Population dynamics of hispid cotton rats (Sigmodon hispidus) across a nitrogen-amended landscape

2003 ◽  
Vol 81 (6) ◽  
pp. 994-1003 ◽  
Author(s):  
Jay E Clark ◽  
Eric C Hellgren ◽  
Eric E Jorgensen ◽  
Susan J Tunnell ◽  
David M Engle ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Survival Rates ◽  
Canopy Cover ◽  
Sigmodon Hispidus ◽  
Old Field ◽  
Higher Plant ◽  
Population Growth Rates ◽  
Low Level ◽  
Cotton Rats

We conducted a mark–recapture experiment to examine the population dynamics of hispid cotton rats (Sigmodon hispidus) in response to low-level nitrogen amendments (16.4 kg nitrogen/ha per year) and exclosure fencing in an old-field grassland. The experimental design consisted of sixteen 0.16-ha plots with 4 replicates of each treatment combination. We predicted that densities, reproductive success, movement probabilities, and survival rates of cotton rats would be greater on nitrogen-amended plots because of greater aboveground biomass and canopy cover. Population densities of cotton rats tended to be highest on fenced nitrogen plots, but densities on unfenced nitrogen plots were similar to those on control and fenced plots. We observed no distinct patterns in survival rates, reproductive success, or movement probabilities with regard to nitrogen treatments. However, survival rates and reproductive success tended to be higher for cotton rats on fenced plots than for those on unfenced plots and this was likely attributable to decreased predation on fenced plots. As low-level nitrogen amendments continue to be applied, we predict that survival, reproduction, and population-growth rates of cotton rats on control plots, especially fenced plots with no nitrogen amendment, will eventually exceed those on nitrogen-amended plots as a result of higher plant-species diversity, greater food availability, and better quality cover.

Sensitivity of Wild Cotton Rats ( Sigmodon hispidus ) to the Immunotoxic Effects of Low-Level Arsenic Exposure

1998 ◽  
Vol 34 (3) ◽  
pp. 289-296 ◽  
Author(s):  
M. Savabieasfahani ◽  
R. L. Lochmiller ◽  
D. P. Rafferty ◽  
J. A. Sinclair
Keyword(s):  
Arsenic Exposure ◽  
Sigmodon Hispidus ◽  
Low Level ◽  
Wild Cotton ◽  
Cotton Rats

scholarly journals Effects of Supplemental Food on Population Dynamics of Cotton Rats, Sigmodon Hispidus

Ecology ◽  
1995 ◽  
Vol 76 (3) ◽  
pp. 814-826 ◽  
Author(s):  
Terry J. Doonan ◽  
Norman A. Slade
Keyword(s):  
Population Dynamics ◽  
Sigmodon Hispidus ◽  
Supplemental Food ◽  
Cotton Rats

Population Dynamics of Cotton Rats (Sigmodon hispidus) Inhabiting Abandoned Petroleum Landfarms in Oklahoma, USA

Ecotoxicology ◽  
2005 ◽  
Vol 15 (1) ◽  
pp. 19-30
Author(s):  
James A. Wilson ◽  
Robert L. Lochmiller ◽  
David M. Janz
Keyword(s):  
Population Dynamics ◽  
Sigmodon Hispidus ◽  
Cotton Rats

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.

scholarly journals Resistance of Cotton Rats, Sigmodon hispidus, to Primary Infection by Nippostrongylus brasiliensis

2002 ◽  
Vol 64 (5) ◽  
pp. 423-426 ◽  
Author(s):  
Hendra WIBAWA ◽  
Deni NOVIANA ◽  
Kimiyuki TSUCHIYA ◽  
Fadjar SATRIJA ◽  
Yoichiro HORII
Keyword(s):  
Primary Infection ◽  
Nippostrongylus Brasiliensis ◽  
Sigmodon Hispidus ◽  
Cotton Rats

Cotton rats ( Sigmodon hispidus ) with a high prevalence of hydrocephalus without clinical symptoms

2021 ◽  
Author(s):  
Daisuke Kondoh ◽  
Teppei Nakamura ◽  
Erika Tsuji ◽  
Marina Hosotani ◽  
Osamu Ichii ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Sigmodon Hispidus ◽  
High Prevalence ◽  
Cotton Rats

scholarly journals Lifetime reproductive success in a population of female red kangaroos Macropus rufus in the sheep rangelands of western New South Wales: Environmental effects and population dynamics

2004 ◽  
Vol 26 (1) ◽  
pp. 45 ◽  
Author(s):  
AD Bilton ◽  
DB Croft
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
New South ◽  
New South Wales ◽  
Reproductive Potential ◽  
Lifetime Reproductive Success ◽  
South Wales ◽  
Macropus Rufus ◽  
Initial Starting

Female reproductive success and the recruitment of offspring to the next generation are key components of animal population dynamics. With an annual commercial harvest of between 13 and 22% of the red kangaroo (Macropus rufus) population, it is increasingly important that these processes are understood. We used data on the reproductive success of 33 free-ranging female M. rufus on Fowlers Gap station in far western New South Wales to determine the expected lifetime reproductive success (LRS) of females within an unharvested population. We also designed a model to generate predictions about female LRS incorporating empirical relationships between a mother?s reproductive success and maternal age, environmental conditions and the sex and survivorship of a previous reproductive attempt. Results from observations on female LRS (calculated from annual weaning rates) and those generated by the model predict that female M. rufus on ?Fowlers Gap? wean, on average, 3.7 young in a lifetime (ranges 0 - 11 and 0 - 20, respectively); representing only 41% of their maximum reproductive potential. Manipulation of initial starting conditions allowed the effect of varying environmental conditions on female LRS to be explored. The condition of the environment when females commence breeding does not appear to significantly affect their overall lifetime reproductive output. However, the occurrence of drought does. Females experiencing two droughts in a lifetime did not live as long and weaned fewer offspring and grandoffspring (from their daughters) than those females experiencing only one drought in a lifetime. In addition to the adverse effect of drought on the reproductive success of female M. rufus in this study, we suggest that, given the relatively high and stable population densities of M. rufus on ?Fowlers Gap?, other mechanisms (acting primarily on juvenile survival) must exist which limit population growth.

scholarly journals Fitness of breeders in social Damaraland mole-rats is independent of group size

2021 ◽  
Author(s):  
Jack Thorley ◽  
Hanna Bensch ◽  
Kyle Finn ◽  
Tim Clutton-Brock ◽  
Markus Zöttl
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Survival Rates ◽  
Group Living ◽  
Adult Survival ◽  
High Survival ◽  
Successful Reproduction ◽  
Related Group ◽  
Group Members ◽  
Using Data

Damaraland mole-rats (Fukomys damarensis) are usually viewed as an obligatorily group living eusocial species in which successful reproduction is dependent on reproductive altruism of closely related group members. However, the reproductive ecology of social mole-rats in their natural environment remains poorly understood and it is unclear to what extent successful reproduction is dependent on assistance from other group members. Using data from a 7-year field study of marked individuals, we show that, after dispersal from their natal group, individuals typically settled alone in new burrow systems where they enjoyed high survival rates, and often remained in good body condition for several years before finding a mate. Unlike most other eusocial or singular cooperative breeders, we found that Damaraland mole-rats reproduced successfully in pairs without helpers and experimentally formed pairs had the same reproductive success as larger established groups. Overall there was only a weak increase in reproductive success with increasing group size and no effect of group size on adult survival rates across the population. Juveniles in large groups grew faster early in life but their growth rates declined subsequently so that they eventually plateaued at a lower maximum body mass than juveniles from small groups. Taken together, our data suggest that the fitness benefits of group living to breeders are small and we suggest that extended philopatry in Damaraland mole-rats has evolved because of the high costs and constraints of dispersal rather than because of strong indirect benefits accrued through cooperative behaviour.

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