4 Winter 2015 conservationnw.org
Bears and other animals on the move need safe passage. Habitat
connectivity can be gained by building wildlife crossings, restoring
habitat or by removing unsustainable roads. © iStock.com/wergodswarrior
Why connect habitat and wildands?
a matter of surViVal
Dave Werntz Science and Conservation
Director, dave@conservationnw.org
Connecting wildlands
For Canada lynx and other wildlife, habitat connectivity is a matter
of life and death.
Lynx populations are spread out across North America in an archi-
pelago of habitat islands. Safe passage among populations ensures that
when one habitat island becomes uninhabitable due to fire or other dis-
turbance, it can be re-colonized by lynx from an adjacent population
when conditions improve.
In this way, networks of interconnected lynx habitat provide for
species persistence over time. Yet habitat connectivity isn't just for fire
dependent species like lynx; it is necessary for all animals, great and small.
Wildlife need to be able to move around their dens and nest sites to
find food and shelter, hook up with suitable mates, and satisfy other basic
needs. Populations that are recovering from over-exploitation or habi-
tat degradation, like many of our endangered species, need to be able to
access unoccupied habitat and maintain genetic interchange between
groups.
Robust connections among habitat areas help wildlife adapt to a
changing climate by allowing movement to new habitat as existing areas
become increasingly inhospitable.
In technical terms, habitat connectivity is a measure of the ability of
wildlife to move among separated patches of habitat. It can occur as dis-
crete generally linear corridors, such as wildlife bridges over Interstate 90,
or more broadly as landscapes that are permeable or supportive of wildlife
movement.
Landscape permeability can be increased by removing barriers to ani-
mal movement, such as roads or development, restoring habitat favored
by dispersing individuals, and reducing exposure to poaching or vehicle
collision.
Not all habitat connectivity is the same. It's largely species-
specific and determined by individual habitat preferences and
mortality risks. For older-forest dependent animals, like fisher,
habitat connections between old-growth reserves is provided
by broad stream-side forest corridors and scattered old-growth
forest stepping stones that span the ground between reserves.
Wolverines, which thrive in remote wilderness landscapes, face
threats from high-speed vehicles when passing over highways
and other roads as they seek new unoccupied habitats as their
populations in Washington rebound.
As with wolverine, reducing the risk of death is a key factor
in providing permeable landscapes for habitat generalists like
grizzly bears and wolves. Decommissioning or closing roads
serves to block access for poachers and other scofflaws, remove
collision risk, and improve habitat security for important prey
species. Removing attractants such as bone piles and carcasses
helps keep wildlife away from the livestock, roadways, and rail
lines that dominate areas between wildlands. Cases of mistaken
identity by hunters are reduced by vigilant education and out-
reach activities.
For many of these iconic wildlife species, connections with
the robust Canadian populations to the north and between
Washington's wildlands in the Cascades and Rocky Mountains
are essential for facilitating recovery and maintaining viability in
the Pacific Northwest, especially as climate change bears down.
"Habitat connectivity
isn't just for fire
dependent species like
lynx; it is necessary
for all animals, great
and small."
Wolverines like this one in the upper
Teanaway Valley are rebounding in
Washington's North Cascades. But they
need safe, connected habitat to reach the
South Cascades and beyond.
Central Cascades Wolverine Study
