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.

Propagation of Alnus maritima [Marsh.] Nutt. (Seaside Alder)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 479b-479
Author(s):  
James A. Schrader ◽  
William R. Graves
Keyword(s):  
Delmarva Peninsula ◽  
Small Tree ◽  
South Central ◽  
Disjunct Populations ◽  
Rooting Of Cuttings ◽  
Sexual Propagation ◽  
Managed Landscapes ◽  
Time Of Collection ◽  
Over Time ◽  
Seaside Alder

We are interested in the potential of seaside alder as a shrub or small tree for managed landscapes. This species has received little attention from horticulturists and occurs naturally only in small, disjunct populations in Maryland and southern Delaware (Delmarva Peninsula), northwestern Georgia, and south-central Oklahoma. Our objective is to optimize asexual (softwood cuttings and tissue culture) and sexual propagation of seaside alder while testing for differences in propagation success among populations. Terminal softwood cuttings collected 11 June 1997 (Delmarva) and 25 Aug. 1997 (Oklahoma) were treated with IBA at various concentrations and provided intermittent mist in a greenhouse for 10 weeks. Up to 44% rooting was achieved by using 1 g IBA/kg on cuttings from Delmarva; replication over time will be used to determine whether poorer rooting of cuttings from Oklahoma (maximum of 17% with 8 g IBA/kg) was due to genotypic effects or the time of collection. Strobili were collected during late 1997 from multiple plants in the three populations. Unstratified seed from Oklahoma showed from 40% to 76% germination after 21 days depending on the tree of origin. The only previous data of germination of unstratified seeds was a report of 5% to 20% for seeds from Delmarva, so provenance as well as stratification effects on germination are being evaluated.

scholarly journals Overfishing and habitat loss drive range contraction of iconic marine fishes to near extinction

2021 ◽  
Vol 7 (7) ◽  
pp. eabb6026
Author(s):  
Helen F. Yan ◽  
Peter M. Kyne ◽  
Rima W. Jabado ◽  
Ruth H. Leeney ◽  
Lindsay N.K. Davidson ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Coastal Waters ◽  
Marine Fishes ◽  
Similar Species ◽  
Range Contraction ◽  
Historical Distribution ◽  
Local Extinctions ◽  
Near Extinction ◽  
Over Time

Extinctions on land are often inferred from sparse sightings over time, but this technique is ill-suited for wide-ranging species. We develop a space-for-time approach to track the spatial contraction and drivers of decline of sawfishes. These iconic and endangered shark-like rays were once found in warm, coastal waters of 90 nations and are now presumed extinct in more than half (n = 46). Using dynamic geography theory, we predict that sawfishes are gone from at least nine additional nations. Overfishing and habitat loss have reduced spatial occupancy, leading to local extinctions in 55 of the 90 nations, which equates to 58.7% of their historical distribution. Retention bans and habitat protections are urgently necessary to secure a future for sawfishes and similar species.

Late Pleistocene chronology and paleoclimate of Vancouver Island determined from cave deposits

1981 ◽  
Vol 18 (11) ◽  
pp. 1643-1652 ◽  
Author(s):  
M. Gascoyne ◽  
D. C. Ford ◽  
H. P. Schwarcz
Keyword(s):  
Late Pleistocene ◽  
Growth Period ◽  
Vancouver Island ◽  
Isotopic Equilibrium ◽  
South Central ◽  
Cave Deposits ◽  
Short Period ◽  
Thermal Buffering

Speleothems from four caves in south-central Vancouver Island have been analysed by the 230Th/234U method. Only speleothems from one cave, Cascade Cave, near Port Alberni, contained sufficient uranium for them to be dated. Twenty-seven ages determined for seven speleothems were found to cluster in two periods: 67–28 ka, corresponding to the Olympia interstadial, and <23–10 ka (or <15 ka if corrected for detrital thorium contamination), corresponding to the Fraser (late Wisconsin) deglaciation and Holocene periods. Two speleothems were found to be deposited in isotopic equilibrium with their seepage waters. Profiles of variations in δ18O of the calcite (δ18Oc) of each of the two deposits show a decrease of 1.3‰ over the growth period, 64–28 ka. At all times, δ18Oc was less than δ18O of modern calcite in the cave. Using modern cave temperature and the variation of δ18O of seawater over the dated period, the profiles of δ18Oc are interpreted in terms of a paleotemperature record for the Olympia interstadial in Vancouver Island. The results show a gradual cooling from 4 °C at 64 ka, to 0 °C between 35 and 28 ka. These results are consistent with conditions necessary for speleothem growth and with published work on surficial Wisconsin deposits in the area. No distinct, short-period warming or cooling events are seen in the record, probably due to thermal buffering by the adjacent ocean.

scholarly journals Screening and management of hypertension in a General Practice Outpatient Department of a tertiary level teaching hospital in eastern region of Nepal

2017 ◽  
Vol 13 (1) ◽  
pp. 58-67
Author(s):  
Ashok Kumar Yadav ◽  
OD Lewis ◽  
SK Sharma ◽  
IP Mahato ◽  
R Bhandari ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Life Style ◽  
Blood Pressure Level ◽  
Outpatient Department ◽  
Systemic Hypertension ◽  
Common Disease ◽  
Eastern Region ◽  
Lifestyle Education ◽  
Over Time

Background: Hypertension is a common disease affecting about 20% of the adult population, both in developed and developing world (WHO 2002). It is one of the serious public health problems. Timely detection, compliance with lifestyle modification and use of drugs are important for effective management of this condition. Objective: To find out the prevalence of systemic hypertension in the general outpatient department and to study the effect of drugs and lifestyle education on the blood pressure over time. Methods: This was an interventional series of cases involving diagnosis and management of patients with BP higher than 140/90 or with known hypertension. All the subjects included were given life style education to see the effect of change of life style on blood pressure over time. Results: A total of 258 subjects were screened and 145 (56%) were diagnosed as hypertensive. Of the total, 75 (29%) had a blood pressure level in pre- hypertensive range. Whereas, 42 (16.3%) had hypertension of stage 1, and 28 (11%) had hypertension of stage 2. Forty- nine patients came for first follow up, 40 patients for second and 10 patients for the third follow up. Blood pressure started to decrease with second follow up. Conclusion: This study demonstrated that the prevalence of hypertension is 56% in the general outpatient department. The lifestyle education can have positive impact on blood pressure control.Health Renaissance 2015;13 (1): 58-67

scholarly journals Soil Development as a Function of Time in the Rouge River Basin, South-Central Ontario

2007 ◽  
Vol 40 (2) ◽  
pp. 207-216 ◽  
Author(s):  
William C. Mahaney ◽  
Kalmia Sanmugadas
Keyword(s):  
River Basin ◽  
Soil Formation ◽  
Exchange Capacity ◽  
Early Holocene ◽  
Soil Thickness ◽  
South Central ◽  
Rouge River ◽  
Extractable Iron ◽  
Over Time ◽  
Changes In Soil Properties

ABSTRACT Three soils of postglacial age, representing a chronosequence in the Rouge River Basin of south-central Ontario, were studied to determine variations in morphological, physical, chemical, and mineralogical properties. These soils, forming in alluvium of mixed mineralogy represent the Late HoIocene (Entisol), Middle Holocene (lnceptisol),and Early Holocene (lnceptisol) surfaces. Horizon differentiation and soil thickness increase with greater age, while pH drops slightly in the sola of the older profiles. Cation exchange capacity (CEC) and organic matter in the surface horizons increases slightly with age, while, for the most part, CaCO3 and Ca/ Mg ratio decrease. Significant changes occur over time, especially with an increase of dithionite-extractable iron with age (from ~ 0.20 in the Late Holocene soil to ~ 0.70 in the Middle to Early Holocene profiles). Illite and illite-smectite tend to decrease with age, being replaced by small amounts of chlorite and vermiculite. In spite of some variability in parent materials due to stratification and preweathering, and minor changes in species composition, the changes in soil properties are attributed to processes of soil formation acting over time.

scholarly journals Recent responses to climate change reveal the drivers of species extinction and survival

2020 ◽  
Vol 117 (8) ◽  
pp. 4211-4217 ◽  
Author(s):  
Cristian Román-Palacios ◽  
John J. Wiens
Keyword(s):  
Climate Change ◽  
Animal Species ◽  
Biodiversity Loss ◽  
Climatic Changes ◽  
Important Work ◽  
Species Extinction ◽  
Major Threat ◽  
Niche Shifts ◽  
Local Extinctions ◽  
Over Time

Climate change may be a major threat to biodiversity in the next 100 years. Although there has been important work on mechanisms of decline in some species, it generally remains unclear which changes in climate actually cause extinctions, and how many species will likely be lost. Here, we identify the specific changes in climate that are associated with the widespread local extinctions that have already occurred. We then use this information to predict the extent of future biodiversity loss and to identify which processes may forestall extinction. We used data from surveys of 538 plant and animal species over time, 44% of which have already had local extinctions at one or more sites. We found that locations with local extinctions had larger and faster changes in hottest yearly temperatures than those without. Surprisingly, sites with local extinctions had significantly smaller changes in mean annual temperatures, despite the widespread use of mean annual temperatures as proxies for overall climate change. Based on their past rates of dispersal, we estimate that 57–70% of these 538 species will not disperse quickly enough to avoid extinction. However, we show that niche shifts appear to be far more important for avoiding extinction than dispersal, although most studies focus only on dispersal. Specifically, considering both dispersal and niche shifts, we project that only 16–30% of these 538 species may go extinct by 2070. Overall, our results help identify the specific climatic changes that cause extinction and the processes that may help species to survive.

scholarly journals Cuando la mano de obra se subleva: estrategias terratenientes durante la reforma agraria chilena (1964-1973)

2018 ◽  
pp. 201-230
Author(s):  
Mathias Órdenes ◽  
José Díaz-Diego ◽  
◽  
Keyword(s):  
Agrarian Reform ◽  
Central Chile ◽  
South Central ◽  
Rural World ◽  
Peasant Movement ◽  
Key Aspects ◽  
Over Time

The object of this article is to describe and analyze the strategies landowners used against mobilized workers in south-central Chile during the agrarian reform. Key aspects analyzed in the development of landowner strategies include the traditional composition of the rural world, the changes occurring in the socio-political panorama over time, as well as workers’ unions and landowner organizations. Along with the potential for violence, unusual actions included patron organization unity, a propositional discourse opposing agrarian reform, a search for agreements with the peasant movement, and the establishment of an alliance with higher-level legal and tenant resources. A review of bibliographic, documentary and archival sources offers greater understanding of the reformist period. It has traditionally been conceptualized through a historiographic narrative of interclass struggles and political and labor confrontation, but here incorporates variables that include negotiation, coalitions and modernization.

How do marine closures affect the analysis of catch and effort data?

2015 ◽  
Vol 72 (8) ◽  
pp. 1177-1190 ◽  
Author(s):  
Kotaro Ono ◽  
André E. Punt ◽  
Ray Hilborn
Keyword(s):  
Time Series ◽  
Data Collection ◽  
Population Status ◽  
Catch Per Unit Effort ◽  
Ancillary Data ◽  
Closed Area ◽  
Imputation Approach ◽  
Index Of Abundance ◽  
Standardization Methods ◽  
Over Time

Fishery managers increasingly use marine closures as a tool to conserve ecosystems, biodiversity, and fish abundance. Despite the suggested benefits of closed areas, the limited or no data collection within them leads to difficulties assessing the population status. We investigated how spatial closures impacted the reliability of indices of abundance obtained from standardization methods applied to catch per unit effort data. The presence of closed areas generally introduced a bias in the derived index of abundance, and the magnitude of bias increased as the portion of the population in closed areas increased. In general, restricting the data to the areas that have been continuously fished over time performed best when spatial closures protected a small to medium portion of the population. However, as the portion of the population that was protected increased, the time series bias associated with this approach increased, and the use of an imputation approach was needed for adequate performance. Similarly, the collection of ancillary data in the closed area reduced bias in the estimate of final year depletion when area closures protected a large portion of the population.

scholarly journals Variation over time in the prevalences of three viruses of the grapevine leafroll complex in a commercial vineyard in south-central Chile

2013 ◽  
Vol 40 (1) ◽  
pp. 139-147
Author(s):  
María Valentina Mujica ◽  
Roxana Mora ◽  
Marlene Rosales ◽  
Claudio Sandoval
Keyword(s):  
Central Chile ◽  
South Central ◽  
Commercial Vineyard ◽  
Over Time

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.

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