Herrero, Annika
(Helsingin yliopisto, 2021)
Large terrestrial carnivores are capable of long dispersal distances and thus
have a potentially high rate of gene flow between populations. Even with such
high mobility, discontinuous habitat and human-caused mortality may
constrain dispersal and gene flow. Therefore, isolation of populations because
of habitat fragmentation may cause genetic structuring in them because of
genetic drift. In a continuous population, geographic barriers should not
significantly affect dispersal and gene flow, so the effects of social, ecological
and evolutionary forces are easier to detect.
In large carnivores, males generally disperse more often and earlier than
females and their dispersal distances are longer than those of females. The
direction of sex-bias in dispersal is commonly explained by inbreeding
avoidance, polygynous mating system and male-male competition.
Remaining in, or near, the natal home range is explained by kin selection and
inclusive fitness. Molecular evidence reveals the spatial genetic structure and
clustering of relatives and family lines that may underlie these traits.
We studied the spatial genetic relatedness, family structure, movement
patterns and sex- bias of dispersal in the Eurasian lynx (Lynx lynx) in an
unfragmented population in southern Finland. We used GIS and resource
selection functions to analyse telemetry data of dispersing lynx and genetic
methods to analyse data obtained from hunted lynx. Dispersal onset age,
duration, distance, route or route linearity did not differ statistically between
males and females that dispersed. However, the small number of females and
the high variation in all dispersal parameters likely affected the outcome of
analysis. Linear distance between the start and the end comprised only 20 %
of the total dispersal route. Lynx selected their habitat non-randomly. During
daylight hours lynx were more discerning in their habitat selection, while most
of the traveling took place at night, reflecting the crepuscular and nocturnal
activity of the lynx.
According to the results of genetic analyses, the majority of females stayed
close to their natal home range after reaching independence. Males dispersed
and settled randomly in space. This led to genetic differentiation and spatial
clustering of related females but not of males.
Females form the backbone of the local populations, and genetic evidence
is in line with the idea that females facilitate the settling of related females. In
contrast to females, for males, relatedness is inversely important to avoid
inbreeding. Hunting of adult lynx may disturb the forming of matrilineages
and decrease genetic variation. Hunting should aim at mimicking a natural
mortality pattern, which means hunting mostly young lynx, as the natural
adult survival in Eurasian lynx is high.