Metapopulation

What is a metapopulation?

Metapopulations are groups of local populations that are loosely linked by immigration and emigration. Local populations are founded, grow larger and are extirpated independently of one another, but the number of local populations existing at any one time is relatively stable.

Demonstrating the existence of metapopulations in nature is difficult because it requires long term data on populations dynamics, which seldom exists. In the absence of this data, we have included species in this category on the basis of available life-history information. Those that breed in the same location as their parents, have very limited dispersal, and/or have naturally patchy distributions are likely to exist as metapopulations.

 Community mapping network

Requirements include:

  • suitable habitat patches in close enough proximity to one another for occasional individuals to move between them.
  • rates of habitat patch creation sufficient to balance habitat losses to natural succession.

Threats include:

  • barriers to movement between local populations.
  • reduced rates of habitat creation caused by fire suppression or other changes in natural disturbance frequencies.
  • increased rates of habitat loss from human or natural causes.

Abbotsford, bc (c)Mike Pearson

Strategies:

Maintain or increase size and density of suitable habitat patches

  • Restore or maintain habitats on local government lands to successional stages appropriate for the species .
  • Target habitats that support, or are close to habitats that support, existing local populations for acquisition by purchase or dedication or for protection by conservation covenants.
  • Include information about metapopulations in public education materials and programs.
  • Maintain natural frequencies of events that create suitable habitat on the landscape (e.g. fire or flood frequencies).

Provide safe passage between habitats

Dry culvert, chilliwack, bc (c) Mike Pearson

  • Target potential dispersal corridors between existing habitats for purchase, dedication, or protection by conservation covenant.
  • Include safe passage features for aquatic and terrestrial species in local government infrastructure. These might include dry culverts under roadways, bridges that land animals can pass beneath, fencing to funnel animals to safe crossing points, and watercourse crossings that facilitate fish passage.
  • Require that transportation infrastructure in developments include safe passage features for terrestrial and aquatic species using the subdivision and development permit processes.
  • Erect cautionary signs along roads where wildlife cross frequently.