Current Edge Daily Brief 9th October 2025

TH Science: India’s invasive species present a dilemma: document or conserve

Syllabus: Pre/Mains – Environment

Why in News?

Scientists warn invasive alien species (IAS) are rapidly degrading India’s ecosystems, forcing debate: document first or conserve parallelly?

❖ Invasive Alien Species (IAS): Scale & Impact

• 37,000 alien spp. globally → +200/year (10% harmful) ✦ Source: K.V. Sankaran
• India → 139 invasive spp. (↑ insect pests) ✦ Source: ATREE
• Effects → Biodiversity loss, native spp. extinction, habitat destruction, altered ecosystem functions

❖ Key Invasive Examples & Ecological Effects

1. Terrestrial Flora

• Lantana camara → from ornamental shrub → invasive in elephant habitats → ↓ mobility, ↑ human-wildlife conflict
• Prosopis juliflora (Gando Bawar) → introduced for soil salinity control → now covers 50–60% Banni grassland → ↓ grasses, ↑ soil salinity, ↓ groundwater, disrupts pastoralism

2. Aquatic Flora

• Water hyacinth, Alligator weed, Duck weed, Water lettuce → choke lakes/rivers → ↓ light penetration, ↑ eutrophication, threaten migratory birds (Kaziranga, Assam)

3. Fauna

• Yellow crazy ant → ↓ native ants → pest control imbalance
• 626 alien aquatic spp. in India (via aquarium trade, aquaculture) → threaten 1,070 native freshwater fishes

❖ Ecological & Functional Disruptions

• Soil → altered porosity, nutrient balance
• Water → ↑ turbidity, ↓ oxygen, light blockage
• Species-level → ↓ survival, reproduction, genetic diversity
• Population-level → ↓ size, range; local extinctions
• Ecosystem-level → altered food webs, energy flow, nutrient cycling; ecosystem regime shift

❖ Challenges: Poor Documentation & Knowledge Gaps

• Few spp. well-studied (e.g. Parthenium, Lantana, Prosopis)
• Limited invasion history, spatial mapping, or impact data
• Freshwater invasion biology → still nascent in India

❖ Policy & Research Dilemma: Document vs. Conserve

• Two paths → (i) Document fully before conservation, or (ii) Parallel documentation & management
• Consensus → Parallel approach better → site-specific studies endless, resources limited
• Use global data → adapt to Indian ecosystems

❖ Way Forward

• Develop standardised quantitative frameworks → map cumulative IAS effects
• Identify high-impact spp. & hotspots → prioritise management
• Promote interdisciplinary collaboration → scientists + policymakers + local communities
• Enable citizen science atlases → track spread & intensity
• Combine impact assessment + eradication → holistic ecosystem restoration

Core Insight:

Invasive Species management in India needs dual-track action — simultaneous documentation & conservation — guided by quantitative mapping, participatory science, and adaptive ecological planning.

Test Your Knowledge 02

Q. Which of the following pairs is correctly matched with its ecological consequence in India?

Species → Impact

1. Lantana camara → Enhances forage for elephants
2. Prosopis juliflora → Increases soil salinity and groundwater depletion
3. Water hyacinth → Improves oxygen availability in aquatic systems
4. Yellow crazy ant → Increases population of native pest-controlling ants

(a) 1 and 2 only
(b) 2 only
(c) 2 and 4 only
(d) 1, 3, and 4 only

Hint: Prosopis juliflora worsens salinity and depletes water. Others have negative effects: Lantana reduces forage, Water hyacinth depletes oxygen, Yellow crazy ant reduces native ants.

Q. Consider the following impacts:

1. Reduction in predator–prey balance
2. Genetic erosion of native populations
3. Decline in primary productivity
4. Enhancement of nutrient cycling efficiency

Which of the above are true impacts of invasive alien species?

(a) 1, 2, and 3 only
(b) 1, 3, and 4 only
(c) 2 and 4 only
(d) 1, 2, 3, and 4

Hint: Invasive Species reduce biodiversity and disrupt productivity, but they do not enhance nutrient cycling; they generally destabilize it.