  
pp. 327-337 ◽  
Author(s):  
JENNIFER L. LAVERS ◽  
SIMEON LISOVSKI ◽  
ALEXANDER L. BOND
Keyword(s):  
Western Australia ◽  
Survival Rates ◽  
Adult Survival ◽  
Seabird Species ◽  
Movement Data ◽  
Central Indian Ocean ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Fisheries Bycatch ◽  
Western Australian

SummarySeabirds face diverse threats on their breeding islands and while at sea. Human activities have been linked to the decline of seabird populations, yet over-wintering areas typically receive little or no protection. Adult survival rates, a crucial parameter for population persistence in long-lived species, tend to be spatially or temporally restricted for many seabird species, limiting our understanding of factors driving population trends at some sites. We used bio-loggers to study the migration of Western Australian Flesh-footed Shearwaters Ardenna carneipes carneipes and estimated adult survival over five years. Western Australia is home to around 35% of the world’s breeding Flesh-footed Shearwaters, a population which was up-listed to Vulnerable in 2015. During the austral winter, shearwaters migrated across the central Indian Ocean to their non-breeding grounds off western Sri Lanka. Low site fidelity on breeding islands, mortality of adult birds at sea (e.g. fisheries bycatch), and low annual breeding frequency likely contributed to the low estimated annual adult survival (2011–2015: ϕ = 0.634-0.835).

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

Migration distance is a fundamental axis of the slow-fast continuum of life history in boreal birds

The Auk ◽  
2021 ◽  
Author(s):  
Benjamin M Winger ◽  
Teresa M Pegan
Keyword(s):  
Life History ◽  
Survival Rates ◽  
Reproductive Investment ◽  
Seasonal Migration ◽  
Adult Survival ◽  
Vital Rates ◽  
Long Distance ◽  
Migration Distance ◽  
Breeding Grounds ◽  
Survival And Reproduction

Abstract Seasonal migration is intrinsically connected to the balance of survival and reproduction, but whether migratory behavior influences species’ position on the slow-fast continuum of life history is poorly understood. We found that boreal-breeding birds that migrate long distances exhibit higher annual adult survival and lower annual reproductive investment relative to co-distributed boreal species that migrate shorter distances to winter closer to their breeding grounds. Our study uses “vital rates” data on reproductive output and survivorship compiled from the literature for a species assemblage of 45 species of mostly passerine birds. These species breed sympatrically in North American boreal forests but migrate to a diversity of environments for the northern winter. After controlling for body size and phylogeny, migration distance and apparent annual adult survival are positively related across species. Both migration distance and survival are positively correlated with wintering in environments that are warmer, wetter, and greener. At the same time, longer migrations are associated with reduced time spent on the breeding grounds, lower clutch sizes, and lower fecundity (clutch size × maximum number of broods per year). Although seasonal migration is often associated with high mortality, our results suggest that long-distance migration imposes selection pressures that both confer and demand high adult survival rates. That is, owing to the reproductive cost of long-distance migration, this strategy can only persist if balanced by high adult survival. Our study supports the idea that migration evolves to promote survival of species breeding in seasonal environments. In boreal birds, the evolution of the longest migrations yields the highest survival, but at an inherent cost to annual fecundity. Our results therefore reveal migratory distance as a fundamental axis of the slow-fast continuum that predicts, and is inextricable from, the balance of survival and reproduction.

Egg to adult survival of the bush fly, Musca vetustissima Walker (Diptera: Muscidae), in irrigated pastures when flood-caused mortality is prevented

1986 ◽  
Vol 76 (1) ◽  
pp. 59-62 ◽  
Author(s):  
J. N. Matthiessen ◽  
L. Hayles
Keyword(s):  
Western Australia ◽  
Adult Survival ◽  
Cattle Dung ◽  
Irrigation Period ◽  
Western Australian ◽  
Australian Summer

AbstractSurvival of Musca vetustissima Walker from egg to adult in nutritious cattle dung from pasture irrigated during the dry south-western Australian summer was measured in the field. When drowning was prevented by placing dung on a low embankment, survival was high for only the first two months of the fly season, which included the first month of the five-month irrigation period. Substantial emergence of wild M. vetustissima adults from naturally- infested dung occurred only around that time. Survival was so low during the last four months of irrigation, even in the absence of mortality caused by drowning, that irrigated pasture areas in south-western Australia are unlikely to have significantly greater potential for breeding of M. vetustissima than non-irrigated pastures during most of the summer.

Reproductive Periodicity in a Population of Crested Terns, Sterna bergii Lichtenstein in South Australia

1985 ◽  
Vol 12 (1) ◽  
pp. 95 ◽  
Author(s):  
JN Dunlop
Keyword(s):  
Western Australia ◽  
South Australia ◽  
Seabird Species ◽  
Sedentary Population ◽  
Breeding Cycles ◽  
Breeding Condition ◽  
Australian Coastline ◽  
Reproductive Cycles ◽  
Western Australian

Crested terns breeding in the Fremantle area of south-western Australia nest over an 8-month period, from early April to early November. However, laying is markedly bimodal, with subseasons in autumn and spring. Observations of individually marked breeding crested terns indicated a sedentary population utilizing a number of alternative, traditional colony sites all of which were within the study area. Individual crested terns tended to lay in the same part of the season as in the previous year. Colonies made up of terns with similarly phased reproductive cycles formed at different times within the protracted laying period. Individuals completed only one nesting cycle within a season, remaining in breeding condition for approximately 11-13 weeks. Breeding cycles were broadly circannual but potentially sub-annual. Despite superficial similarities at the populational level, this laying pattern differs markedly from that recorded for the silver gull in the same area. The pattern of breeding shown by crested terns therefore provides a second model to explain the double-nesting phenomenon observed in a number of seabird species on the western Australian coastline.

Factors that contribute to urban–rural gradients in risk of schizophrenia: Comparing Danish and Western Australian registers

2021 ◽  
pp. 000486742110096
Author(s):  
Oleguer Plana-Ripoll ◽  
Patsy Di Prinzio ◽  
John J McGrath ◽  
Preben B Mortensen ◽  
Vera A Morgan
Keyword(s):  
Confidence Interval ◽  
Western Australia ◽  
Urban Areas ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Hazard Ratio ◽  
Indigenous Status ◽  
Increased Risk ◽  
The Relationship ◽  
Western Australian

Introduction: An association between schizophrenia and urbanicity has long been observed, with studies in many countries, including several from Denmark, reporting that individuals born/raised in densely populated urban settings have an increased risk of developing schizophrenia compared to those born/raised in rural settings. However, these findings have not been replicated in all studies. In particular, a Western Australian study showed a gradient in the opposite direction which disappeared after adjustment for covariates. Given the different findings for Denmark and Western Australia, our aim was to investigate the relationship between schizophrenia and urbanicity in these two regions to determine which factors may be influencing the relationship. Methods: We used population-based cohorts of children born alive between 1980 and 2001 in Western Australia ( N = 428,784) and Denmark ( N = 1,357,874). Children were categorised according to the level of urbanicity of their mother’s residence at time of birth and followed-up through to 30 June 2015. Linkage to State-based registers provided information on schizophrenia diagnosis and a range of covariates. Rates of being diagnosed with schizophrenia for each category of urbanicity were estimated using Cox proportional hazards models adjusted for covariates. Results: During follow-up, 1618 (0.4%) children in Western Australia and 11,875 (0.9%) children in Denmark were diagnosed with schizophrenia. In Western Australia, those born in the most remote areas did not experience lower rates of schizophrenia than those born in the most urban areas (hazard ratio = 1.02 [95% confidence interval: 0.81, 1.29]), unlike their Danish counterparts (hazard ratio = 0.62 [95% confidence interval: 0.58, 0.66]). However, when the Western Australian cohort was restricted to children of non-Aboriginal Indigenous status, results were consistent with Danish findings (hazard ratio = 0.46 [95% confidence interval: 0.29, 0.72]). Discussion: Our study highlights the potential for disadvantaged subgroups to mask the contribution of urban-related risk factors to risk of schizophrenia and the importance of stratified analysis in such cases.

scholarly journals Warming Arctic summers unlikely to increase productivity of shorebirds through renesting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah T. Saalfeld ◽  
Brooke L. Hill ◽  
Christine M. Hunter ◽  
Charles J. Frost ◽  
Richard B. Lanctot
Keyword(s):  
Climate Change ◽  
Survival Rates ◽  
The Arctic ◽  
Adult Survival ◽  
Chick Survival ◽  
Ecological Processes ◽  
Bird Populations ◽  
Phenological Mismatch ◽  
Daily Survival ◽  
Adequate Food

AbstractClimate change in the Arctic is leading to earlier summers, creating a phenological mismatch between the hatching of insectivorous birds and the availability of their invertebrate prey. While phenological mismatch would presumably lower the survival of chicks, climate change is also leading to longer, warmer summers that may increase the annual productivity of birds by allowing adults to lay nests over a longer period of time, replace more nests that fail, and provide physiological relief to chicks (i.e., warmer temperatures that reduce thermoregulatory costs). However, there is little information on how these competing ecological processes will ultimately impact the demography of bird populations. In 2008 and 2009, we investigated the survival of chicks from initial and experimentally-induced replacement nests of arcticola Dunlin (Calidris alpina) breeding near Utqiaġvik, Alaska. We monitored survival of 66 broods from 41 initial and 25 replacement nests. Based on the average hatch date of each group, chick survival (up to age 15 days) from replacement nests (Ŝi = 0.10; 95% CI = 0.02–0.22) was substantially lower than initial nests (Ŝi = 0.67; 95% CI = 0.48–0.81). Daily survival rates were greater for older chicks, chicks from earlier-laid clutches, and during periods of greater invertebrate availability. As temperature was less important to daily survival rates of shorebird chicks than invertebrate availability, our results indicate that any physiological relief experienced by chicks will likely be overshadowed by the need for adequate food. Furthermore, the processes creating a phenological mismatch between hatching of shorebird young and invertebrate emergence ensures that warmer, longer breeding seasons will not translate into abundant food throughout the longer summers. Thus, despite having a greater opportunity to nest later (and potentially replace nests), young from these late-hatching broods will likely not have sufficient food to survive. Collectively, these results indicate that warmer, longer summers in the Arctic are unlikely to increase annual recruitment rates, and thus unable to compensate for low adult survival, which is typically limited by factors away from the Arctic-breeding grounds.

Life cycle of the western school prawn, Metapenaeus dalli Racek, in a Western Australian estuary

1986 ◽  
Vol 37 (1) ◽  
pp. 95 ◽  
Author(s):  
IC Potter ◽  
JW Penn ◽  
KS Brooker
Keyword(s):  
Life Cycle ◽  
Western Australia ◽  
Sexual Maturity ◽  
Second Year Of Life ◽  
Second Year ◽  
Australian Estuary ◽  
Western Australian

The absence of marine records for M. dalli below latitude 31�S., together with data on gonadal stages and spermatophore deposition on females of this species in the Swan estuary, provide very strong indications that the western school prawn typically breeds in estuarine environments in south-western Australia. The 0 + recruits, which first appeared in samples in February, remained in the estuary during the following months and by November had reached a size suitable for exploitation. At this time they were approaching sexual maturity and were starting to move from the shallows to the deeper waters of the estuary where they remained for their second year of life. In contrast to Australian Penaeus species, M. dalli mates during the intermoult period when the shell is hard rather than immediately after moulting.

Aspects of reproduction, and morphology of the penis, of Pseudantechinus woolleyae (Marsupialia : Dasyuridae)

2017 ◽  
Vol 65 (6) ◽  
pp. 357 ◽  
Author(s):  
P. A. Woolley
Keyword(s):  
Western Australia ◽  
Arid Regions ◽  
Wide Distribution ◽  
Erectile Tissue ◽  
Australian Museum ◽  
Seasonal Breeder ◽  
Males And Females ◽  
One Year ◽  
Western Australian

Woolley’s Pseudantechinus, P. woolleyae, has remained virtually unstudied in the 30 years since its recognition in 1988 as a species distinct from P. macdonnellensis. It has a wide distribution in arid regions of Western Australia. What little is known of its biology comes largely from studies carried out over the years 1988–91 on one wild-caught female and her offspring, and a few specimens held in the collection of the Western Australian Museum. P. woolleyae is a seasonal breeder and young are born from late July to early October. They mature when ~7 months old. Both males and females are potentially capable of breeding in more than one year. Males have accessory erectile tissue that does not form an appendage on the penis.

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