 |
Broad-scale movements of
mountain ungulates: carrying genes and
pathogens between populations.
Marco Festa-Bianchet,
Departement de biologie, Universite de Sherbrooke, Sherbrooke,
Quebec J1K 2R1 Canada
Abstract: Mountain-dwelling ungulates, including wild
sheep (Ovis spp.) and goats (Capra spp.) often make
long-distance movements. These movements may involve seasonal
migrations to search for mates or food, exploit salt licks or
avoid predators. Individual animals can
move linear distances of over 80 km,
and animals from one population can range over more than 2000 km2
of valleys and mountains. Neighboring populations often have
overlapping seasonal ranges, where animals may contact with each
other. Seasonal migrations along
altitudinal gradients take advantage
of differences in timing of green-up to exploit seasonal ranges
with different plant phenologies, but some female movements to
cliffs or to very high altitude are motivated by predator
avoidance rather than forage selection. Permanent dispersal is
rare in many species, but males may move to distant groups of
females during the rut, ensuring gene flow. Travel routes,
particularly those through inhospitable habitat, are learned from
conspecifics and transmitted culturally. A major challenge of
reintroduction programs is that animals must learn the location of
seasonal ranges and safe travel routes. Mountain ungulates are
sensitive to barriers that cut or decrease connectivity, but are
also
very effective at carrying problems
such as exotic diseases and genetic pollution over large areas.
Contact with domestic livestock or introduced exotics at a single
site can transmit pathogens or genes that can then be carried to a
very large metapopulation. In the presence of these threats,
managing to increase connectivity may not be the best strategy.
|
