scholarly journals Survival during the pre-fledging period rather than during post-fledging drives variation in local recruitment of an endangered migratory shorebird, the Southern Dunlin Calidris alpina schinzii

2020 ◽  
Author(s):  
Veli-Matti Pakanen ◽  
Robin Hagstedt ◽  
Angela Pauliny ◽  
Donald Blomqvist
Keyword(s):  
Annual Variation ◽  
Local Population ◽  
Chick Survival ◽  
Breeding Sites ◽  
Calidris Alpina ◽  
Brood Survival ◽  
Annual Range ◽  
Capture Recapture ◽  
Study Population ◽  
Local Recruitment

Abstract The declines in wet-grassland breeding shorebird populations are considered to mainly result from changes in reproduction. While there is plenty of information on nest survival, little reliable information exists on local recruitment due to confounding effects of permanent emigration. Furthermore, few studies have been able to study the roles of pre- and post-fledging survival on local recruitment. Therefore, it is unclear whether local recruitment of young reflects conditions at the breeding sites or at non-breeding sites. We studied an isolated population of the endangered Southern Dunlin (Calidris alpina schinzii) breeding on the west coast of Sweden to examine (1) brood survival (probability of at least one chick fledging) by following broods fates and (2) local recruitment (survival from hatching to 1 year old) using capture-recapture data. We then examined how much of the annual variation in juvenile survival was explained by variation in brood survival. Brood survival was on average 0.58 (annual range 0.08–1.00) and explained 64% of variation in annual local recruitment. Still local recruitment was rather high for a shorebird (0.17, SE = 0.023), which reflects the isolated nature of the study population. Our results suggest that local recruitment seems to be mainly constrained by chick survival during the pre-fledging period. Therefore, management of breeding sites leading to increased brood survival, e.g., reducing predation on chicks, should have strong impacts on local recruitment and local population growth.

scholarly journals On valuing patches: estimating contributions to metapopulation growth with reverse-time capture–recapture modelling

2011 ◽  
Vol 279 (1728) ◽  
pp. 480-488 ◽  
Author(s):  
Jamie S. Sanderlin ◽  
Peter M. Waser ◽  
James E. Hines ◽  
James D. Nichols
Keyword(s):  
Population Growth ◽  
Local Population ◽  
Peripheral Populations ◽  
Reverse Time ◽  
Genetic Population ◽  
Local Populations ◽  
Local Survival ◽  
Capture Recapture ◽  
Local Recruitment ◽  
Analytical Approaches

Metapopulation ecology has historically been rich in theory, yet analytical approaches for inferring demographic relationships among local populations have been few. We show how reverse-time multi-state capture–recapture models can be used to estimate the importance of local recruitment and interpopulation dispersal to metapopulation growth. We use ‘contribution metrics’ to infer demographic connectedness among eight local populations of banner-tailed kangaroo rats, to assess their demographic closure, and to investigate sources of variation in these contributions. Using a 7 year dataset, we show that: (i) local populations are relatively independent demographically, and contributions to local population growth via dispersal within the system decline with distance; (ii) growth contributions via local survival and recruitment are greater for adults than juveniles, while contributions involving dispersal are greater for juveniles; (iii) central populations rely more on local recruitment and survival than peripheral populations; (iv) contributions involving dispersal are not clearly related to overall metapopulation density; and (v) estimated contributions from outside the system are unexpectedly large. Our analytical framework can classify metapopulations on a continuum between demographic independence and panmixia, detect hidden population growth contributions, and make inference about other population linkage forms, including rescue effects and source–sink structures. Finally, we discuss differences between demographic and genetic population linkage patterns for our system.

scholarly journals Breeding transients in capture–recapture modeling and their consequences for local population dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Daniel Oro ◽  
Daniel F. Doak
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Population Growth Rate ◽  
Local Population ◽  
Environmental Stochasticity ◽  
Adult Survival ◽  
Local Survival ◽  
First Reproduction ◽  
Capture Recapture

Abstract Standard procedures for capture–mark–recapture modelling (CMR) for the study of animal demography include running goodness-of-fit tests on a general starting model. A frequent reason for poor model fit is heterogeneity in local survival among individuals captured for the first time and those already captured or seen on previous occasions. This deviation is technically termed a transience effect. In specific cases, simple, uni-state CMR modeling showing transients may allow researchers to assess the role of these transients on population dynamics. Transient individuals nearly always have a lower local survival probability, which may appear for a number of reasons. In most cases, transients arise due to permanent dispersal, higher mortality, or a combination of both. In the case of higher mortality, transients may be symptomatic of a cost of first reproduction. A few studies working at large spatial scales actually show that transients more often correspond to survival costs of first reproduction rather than to permanent dispersal, bolstering the interpretation of transience as a measure of costs of reproduction, since initial detections are often associated with first breeding attempts. Regardless of their cause, the loss of transients from a local population should lower population growth rate. We review almost 1000 papers using CMR modeling and find that almost 40% of studies fitting the searching criteria (N = 115) detected transients. Nevertheless, few researchers have considered the ecological or evolutionary meaning of the transient phenomenon. Only three studies from the reviewed papers considered transients to be a cost of first reproduction. We also analyze a long-term individual monitoring dataset (1988–2012) on a long-lived bird to quantify transients, and we use a life table response experiment (LTRE) to measure the consequences of transients at a population level. As expected, population growth rate decreased when the environment became harsher while the proportion of transients increased. LTRE analysis showed that population growth can be substantially affected by changes in traits that are variable under environmental stochasticity and deterministic perturbations, such as recruitment, fecundity of experienced individuals, and transient probabilities. This occurred even though sensitivities and elasticities of these parameters were much lower than those for adult survival. The proportion of transients also increased with the strength of density-dependence. These results have implications for ecological and evolutionary studies and may stimulate other researchers to explore the ecological processes behind the occurrence of transients in capture–recapture studies. In population models, the inclusion of a specific state for transients may help to make more reliable predictions for endangered and harvested species.

Modelling survival and breeding dispersal to unobservable nest sites

2016 ◽  
Vol 43 (5) ◽  
pp. 411 ◽  
Author(s):  
Giacomo Tavecchia ◽  
Ana Sanz-Aguilar ◽  
Belinda Cannell
Keyword(s):  
Breeding Site ◽  
Demographic Parameters ◽  
Breeding Dispersal ◽  
Artificial Nests ◽  
Breeding Sites ◽  
Nest Sites ◽  
Local Survival ◽  
Permanent Migration ◽  
Capture Recapture ◽  
Event Capture

Context Demographic parameters in wildlife populations are typically estimated by monitoring a limited number of individuals in observable sites and assuming that these are representative of the whole population. If individuals permanently disperse to unobservable breeding sites, recruitment and immature survival are expected to be negatively biased and breeding-site fidelity cannot be investigated. Aims To develop a method to obtain unbiased estimated of survival, recruitment and breeding dispersal when individuals can move to, or recruit in, unobservable sites. Methods We used the flexibility of multi-event capture–recapture models to estimate dispersal and recruitment to unobservable sites, merging observations made at two sites within the same breeding locations. We illustrated the model with data on little penguin (Eudyptula minor) breeding in artificial as well as in natural nests. Natural nests are unknown or inaccessible and birds in these sites remain unobservable. Encounters at beaches surrounding the colony suggested that marked animals can permanently move to unobservable nests. We built the multi-event model considering two possible states of the individuals (alive breeding in a nest box and alive in a natural nest) and three types of observations (encountered at a nest only, encountered at the beach only and encountered at both places). This model ensured that the breeding dispersal to unobservable places became estimable. Key results Results indicate that the estimated survival was 8% higher than when recaptures at artificial nests were analysed alone. Also, fidelity to artificial nests was 12% lower than to natural nests. This might reflect the greater availability of natural sites or, alternatively, a heterogeneity between these two types of nest. Conclusions We obtained an estimate of local survival of little penguins breeding at Penguin Island that incorporates the permanent migration to unobservable sites and found an asymmetric dispersion towards natural nests. Implication Our conclusions suggest a need for more careful treatment of data derived from artificial sites alone, as demographic parameters might be underestimated if animals prefer natural breeding sites or if they are in greater proportion compared with artificial ones. The analytical approach presented can be applied to many biological systems, when animals might move into inaccessible or unobservable breeding sites.

scholarly journals Predicting Neck Abscess with Contrast-Enhanced Computed Tomography

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Melisa Lim Seer Yee ◽  
Noraini Abdul Rahim ◽  
Ning Ajleaa Ngah ◽  
Yang Faridah Abdul Aziz ◽  
Sethu Subha
Keyword(s):  
Computed Tomography ◽  
Predictive Value ◽  
Imaging Modality ◽  
Local Population ◽  
High Sensitivity ◽  
Neck Abscess ◽  
Contrast Enhanced ◽  
Study Population ◽  
Enhanced Computed Tomography ◽  
Contrast Enhanced Computed Tomography

Neck abscesses are difficult to diagnose and treat. Currently, contrast-enhanced computed tomography (CECT) is the imaging modality of choice. The study aims to determine the predictive value of CECT findings in diagnosing neck abscess, causes of neck abscess and the most common neck space involved in the local population. 84 consecutive patients clinically suspected to have neck abscess who underwent CECT and surgical confirmation of pus were included. Demographic and clinical data were recorded. 75 patients were diagnosed as having neck abscess on CECT; out of those 71 patients were found to have pus. Overall CECT findings were found to have a high sensitivity (98.6%) and positive predictive value (PPV) (94.7%) but lower specificity (67.2%) in diagnosing neck abscess. The CECT diagnostic criterion with the highest PPV is the presence of rim irregularity (96%). The most common deep neck space involved is the submandibular compartment, which correlates with the finding that odontogenic cause was the most common identifiable cause of abscess in the study population. Thus, in a patient clinically suspected of having neck abscess, CECT findings of a hypodense mass with rim irregularity are helpful in confirming the diagnosis and guiding clinical management.

scholarly journals On the annual variation of the magnetic declination, at different periods of the day

1854 ◽  
Vol 6 ◽  
pp. 73-74
Keyword(s):  
Annual Variation ◽  
Graphical Representation ◽  
Horizontal Line ◽  
Annual Variations ◽  
Cape Of Good Hope ◽  
Magnetic Declination ◽  
Annual Range ◽  
The Hours ◽  
The Mean ◽  
St Helena

In this communication the author has arranged and presented together the Annual variations which the magnetic declination undergoes at every hour of the day at the four Colonial Observatories established by the British government, at Toronto, Hobarton, the Cape of Good Hope and St. Helena. This has been done by means of a graphical representation, in which the annual variations at every hour are shown by vertical lines varying in length according to the amount of the range of the annual variation at each hour; each line having also small cross lines marking the mean positions of the several months in the annual range. The mean declination in the year at the respective hours is marked by a horizontal line which crosses all the verticals at each station. The hours are those of mean solar time at each station, the day commencing at noon.

scholarly journals Temporal and spatial variation in age-specific survival rates of a long-lived mammal, the Hawaiian monk seal

2006 ◽  
Vol 274 (1608) ◽  
pp. 407-415 ◽  
Author(s):  
Jason D Baker ◽  
Paul M Thompson
Keyword(s):  
Survival Rates ◽  
Adult Survival ◽  
Age Classes ◽  
Temporal And Spatial Variation ◽  
Monachus Schauinslandi ◽  
Breeding Sites ◽  
Capture Recapture ◽  
Temporal And Spatial ◽  
Spatio Temporal ◽  
Monk Seals

Estimates of variability in pinniped survival rates are generally based on observations at single sites, so it is not certain whether observed rates represent the whole population. Here, we provide a comprehensive analysis of spatio-temporal variation in age-specific survival rates for endangered Hawaiian monk seals ( Monachus schauinslandi ) based on capture–recapture analyses of more than 85% of the pups weaned in this population over the last two decades. Uniquely, these data have been collected from six subpopulations, encompassing all major breeding sites across its 1800 km long core range. Analyses of individual subpopulations revealed similar patterns in age-specific survival, characterized by the relatively low survival rates from weaning to 2 years of age, intermediate rates to 4 years of age, and then by relatively high ‘mature’ survival rates until 17 years of age, after which a senescent decline was observed. Juvenile, subadult and adult survival rates all varied significantly over time. Trends in survival among subpopulations were coherent with their relative geographical positions, suggesting regional structuring and connectedness within the archipelago. Survival rates for different age classes tended to be positively correlated, suggesting that similar factors may influence the survival for seals of all ages.

scholarly journals Abundance and survival estimates of the southeastern Pacific humpback whale stock from 1991–2006 photo-identification surveys in Ecuador

2020 ◽  
pp. 301-307 ◽  
Author(s):  
Fernando Félix ◽  
Cristina Castro ◽  
Jeffrey L. Laake
Keyword(s):  
Annual Variation ◽  
Humpback Whales ◽  
Collaborative Effort ◽  
Transient Effect ◽  
Photo Identification ◽  
Migration Timing ◽  
Open Population ◽  
Southeastern Pacific ◽  
Capture Recapture ◽  
Wintering Areas

Southeastern Pacific humpback whales (Breeding Stock G) breed along the northwestern coast of South America and farther north up to CostaRica. Photo-identification surveys conducted aboard whalewatching vessels during the migration/breeding season from June to September between1991 and 2006 off the coast of Ecuador (2°S, 81°W) have produced a database of 1,511 individual whales. Comparisons of photographs produced190 between-year re-sightings of 155 individual whales. Closed and open capture-recapture models were used to estimate abundance and survival.The best estimate of abundance in 2006 with the Chapman modified-Petersen was 6,504 (95% CI: 4,270–9,907; CV = 0.21). Abundance estimatesfrom open population models were considerably lower due to heterogeneity in capture probability which produced a ‘transient’ effect. Our bestestimate of true survival was 0.919 (95% CI: 0.850–0.958). Heterogeneity most likely occurred from inter-annual variation in sampling and unknownstructure and variation in the migration timing and corridor. A more extensive collaborative effort including other wintering areas further north aswell as integrating breeding-feeding data will help to reduce heterogeneity and increase precision in abundance and survival estimates.

scholarly journals Modern distribution, new breeding and moulting places of the Mute Swan (Cygnus olor Gmelin) in the Leningrad region in 2005–2015

2016 ◽  
Author(s):  
Sergey Kouzov ◽  
Anna Loseva
Keyword(s):  
Local Population ◽  
Weather Conditions ◽  
Current Status ◽  
Leningrad Region ◽  
Mute Swan ◽  
Territorial Expansion ◽  
Breeding Sites ◽  
Cygnus Olor ◽  
Mass Reproduction ◽  
Centers Of Mass

The article presents new data on nesting and moulting places of Mute Swan Cygnus olor Gmelin in the Leningrad region, observed in 2005–2015, describes the current status of its breeding and moulting places in the region, discovered in previous decades. An analysis of the spatial and landscape distribution of this species and the nature of its changes in recent years is given. The analysis shows that a significant increase in the number of breeding sites and moulting of the Mute Swan in the Leningrad region has not led to a marked increase in the local population. New places are populated primarily by solitary nesting pairs and small groups of moulting individuals, unlike some of the previously populated centers of mass reproduction and moult on Kurgalsky Peninsula and Seskar archipelago, where initially there was a high density of breeding and moulting birds. It may be characterised as a very low territorial expansion of the nesting area, but mainly as the colonization of empty loci in its old borders. Such type of colonization along with strong inter-seasonal local population dynamics depending on weather conditions, show the presence of climatical limit of the distribution of the this species in the region. Refs 58. Figs 6. Tables 1.

Pilot action within the framework of the Mig-HealthCare project - implementation of community-based pilot studies addressing health inequalities of migrants and refugees

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
K Zota ◽  
P Karnaki ◽  
A Gil-Salmerón ◽  
E Riza ◽  
J Garcés-Ferrer ◽  
...  
Keyword(s):  
Service Providers ◽  
Local Population ◽  
Target Groups ◽  
Community Based ◽  
Pilot Studies ◽  
Breast And Cervical Cancer ◽  
Implementation Context ◽  
Study Population ◽  
Pilot Implementation ◽  
The Impact

Abstract In the framework of the Mig-HealthCare project, a roadmap to community-based health care was developed including a toolbox and an algorithm. The Mig-HealthCare partners piloted parts of the roadmap in 8 EU countries. Piloting included actions on health promotion issues for migrants/refugees, mental health issues, non-communicable diseases, screening for breast and cervical cancer and vaccination issues. Two recommended practices were also piloted among migrants/refugees namely the 'circle of health' and health mentors while the Greek partner tested the developed algorithm in various health settings. All pilots were evaluated using common and pilot specific indicators for (a) appropriateness: the extent to which the piloted interventions were suitable for the target groups (service providers and/or migrants/refugees) (b) effectiveness: the extent to which the pilots' objectives were achieved, or are expected to be achieved, taking into account their relative importance (c) satisfaction: the extent to which pilots meet or surpass target groups and stakeholders (refugee/migrants, service providers and local population) expectation and needs (d) sustainability: the continuation of benefits from the pilot. Sustainability in the pilot implementation context is the ability of key target groups to sustain pilot benefits. Moreover, the impact of the interventions and their results should be sustainable in time. The impact of the pilots on the study population as well as implications for community-level health services are discussed.

Land and sea-based observations and first satellite tracking results support a New Ireland breeding site for the Critically Endangered Beck’s Petrel Pseudobulweria beckii

2019 ◽  
Vol 30 (1) ◽  
pp. 58-74
Author(s):  
MATT J. RAYNER ◽  
KAREN A. BAIRD ◽  
JEREMY BIRD ◽  
STEVE CRANWELL ◽  
ANDRĒ F. RAINE ◽  
...  
Keyword(s):  
East Coast ◽  
Local Population ◽  
Satellite Telemetry ◽  
Breeding Site ◽  
Satellite Tracking ◽  
Critically Endangered ◽  
Satellite Transmitter ◽  
Breeding Sites ◽  
Pelagic Habitat ◽  
Near Shore

SummaryThe Beck’s Petrel Pseudobulweria beckii is a ‘Critically Endangered’ seabird whose breeding sites remain unknown. Historic observations suggest the species’ distribution is concentrated in the Bismarck Archipelago and particularly southern New Ireland. Over the course of two research expeditions in 2016 and 2017 we used on-land and at-sea observations, local interviews and satellite telemetry to understand the distribution of the species, its at-sea movements and potential breeding locations. Land-based and at-sea observations indicated that the area of Silur Bay in southern New Ireland was a significant site for Beck’s Petrel with numbers of birds increasing near shore prior to dusk and birds observed in spotlights over land. A local population is estimated to be in the low thousands. In 2017 a single Beck’s was captured at sea, fitted with a satellite transmitter and tracked for eight months. This bird maintained a core distribution off the south-east coast of New Ireland and north of Bougainville for 122 days. During the tracking period, the bird was located over land at night seven times; predominantly over southern New Ireland, where the signal was also lost for extended periods suggesting occupancy of an underground burrow. In August the bird migrated 1,400 km to a core pelagic habitat north of West Papua before the signal was eventually lost. Our combination of land- and sea-based observations and analysis of behaviour from satellite tracking supports the conclusion that a breeding site for Beck’s Petrel lies in the inland mountains of southern New Ireland and most likely in the high-altitude zone (> 2000 m) of the Hans Meyer Range. Further investigations are required to determine the exact location of breeding colonies in the mountains of southern New Ireland and the importance of a potential west Papuan non-breeding pelagic habitat for the species.

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