Showing papers by "Olof Liberg published in 2005"

Severe inbreeding depression in a wild wolf (Canis lupus) population

Abstract: The difficulty of obtaining pedigrees for wild populations has hampered the possibility of demonstrating inbreeding depression in nature. In a small, naturally restored, wild population of grey wolves in Scandinavia, founded in 1983, we constructed a pedigree for 24 of the 28 breeding pairs established in the period 1983–2002. Ancestry for the breeding animals was determined through a combination of field data (snow tracking and radio telemetry) and DNA microsatellite analysis. The population was founded by only three individuals. The inbreeding coefficient F varied between 0.00 and 0.41 for wolves born during the study period. The number of surviving pups per litter during their first winter after birth was strongly correlated with inbreeding coefficients of pups ( R 2 =0.39, p

Red fox removal and roe deer fawn survival—a 14-year study

Abstract: We studied the impact of red fox (Vulpes vulpes) predation on free-ranging roe deer (Capreolus capreolus) neonates during 14 years in a mixed forest/agricultural landscape in south central Sweden. A large-scale natural predator removal experiment occurred when an outbreak of sarcoptic mange (Sarcoptes scabiei) reduced the red fox population initially and caused subsequent variations in red fox abundance. We estimated relative red fox abundance by dividing number of fox observations with number of person-days in field. Red fox predation accounted for 88% of known mortality in roe deer fawns. Predation was closely correlated to red fox abundance, and there was a strong negative correlation between fox abundance and overall fawn survival. Fox abundance was the only factor with a significant effect on between year variation in fawn survival. Annual predation varied between zero and 90%. Our study recorded the highest predation rates for roe deer juveniles established to date. High fawn survival in years of low fox abundance suggested that predation mortality was additive during summer. Our results supported the conclusion that the large national increase of roe deer in Sweden during the 1980s and 1990s was related to lower fox predation on fawns and also indicated that the roe deer population density was well below habitat carrying capacity at the onset of the mange epidemic. In Sweden, in general, a thorough fox control will most likely result in increased fawn survival and higher potential roe deer harvest.

Big mothers invest more in daughters – reversed sex allocation in a weakly polygynous mammal

Abstract: How mothers allocate resources to offspring is central to understanding life history strategies. High quality mothers are predicted to favour investment in sons over daughters when to do so increases inclusive fitness. This is the case in ungulates with polygynous mating systems, where reproductive success is more variable among males than females, but information is scarce on sex allocation in less polygynous species. Here, for the weakly dimorphic roe deer, we show that as maternal capacity to invest increases, mothers increase allocation to daughters more than to sons, so that relative allocation to daughters increases markedly with increasing maternal quality. This cannot be explained by a between sex difference in growth priority, hence we conclude that this is evidence for active maternal discrimination. Further, we demonstrate that condition differences between offspring persist to adulthood. For high quality mothers of weakly polygynous species, daughters may be more valuable than sons.

Severe inbreeding depression in a wild wolf

Abstract: The difficulty of obtaining pedigrees for wildpopulations has hampered the possibility ofdemonstrating inbreeding depression in nature.In a small, naturally restored, wild population ofgrey wolves in Scandinavia, founded in 1983, weconstructed a pedigree for 24 of the 28 breedingpairs established in the period 1983–2002. Ances-try for the breeding animals was determinedthrough a combination of field data (snow track-ing and radio telemetry) and DNA microsatelliteanalysis. The population was founded by onlythree individuals. The inbreeding coefficient Fvaried between 0.00 and 0.41 for wolves bornduring the study period. The number of survivingpups per litter during their first winter after birthwas strongly correlated with inbreeding coeffi-cients of pups (R

Rovvilt og Samfunn (RoSa). Det skandinaviske ulveprosjektet – SKANDULV. Oversikt over gjennomførte aktiviteter i 2000-2004

Abstract: ................................................................................................................................. 10 Innhold.................................................................................................................................... 18 Forord ..................................................................................................................................... 20 1 Innledning.......................................................................................................................... 21 2 Studieområder .................................................................................................................. 23 2.1 Nordområdet ............................................................................................................... 23 2.2 Sørområdet ................................................................................................................. 23 3 Materiale og metoder........................................................................................................ 23 3.1 Fangst av ulv ................................................................................................................ 23 3.2 Merkemetoder............................................................................................................... 24 3.3 Lokalisering av ulv ........................................................................................................ 25 4 Bestandsutvikling............................................................................................................. 26 4.1 Utvikling av ulvebestanden i Skandinavia fra 1800-tallet til i dag ................................ 26 4.2 Bestandsovervåking.................................................................................................... 28 4.2.1 Organisering av bestandsovervåkingen ........................................................... 28 4.2.2 Beregning av bestandsstørrelsen etter inventeringsdata.................................. 29 4.2.3 Beregning av bestandsstørrelsen etter reproduksjonsdata .............................. 30 4.2.4 Beregning av bestandsstørrelsen etter andel ulv i stasjonære flokker og par .. 30 4.3 Reproduksjon.............................................................................................................. 31 4.3.1 Tidspunkt for yngling ........................................................................................ 31 4.3.2 Reproduktiv alder og kullstørrelser ................................................................... 32 4.3.3 Dokumenterte ynglinger av ulv i Norge og Sverige 1978 – 2004...................... 33 4.4 Dødelighet og overlevelse........................................................................................... 33 4.4.1 Metoder for overvåking av overlevelse ............................................................. 33 4.4.2 Dødelighet blant ulv i Norge og Sverige ........................................................... 36 4.4.3 Dødsårsaker ..................................................................................................... 38 4.5 Tilvekst........................................................................................................................ 38 5 Genetikk............................................................................................................................. 40 5.1 Den norsk-svenske ulvebestandens opphav............................................................... 41 5.1.1 Oppbyggingen av stamtreet ............................................................................. 44 5.2 Slektskap og innavl i den skandinaviske ulvebestanden............................................. 45 5.2.1 Mål på innavl .................................................................................................... 46 5.2.2 Tidlig feltarbeid og samarbeid viktig ................................................................. 46 5.2.3 Beregning av innavlsgraden ............................................................................. 47 5.2.4 Morsog farslinjer............................................................................................. 47 5.2.5 Annet bruk av slektskapsanalysene ................................................................. 47 6 Spredningsbiologi ............................................................................................................ 48 6.1 Utvandring: alder og tidspunkt på året ........................................................................ 48 6.2 Spredningsmønster og -distanser ............................................................................... 49 7 Sosial organisering .......................................................................................................... 51 7.1 Flokkdannelse............................................................................................................. 51 7.2 Revirstørrelser og romlig fordeling av revir ................................................................. 52

Scandlynx: a vision for coordinated lynx research in Scandinavia

Abstract: © Norwegian Institute for Nature Research The publication may be freely cited where the source is acknowledged