scholarly journals Heterogeneity in body condition, survival, and seasonal origins among lesser snow and Ross's geese

2018 ◽  
Author(s):  
◽  
Drew N. Fowler

Individual heterogeneity in fitness within a population is well established and provides the required variability for natural selection to take place. Yet, in the case of overabundant midcontinent lesser snow (Anser caerulescens caerulescens) and Ross's geese (A. rossii), individual variation in regards to harvest effects on population growth has largely not been considered when evaluating management actions to reduce population size. In this dissertation, I first examined heterogeneity in body condition among hunter harvested individuals and the general population of midcontinent lesser snow and Ross's geese during the spring Light Goose Conservation Order in 2015 and 2016 across Arkansas, Missouri, Nebraska, and South Dakota. I found a body condition bias in decoy harvested geese, such that individuals removed by hunters were in lower body condition (less lipid content) relative to the general population. This finding suggests that disproportionate removal of lower conditioned individuals is a feature of the currently observed compensatory nature of harvest among midcontinent light geese. I also explored methods to estimate the magnitude of individual variation in survival rates of adult lesser snow geese using mark-recovery data via a Bayesian state-space model. I identified limitations to estimating heterogeneous survival rates using mark-recovery data alone and suggest future simulations to explore alternative methodological approaches. Finally, I evaluated differences in spring body condition among individuals using different wintering habitats through stable isotope analysis. I found that individuals overwintering in coastal marsh habitats had lower lipid reserves relative to those individuals overwintering in rice-based agricultural landscapes, suggesting a carry-over effect from winter habitat use that may influence harvest susceptibility or other fitness parameters. In conclusion, continued research to identify the amount of individual variation in survival parameters of cohort specific geese can further elucidate the role of heterogeneity on the Light Goose Conservation Order attempts to reduce population size.

The Auk ◽  
2006 ◽  
Vol 123 (2) ◽  
pp. 405-418 ◽  
Author(s):  
Jón Einar Jónsson ◽  
Alan D. Afton ◽  
Ray T. Alisauskas ◽  
Cynthia K. Bluhm ◽  
Mohamed E. El Halawani

AbstractWe investigated effects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereafter “Snow Geese”) and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood patch area, and body condition would be stronger in Ross's Geese than in the larger Snow Geese. We found that brood patch area was positively related to clutch volume and inversely related to prolactin levels in Ross's Geese, but not in Snow Geese. Nest size, nest habitat, and first egg date did not affect brood patch area in either species. Prolactin levels increased as incubation progressed in female Snow Geese, but this relationship was not significant in Ross's Geese. Prolactin levels and body condition (as indexed by size-adjusted body mass) were inversely related in Ross's Geese, but not in Snow Geese. Our findings are consistent with the prediction that relationships between prolactin levels, brood patch area, and body condition are relatively stronger in Ross's Geese, because they mobilize endogenous reserves at faster rates than Snow Geese.Factores Ecológicos y Fisiológicos que Afectan el Área del Parche de Incubación y los Niveles de Prolactina en Gansos Nidificantes del Ártico


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi87-vi88
Author(s):  
Jennifer Murillo ◽  
Elizabeth Anyanda ◽  
Jason Huang

Abstract Gliomas are the most common primary malignant brain tumor in the United States with previous studies showing the incidence varied by age, sex, and race or ethnicity. Survival after diagnosis has also been shown to vary by these factors. Also, socioeconomic status and its association with various cancers have also been studied at length over time. PURPOSE: The purpose of our research was to quantify the differences in incidence and survival rates of gliomas in 15 years and older by income level. METHODS: This population-based study obtained incidence and survival data from the Incidence-SEER Research Database the general population. Average age incidence were generated by glioma groups and grouped by income levels. Survival rates were generated by overall glioma diagnosis grouped by observed survival at 12, 24, 36, 48 and 60 months and by again by income levels. The analysis included 94,207 patients with glioma diagnosed in those aged 15 years or older. RESULTS: Overall, 94, 207 patients diagnosed with glioma were analyzed. Of these, 1,089 (1.16%) fell into the < $35k group, 1,684 (1.79%) in the $35k-$40k group, 3,473 (3.69%) in the $40k-$45k group, 5,647 (5.99%) in the $45k-$50k group, 7,138 (7.58%) in the $50k-$55k group, 6,468 (6.87%) in the $55k-$60k group, 15,348 (16.29%) in the $60k-$65k group, 13,216 (14.03%) in the $65k-$70k group, 9,035 (9.59%) in the $70k-$75k group, and 31,109 (33.02%) fell in > $75k group. The data was also broken further down into survivability showing average survival. CONCLUSION: Incidence of glioma and 12, 24, 36, 48 and 60 month survival rates after diagnosis vary significantly by income level with higher income level greater than $75,000+ having higher incidence and higher survival rates compared with lower income levels. Further research is needed to help determine risk factors and barriers to care to help reveal health disparities.


Parasitology ◽  
2017 ◽  
Vol 144 (9) ◽  
pp. 1221-1228 ◽  
Author(s):  
SHUN ZHOU ◽  
HONG ZOU ◽  
SHAN G. WU ◽  
GUI T. WANG ◽  
DAVID J. MARCOGLIESE ◽  
...  

SUMMARYField surveys indicate that host population size, rather than density, is the most important determinant of monogenean infection dynamics. To verify this prediction, epidemic parameters were monitored for 70 days at five host population sizes held at constant density using a goldfish – Gyrodactylus kobayashii laboratory model. During the first 20 days, the rate of increase of prevalence and mean abundance was faster in small host populations. Total mean prevalence and total mean abundance throughout the experiment were not significantly affected by host population sizes. Higher transmission rates were detected in larger host populations. However, there were no significant differences in effective contact rates among the five host populations on each sampling day during the first 20 days, implying that contact rates may be saturated at a sufficiently high host density. These results demonstrate that the epidemic occurs more quickly in smaller host populations at the beginning of the experiment. However, the epidemic is independent of the host population size due to the similar effective contact rates in the five population sizes. Significant negative influence of the initial body condition (Kn) of uninfected goldfish on total mean abundance of parasites suggests that susceptibility of hosts is also a determinant of parasite transmission.


The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
Ana M González ◽  
Scott Wilson ◽  
Nicholas J Bayly ◽  
Keith A Hobson

Abstract In the Neotropics, coffee production occurs on a large scale in some of the planet’s most biodiverse regions: tropical mountains. Coffee production systems involving shade trees are considered to have a lower impact on biodiversity than alternative sun coffee. To date, the majority of evidence for the value of shade coffee plantations has not taken into account the relative quality of this habitat compared to the native forests they replaced. We determined the suitability of shade coffee and forest as winter habitat for Canada Warbler (Cardellina canadensis) by comparing variation in the likelihood of capturing individuals, seasonal changes in body condition, and estimates of annual survival between the 2 habitats. We also determined the effect of the strong 2015–2016 El Niño event on survival. Males were relatively more likely to be captured in forest than females and this likelihood increased during drier years. Body condition change over the winter and apparent annual survival were similar for individuals that used forest and coffee. However, condition and survival decreased in both habitats during the El Niño year. Apparent survival was also lower for individuals carrying a radiotag or geolocator. Our findings suggest that shade coffee with high canopy cover and height offers similar benefits to forest in terms of body condition and survival. Landscape conservation approaches, promoting diverse matrices of structurally complex shade coffee and forest might best ensure long-term survival in Neotropical migrants like Canada Warbler.


1999 ◽  
Vol 29 (2) ◽  
pp. 485-489 ◽  
Author(s):  
J. J. CLAUS ◽  
G. J. M. WALSTRA ◽  
P. M. BOSSUYT ◽  
S. TEUNISSE ◽  
W. A. VAN GOOL

Background. We studied whether heterogeneous profiles of cognitive function are relevant to survival in patients with early Alzheimer's disease.Methods. CAMCOG subscales of cognitive function were used as predictors of survival, together with gender in 157 consecutively referred patients with early Alzheimer's disease. Statistical analysis was performed with Cox proportional hazards analysis and Kaplan–Meier survival curves. Survival rates were compared with those in the general population.Results. Eighty patients (51%) died during the follow-up that extended to 5·7 years, with a median survival of 4·4 years after entry. Only the praxis subscore was statistically significant related to survival (P<0·0001). Its predictive power was based on only two items, including copying ability for a spiral and a three-dimensional house, independent of age, sex, education, overall CAMCOG score, dementia severity and symptom duration. Kaplan–Meier curves for the combined score of these items (0, 1, or 2) showed three groups with significantly different survival rates for both men and women. Comparison of gender specific survival rates with data from the general population showed that excess mortality was statistically significant (P<0·01) higher in men (51%) than in women (21%) after follow-up extending to 5 years.Conclusions. A simple test of copying ability defines subgroups of AD patients with large differences in survival rates. This suggests that parietal lobe impairment is an important predictor of mortality in AD. Also, the course of AD may be more benign in women than in men.


2019 ◽  
Vol 30 (3) ◽  
pp. 394-399
Author(s):  
Daniel Hernandez-Vaquero ◽  
Rocio Diaz ◽  
Alberto Alperi ◽  
Marcel G Almendarez ◽  
Alain Escalera ◽  
...  

Abstract OBJECTIVES Surgical aortic valve replacement (SAVR) changes the natural history of severe aortic stenosis. However, whether the life expectancy of patients with severe aortic stenosis undergoing this surgical procedure is fully restored is unknown. The objective of this study was to assess if the life expectancy of patients aged &gt;75 years is fully restored after undergoing surgery for severe aortic stenosis. METHODS We compared long-term survival of a group of patients aged &gt;75 years, who underwent SAVR at our institution with the long-term survival of the general population. We matched each patient with 100 simulated individuals (control group) of the same age, sex and geographical region who died as indicated by the National Institute of Statistics. We compared survival curves and calculated hazard ratio (HR) or incidence rate ratio. Statistical significance existed if confidence intervals (CIs) did not overlap or did not include the value 1, as appropriate. RESULTS Average life expectancy of surgical patients who survived the postoperative period was 90.91 months (95% CI 82.99–97.22), compared to 92.94 months (95% CI 92.39–93.55) in the control group. One-, 5- and 8-year survival rates for SAVR patients who were discharged from the hospital were 94.9% (95% CI 92.74–96.43%), 71.66% (95% CI 67.37–75.5%) and 44.48% (95% CI 38.14–50.61%), respectively, compared to that of the general population: 95.8% (95% CI 95.64–95.95%), 70.64% (95% CI 70.28%–71%) and 47.91% (95% CI 47.52–48.31%), respectively (HR 1.07, 95% CI 0.94–1.22). CONCLUSION For patients over the age of 75 years who underwent SAVR and survived the postoperative period, life expectancy and survival rates were similar to that of the general population.


2009 ◽  
Vol 7 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Renato Hajenius Aché de Freitas ◽  
Ricardo S. Rosa ◽  
Bradley M. Wetherbee ◽  
Samuel H. Gruber

Sharks face a number of obstacles for surviving their first several years of life and many species occupy nursery areas. Although estimates of survival, particularly for young age classes, are essential for assessing, monitoring and effectively managing animal populations, there have been relatively few calculations of survival within shark populations and even fewer estimates based on direct methods for sharks on their nursery grounds. We used tag-recapture methods to estimate the population size and survival of juvenile lemon sharks (Negaprion brevirostris) on their nursery grounds at Atol das Rocas, a marine protected area in Brazil. Sharks were sampled from1999 to 2003. Population size estimates ranged from 12 to 100 juvenile sharks and survival estimates ranged between 24-54% with a mean of 44.6% over the most robust sampling periods. The population of juvenile lemon sharks declined over the course of our study, whereas survival rates may have increased over the same time period. Even a modest level of fishing and removal of mature females in adjacent areas may dramatically affect small populations of sharks within a small and isolated nursery such as Atol das Rocas. The lower survival rates and population size at Atol das Rocas could be the result of differences in physical characteristics of this nursery in comparison to others used by lemon sharks in the northwestern Atlantic. Such comparatively lower populational parameters suggest that the population of young lemon sharks is fragile at the Atol das Rocas nursery.


2006 ◽  
Vol 43 (3) ◽  
pp. 464-473 ◽  
Author(s):  
NIALL H. K. BURTON ◽  
MARK M. REHFISCH ◽  
NIGEL A. CLARK ◽  
STEPHEN G. DODD

1994 ◽  
Vol 84 (4) ◽  
pp. 521-527 ◽  
Author(s):  
J.J. Lutwama ◽  
L.G. Mukwaya

AbstractMultiple mark-release-recapture experiments were carried out on females of three anthropophilic populations of Aedes simpsoni (Theobald) complex at Nkokonjeru and Bwamba in Uganda to determine and compare the population size, survival rates and longevity of the adult stages. There were high recapture rates (26.23%, 2 7.42% and 28.28%) at the different sites. The population sizes, estimated by Jolly's stochastic method for the three sites (465, 561 and 675 female mosquitoes) were not significantly different, neither were the survival rates of the females (0.6026, 0.7145 and 0.8152). Other parameters estimated for the three populations were also similar. Population size estimates by Jolly's stochastic model and the simple Lincoln Index methods were not in agreement. The other method over-estimated population size. Since the estimated parameters for the Nkokonjeru population are similar to those of the Bwamba populations, there is a potential for the transmission of yellow fever virus to the human population at Nkokonjeru, as at Bwamba.


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