Seasonal mountain lion predation on a feral horse population

1992 ◽  
Vol 70 (5) ◽  
pp. 929-934 ◽  
Author(s):  
John W. Turner Jr. ◽  
Michael L. Wolfe ◽  
Jay F. Kirkpatrick
Keyword(s):  
Survival Rate ◽  
First Year ◽  
Horse Population ◽  
Feral Horses ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Felis Concolor ◽  
Feral Horse ◽  
Annual Cohort ◽  
Demographic Impact

A population of feral horses (Equus caballus) was studied from 1986 to 1991 to determine the demographic impact of predation by the mountain lion (Felis concolor). The population, inhabiting a 600-km2 area on the central California – Nevada border comprised approximately 162 individuals > 1 year old, with an average of 9 yearlings, 8 two-year-olds, and 144 adults. Numbers of horses varied by only 4–8% and showed no consistent trend. The parturition peak spanned May and June, when 80% of foaling occurred. One-third of the average annual cohort of 33 foals was missing by July and only half of the cohort remained by October. The mean first-year survival rate estimated from the differential incidence of foals and yearlings in successive years was 0.27, which was less than one-third of the foal survival rate reported for other feral horse populations. A minimum of four adult mountain lions used the study area each year between May and October. Of 28 foal carcasses located from May to mid-July, at least 82% were the result of mountain lion kills. No evidence of predation on older horses was observed, but mountain lions preyed on mule deer (Odocoileus hemionus) during winter. We conclude that the growth of this horse population is limited by predation.

scholarly journals Feral Horse Distribution, Habitat Use and Population Dynamics in Theodore Roosevelt National Park

1990 ◽  
Vol 14 ◽  
pp. 123-125
Author(s):  
Clayton Marlow ◽  
Leonard Gagnon ◽  
Elena Hovland ◽  
Lynn Irby
Keyword(s):  
National Park ◽  
Home Range Size ◽  
Home Ranges ◽  
Theodore Roosevelt ◽  
Horse Population ◽  
Feral Horses ◽  
Population Growth Rates ◽  
Feral Horse ◽  
Theodore Roosevelt National Park ◽  
Reproductive Rates

Description of the ecological niche feral horses fill in Theodore Roosevelt National Park requires information on reproductive rates, home range size, individual and band affinity to home ranges, food and shelter requirements and seasonal diets. Therefore, the initial objectives will be to: 1. identify the number, size and location of home ranges for harem and bachelor stallion bands; 2. describe daily and seasonal movements of bands within identified home ranges; 3. describe the vegetation habitat types and landform types used by horses for mating, foaling, foraging, and resting cover; 4. describe seasonal horse diets; and 5. collect data on sex, age and social hierarchy within respective bands to facilitate estimation of horse population growth rates. Ultimately, this information will be used to accomplish the project goal; integrate horse requirements with those of elk, bison and the Park's vegetation communities to determine the large ungulate carrying capacity of Theodore Roosevelt National Park.

Prospects for immunocontraception in feral horse population control: exploring novel targets for an equine fertility vaccine

2016 ◽  
Vol 28 (7) ◽  
pp. 853 ◽  
Author(s):  
Aleona Swegen ◽  
R. John Aitken
Keyword(s):  
Vaccine Development ◽  
Population Control ◽  
Future Research ◽  
Economic Damage ◽  
The Novel ◽  
Horse Population ◽  
Feral Horses ◽  
Feral Horse ◽  
Species Specific ◽  
Free Ranging

Feral horses populate vast land areas and often induce significant ecological and economic damage throughout the landscape. Non-lethal population control methods are considered favourable in light of animal welfare, social and ethical considerations; however, no single effective, safe and species-specific contraceptive agent is currently available for use in free-ranging wild and feral horses. This review explores aspects of equine reproductive physiology that may provide avenues for the development of specific and long-lasting immunocontraceptive vaccines and some of the novel strategies that may be employed to facilitate appropriate antigen discovery in future research. Potential antigen targets pertaining to spermatozoa, the ovary and oocyte, as well as the early conceptus and its associated factors, are reviewed in the context of their suitability for immunocontraceptive vaccine development.

Estimating distribution and abundance of feral horses (Equus caballus) in a coniferous plantation in Australia, using line-transect surveys of dung

2016 ◽  
Vol 43 (7) ◽  
pp. 604 ◽  
Author(s):  
Magdalena A. Zabek ◽  
David M. Berman ◽  
Simon Blomberg ◽  
John Wright
Keyword(s):  
Population Distribution ◽  
Decay Rates ◽  
Line Transect ◽  
Population Abundance ◽  
Horse Population ◽  
Feral Horses ◽  
Feral Horse ◽  
Coniferous Plantation ◽  
The Mean ◽  
Strip Transect

Context Feral horses are a growing problem in Australia, despite implementation of management strategies. The incidence of horse sightings and horse-associated vehicle collisions within the Tuan and Toolara State Forest (TTSF), a coniferous plantation in south-eastern Queensland, has increased in the past decade, indicating an increase in population and the necessity to undertake an accurate appraisal of population abundance. Aim To determine the feasibility of using dung counts, defecation and dung-decay rates to determine the distribution and abundance of feral horse population in a managed coniferous plantation where dense vegetation prohibits the use of visual-based animal detection methods. Methods Population distribution was assessed by dung count incorporated into a vehicle strip-transect survey on 582 km of forest tracks. Population abundance was estimated from dung density, the mean defecation frequency of feral horses, and the mean number of days required for dung to decay. Dung density was obtained from on-ground distance line-transect survey that sampled all representative plantation habitats and consisted of 111 transects totalling 44.3 km. Key results The strip-transect survey clearly showed that although feral horses were dispersed across the plantation, the distribution was uneven, with the central region of the plantation being the most heavily populated. The combination of dung counts, defecation rate (mean ± s.d., 7.97 ± 8.74) over 24 h and dung-decay rate (444 ± 150.7 days) provided an estimation of the density of feral horses in various habitats and indicated that the plantation was occupied by 1321 (95% CI 940–1965) horses, which corresponded to an average density of 1.8 horses km–2. The method clearly identified variations in horse abundance among the various habitats within the surveyed areas. Open habitats, created following harvesting, showed higher occurrence rates, whereas the habitats of mature forest were scantily occupied. Key conclusions Dung counts are a simple, effective and practical technique that can provide information on distribution and abundance of feral horse population in densely forested habitats where visual-based techniques are not applicable. However, unbiased and precise defecation and decay rates must be estimated. Implications The study validated the use of dung counts to provide information on feral horse distribution and abundance in densely forested environments where direct methods of census may be difficult to obtain. The methods are applicable to a range of ecosystems, but defecation and dung-decay rates must be determined separately for each ecosystem.

Identifying individual mountain lions Felis concolor by their tracks: refinement of an innovative technique

1999 ◽  
Vol 88 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Melissa M Grigione ◽  
Prabir Burman ◽  
Vernon C Bleich ◽  
Becky M Pierce
Keyword(s):  
Mountain Lions ◽  
Felis Concolor ◽  
Innovative Technique

Renal transplantation in the first year of life: the treatment of choice for infants with end-stage renal disease.

1992 ◽  
Vol 2 (12) ◽  
pp. S228
Author(s):  
J S Najarian ◽  
P S Almond ◽  
M Mauer ◽  
B Chavers ◽  
T Nevins ◽  
...  
Keyword(s):  
Renal Failure ◽  
Renal Transplantation ◽  
Survival Rate ◽  
Living Donor ◽  
Patient Survival ◽  
First Year ◽  
End Stage Renal Failure ◽  
End Stage ◽  
First Year Of Life ◽  
Patient Survival Rate

The treatment of choice for end-stage renal failure within the first year of life is controversial. Between September 1970 and February 1991, we performed 28 kidney transplants (27 primary, 1 retransplant, 23 living donor, 5 cadaver) in infants less than 1 yr of age (mean, 7 +/- 2 months; range, 6 wk to 12 months). The 1-yr patient survival rate for living donor recipients was 100% versus 20% for cadaver recipients (P = 0.0001). The 1-yr graft survival rate for living donor recipients was 96% versus 20% for cadaver recipients (P = 0.001). The 1-yr patient survival rate for cyclosporin A (CSA) recipients (N = 12) was 100% versus 75% for non-CSA recipients (P = 0.03). The 1-yr graft survival rate for CSA recipients was 92% versus 75% for non-CSA recipients (P = 0.08). There was no difference in the number of rejection episodes or serum creatinine levels in CSA versus non-CSA recipients. Compared with pretransplant values, the mean posttransplant standard deviation scores (SDS) for height (N = 18), weight (N = 22), and head circumference (N = 8) improved: height SDS from -1.9 to -1.5 (not significant); weight SDS from -2.5 to 0.6 (P less than 0.0005); head circumference SDS from -2.0 to -0.7 (P = 0.01). Because no other renal replacement therapy can match these results, we conclude that renal transplantation is the treatment of choice for infants with end-stage renal failure.

scholarly journals Effectiveness of riluzole in the treatment of amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Renato Puccioni Sohler ◽  
Gabriel Pinto Mendonça ◽  
Rodrigo Cesar Carvalho Freitas ◽  
José Roberto Ribas
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Survival Rate ◽  
Motor Neuron ◽  
Placebo Treatment ◽  
First Year ◽  
Advanced Stage ◽  
Mesh Terms ◽  
Student Test ◽  
The Difference ◽  
Lateral Sclerosis

Background: amyotrophic lateral sclerosis (ALS) is a motor neuron degenerative disease with high mortality and few therapies. One of these is riluzole, inspite of uncertainty effectiveness. Objective: the aim of this study was to evaluate the survival rate associated with the use of this medication in the treatment of ALS. Methods: The study was based on a narrative review of the scientific articles that used randomized controled trials with riluzole for ALS. We selected articles published in english during the period of January 1th, 2000 to December 31th, 2020. The MeSH terms “amyotrophic lateral sclerosis” or “motor neuron disease” and “riluzole” or “rilutek” were used in Pubmed and Lilacs databases. Studies that used only patients with advanced stage ALS were excluded. The t-Student test between sample means was applied to determine the significance of the difference between the survival time (years) of the riluzole and placebo treatment, for a 95% confidence level. Results: through the search, four articles were obtained (Table 1). Conclusion: Data analysis showed that riluzole is only effective in the first year. From the second onward, it does not exceed the results of the placebo.

scholarly journals Mountain lion ( Puma concolor ) feeding behavior in the Little Missouri Badlands of North Dakota

2015 ◽  
Vol 97 (2) ◽  
pp. 373-385 ◽  
Author(s):  
David T. Wilckens ◽  
Joshua B. Smith ◽  
Stephanie A. Tucker ◽  
Daniel J. Thompson ◽  
Jonathan A. Jenks
Keyword(s):  
North Dakota ◽  
Puma Concolor ◽  
Feeding Habits ◽  
Total Biomass ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Gps Collars ◽  
The North ◽  
Kill Rate ◽  
Prey Populations

Abstract Recent recolonization of mountain lions ( Puma concolor ) into the Little Missouri Badlands of North Dakota has led to questions regarding the potential impacts of predation on prey populations in the region. From 2012 to 2013, we deployed 9 real-time GPS collars to investigate mountain lion feeding habits. We monitored mountain lions for 1,845 telemetry-days, investigated 506 GPS clusters, and identified 292 feeding events. Deer ( Odocoileus spp.) were the most prevalent item in mountain lion diets (76.9%). We used logistic regression to predict feeding events and size of prey consumed at an additional 535 clusters. Our top model for predicting presence of prey items produced a receiver operating characteristic score of 0.90 and an overall accuracy of 81.4%. Application of our models to all GPS clusters resulted in an estimated ungulate kill rate of 1.09 ungulates/week (95% confidence interval [ CI ] = 0.83–1.36) in summer (15 May‒15 November) and 0.90 ungulates/week (95% CI = 0.69–1.12) in winter (16 November‒14 May). Estimates of total biomass consumed were 5.8kg/day (95% CI = 4.7–6.9) in summer and 7.2kg/day (95% CI = 5.3–9.2) in winter. Overall scavenge rates were 3.7% in summer and 11.9% in winter. Prey composition included higher proportions of nonungulates in summer (female = 21.5%; male = 24.8%) than in winter (female = 4.8%; male = 7.5%). Proportion of juvenile ungulates in mountain lion diets increased during the fawning season (June‒August) following the ungulate birth pulse in June (June–August = 60.7%, 95% CI = 43.0–78.3; September–May = 37.2%, 95% CI = 30.8–43.7), resulting in an ungulate kill rate 1.61 times higher (1.41 ungulates/week, 95% CI = 1.12–1.71) than during the remainder of the year (0.88 ungulates/week, 95% CI = 0.62–1.13). Quantifying these feeding characteristics is essential to assessing the potential impacts of mountain lions on prey populations in the North Dakota Badlands, where deer dominate the available prey base and mountain lions represent the lone apex predator.

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