SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Clausen Preben) "

Sökning: WFRF:(Clausen Preben)

  • Resultat 1-10 av 19
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Fox, Anthony D., et al. (författare)
  • Current and potential threats to Nordic duck populations - a horizon scanning exercise
  • 2015
  • Ingår i: Annales Zoologici Fennici. - 0003-455X .- 1797-2450. ; 52:4, s. 193-220
  • Tidskriftsartikel (refereegranskat)abstract
    • We review the current and future threats to duck populations that breed, stage, moult and/or winter in the Nordic countries. Migratory duck species are sensitive indicators of their changing environment, and their societal value confirms the need to translate signals from changes in their distribution, status and abundance into a better understanding of changes occurring in their wetland environments. We used expert opinion to highlight 25 major areas of anthropogenic change (and touch briefly on potential mitigation measures through nature restoration and reserve management projects) that we consider key issues likely to influence Nordic duck populations now and in the near future to stimulate debate, discussion and further research. We believe such reviews are essential in contributing to development of successful management policy as well as stimulating specific research to support the maintenance of duck species in favourable future conservation status in the face of multiple population pressures and drivers.
  •  
2.
  • Fox, Anthony D., et al. (författare)
  • Current and potential threats to Nordic duck populations - a horizon scanning exercise
  • 2015
  • Ingår i: Annales Zoologici Fennici. - : Finnish Zoological and Botanical Publishing Board. - 0003-455X. ; 52:4, s. 193-220
  • Tidskriftsartikel (refereegranskat)abstract
    • We review the current and future threats to duck populations that breed, stage, moult and/or winter in the Nordic countries. Migratory duck species are sensitive indicators of their changing environment, and their societal value confirms the need to translate signals from changes in their distribution, status and abundance into a better understanding of changes occurring in their wetland environments. We used expert opinion to highlight 25 major areas of anthropogenic change (and touch briefly on potential mitigation measures through nature restoration and reserve management projects) that we consider key issues likely to influence Nordic duck populations now and in the near future to stimulate debate, discussion and further research. We believe such reviews are essential in contributing to development of successful management policy as well as stimulating specific research to support the maintenance of duck species in favourable future conservation status in the face of multiple population pressures and drivers.
  •  
3.
  • Beekman, Jan, et al. (författare)
  • Long-term population trends and shifts in distribution of Bewick's swans cygnus columbianus bewickii wintering in northwest Europe
  • 2020
  • Ingår i: Wildfowl. - 0954-6324. ; :69, s. 73-102
  • Tidskriftsartikel (refereegranskat)abstract
    • Coordinated international censuses of the Northwest European Bewick's Swan Cygnus columbianus bewickii population have been undertaken across the swans' wintering range at c. 5-year intervals since 1984. During the early years of the study, numbers increased steadily to a peak of 29,780 individuals in January 1995, but then declined by 39.4% to 18,057 swans counted in January 2010 before showing a partial recovery to 20,149 recorded in January 2015. Changes in distribution across the wintering range were also recorded; a higher proportion of the population now remains in more easterly countries (notably Germany) in mid-winter, whilst only a handful of birds migrated to Ireland (at the western edge of the range) during the 2000s compared to >1,000 wintering there at the start of the study. Variation between censuses in the proportion of swans recorded in different parts of the range were attributable to weather conditions, with more swans wintering further north in warmer years. The overall percentage of cygnets recorded in each of the census years ranged from 9.6% in 2010 to 13.2% in 2005, with no obvious consistency over time in the distribution of cygnets across the wintering range. There were however changes between 1990 and 2015 in the swans' use of feeding habitats, with a decline in the proportion of birds on pasture and a corresponding increase in those on arable land. Decreases in the total population size and changes in distribution in the 21st century have implications for the designation and resultant protection of sites of international importance for the species.
  •  
4.
  • Dalby, Lars, et al. (författare)
  • The status of the Nordic populations of the Mallard (Anas platyrhynchos) in a changing world
  • 2013
  • Ingår i: Ornis Fennica. - : Finnish Omithological Soc. - 0030-5685. ; 90:1, s. 2-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Dabbling ducks (Anas spp.) are importantmigratory quarry species, protected as a shared resource under international legislation. However, there is a lack of sufficient high-quality data on vital demographic rates and long-term trends in numbers to judge the conservation status of many duck populations at the flyway level. In response to reported declines in the North-West European flyway population of theMallard, we compiled available data on this species in the Nordic countries up to 2010. Generally, national breeding numbers showed increasing trends, wintering abundance showed variable trends, and productivitymeasures indicated stable or increasing trends.Major knowledge gaps were identified, namely the size of hunting bags, the influence of the released Mallards and the role of short-stopping in explaining changing patterns of wintering abundance across the North-West European flyway. Numerically the Nordic breeding population appears in “good condition”, and the wintering numbers have been either stable or increasing in the last two decades. The annual number of releases needs to be determined in order to judge the sustainability of the current levels of exploitation. Overall, none of the indicators showed alarming signs for the Mallard population in the Nordic countries when considered in isolation. However, the widespread decline in wintering numbers elsewhere across North-western Europe requires urgent pan-European action.
  •  
5.
  • Dalby, Lars, et al. (författare)
  • The status of the Nordic populations of the Mallard (Anas platyrhynchos) in a changing world
  • 2013
  • Ingår i: Ornis Fennica. - : University of Helsinki. - 0030-5685. ; 90:1, s. 2-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Dabbling ducks (Anas spp.) are important migratory quarry species, protected as a shared resource under international legislation. However, there is a lack of sufficient high-quality data on vital demographic rates and long-term trends in numbers to judge the conservation status of many duck populations at the flyway level. In response to reported declines in the North-West European flyway population of the Mallard, we compiled available data on this species in the Nordic countries up to 2010. Generally, national breeding numbers showed increasing trends, wintering abundance showed variable trends, and productivity measures indicated stable or increasing trends. Major knowledge gaps were identified, namely the size of hunting bags, the influence of the released Mallards and the role of short-stopping in explaining changing patterns of wintering abundance across the North-West European flyway. Numerically the Nordic breeding population appears in "good condition", and the wintering numbers have been either stable or increasing in the last two decades. The annual number of releases needs to be determined in order to judge the sustainability of the current levels of exploitation. Overall, none of the indicators showed alarming signs for the Mallard population in the Nordic countries when considered in isolation. However, the widespread decline in wintering numbers elsewhere across North-western Europe requires urgent pan-European action.
  •  
6.
  •  
7.
  •  
8.
  • Davranche, Aurélie, et al. (författare)
  • Space based tools to monitor the habitats of migratory waterbirds
  • 2010
  • Ingår i: The abstract book. ; , s. 44-
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Natural fluctuations in the availability of suitable habitat coupled with anthropogenic activities (hunting, agriculture, tourism, urbanism) and anticipated modifications due to climate change confront migratory waterbirds with a formidable challenge. Among them, dabbling ducks, greatly rely on local exogenous resources to fulfil their energy requirements. Habitat suitability along their flyway is of primary importance as any change might induce dramatic effects on individual survival and breeding success. Although, the monitoring of such sensitive flooded areas that are wetlands stopover sites is usually complex, space based techniques, with an exhaustive and systematic covering of the territory and a periodical data acquisition, can explore cost-efficiently the ecological conditions for migratory species in these environments. Hence, multiseason reflectance data from radiometrically and geometrically corrected multispectral SPOT-5 scenes, combined with thorough field campaigns and land cover digitizing using data mining, can provide robust tools for habitat monitoring and help the conservation of wetlands for migrants.
  •  
9.
  • Davranche, Aurélie, et al. (författare)
  • Space based tools to monitor the habitats of migratory waterbirds
  • 2010
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Natural fluctuations in the availability of suitable habitat coupled with anthropogenic activities (hunting, agriculture, tourism, urbanism) and anticipated modifications due to climate change confront migratory waterbirds with a formidable challenge. Among them, dabbling ducks, greatly rely on local exogenous resources to fulfil their energy requirements. Habitat suitability along their flyway is of primary importance as any change might induce dramatic effects on individual survival and breeding success. Although, the monitoring of such sensitive flooded areas that are wetlands stopover sites is usually complex, space based techniques, with an exhaustive and systematic covering of the territory and a periodical data acquisition, can explore cost-efficiently the ecological conditions for migratory species in these environments. Hence, multiseason reflectance data from radiometrically and geometrically corrected multispectral SPOT-5 scenes, combined with thorough field campaigns and land cover digitizing using data mining, can provide robust tools for habitat monitoring and help the conservation of wetlands for migrants.
  •  
10.
  • Elmberg, Johan, 1960-, et al. (författare)
  • The scientific basis for a new and sustainable management of migratory European ducks
  • 2006
  • Ingår i: Wildlife Biology. - 0909-6396 .- 1903-220X. ; 12:2, s. 121-127
  • Tidskriftsartikel (refereegranskat)abstract
    • It is an axiom in ecology that knowing the sheer number of individuals in a population is of very little help if the objective is to understand future and past changes in population size. Yet, this is exactly how migratory European ducks are monitored, many of which are important quarry species in several countries. We argue that present monitoring is insufficient to address objectives of wise use and sustainability such as those emphasised in recent management directives and multilateral international agreements. The two main problems are the almost total lack of reliable data on recruitment and mortality. We advocate a pan-European monitoring system based on undisputed scientific principles; i.e. a long-term, coordinated and standardised scheme that produces data about vital rates of duck populations as well as about harvest size. Data from such a scheme can be used by game biologists to produce predictive tools, thus providing a functional basis for management decisions for adaptive harvesting and conservation alike.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 19

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy