scholarly journals Have Lesser Scaup, Aythya affinis, Reproductive Rates Declined in Parkland Manitoba?

2003 ◽  
Vol 117 (4) ◽  
pp. 582 ◽  
Author(s):  
David N. Koons ◽  
Jay J. Rotella
Keyword(s):  
Local Population ◽  
Population Decline ◽  
Proximate Cause ◽  
Aythya Affinis ◽  
The Past ◽  
Duckling Survival ◽  
Demographic Rates ◽  
Lesser Scaup ◽  
Reproductive Rates

Long-term surveys indicate that the scaup populations have declined over the past 20 years, and that this is probably the result of decreases in Lesser Scaup (Aythya affinis) rather than Greater Scaup (Aythya marila) numbers. To identify factors possibly related to the decline, we estimated demographic parameters for a local population of Lesser Scaup at Erickson, Manitoba, that was well studied before declines occurred and compared these estimates to historic rates. On average, nests were initiated later than in the past, and recent estimates of nesting success and duckling survival were lower than historical estimates. Breeding-season survival of adult females was estimated as 72.6%, with most (83%) mortality occurring during nesting. Current estimates of demographic rates at Erickson are too low to maintain a stable local population, and suppressed reproductive rates might be the proximate cause of the local population decline.

scholarly journals Reproductive Rates in Lesser Scaup (Aythya affinis) in Southwestern Manitoba: Another Look at the Data

2016 ◽  
Vol 130 (2) ◽  
pp. 110 ◽  
Author(s):  
Gord Hammell
Keyword(s):  
Reproductive Success ◽  
Population Decline ◽  
Food Resources ◽  
Egg Laying ◽  
Aythya Affinis ◽  
The Past ◽  
Age Class ◽  
Lesser Scaup ◽  
Continental Population ◽  
Reproductive Rates

Surveys indicate that Lesser Scaup (Aythya affinis) populations declined during the early 1980s and have since remained below conservation goals. Reasons suggested for the decline include chemical contamination, climate change, and reduced food resources. According to the latter theory, reproductive success of Lesser Scaup has declined because females now arrive on the breeding grounds with fewer nutrient reserves than in the past and this diminished body condition is the result of reduced food resources available at wintering and/or migration areas. To determine whether reproductive success has declined over time, I examined selected Lesser Scaup reproductive rates from 2008 to 2014 in southwestern Manitoba and compared them with those recorded before the continental population decline. Estimated productivity (age class IIa broods/pair), hatching date, Ia and IIa brood size, duckling survival rate (first sighting to age class IIa), and proportion of age class IIa broods with females in attendance were unchanged from values recorded in 1970–1972. Thus, if females are arriving on southern breeding areas with reduced body reserves, they may be recovering these losses before nesting, enabling them to attain reproductive rates similar to those in the past. In addition, these results are consistent with the hypothesis that reduced food resources at non-breeding areas could affect recruitment of southern prairie-parkland breeders to a lesser extent than northern breeders because of the longer time between arrival and egg-laying in the south.

scholarly journals Timing and severity of immunizing diseases in rabbits is controlled by seasonal matching of host and pathogen dynamics

2015 ◽  
Vol 12 (103) ◽  
pp. 20141184 ◽  
Author(s):  
Konstans Wells ◽  
Barry W. Brook ◽  
Robert C. Lacy ◽  
Greg J. Mutze ◽  
David E. Peacock ◽  
...  
Keyword(s):  
Local Population ◽  
Disease Outbreaks ◽  
Maternal Antibodies ◽  
Timing Of Reproduction ◽  
Demographic Rates ◽  
Pathogen Dynamics ◽  
Rabbit Haemorrhagic Disease ◽  
Seasonal Epidemics ◽  
Haemorrhagic Disease

Infectious diseases can exert a strong influence on the dynamics of host populations, but it remains unclear why such disease-mediated control only occurs under particular environmental conditions. We used 16 years of detailed field data on invasive European rabbits ( Oryctolagus cuniculus ) in Australia, linked to individual-based stochastic models and Bayesian approximations, to test whether (i) mortality associated with rabbit haemorrhagic disease (RHD) is driven primarily by seasonal matches/mismatches between demographic rates and epidemiological dynamics and (ii) delayed infection (arising from insusceptibility and maternal antibodies in juveniles) are important factors in determining disease severity and local population persistence of rabbits. We found that both the timing of reproduction and exposure to viruses drove recurrent seasonal epidemics of RHD. Protection conferred by insusceptibility and maternal antibodies controlled seasonal disease outbreaks by delaying infection; this could have also allowed escape from disease. The persistence of local populations was a stochastic outcome of recovery rates from both RHD and myxomatosis. If susceptibility to RHD is delayed, myxomatosis will have a pronounced effect on population extirpation when the two viruses coexist. This has important implications for wildlife management, because it is likely that such seasonal interplay and disease dynamics has a strong effect on long-term population viability for many species.

scholarly journals Nutrient Reserves of Lesser Scaup (Aythya Affinis) During Spring Migration in the Mississippi Flyway: A Test of the Spring Condition Hypothesis

The Auk ◽  
2004 ◽  
Vol 121 (3) ◽  
pp. 917-929 ◽  
Author(s):  
Michael J. Anteau ◽  
Alan D. Afton
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Body Condition ◽  
Female Body ◽  
Population Decline ◽  
Spring Migration ◽  
Aythya Affinis ◽  
Lesser Scaup ◽  
Nutrient Reserves ◽  
Mineral Reserves

AbstractThe continental scaup population (Lesser [Aythya affinis] and Greater [A. marila] combined) has declined markedly since 1978. One hypothesis for the population decline states that reproductive success has decreased because female scaup are arriving on breeding areas in poorer body condition than they did historically (i.e. spring condition hypothesis). We tested one aspect of that hypothesis by comparing body mass and nutrient reserves (lipid, protein, and mineral) of Lesser Scaup at four locations (Louisiana, Illinois, Minnesota, and Manitoba) between the 1980s and 2000s. We found that mean body mass and lipid and mineral reserves of females were 80.0, 52.5, and 3.0 g higher, respectively, in the 2000s than in the 1980s in Louisiana; similarly, body mass and lipid and mineral reserves of males were 108.8, 72.5, and 2.5 g higher, respectively. In Illinois, mean body mass and lipid reserves of females were 88.6 and 56.5 g higher, respectively, in the 2000s than in the 1980s; similarly, body mass and lipid and mineral reserves of males were 80.6, 76.0, and 2.7 g higher, respectively. Mean body mass of females were 58.5 and 58.9 g lower in the 2000s than in the 1980s in Minnesota and Manitoba, respectively; mean body mass of males, similarly, were 40.7 g lower in Minnesota. Mean lipid reserves of females in the 2000s were 28.8 and 27.8 g lower than those in the 1980s in Minnesota and Manitoba, respectively. Mean mineral reserves of females in the 2000s were 3.2 g lower than those in the 1980s in Manitoba. Consequently, females arriving to breed in Manitoba in the 2000s had accumulated lipid reserves for 4.1 fewer eggs and mineral reserves for 0.8 fewer eggs than those arriving to breed there in the 1980s. Accordingly, our results are consistent with the spring condition hypothesis and suggest that female body condition has declined, as reflected by decreases in body mass, lipids, and mineral reserves that could cause reductions in reproductive success and ultimately a population decline.

scholarly journals Dynamiken i smålommens Gavia stellata val av häckningslokaler – övergivande, ny- och återetableringar

Ornis Svecica ◽  
2013 ◽  
Vol 23 (3–4) ◽  
pp. 130-142
Author(s):  
Mats O G Eriksson ◽  
Matti Åhlund
Keyword(s):  
Breeding Success ◽  
Population Decline ◽  
The Other ◽  
Southern Sweden ◽  
Breeding Sites ◽  
The Past ◽  
Breeding Seasons

Red-throated Loons Gavia stellata have disappeared from breeding sites regularly used in the mid-1990s, but it is not clear if this reflects a population decline or movements to other sites. Therefore, we searched for potential breeding sites, including sites with old records, in three regions in southern Sweden, where it was possible to repeat surveys conducted in the past. A pattern of abandonment and return to breeding sites was verified; around 30% of the sites were abandoned over a 10-year period, but the loss was largely compensated by establishment at new sites or return to sites used in the past. But almost one quarter of the sites were used in about 75% of the breeding seasons across a period of more than 30 years. Annual breeding success at these sites did not differ from that at the other, less frequently used sites. However, the most continuously used sites produce a larger total of young than other sites and are therefore important for long-term recruitment. They should be identified and prioritised for protection and management.

The past of Europe's demographic future

1999 ◽  
Vol 7 (4) ◽  
pp. 529-550 ◽  
Author(s):  
Dirk J. Van De Kaa
Keyword(s):  
Fertility Decline ◽  
Population Decline ◽  
Reproductive Potential ◽  
Reproductive Capacity ◽  
The Past ◽  
Average Family Size ◽  
Low Levels ◽  
High Level ◽  
The 19Th Century

The reproductive capacity of our species is far in excess of its needs. If all women used their reproductive potential to the full they would give birth to about 15 children on average. As averages of 6 or 7 were once sufficient to compensate for the high level of mortality, and higher numbers would have led to unacceptably high levels of population growth, that, presumably, is the level of fertility found in traditional European societies and in developing countries before the onset of fertility decline. In European societies, fertility decline began in the 19th century. It was a reaction to the disequilibrium that resulted from the long-term decline in mortality. However, a clear sequence cannot always be established. The assumption that prevailed in the 1950s and 1960s that this demographic transition, as it is customarily called, would lead to a new equilibrium appears not to have been well founded. Average family size has declined to such low levels that the age structure is seriously affected and the replacement of generations is no longer assured. A new disequilibrium has resulted. If this is a temporary phenomenon it is not an important issue. However, if it has to be assumed that future generations will also limit their reproduction to not more than 10% of their potential, the perspective is different. Even with continued high levels of immigration, population decline will then become inevitable. While some argue this will turn out to be beneficial, it is not without disadvantages.

Enabling Community Well-being Self-Monitoring in the Context of Mining: The Naskapi Nation of Kawawachikamach

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Robert Klinck ◽  
Ben Bradshaw ◽  
Ruby Sandy ◽  
Silas Nabinacaboo ◽  
Mannie Mameanskum ◽  
...  
Keyword(s):  
Indigenous Peoples ◽  
Well Being ◽  
Aboriginal Community ◽  
Self Monitoring ◽  
Community Engaged Research ◽  
The Past ◽  
Mineral Development ◽  
Iron Deposits ◽  
Term Monitoring

The Naskapi Nation of Kawawachikamach is an Aboriginal community located in northern Quebec near the Labrador Border. Given the region’s rich iron deposits, the Naskapi Nation has considerable experience with major mineral development, first in the 1950s to the 1980s, and again in the past decade as companies implement plans for further extraction. This has raised concerns regarding a range of environmental and socio-economic impacts that may be caused by renewed development. These concerns have led to an interest among the Naskapi to develop a means to track community well-being over time using indicators of their own design. Exemplifying community-engaged research, this paper describes the beginning development of such a tool in fall 2012—the creation of a baseline of community well-being against which mining-induced change can be identified. Its development owes much to the remarkable and sustained contribution of many key members of the Naskapi Nation. If on-going surveying is completed based on the chosen indicators, the Nation will be better positioned to recognize shifts in its well-being and to communicate these shifts to its partners. In addition, long-term monitoring will allow the Naskapi Nation to contribute to more universal understanding of the impacts of mining for Indigenous peoples.

Courting the Youth Vote in 2008: The Obama Effect

2009 ◽  
Vol 5 ◽  
Author(s):  
Lindsey C Bohl
Keyword(s):  
Presidential Elections ◽  
Voter Registration ◽  
The Internet ◽  
The Past ◽  
Several Variables ◽  
High Turnout ◽  
Short And Long Term ◽  
Use Of The Internet ◽  
Youth Vote

This paper examines a few of the numerous factors that may have led to increased youth turnout in 2008 Election. First, theories of voter behavior and turnout are related to courting the youth vote. Several variables that are perceived to affect youth turnout such as party polarization, perceived candidate difference, voter registration, effective campaigning and mobilization, and use of the Internet, are examined. Over the past 40 years, presidential elections have failed to engage the majority of young citizens (ages 18-29) to the point that they became inclined to participate. This trend began to reverse starting in 2000 Election and the youth turnout reached its peak in 2008. While both short and long-term factors played a significant role in recent elections, high turnout among youth voters in 2008 can be largely attributed to the Obama candidacy and campaign, which mobilized young citizens in unprecedented ways.

Impact of FII’s and FDI’s on Indian Stock Market

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Global Economy ◽  
Short Term ◽  
Earnings Growth ◽  
The Past ◽  
Bull Market ◽  
Indian Stock Market

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.

Lesser Scaup (Aythya affinis)

2014 ◽  
Author(s):  
Michael J. Anteau ◽  
Jean-Michel DeVink ◽  
David N. Koons ◽  
Jane E. Austin ◽  
Christine M. Custer ◽  
...  
Keyword(s):  
Aythya Affinis ◽  
Lesser Scaup

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

2019 ◽  
Vol 20 (3) ◽  
pp. 251-264 ◽  
Author(s):  
Yinlu Feng ◽  
Zifei Yin ◽  
Daniel Zhang ◽  
Arun Srivastava ◽  
Chen Ling
Keyword(s):  
Chinese Medicine ◽  
Cell Therapy ◽  
Future Research ◽  
The Past ◽  
Promising Strategy ◽  
Wide Range ◽  
New Directions ◽  
Gene And Cell Therapy ◽  
Proteins And Peptides

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

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