Global warming forces changes to ecosystems and those changes stress the ecosystem’s species to different degrees. Both ecosystems and their species respond to these changes by migrating to climatic zones where temperatures and other environmental conditions are optimal. The speed and direction at which a species geographically relocates are referred to as climate velocity.
A review of 12,000 species of plants, animals, bacteria, and fungi documented their population shifts in response to temperature changes. Amphibians are moving upslope to higher elevations at 12 meters per year. Insects show a poleward migration at 18.5 meters per year. But the most dramatic shifts are in marine species as they migrate poleward at an average rate of six kilometers per year. Comparatively, terrestrial species migrate at an average rate of 1.8 meters per year.
Ecosystem Migration
The ability to migrate is dependent on many factors. If migration occurs on land, then geographic barriers come under consideration. If a species requires a specific food source, then either the food source must migrate, or that the same food source must be present at the new location.
This food-web dependency leads to the concept of ecosystem migration. When fundamental climatic conditions change, then entire ecosystems can slowly migrate to follow optimal climatic conditions. This type of adaptation is heavily influenced by the presence or absence of geographical and human-made barriers.
Rapid species migration in marine environments is enabled by the ability of entire food chains to migrate in mass because of the lack of geographic barriers in the open oceans. If heat is the environmental condition driving migration, then movement poleward is a viable solution in the oceans, because the general trend is warmer waters in the tropics and cooler waters towards the poles. Some marine species also have the leeway to move deeper when conditions on the surface become too warm. However, vertical migration must be balanced with enough sunlight to let primary producers grow and thrive.
But forests are often the foundation of terrestrial ecosystems. The trees cannot rapidly relocate, so multiple decades are required for forest ecosystems to shift. Seeds must spread, and new trees must grow for the forests to relocate.
Species dispersal
Physiology also plays a role in species migration. Thus, the climate velocity for each species is different. Warm-blooded animals tolerate a broader temperature range since they can regulate their body temperature. Physiological and behavioral adaptation to changing environmental conditions is an alternative to migration for some species. Others, however, have no choice but to move.
Within an ecosystem, the needs of individual species are different; thus, they may migrate at different rates. So when species that are vital links in the food web migrate rapidly, they cause massive disruption to the ecosystem’s food web. Climate velocity determines where species relocate and the rate at which they disperse. Vast differences in climate velocity between species disrupt an ecosystem and force transformations. We can’t currently know whether these transformations will be positive or negative from the perspective of human beings.
Archeanweb:
Species adaptation to climate change (Source: ArcheanWeb) – https://archeanweb.com/2020/03/31/species-adaptation-to-climate-change/ Also:
Changing currents cause North Atlantic ecosystem drift (Source: ArcheanWeb) – https://archeanweb.com/2020/05/07/changing-currents-cause-north-atlantic-ecosystem-drift/ Also:
Sources:
Thousands of Species Are Fleeing to Earth’s Poles en Masse, And a Pattern’s Emerging (By Carly Cassella; Science Alert) – https://www.sciencealert.com/as-the-world-gets-hotter-thousands-of-species-are-fleeing-to-earth-s-poles Also:
How fast will you need to flee from the heat? There’s a word for that. (By Kate Yoder, Grist) – https://grist.org/climate/how-fast-will-you-need-to-flee-from-the-heat-theres-a-word-for-that/ Also:
Feature Image: Migrating mammals (Modified) – By USFWS – Pacific Region – Migrating mammals, Public Domain, https://commons.wikimedia.org/w/index.php?curid=48766157