Natural Corridors 2018-10-23T09:52:09-04:00

Natural Corridors

Butterfly Riparian Zones

st-franci-satyrRiparian zones are natural corridors that help sustain subpopulations within a constantly shifting landscape.

One example of the use of riparian zones as natural corridors is the St. Francis’ satyr, an endangered butterfly found only on one military base in the United States.  The butterfly is dependent on ephemeral wetlands along stream corridors to disperse into emerging suitable habitat. Suitable habitat is determined by beaver and fire activity, and as a result is constantly shifting.

To sustain the larger metapopulation, individuals must be able to travel along riparian corridors to find a developing patch. Without these natural corridors, subpopulations would become isolated and lose their ability to disperse effectively.

North American Migratory Flyways

USGS-flyway-mapMigratory birds and insects have a strong need for corridors, even though they spend much of their time in the air rather than on the ground. Connected corridors provide habitat for resting and feeding, and ensure that species are able to continue on their migratory journey without encountering large gaps of unsuitable habitat.

Protection of these “flyways” as natural corridors for migratory species is critical to ensure that they are able to reach desired breeding or wintering grounds. North America has four main migratory flyways: the Pacific Flyway, Central Flyway, Mississippi Flyway and Atlantic Flyway.

Pacific Ocean Corridors

Similar to terrestrial ecosystems, marine ecosystems can support naturally occurring corridors within the larger expanse of the ocean.

In the Pacific Ocean, two main corridors are used by marine wildlife: the California Current, which flows south along the west coast of North America, and a trans-oceanic corridor called the North Pacific Transition Zone, which forms the border between cold sub-Arctic waters and warmer subtropical waters.

These areas tend to attract large numbers of individuals due to high prey abundance such as zooplankton and fish, which in turn attract large predators. Species that use these corridors include whales, sharks, seals, seabirds, turtles and tunas.