Reproduction and persistence of Vancouver Island marmots (Marmota vancouverensis) in natural and logged habitats

1996 ◽  
Vol 74 (4) ◽  
pp. 678-687 ◽  
Author(s):  
Andrew A. Bryant
Keyword(s):  
Adult Female ◽  
Vancouver Island ◽  
Reproductive Value ◽  
Natural Habitats ◽  
Demographic Trends ◽  
Female Age ◽  
Subalpine Meadows ◽  
Reproductive Rates

I tagged and monitored Vancouver Island marmots (Marmota vancouverensis) to investigate demographic trends among colonies inhabiting natural subalpine meadows and recently logged habitats. Marmota vancouverensis exhibits low reproductive rates, with litter sizes of 2–5 ([Formula: see text], SD = 0.83, n = 36). Females are capable of breeding at age 3, but most animals did not breed until age 4 ([Formula: see text] years, SD = 0.82 years, n = 13), and displayed a nonreproductive interval of at least 1 year between litters ([Formula: see text] years, SD = 0.76 years, n = 6). Persistence of marmots was higher at natural sites than in logged areas (65 versus 48%). Maximum female age was 9 years in natural habitats and 5 years in clearcuts. No adult female inhabiting a clearcut (n = 14) produced more than a single litter, while 5 of 14 females in natural habitats produced 11 litters. The net reproductive value of colonies in clearcut habitats was less than half that of natural colonies (0.25 versus 0.72). Recently logged habitats may act as a demographic "sink" by consuming more dispersers than they produce, and therefore impede the recolonization of distant natural habitats.

Distribution and abundance of Vancouver Island marmots (Marmota vancouverensis)

1996 ◽  
Vol 74 (4) ◽  
pp. 667-677 ◽  
Author(s):  
Andrew A. Bryant ◽  
Doug W. Janz
Keyword(s):  
Life Style ◽  
Vancouver Island ◽  
Population Fluctuations ◽  
Population Status ◽  
Patchy Distribution ◽  
Subalpine Meadows ◽  
South Central ◽  
Historic Records ◽  
Local Extinctions ◽  
Over Time

We analysed historic records and annual counts to assess the population status of Vancouver Island marmots (Marmota vancouverensis). Since 1972, marmots have been found at 47 sites on 15 mountains. All but 2 colonies were located within 5 adjacent watersheds on south-central Vancouver Island. Counts underestimated actual marmot abundance. For most site–year combinations, observers probably counted 66–78% of adults and 75–89% of juveniles. Reproductive colonies typically contained fewer than 5 adults ([Formula: see text], SE = 0.61, n = 34). Most animals were found at elevations above 1000 m (81%), on south- to west-facing slopes (74%). After 1981, marmots colonized 11 habitats created by logging of forests above 700 m. Numbers of adults were above average (134–147%) during the early 1980s and have been near or below average since 1990 (58–99%). The current (1995) population contains 100–200 animals, including 50–100 animals in logged habitats. Marmota vancouverensis is rare primarily because of the small size and patchy distribution of natural subalpine meadows on Vancouver Island. The species is apparently adapted to a metapopulation life-style, in which a network of small colonies exhibit population fluctuations, local extinctions and recolonizations over time.

scholarly journals Germination and sporophytic development of Regnellidium diphyllum Lindman (Marsileaceae) in the presence of hexavalent chromium

2010 ◽  
Vol 70 (4 suppl) ◽  
pp. 1149-1153 ◽  
Author(s):  
MA. Kieling-Rubio ◽  
A. Droste ◽  
PG Windisch
Keyword(s):  
Water Pollution ◽  
Hexavalent Chromium ◽  
Primary Root ◽  
Growth Chamber ◽  
Aquatic Environments ◽  
Natural Occurrence ◽  
Natural Habitats ◽  
Standard Solution ◽  
Reproductive Rates ◽  
Sporophytic Development

Regnellidium diphyllum Lindman is a heterosporous fern, growing in aquatic environments and surrounding wetlands, which is assumed to be threatened by increasing water pollution and disappearance of its natural habitats. Among contaminants, hexavalent chromium - Cr(VI) - is known to be present in effluents from some leather tanning factories. Megaspore germination tests were performed using Meyer's solution, at concentrations 0 (control), 0.1, 0.5, 1, 5, 10, 15, 20, 30, 50, and 80 mg.L-1, from a standard solution of Titrisol® 1000 mg.L-1. The primary development of apomictic sporophytes was studied using solutions containing 0.025 to 4.8 mg.L-1 of Cr(VI). The experiments were conducted in a growth chamber at 24 ± 1 ºC and for a 12-hour photoperiod under fluorescent lights, providing a nominal irradiance of 77 µmol.m-2/s. Significant differences in megaspore germination, with subsequent sporophytic development, were verified from 0.5 mg.L-1 Cr(VI) concentration onwards. Growth of primary root and primary and secondary leaves was significantly reduced at 3.2 mg.L-1 Cr(VI) concentration or higher. Considering the pollution from Cr(VI) in some areas of R. diphyllum natural occurrence, these data indicate that low reproductive rates and disappearance of populations are likely to occur in these situations.

Influence of Age and Time on Reproductive Performance of Female Lesser Scaup

The Auk ◽  
1984 ◽  
Vol 101 (2) ◽  
pp. 255-265 ◽  
Author(s):  
Alan D. Afton
Keyword(s):  
Reproductive Performance ◽  
Theoretical Models ◽  
Reproductive Value ◽  
Female Age ◽  
Aythya Affinis ◽  
Lesser Scaup ◽  
Variable Environments ◽  
Water Conditions ◽  
Age Variation ◽  
The Individual

Abstract I examined the influence of age and time on female reproductive performance in a marked population of Lesser Scaup (Aythya affinis) breeding in southwestern Manitoba from 1977 to 1980. Arrival date and length of prelaying period varied among years but were not related to female age. Rate of nonbreeding and nest-initiation date varied among years and by female age. Age variation in nonbreeding was due to the failure of yearlings and a few 2-yr-olds to breed. Yearlings began laying an average of 5-8 days later than older females. Clutch size increased with female age but showed no significant annual variation despite extreme changes in water conditions. Reproductive performance generally increased with female age and with improving water conditions. These results were consistent with theoretical models that predict that reproductive effort (RE) increases with age or with declining residual reproductive value. My data support Williams' (1966) prediction that organisms adapted to living in variable environments adjust their RE in relation to probability of success. Female Lesser Scaup exhibited a temporally dynamic reproductive strategy, and natural selection seemingly has favored "yes-if" genes (Williams 1966) that effect breeding only when conditions are favorable for the individual.

Reproductive rates of wild and captive Vancouver Island marmots (Marmota vancouverensis)

2005 ◽  
Vol 83 (5) ◽  
pp. 664-673 ◽  
Author(s):  
Andrew A Bryant
Keyword(s):  
Reproductive Performance ◽  
Vancouver Island ◽  
Social Constraints ◽  
Wild Populations ◽  
Wild Female ◽  
In Captivity ◽  
In The Wild ◽  
Reproductive Rates ◽  
Using Data ◽  
Old Females

I evaluated reproductive rates of the critically endangered Vancouver Island marmot (Marmota vancouverensis Swarth, 1911) using data from captive and wild populations over the 1980–2004 period. Results were similar to those reported for other alpine-dwelling marmots, including the closely related Marmota caligata (Eschscholtz, 1829) and Marmota olympus (Merriam, 1898). Most females in captivity first bred at age 3 or 4 (Tbreed = 4.3 years, SD = 1.15, n = 9), an age not significantly different from that observed in the wild (Tbreed = 3.6 years, SD = 1.2, n = 16). Numbers of pups weaned per litter were similar in captivity (Npups = 3.0, SD = 1.4, n = 25) and in the wild (Npups = 3.4, SD = 1.1, n = 58). Females were capable of weaning pups in consecutive years (46.4%, n = 13) but often skipped 1 year (39.3%, n = 11) or 2 years (14.3%, n = 4) between litters. Two-year-old females weaned pups infrequently (Pbreed = 0.09, n = 43) and older females were far more likely to breed (Pbreed = 0.40, n = 200); in neither case were significant captive-wild differences found. The oldest breeding female was 10 years old, but sample sizes for marmots older than 8 years were small and maximum breeding age may be underestimated. Between-litter intervals in captivity (Tbetween = 1.4 years, SD = 0.7, n = 11) were significantly shorter than in the wild (Tbetween = 1.9 years, SD = 0.7, n = 17). Sex ratios of weaned pups did not differ from 1:1 in the wild (female/male = 1.04) but were significantly skewed towards males in captivity (female/male = 0.56). I conclude that reproductive performance in Vancouver Island marmots is limited both by body condition and social constraints.

scholarly journals Nest Depredation, Brood Parasitism, and Reproductive Variation in Island Populations of Song Sparrows (Melospiza Melodia)

The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 784-794 ◽  
Author(s):  
Scott Wilson ◽  
Peter Arcese
Keyword(s):  
Brood Parasitism ◽  
Regional Scale ◽  
Vancouver Island ◽  
Reproductive Rate ◽  
Egg Laying ◽  
Melospiza Melodia ◽  
Biotic Factors ◽  
Island Populations ◽  
Nest Depredation ◽  
Reproductive Rates

Abstract Theory suggests that the persistence of metapopulations will be influenced by the degree of synchrony in the dynamics of their component populations. Various studies have shown that climate can promote synchrony in the size of adjacent populations linked by dispersal, but fewer studies have examined the effects of climate on underlying demographic rates. We studied annual variation in the timing of breeding and reproductive rates in Song Sparrow (Melospiza melodia) on islands linked by dispersal to determine whether biotic factors acting at local scales or climatic factors acting at a regional scale were more influential of variation in demography. The onset of egg laying varied markedly among years but was roughly synchronous across islands within years. Despite this synchrony, island populations varied markedly in reproductive rate, mainly from spatial variation in nest depredation and brood parasitism. In general, populations farther from Vancouver Island and with fewer resident predators experienced less nest depredation and brood parasitism, and higher reproductive rates, than populations closer to Vancouver Island. Our results show that even when climate acts regionally to synchronize reproductive timing in adjacent populations, its effects on reproductive rate may be overridden by biotic factors that vary among populations. Depredación de Nidos, Parasitismo de Cría y Variación Reproductiva en Poblaciones Isleñas de Melospiza melodia

Chronic Refractory Cough: A Case Study

2017 ◽  
Vol 2 (3) ◽  
pp. 57-62
Author(s):  
Anna Maria Siciliano
Keyword(s):  
Quality Of Life ◽  
Adult Female ◽  
Chronic Cough ◽  
Treatment Regime ◽  
Speech Language Pathology ◽  
Old Adult ◽  
Language Pathology

This paper presents a successful behavioral case study in treatment of chronic refractory cough in a 60-year-old adult female. The efficacy for speech-language pathology treating chronic cough is discussed along with description of treatment regime. Discussion focuses on therapy approaches used and the patient's report of changes in quality of life and frequency, duration, and severity reduction of her cough after treatment.

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