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Thursday, August 14, 2025

10 UPSC Prelims-style questions on water hyacinth, invasive species, and related environmental terms:

10 UPSC Prelims-style questions on water hyacinth, invasive species, and related environmental terms:


1. Which of the following is an invasive alien species in India?

A. Water Hyacinth
B. Salicornia
C. Nymphaea
D. Lotus

Answer: A. Water Hyacinth

Explanation: Eichhornia crassipes (Water Hyacinth) is an invasive alien species introduced as an ornamental plant. Salicornia, Nymphaea, and Lotus are native or non-invasive species.


2. What is the primary ecological threat caused by water hyacinth?

A. Soil erosion
B. Blocking sunlight and depleting oxygen in water
C. Increasing river flow speed
D. Reducing water acidity

Answer: B. Blocking sunlight and depleting oxygen in water

Explanation: Dense mats prevent sunlight penetration and reduce dissolved oxygen, affecting aquatic life.


3. Vembanad Lake, often in news due to water hyacinth, is located in which state?

A. Tamil Nadu
B. Karnataka
C. Kerala
D. Odisha

Answer: C. Kerala

Explanation: Vembanad Lake is the largest lake in Kerala and a Ramsar site, heavily impacted by water hyacinth.


4. Which of the following conventions is related to wetland conservation?

A. Ramsar Convention
B. CITES
C. Montreal Protocol
D. Kyoto Protocol

Answer: A. Ramsar Convention

Explanation: The Ramsar Convention (1971) aims at conserving and sustainably using wetlands of international importance.


5. Prosopis juliflora, often mentioned in news, is an example of:

A. Native aquatic plant
B. Invasive alien species
C. Medicinal plant
D. Endangered species

Answer: B. Invasive alien species

Explanation: Prosopis juliflora is an invasive tree species spreading in arid regions of India, affecting native biodiversity.


6. Which of the following is a greenhouse gas released by decaying water hyacinth?

A. Carbon dioxide
B. Methane
C. Nitrous oxide
D. Ozone

Answer: B. Methane

Explanation: Methane released during decomposition of water hyacinth is over 25 times more potent than CO₂ in trapping heat.


7. Lantana camara in India is categorized as:

A. Endangered species
B. Invasive alien species
C. Aquatic plant
D. Medicinal herb

Answer: B. Invasive alien species

Explanation: Lantana camara is a terrestrial invasive species, widespread in forests, affecting native flora.


8. Which of the following strategies are used for managing water hyacinth?

  1. Mechanical removal

  2. Biological control

  3. Making handicrafts

A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2, and 3

Answer: D. 1, 2, and 3

Explanation: Management includes mechanical removal, biological control (weevils), and utilizing hyacinth for handicrafts or biofuel.


9. Which Indian state has the Kuttanad region, often affected by water hyacinth?

A. Maharashtra
B. Kerala
C. West Bengal
D. Assam

Answer: B. Kerala

Explanation: Kuttanad, the “rice bowl of Kerala,” faces irrigation blockages and agricultural losses due to water hyacinth.


10. Which of the following statements about Ramsar Sites is/are correct?

  1. They are wetlands of international importance.

  2. India has over 50 Ramsar Sites.

  3. The Convention mandates the eradication of invasive species.

A. 1 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2, and 3

Answer: B. 1 and 2 only

Explanation: Ramsar Sites are internationally important wetlands. India currently has 75 Ramsar Sites (as of 2024). The convention promotes conservation but does not mandate eradication of invasive species.

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