Relevance: GS-III (Environment & Ecology – Climate Change, Biodiversity) | Source: The Hindu 

1. The Core Issue: An Ecological Invasion

The Arctic, traditionally a frozen and barren landscape, is undergoing a rapid transformation known as “Greening.” As the region warms due to climate change, it is losing its natural defense—extreme cold.

• The Threat: A new study warns that nearly 2,554 weed and invasive plant species from around the world could soon invade the Arctic. These “alien” plants threaten to permanently alter the fragile Tundra ecosystem, replacing native mosses and lichens with tall grasses and shrubs.

2. Drivers of Invasion: Why is this happening?

The invasion is driven by a combination of warming temperatures and human movement:

• Climate Change (The Pull Factor): Rising temperatures are removing thermal barriers. Regions like Western Alaska, Southern Greenland, and Northern Iceland are developing “suitable climatic niches” (habitable conditions) for plants that previously could not survive there.
• Human Activity (The Push Factor):
  • “Transport-Stowaways”: About 48% of these invasive seeds arrive by sticking to the boots of tourists, vehicles, or cargo ships.
  • “Last-Chance Tourism”: Ironically, tourists rushing to see the melting Arctic before it disappears are accelerating its destruction by unknowingly carrying alien seeds.

3. Ecological Impact: A Vicious Cycle

• Tundra Transformation: Native Arctic plants are mostly non-vascular (low-lying mosses/lichens). They grow slowly. Invasive vascular plants (tall weeds) grow fast and outcompete them for sunlight and nutrients.
• The Mosquito Threat: Warming is allowing mosquitoes to survive in new areas (e.g., Iceland). If they reach places like Antarctica (currently the only mosquito-free continent), they could introduce diseases to wildlife like penguins and seals that have no natural immunity.

UPSC Value Box

Concept: “Borealization” & Albedo Effect

• Borealization: The process where Arctic Tundra (treeless plain) is replaced by Boreal ecosystems (forests/shrubs) due to warming.
• Albedo Feedback Loop:
  • Normal: Snow/Ice is white (High Albedo) $\rightarrow$ Reflects sunlight $\rightarrow$ Keeps region cold.
  • Invasion: Tall, dark invasive shrubs replace snow (Low Albedo) $\rightarrow$ Absorb sunlight $\rightarrow$ Accelerate warming further.

Global Framework:

• Kunming-Montreal Global Biodiversity Framework (Target 6): Explicitly aims to reduce the introduction of Invasive Alien Species by 50% by 2030.

Q. With reference to the ecological changes in polar regions, the term “Borealization” best describes which of the following phenomena?

1. The expansion of forest and shrub ecosystems into the treeless Arctic tundra due to warming.
2. The rapid melting of permafrost leading to the release of methane.
3. The migration of polar bears towards human settlements in search of food.
4. The formation of new ice sheets in the Antarctic region.

Answer: (a)