SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:0030 1299 OR L773:1600 0706 ;pers:(Gunnarsson Gunnar)"

Sökning: L773:0030 1299 OR L773:1600 0706 > Gunnarsson Gunnar

  • Resultat 1-4 av 4
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Elmberg, Johan, et al. (författare)
  • Within-season sequential density dependence regulates breeding success in mallards Anas platyrhynchos
  • 2005
  • Ingår i: Oikos. - 0030-1299 .- 1600-0706. ; 108, s. 582-590
  • Tidskriftsartikel (refereegranskat)abstract
    • Density dependence in vital rates is a key issue in population ecology but remains largely unexplored experimentally. We studied breeding success, lake use, and prey availability in wild mallards Anas platyrhynchos on small nemoral lakes in a replicated, two-year cross-over experiment in which pair density was increased. The number of wild mallards that settled on lakes prior to introductions of extra pairs did not differ between control and introduction years. Introductions led to a lake-level reduction in the number of broods observed. However, the number of stage 2/ (almost fledged) ducklings did not differ between treatments, nor did lake utilization by nonbreeding adults, broods and ducklings. Prey resource availability differed greatly among lakes, but it did not correlate with breeding success. Partialling out the possible effect of food competition from wild adult nonbreeding mallards did not change this conclusion. Our study demonstrates sequential density dependence in breeding success; introductions caused a decrease in brood number, but despite fewer broods a similar number of nearly fledged ducklings were produced. We suggest that predation and/or lake change of broods soon after hatching created these patterns. We conclude that using a single and late measure of breeding success such as fledged birds can mask regulatory processes. Implications of density dependence and its relation to individual reproductive success are understood better if breeding success is decomposed into nest success, duckling survival and fledgling survival.
  •  
2.
  • Elmberg, Johan, et al. (författare)
  • Within-season sequential density dependence regulates breeding success in mallards Anas platyrhynchos
  • 2005
  • Ingår i: Oikos. - : Wiley-Blackwell Publishing Ltd. - 0030-1299 .- 1600-0706. ; 108, s. 582-590
  • Tidskriftsartikel (refereegranskat)abstract
    • Density dependence in vital rates is a key issue in population ecology but remains largely unexplored experimentally. We studied breeding success, lake use, and prey availability in wild mallards Anas platyrhynchos on small nemoral lakes in a replicated, two-year cross-over experiment in which pair density was increased. The number of wild mallards that settled on lakes prior to introductions of extra pairs did not differ between control and introduction years. Introductions led to a lake-level reduction in the number of broods observed. However, the number of stage 2/ (almost fledged) ducklings did not differ between treatments, nor did lake utilization by nonbreeding adults, broods and ducklings. Prey resource availability differed greatly among lakes, but it did not correlate with breeding success. Partialling out the possible effect of food competition from wild adult nonbreeding mallards did not change this conclusion. Our study demonstrates sequential density dependence in breeding success; introductions caused a decrease in brood number, but despite fewer broods a similar number of nearly fledged ducklings were produced. We suggest that predation and/or lake change of broods soon after hatching created these patterns. We conclude that using a single and late measure of breeding success such as fledged birds can mask regulatory processes. Implications of density dependence and its relation to individual reproductive success are understood better if breeding success is decomposed into nest success, duckling survival and fledgling survival.
  •  
3.
  •  
4.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-4 av 4
Typ av publikation
tidskriftsartikel (4)
Typ av innehåll
refereegranskat (4)
Författare/redaktör
Elmberg, Johan (4)
Nummi, Petri (4)
Pöysä, Hannu (4)
Sjöberg, Kjell (4)
Lärosäte
Högskolan Kristianstad (4)
Språk
Engelska (4)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (3)

År

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