Differential mortality of sympatric snowshoe hares and cottontail rabbits in central Wisconsin

1993 ◽  
Vol 71 (8) ◽  
pp. 1694-1697 ◽  
Author(s):  
Lloyd B. Keith ◽  
Sara E. M. Bloomer
Keyword(s):  
Low Temperatures ◽  
Escape Behavior ◽  
Survival Rates ◽  
Differential Mortality ◽  
Interspecific Difference ◽  
High Survival ◽  
Sylvilagus Floridanus ◽  
Proximate Cause ◽  
Snowshoe Hares ◽  
Foot Loading

During 1990 and 1991 we livetrapped and radio-collared cottontail rabbits (Sylvilagus floridanus) and snowshoe hares (Lepus americanus) on five sites (three in lowland deciduous cover, two in conifer bogs) in central Wisconsin. The survival rates of these sympatric cottontails and snowshoes were equally high during snow-free periods from mid-March through October. With the onset of persistent snow cover (mean depth 20 cm) and low temperatures (mean daily minimum −14 °C) in November 1991, the 60-day survival rate of cottontails plummeted from 0.89 to 0.18 (P < 0.01) whereas snowshoe survival declined only moderately from 0.84 to 0.63 (P = 0.19). This interspecific difference reflected continued high survival of snowshoes (0.80), but not of cottontails (0.15), in the conifer bogs. Predation, primarily by coyotes, was the proximate cause of 37 of 39 rabbit and hare deaths, and was thus the overwhelming determinant of survival. We speculate that where persistent snow and low temperatures characterize winter, the cottontail's greater foot loading, brown coloration, and escape behavior markedly increase its vulnerability to predators. This probably explains the absence of cottontails from the forests of northern Wisconsin.

Impact of helminth parasitism on a snowshoe hare population in central Wisconsin: a field experiment

1995 ◽  
Vol 73 (10) ◽  
pp. 1891-1898 ◽  
Author(s):  
Sara E. M. Bloomer ◽  
Thomas Willebrand ◽  
Ingegerd M. Keith ◽  
Lloyd B. Keith
Keyword(s):  
Survival Rates ◽  
Snowshoe Hare ◽  
Marrow Fat ◽  
Proximate Cause ◽  
Risk Of Death ◽  
Snowshoe Hares ◽  
Condition Indices ◽  
Time Specific ◽  
And Control ◽  
Hare Population

We tested the hypothesis that helminth parasitism is demographically significant to a noncyclic population of snowshoe hares (Lepus americanus) near the species' geographic boundary in central Wisconsin (U.S.A.). During November 1988 to December 1991, we injected 93 individuals (≥760 g, aged ≥2 months) with anthelmintics: Ivermectin for nematode and Droncit for cestode infections. We injected 98 control hares with propylene glycol, the common vehicle for both drugs. All treated and control hares were radio-collared with mortality-sensing transmitters and monitored daily to weekly from the ground or air. Prevalence and intensity of lungworms (Protostrongylus boughtoni), intestinal worms (Nematodirus triangularis), and stomach worms (Obeliscoides cuniculi) were markedly reduced by Ivermectin treatment. No other nematodes were found to be present. Treatment with Droncit to remove intestinal cestodes was apparently unnecessary, as prevalence among necropsied untreated hares and controls was just 10%. We compared body-condition indices (mass changes, response to trap stress, and bone-marrow fat), reproduction (pregnancy rate and litter size), home-range sizes, and time-specific survival rates of anthelmintic-treated versus control hares. None of these demographic variables differed significantly between treated and control cohorts, nor was there any evidence that parasitism increased the risk of death from predation, which was the proximate cause of 96% of all natural mortalities. We conclude that helminth parasitism played no detectable role in the dynamics of this Wisconsin snowshoe hare population.

Survival of juvenile hares during a cyclic population increase

1998 ◽  
Vol 76 (10) ◽  
pp. 1949-1956 ◽  
Author(s):  
Elizabeth A Gillis
Keyword(s):  
Cause Of Death ◽  
Food Availability ◽  
Survival Rates ◽  
Lepus Americanus ◽  
Population Increase ◽  
Differential Survival ◽  
Proximate Cause ◽  
Supplemental Food ◽  
Snowshoe Hares ◽  
And Control

Snowshoe hares (Lepus americanus) are multilittered synchronous breeders that produce up to four distinct litters of young each summer. I used radiotelemetry to determine the effects of juvenile cohort (i.e., litter group) and food availability on postweaning survival of hares in the southwestern Yukon during the increase phase of a hare cycle. During the study, I monitored 86 juvenile hares from control areas and areas in which supplemental food was provided. Twenty-eight-day survival did not differ between food addition and control areas for any juvenile cohort, and survival rates of juveniles (all cohorts combined) did not differ significantly from those of adults (juveniles: 0.91 per 28 days; adults: 0.93 per 28 days). However, when examined by juvenile cohort, survival of third and fourth litters was significantly lower than that of adults and first and second litters. These differences were the result of differential survival among the juvenile cohorts during a 3-month period in the fall (September-November). Predation was the primary proximate cause of death for weaned juvenile hares, accounting for 86% of deaths.

scholarly journals First estimates of survival and densities of invasive alien Eastern cottontail (Sylvilagus floridanus) in Italy: a capture-recapture approach

2019 ◽  
Author(s):  
Jacopo Cerri ◽  
Sandro Bertolino
Keyword(s):  
North America ◽  
Native Species ◽  
Survival Rates ◽  
Northern Italy ◽  
High Survival ◽  
Sylvilagus Floridanus ◽  
Open Population ◽  
Capture Recapture ◽  
Eastern Cottontail ◽  
Selection Of

The Eastern cottontail (Sylvilagus floridanus) has become invasive in Central and Northern Italy, where it affects prey-predator dynamics between native species. Although many different studies explored survival rates and the density of cottontails in North America, no information is available for its invasive range. Between December 2003 and October 2005, a capture-recapture scheme for Eastern cottontails was enforced on the Orba River, Italy. We fitted an open-population Cormack-Jolly-Seber model to estimate survival of adult individuals (n=258) and their density in the study area. Adult cottontails showed a constant survival (phi = 0.84 ± 0.02) across the various sessions, as well as between individuals of different sexes. Capture probabilities and densities varied seasonally, with densities ranging between 2.06 ± 1.24 and 8.00 ± 4.60 cottontails/hectare, with an average of 4.72 individuals/hectare.Eastern cottontails are characterized by high survival and high densities, in their invaded range in Italy. Although densities are comparable to those reported in North America, our analysis focused on adult cottontails only and overall densities are certainly higher. Moreover, our estimates, obtained through a capture-recapture approach, were higher than those reported in previous studies from Italy that adopted nocturnal spotlight censuses. Spotlight transects are likely to underestimate cottontail densities, due to nocturnal habitat selection of cottontails, which might decrease their detectability.

scholarly journals First estimates of survival and densities of invasive alien Eastern cottontail (Sylvilagus floridanus) in Italy: a Bayesian robust design approach

2020 ◽  
Author(s):  
Jacopo Cerri ◽  
Laura Gola ◽  
Aurelio Perrone ◽  
Sandro Bertolino
Keyword(s):  
North America ◽  
Robust Design ◽  
Native Species ◽  
Survival Rates ◽  
High Survival ◽  
Sylvilagus Floridanus ◽  
Capture Recapture ◽  
Males And Females ◽  
Eastern Cottontail ◽  
Selection Of

The Eastern cottontail (Sylvilagus floridanus) has become invasive in Central and Northern Italy, where it affects prey-predator dynamics between native species. Although many different studies explored survival rates and the density of cottontails in North America, no information is available for its invasive range. Between December 2003 and October 2005, a capture-recapture scheme for Eastern cottontails was enforced on the Orba River, Italy. We fitted a Bayesian version of the Pollock’s Closed Robust Design to estimate the survival of adult male and female cottontails (n=258) and their density in the study area. Adult cottontails showed minor seasonal differences in survival, with no clear differences between males and females. Densities varied seasonally, with females having higher densities (min = 80 individuals/km2; max = 553 individuals/km2) than males (min = 56 individuals/km2; max = 337 individuals/km2).Eastern cottontails are characterized by high survival and high densities, at least when adults, in their invaded range in Italy. Although densities are comparable to those reported in North America, our analysis focused on adult cottontails only and overall densities are certainly higher. Moreover, our estimates, obtained through a capture-recapture approach, were higher than those reported in previous studies from Italy based on nocturnal spotlight censuses. Spotlight transects are likely to underestimate cottontail densities, due to nocturnal habitat selection of cottontails, which might decrease their detectability.

scholarly journals Cognitive decline in patients with prostate cancer: study protocol of a prospective cohort, NEON-PC

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043844
Author(s):  
Natalia Araujo ◽  
Samantha Morais ◽  
Ana Rute Costa ◽  
Raquel Braga ◽  
Ana Filipa Carneiro ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cognitive Decline ◽  
Cognitive Performance ◽  
Androgen Deprivation Therapy ◽  
Survival Rates ◽  
Cardiovascular Complications ◽  
Androgen Deprivation ◽  
High Survival ◽  
The Impact

IntroductionProstate cancer is the most prevalent oncological disease among men in industrialised countries. Despite the high survival rates, treatments are often associated with adverse effects, including metabolic and cardiovascular complications, sexual dysfunction and, to a lesser extent, cognitive decline. This study was primarily designed to evaluate the trajectories of cognitive performance in patients with prostate cancer, and to quantify the impact of the disease and its treatments on the occurrence of cognitive decline.MethodsParticipants will be recruited from two main hospitals providing care to approximately half of the patients with prostate cancer in Northern Portugal (Portuguese Institute of Oncology of Porto and São João Hospital Centre), and will comprise a cohort of recently diagnosed patients with prostate cancer proposed for different treatment plans, including: (1) radical prostatectomy; (2) brachytherapy and/or radiotherapy; (3) radiotherapy in combination with androgen deprivation therapy and (4) androgen deprivation therapy (with or without chemotherapy). Recruitment began in February 2018 and is expected to continue until the first semester of 2021. Follow-up evaluations will be conducted at 1, 3, 5, 7 and 10 years. Sociodemographic, behavioural and clinical characteristics, anxiety and depression, health literacy, health status, quality of life, and sleep quality will be assessed. Blood pressure and anthropometrics will be measured, and a fasting blood sample will be collected. Participants’ cognitive performance will be evaluated before treatments and throughout follow-up (Montreal Cognitive Assessment and Cube Test as well as Brain on Track for remote monitoring). All participants suspected of cognitive impairment will undergo neuropsychological tests and clinical observation by a neurologist.Ethics and disseminationThe study was approved by the Ethics Committee of the hospitals involved. All participants will provide written informed consent, and study procedures will be developed to ensure data protection and confidentiality. Results will be disseminated through publication in peer-reviewed journals and presentation in scientific meetings.

scholarly journals Bone marrow niche crosses paths with BMPs: a road to protection and persistence in CML

2019 ◽  
Vol 47 (5) ◽  
pp. 1307-1325 ◽  
Author(s):  
Caroline Busch ◽  
Helen Wheadon
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Bone Morphogenetic Proteins ◽  
Kinase Inhibitor ◽  
Survival Rates ◽  
High Survival ◽  
Bone Marrow Niche ◽  
Matrix Deposition ◽  
Bmp Receptors ◽  
Number Of Patients

Abstract Chronic myeloid leukaemia (CML) is a paradigm of precision medicine, being one of the first cancers to be treated with targeted therapy. This has revolutionised CML therapy and patient outcome, with high survival rates. However, this now means an ever-increasing number of patients are living with the disease on life-long tyrosine kinase inhibitor (TKI) therapy, with most patients anticipated to have near normal life expectancy. Unfortunately, in a significant number of patients, TKIs are not curative. This low-level disease persistence suggests that despite a molecularly targeted therapeutic approach, there are BCR-ABL1-independent mechanisms exploited to sustain the survival of a small cell population of leukaemic stem cells (LSCs). In CML, LSCs display many features akin to haemopoietic stem cells, namely quiescence, self-renewal and the ability to produce mature progeny, this all occurs through intrinsic and extrinsic signals within the specialised microenvironment of the bone marrow (BM) niche. One important avenue of investigation in CML is how the disease highjacks the BM, thereby remodelling this microenvironment to create a niche, which enables LSC persistence and resistance to TKI treatment. In this review, we explore how changes in growth factor levels, in particular, the bone morphogenetic proteins (BMPs) and pro-inflammatory cytokines, impact on cell behaviour, extracellular matrix deposition and bone remodelling in CML. We also discuss the challenges in targeting LSCs and the potential of dual targeting using combination therapies against BMP receptors and BCR-ABL1.

scholarly journals Survival Rate of 1008 Short Dental Implants with 21 Months of Average Follow-Up: A Retrospective Study

2020 ◽  
Vol 9 (12) ◽  
pp. 3943
Author(s):  
João Caramês ◽  
Ana Catarina Pinto ◽  
Gonçalo Caramês ◽  
Helena Francisco ◽  
Joana Fialho ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Survival Rate ◽  
Dental Implants ◽  
Cox Regression ◽  
Survival Rates ◽  
High Survival ◽  
Implant Survival ◽  
Posterior Maxilla ◽  
Clinical Records

This retrospective study evaluated the survival rate of short, sandblasted acid-etched surfaced implants with 6 and 8 mm lengths with at least 120 days of follow-up. Data concerning patient, implant and surgery characteristics were retrieved from clinical records. Sandblasted and acid-etched (SLA)-surfaced tissue-level 6 mm (TL6) or 8 mm (TL8) implants or bone-level tapered 8 mm (BLT8) implants were used. Absolute and relative frequency distributions were calculated for qualitative variables and mean values and standard deviations for quantitative variables. A Cox regression model was performed to verify whether type, length and/or width influence the implant survival. The cumulative implant survival rate was assessed by time-to-event analyses (Kaplan–Meier estimator). In all, 513 patients with a mean age of 58.00 ± 12.44 years received 1008 dental implants with a mean follow-up of 21.57 ± 10.77 months. Most implants (78.17%) presented a 4.1 mm diameter, and the most frequent indication was a partially edentulous arch (44.15%). The most frequent locations were the posterior mandible (53.97%) and the posterior maxilla (31.55%). No significant differences were found in survival rates between groups of type, length and width of implant with the cumulative rate being 97.7% ± 0.5%. Within the limitations of this study, the evaluated short implants are a predictable option with high survival rates during the follow-up without statistical differences between the appraised types, lengths and widths.

Overstory treatment and planting season affect survival of replacement tree species in emerald ash borer threatened Fraxinus nigra forests in Minnesota, USA

2015 ◽  
Vol 45 (12) ◽  
pp. 1728-1738 ◽  
Author(s):  
Christopher E. Looney ◽  
Anthony W. D’Amato ◽  
Brian J. Palik ◽  
Robert A. Slesak
Keyword(s):  
Tree Species ◽  
Group Selection ◽  
Survival Rates ◽  
Emerald Ash Borer ◽  
Species Selection ◽  
Ecosystem Functions ◽  
Control Group ◽  
High Survival ◽  
Fraxinus Nigra ◽  
Black Ash

Fraxinus nigra Marsh. (black ash) wetland forests in northern Minnesota, USA, are threatened by the invasive insect, emerald ash borer (Agrilus planipennis Fairmaire (EAB)). A potential management option is promoting regeneration of tree species that are not EAB hosts to maintain ecosystem functions. Using an operational-scale field experiment, we examined the survival of 12 alternative tree species in response to different canopy treatments. We planted the seedlings in 1.6 ha plots assigned to four replicated canopy treatments: untreated control, group selection (0.04 ha gaps, 20% of stand), black ash girdling to emulate EAB-induced mortality, and clearcut. Fall and spring plantings were used to compare the effects of spring ponding. Control (32.9%), group selection (34.5%), and girdling (33.3%) treatments had comparable overall seedling survival. Survival in the clear-cut treatments was significantly lower (22%). Species selection, overstory treatment, and season of planting together resulted in survival rates ranging from 0.08% to 94.1%. Conifer species had low overall rates of survival (10.7%), whereas some species with native ranges not presently overlapping with northern F. nigra forests, e.g., Quercus bicolor Willd. (75.5%), had high survival rates. If growth is light-limited, group selection may be effective in promoting recruitment and supporting a larger variety of species.

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