scholarly journals Historical surveys reveal a long-term decline in muskrat populations

2021 ◽  
Author(s):  
Carrie Sadowski ◽  
Jeff Bowman
Keyword(s):  
Population Decline ◽  
Time Frame ◽  
Current Status ◽  
Population Declines ◽  
Ongoing Research ◽  
Wetland Ecosystems ◽  
Aquatic Mammal ◽  
Integral Role ◽  
Great Lakes Coastal Wetlands ◽  
Point Pelee

The muskrat (Ondatra zibethicus) is an iconic species in Canada, valued for both its fur and its integral role in wetland ecosystems, and widely regarded for its perseverance. However, the resilience of this semi-aquatic mammal seems to be in question now as increasing evidence points to widespread population declines. Recent analyses of harvest data across North America suggest a reduction in their numbers, but this has not been widely corroborated by population surveys. In this study we replicated historic muskrat house count surveys at two large Great Lakes coastal wetlands and present confirmation that declines in muskrat harvest correspond to actual declines in muskrat abundance. At the Point Pelee National Park marsh and the Matchedash Bay-Gray Marsh wetland we found that mean muskrat house counts declined by 93% and 91% respectively between historic surveys 40-50 years ago and contemporary surveys over the past five years. The factors responsible for these dramatic declines remain unclear but there may be a relationship with changes in the habitat quality of these wetlands that have occurred over the same time frame. Not only is the loss of muskrats an issue for the resulting loss of the wetland ecosystem services they provide, but it may be an indication of broader marsh ecosystem degradation. As such, a scarcity of muskrats should be considered a red flag for the state of biodiversity in our wetlands. Continued surveys and ongoing research are needed to shed more light on the current status of muskrat populations and their marsh habitats across their native range. Keywords: Fur harvest; Muskrat; Ondatra; Population decline; Typha; Wetlands

scholarly journals Loss of cultural song diversity and the convergence of songs in a declining Hawaiian forest bird community

2019 ◽  
Vol 6 (8) ◽  
pp. 190719
Author(s):  
Kristina L. Paxton ◽  
Esther Sebastián-González ◽  
Justin M. Hite ◽  
Lisa H. Crampton ◽  
David Kuhn ◽  
...  
Keyword(s):  
Population Decline ◽  
Bird Community ◽  
Time Frame ◽  
Population Declines ◽  
Honest Signal ◽  
Acoustic Characteristics ◽  
Song Complexity ◽  
Hawaiian Honeycreepers ◽  
Vocal Signals ◽  
Declining Species

The effects of population decline on culturally transmitted behaviours in animals have rarely been described, but may have major implications to population viability. Learned vocal signals in birds are of critical importance to behaviours associated with reproduction, intrasexual interactions and group cohesion, and the complexity of vocal signals such as song can serve as an honest signal of an individual's quality as well as the viability of a population. In this study, we examined how rapid population declines recently experienced by Hawaiian honeycreepers on the island of Kaua‘i (USA) may have influenced the diversity, complexity and similarity of learned honeycreeper songs. We analysed the acoustic characteristics of songs recorded during three time periods over a 40-year time frame for three species of declining Kaua‘i honeycreepers. We detected a loss of song complexity and diversity over the 40-year time period that paralleled dramatic population declines. Concurrent with the loss of complexity, we also found that the acoustic characteristics of the three honeycreepers' songs became more similar to one another. To our knowledge, this is the first documentation of convergence of acoustic characteristics among rapidly declining species. The reduction in song complexity and diversity and convergence of songs not only signals a loss of culturally transmitted behaviours in these endemic Hawaiian honeycreepers, but also potential challenges to the recovery of these rapidly declining species. Moreover, the present study highlights that there is a ‘hidden’ cost to declining populations beyond just the loss of individuals that is not often considered, the loss of culturally transmitted social behaviours.

Current Status, Design and Performance Trends for the Regenerative Flow Compressors and Pumps

2002 ◽  
Author(s):  
Mukarrum Raheel ◽  
Abraham Engeda
Keyword(s):  
Performance Improvement ◽  
Current Status ◽  
Ongoing Research ◽  
Performance Trends ◽  
The Family ◽  
Working Principle ◽  
Low Specific Speed ◽  
And Performance ◽  
Number Of Publications ◽  
Regenerative Flow

Regenerative flow compressors and pumps, hereafter called RFC/RFP have found many applications in industry; still they are the most neglected turbomachines in the family of dynamic compressors. The number of publications existing in literature is very small compared to the large number of papers about the centrifugal and axial turbocompressors. This paper gives a detail discussion of fundamentals and working principle of regenerative turbomachines. Regenerative compressors are compared with centrifugal compressors and the importance of regenerative turbomachines in low specific speed range is emphasized. The major findings of available literature on regenerative turbomachine are summarized. The current status, limitations and some of the challenges faced by RFC/RFP are assessed in context of performance improvement. The paper concludes with an overview of ongoing research and future directions to be followed for performance improvement of this neglected class of turbomachines.

Medical device’s regulation in South-East Asian countries: Current status and gap areas

2021 ◽  
pp. 173-179
Author(s):  
Vivekanandan Kalaiselvan ◽  
Aishwarya G. ◽  
Ashish Sharma
Keyword(s):  
Adverse Event ◽  
Medical Device ◽  
Medical Devices ◽  
East Asian ◽  
Time Frame ◽  
Adverse Event Reporting ◽  
World Health ◽  
Current Status ◽  
Event Reporting ◽  
Medical Device Regulation

As Medical device application in disease prevention, diagnosis or treatment is evolving to a greater extent; there is a need for regulation to monitor its quality, safety and efficacy. The present article attempts to study the medical device regulation available in eleven South-East Asian World Health Organization (WHO) member countries. The information searched from the available sources reveals that medical device regulation exists in seven countries. Most of the countries follow the International Organization for Standardization (ISO) 13485 for their quality standards in medical devices. Most countries also specified the time frame and authority to which adverse event is to be reported. Countries like India and Thailand have separate Adverse Event reporting forms for the medical device. The present study reveals that there is no separate web-based database for adverse event reporting of medical devices. Therefore, WHO South-East Asian Regulators Network (SEARN) under South East Regulatory Office (SERO) office may provide handholding support to these regions in developing a common software or tool for the management and analysis of signals arising from the adverse events.

11. Mitigation of Wildlife Collision Mortality at Little Cataraqui Creek Wetland

2018 ◽  
Author(s):  
Erin Keenan ◽  
Jeffy Henderson ◽  
Lauren Malo ◽  
Diana Pedersen
Keyword(s):  
Coastal Wetland ◽  
Public Awareness ◽  
Population Decline ◽  
Urban Traffic ◽  
Coastal Marsh ◽  
Road Mortality ◽  
Wetland Ecosystems ◽  
Turtle Species ◽  
Wetland Species ◽  
Specific Species

               Our research team is concerned with potential reptile and amphibian road mortality through Little Cataraqui Creek wetland along Front Rd. and Bath Rd. in Kingston, Ontario. The coastal marsh is a provincially significant wetland that supports species of migrating and breeding waterfowl, wetland dependent reptiles and amphibians, and may support some of Ontario’s threatened turtle species. The coastal wetland also provides a protected nesting area for a migrating species within Lake Ontario. Specific species of turtles, salamanders and frogs will be investigated.  Our team will identify general breeding, nesting and migratory behavior patterns of associated wetland species, and establish potential indirect effects on the wetland ecosystem due to population decline. Traffic volume and speed limits of Front Rd. and Bath Rd. at Little Cataraqui Creek Wetland will be identified, and any current wildlife crossing systems in place will be evaluated. Based on this research, our team will establish the significance of wildlife road mortality within Little Cataraqui Creek Wetland at Front Rd. and Bath Rd., and propose suitable mitigation techniques. These techniques may include implementing structural design solutions such as road barriers, culverts, etc., as well as increasing public awareness of wildlife crossing on Bath Rd. and Front Rd. by proposing appropriate traffic laws in the area. Themes include wetland species breeding and nesting behavior, and urban/traffic development issues surrounding wetland ecosystems.

scholarly journals Knowledge Management and World Class Manufacturing: an initial approach based on a literature review

2017 ◽  
Vol 22 (2) ◽  
pp. 244-263
Author(s):  
Rafael de Carvalho Mendes ◽  
Max Cirino de Mattos
Keyword(s):  
Knowledge Management ◽  
Literature Review ◽  
Time Frame ◽  
Primary Sources ◽  
Just In Time ◽  
Total Quality ◽  
Ongoing Research ◽  
Current Scenario ◽  
World Class ◽  
World Class Manufacturing

ABSTRACT This paper presents the partial results of an ongoing research on the proposal of a methodology for the integration between Knowledge Management (KM) and World Class Manufacturing (WCM). The initial investigation of theoretical and conceptual nature aimed at developing a comprehensive and current vision on KM, WCM, and how (or "whether") these constructs relate to one another. The primary sources for the literature review were Web of Science, Scopus, Emerald, Ebsco, SciELO and Spell, and the time frame was 2000 to 2016. The analysis of the selected papers showed that, although the initial WCM model evolved into a "new WCM" in the 2000s, the literature is still focused on the broad conceptual aspects and basic methods and tools, such as Total Quality Process, Total Productive Maintenance and Just-in-Time, conceived in the Toyota Production System, which shows the need for more studies focused on the current scenario of companies associated with the "new WCM" and its Methods and Tools. Only one article explicitly addressing the interaction between KM theories with WCM was found in the databases surveyed, thus reinforcing the lack of theoretical approximation of these constructs.

Conservation biology of marine fishes: perceptions and caveats regarding assignment of extinction risk

2001 ◽  
Vol 58 (1) ◽  
pp. 108-121 ◽  
Author(s):  
Jeffrey A Hutchings
Keyword(s):  
Population Size ◽  
Extinction Risk ◽  
Population Decline ◽  
Empirical Support ◽  
Marine Fishes ◽  
Marine Biodiversity ◽  
Population Declines ◽  
High Fecundity ◽  
Reproductive Rates ◽  
Biological Extinction

Quantitative criteria used to assign species to categories of extinction risk may seriously overestimate these risks for marine fishes. Contemporary perception is that marine fishes may be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses that marine fish are more likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more rapidly from prolonged population declines than nonmarine fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse-population recovery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats associated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine fishes to at-risk categories would be inconsistent with a precautionary approach to fisheries management and the conservation of marine biodiversity.

Cultural management of HLB: current status and on-going research

2021 ◽  
Author(s):  
Berta Alquezar ◽  
Lourdes Carmona ◽  
Stefania Bennici ◽  
Marcelo Pedreira Miranda ◽  
Renato Bassanezi ◽  
...  
Keyword(s):  
Current Status ◽  
Bacterial Disease ◽  
Ongoing Research ◽  
Cultural Management ◽  
Cultural Strategies ◽  
Almost All ◽  
The Impact ◽  
Citrus Disease

Huanglongbing (HLB), formerly known as greening, is a bacterial disease restricted to some Asian and African regions until two decades ago. Nowadays, causing bacteria and their vectors have spread to almost all citrus producing regions, and it is currently considered the most devastating citrus disease. HLB management can be approached in terms of prevention, limiting or avoiding pathogen and associated vectors to reach an area, or in terms of control, trying to reduce the impact of the disease by adopting different cultural strategies depending on infestation/infection levels. In both cases, control of psyllid populations is currently the best way to stop HLB spread. Best cultural actions (CHMAs, TPS system) to attain this goal and thus, able to limit HLB spread, and ongoing research in this regard is summarized in this review.

scholarly journals Evolution of -Cell Replacement Therapy in Diabetes Mellitus: Islet Cell Transplantation

2011 ◽  
Vol 2011 ◽  
pp. 1-21 ◽  
Author(s):  
Cyrus Jahansouz ◽  
Cameron Jahansouz ◽  
Sean C. Kumer ◽  
Kenneth L. Brayman
Keyword(s):  
Diabetes Mellitus ◽  
Cell Transplantation ◽  
Islet Cell ◽  
The United States ◽  
Viable Alternative ◽  
Current Status ◽  
Islet Cell Transplantation ◽  
Ongoing Research ◽  
Control And Prevention ◽  
The 1960S

Diabetes mellitus remains one of the leading causes of morbidity and mortality worldwide. According to the Centers for Disease Control and Prevention, approximately 23.6 million people in the United States are affected. Of these individuals, 5 to 10% have been diagnosed with Type 1 diabetes mellitus (T1DM), an autoimmune disease. Although it often appears in childhood, T1DM may manifest at any age, leading to significant morbidity and decreased quality of life. Since the 1960s, the surgical treatment for diabetes mellitus has evolved to become a viable alternative to insulin administration, beginning with pancreatic transplantation. While islet cell transplantation has emerged as another potential alternative, its role in the treatment of T1DM remains to be solidified as research continues to establish it as a truly viable alternative for achieving insulin independence. In this paper, the historical evolution, procurement, current status, benefits, risks, and ongoing research of islet cell transplantation are explored.

scholarly journals Australian corticolous myxomycetes: models of distribution and development

2019 ◽  
Vol 67 (8) ◽  
pp. 617 ◽  
Author(s):  
Peter Wellman
Keyword(s):  
Population Decline ◽  
Common Species ◽  
Growth Cycle ◽  
Population Increase ◽  
Arid Areas ◽  
Species Assemblage ◽  
Population Declines ◽  
Moist Chamber ◽  
Linear Plot ◽  
Chamber Technique

This paper presents an integrated model of the variation over a continental landmass of myxomycetes, a single-celled organism in the phylum Amoebozoa. Bark samples were collected on long traverses across Australia, and cultivated in Petri dishes by the moist chamber technique to obtain large assemblages of common species. The results of this survey and previous surveys are consistent with there being four major myxomycete assemblages: Tropical, Northern Arid, Southern Arid and Temperate. Where mapped, these species assemblage regions are consistent with the Australian phytogeographical regions. The myxomycetes differ between arid and non-arid areas; the arid areas have slightly higher productivity per wetting event, with members of the Physarales and Liceales relatively important and the Stemonitidales, Trichiales and Cribrariales less important. When the bark samples are placed in a moist culture there is a myxomycete growth cycle and then the population declines to resting phases. The population increase during a growth phase can be modelled by a linear plot of log(abundance) against species rank, where abundance is total harvested spore volume of a species. The population decline appears to be linear from two weeks after watering, declining to negligible activity 4 weeks after watering.

Fates and movements of meadow voles (Microtus pennsylvanicus) following a population decline

1988 ◽  
Vol 66 (2) ◽  
pp. 323-328 ◽  
Author(s):  
Steve Mihok ◽  
Todd Lawton ◽  
Bill Schwartz
Keyword(s):  
Direct Evidence ◽  
Population Decline ◽  
Microtus Pennsylvanicus ◽  
Population Declines ◽  
Severe Winter ◽  
Meadow Voles ◽  
Small Areas ◽  
Small Mustelids ◽  
Winter Population

The movements of 24 meadow voles were monitored with radiotelemetry during summer 1985 near Pinawa, Manitoba, to ascertain fates following a severe winter population decline. Low breeding season survival of 22% per month resulted in the persistence of low numbers through spring 1986. Despite densities of only a few individuals per hectare, voles were captured in both meadows and forests. Some voles first caught in forests (mostly males) moved over large areas (up to 4 ha), including both meadow and forest habitat. In contrast, voles captured in meadows were sedentary, often confining their movements to small areas of 0.1–0.2 ha. Radiotransmitters were recovered from 18 of 19 voles that died during the study. Five voles (28%) appeared to have died in situ; six voles (33%) may have been taken by an unusually clean predator or scavenger. Fates of the remaining voles were uncertain. No direct evidence of predation by small mustelids was found to support the hypothesis that these predators account for the persistence of low density following population declines.

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