Movement
ability and habitat selection of individuals are highly significant in
determining the size of a population and impact the range and survival of the
entire species. Thus, the conservation and management of animal species
requires an understanding of the movement and habitat selection in various
environments. Human-modified landscapes often differ from the natural
environment of a species and can be highly fragmented. For forest-dwelling
species, urbanized areas in particular can pose threats to movement, as
forested areas are scarce and separated by roads and buildings.

      In this thesis I study how an originally
forest-dwelling species, the Eurasian Red squirrel (Sciurus vulgaris) is accustomed to live in human modified
landscapes and move in urban and rural environments. The red squirrel is an
arboreal mammal common in the boreal coniferous forests, but recent findings
have shown the population declining in Finland. The movements of juvenile red
squirrels are followed by radio tracking, and habitat selection, dispersal
distance and movement patterns are examined as a response to landscape
structures.

      The results from the urban environment
show that juvenile red squirrels do not avoid roads during their dispersal. In
addition, mortality due to vehicles was detected low. Although red squirrels prefer
areas with more trees available than in the surrounding urban landscape, they
often use sites with only few trees. At the home range scale, the used area did
not differ greatly from the habitat composition of the available landscape.
Habitat use of juvenile red squirrels differed between the phases of dispersal,
including settling in areas with less deciduous land cover type than in the
natal area. Thus, red squirrels are well adapted to use urbanized areas and
their movements are not inhibited by roads.

      I found surprisingly long dispersal
distances for juvenile red squirrels in the rural study area, with the maximum
being over 16 km. The dispersal distances in the urban area were approximately
only a quarter of those observed in the rural area. The landscape structure
affected the eventual dispersal paths made by juvenile red squirrels; in the
rural landscape, dispersers favored spruce-dominated areas and avoided fields
along their dispersal route, although they occasionally crossed even wide
fields. In the urban landscape, red squirrels preferred areas with deciduous or
coniferous trees. The movement steps made by dispersers were longer in the more
hostile landscape compared to forested areas. Despite these effects on movement
path, the landscape structure only had a minor effect on straight line
dispersal distances moved from the natal nest. Even though the dispersal
distances of red squirrels vary greatly, it is obvious that landscape structure
plays only a very small role in these differences.

      Most of
the dispersing individuals compared potential sites for a home range before
settling into the one they chose. However, in the rural study area, long-distance
dispersing individuals did not compare potential sites and settled in the last site
they visited. Landscape characteristics did not explain the number of revisits
that individuals made to alternative sites, but the number of revisits declined
with a site’s distance to the natal nest and the dispersal distance of
individuals. The effect of landscape variables on decisions regarding where to
settle was small, but surprisingly, in the rural area, juvenile red squirrels
settled in sites with more built area compared to sites where juveniles only
visited but did not settle in. The decision making during natal dispersal seems
to be driven mainly by factors other than landscape characteristics and the
search strategies vary between individuals and study areas.

      In conclusion, juvenile red squirrels are
efficient dispersers, and landscape structure has only a small effect on
dispersal distances and thus possibly on gene flow of the species. Red
squirrels are well-adapted to changing environments; in Finland, their
movements are scarcely restricted by roads or unfavorable agricultural areas.
The species can utilize urban environments and even exhibits a tendency to
settle near human settlement in rural areas. This study has discovered a
significant difference in dispersal distances between urban and rural
environments, raising questions about the reasons behind extensive dispersal
distances in the rural environment.