Climate change matters only because changing conditions affect existing living systems. If life did not exist on the earth, then climate change would be a moot point. So, for living systems, climate change is perceived in terms of how changes in the atmosphere and hydrosphere affect the earth’s biosphere. Therefore, species adaptation to changing conditions is an important aspect of understanding the effects of climate change on our ecosystems.
An “ecosystem” context for climate change is why scientific research puts such an emphasis on tracking the health of individual species. The health of an ecosystem is reflected in the rise or fall of its species populations. Thus, there is value in knowing if a species population is increasing, decreasing, or staying the same.
Species extinction is one of the parameters used by scientists to understand changes to individual ecosystems. The rate at which species loss occurs either locally or globally is a reflection of environmental stress. One of the reasons climate change alarms researchers is because species loss in the Anthropocene is abnormally high. Historically, species have disappeared at a rate of about 0.02 percent every 100 years. However, five hundred species have gone extinct in the past 100 years. This rate is 50 times greater than the background level.
Adapt or perish
The good news is that life is tenacious and resilient. During its four-billion-year journey life survived multiple global climate disasters because of its ability to adapt. When mass extinctions wiped out up to 95 percent of the earth’s species, evolution kicked in, and new species evolved. The rise of mammals started about 65 million years ago when an asteroid struck at the ancient location of the Mexican, Yucatán Peninsula. This asteroid strike initiated the K-T extinction event, which ended the age of the dinosaurs and heralded in the rise of the mammals.
But adaptation through evolution is a process that occurs on a grander scale than short term species adaptation. One of the primary mechanisms for short term species adaptation is migration. Huge bird populations migrate annually. If conditions get too harsh for a species in one environment, then they migrate to a better place.
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 on the scale of decades, then entire ecosystems can slowly migrate to follow optimal climatic conditions. This type of adaptation requires the absence of geographical barriers.
Poleward drift
Oceans are a prime place for observing ecosystem migrations in the absence of geographical barriers. Thus, the effect of rising Anthropocene temperatures on marine ecosystems is observable. Recent research reported in Current Biology documents links between populations of marine species and atmospheric/oceanic warming.
The study involved 304 prominent marine species ranging from phytoplankton to fish and marine mammals. The work demonstrates a poleward drift of the species in modern times. Accordingly, population abundance decreased at the equatorward end of the species range and rose at the poleward end of the range. These species abandoned the warming equatorial waters and migrated north or south towards the poles. This migration from warmer to colder climates may reflect migratory adaptation at the base of the food chain to maintain optimal environmental conditions.
The study focused on species populations and not complete ecosystems. Still, the researchers note: “the temporal population-abundance response of species to warming at any position in their range may not exclusively depend on their thermal physiology but also the responses of the species with which they interact.” The interaction of multiple species within a defined geographical range is at the heart of an ecosystem.
The study leaves many questions unanswered, but it does provide evidence of ecosystem migration in response to global warming. Ecosystems migrate to fulfill the collective needs of the species populating that particular environment.
ArcheanWeb:
Species Loss: Rate of Change Matters (Source: ArcheanWeb) – https://archeanweb.com/2019/12/01/species-loss-rate-of-change-matters/ 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:
As the ocean warms, marine species relocate toward the poles (Source: Cell Press; Science Daily) – https://www.sciencedaily.com/releases/2020/03/200326124155.htm Also:
Reuben A. Hastings, Louise A. Rutterford, Jennifer J. Freer, Rupert A. Collins, Stephen D. Simpson, Martin J. Genner. Climate Change Drives Poleward Increases and Equatorward Declines in Marine Species. Current Biology, 2020; DOI: 10.1016/j.cub.2020.02.043 – https://www.cell.com/current-biology/fulltext/S0960-9822(20)30250-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982220302505%3Fshowall%3Dtrue Also:
Feature Image: Swirling fish schools (
Mass Extinction Events: Life’s Struggle for Survival (By William House) – https://archeanweb.com/2019/12/01/mass-extinction-events-lifes-struggle-for-survival/ Also:
