UPSC Prelims 2018 Q86: Environment & Ecology – Biodiversity & Conservation
- (a) Its extract is widely used in cosmetics.
- (b) It tends to reduce the biodiversity in the area in which it grows.
- (c) Its extract is used in the synthesis of pesticides.
- (d) None of the above
Answer: (b) It tends to reduce the biodiversity in the area in which it grows.
Explanation
Prosopis juliflora - Ecological Concern
Prosopis juliflora (Vilayati kikar / Mesquite) is a highly invasive alien species originally from South and Central America, introduced to India in the 19th century for fuelwood, fodder and greening of degraded lands. It has since become one of India's worst invasive weeds.
| Option | Correct? | Detail |
|---|---|---|
| (a) Extract used in cosmetics | NO | Not a cosmetic species. |
| (b) Tends to REDUCE biodiversity in area it grows | YES | Prosopis juliflora forms impenetrable thickets, displacing native flora, altering soil chemistry (allelopathy), depleting groundwater, and reducing habitat for native fauna. It has invaded arid lands from Rajasthan to Tamil Nadu, notably devastating Banni grasslands in Kutch and displacing native Prosopis cineraria (Khejri). |
| (c) Used in pesticide synthesis | NO | Not a pesticide feedstock. |
| (d) None of the above | WRONG | Option (b) is a well-documented ecological concern with Prosopis juliflora - so “None of the above” cannot be the answer. |
Answer: (b) It tends to reduce the biodiversity in the area in which it grows.
Why each option is right or wrong
- (a) Incorrect. Prosopis juliflora is not a cosmetic-industry plant.
- (b) CORRECT. Prosopis juliflora is a highly invasive alien species that reduces biodiversity, displaces native vegetation, and alters ecosystems - a major ecological problem in Indian arid lands.
- (c) Incorrect. It is not used as a pesticide feedstock.
- (d) Incorrect. The invasive nature of Prosopis juliflora is well-documented ecologically.
Key point
Prosopis juliflora = invasive alien species in India. Reduces biodiversity via allelopathy + thicket formation. Devastates Banni grasslands (Kutch). Displaces native Prosopis cineraria (Khejri) - Rajasthan's state tree. Introduced in 19th century for greening; now a menace.
Remember
Prosopis juliflora (Vilayati kikar or Mesquite), introduced to India from the Americas in the 19th century, is a highly invasive alien species. It forms impenetrable thickets, depletes groundwater, alters soil chemistry through allelopathy, and displaces native vegetation - thereby reducing biodiversity. It has devastated ecosystems like the Banni grasslands in Kutch and displaced the native Khejri (Prosopis cineraria).
Common mistakes
- Confusing Prosopis juliflora (invasive Mesquite from Americas) with Prosopis cineraria (Khejri - native to Thar, Rajasthan's state tree, sacred to Bishnois).
- Assuming any tree is beneficial - invasive species like Prosopis juliflora, Lantana camara, Parthenium hysterophorus are ecological threats.
- Missing the Banni grasslands story - once India's largest grassland, now heavily invaded by Prosopis juliflora.
Exam tip
Top invasive alien species in India: Prosopis juliflora, Lantana camara, Parthenium hysterophorus (Congress grass), Eichhornia crassipes (Water hyacinth), Mikania micrantha, Chromolaena odorata.
Sources
- MoEFCC - National Wildlife Action Plan on Invasive Alien Species
- IUCN - Global Invasive Species Database