Why in the News
A new study published in Insect Conservation and Diversity by researchers from the Wildlife Institute of India finds that land use change and elevation are significantly reshaping spider communities in the north western Indian Himalayas, potentially reducing ecosystem resilience.
What Did the Study Examine?
- Surveyed spiders along an elevational gradient of 1,500 to 4,500 metres in Himachal Pradesh.
- Compared three land use types:
- Forests
- Agricultural lands
- Human dominated regions
- Recorded:
- 2,936 individuals
- 126 species
- 65 genera
- 26 families
What is Functional Diversity?
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- Functional diversity refers to the ecological roles species perform, rather than just counting the number of species.
- Examples of spider traits studied:
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- Circadian activity
- Hunting strata
- Ballooning ability
- Hunting guild
- Prey range
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- Higher functional diversity means:
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- Greater ecological stability
- Better pest control
- More resilience against disturbances
Key Findings
- Decline with Elevation: Species richness and functional redundancy decrease with altitude, with a critical threshold around 3,000 to 3,500 metres near the Himalayan treeline, increasing ecosystem vulnerability.
- Agricultural Homogenisation: Functional diversity remains stable across elevations in agricultural areas, indicating trait homogenisation due to intensification, with dominance of ground dwelling spiders like Lycosidae.
- Forest Elevational Gradients: Forest ecosystems show clear trait shifts with altitude, with communities largely dominated by cathemeral species.
- Human Dominated Landscapes: Greater trait richness at lower elevations supports the intermediate disturbance hypothesis, with presence of synanthropic species adapted to human environments.
Ecological Importance of Spiders
- Among the most voracious arthropod predators.
- Consume over 600 million tonnes of insects annually.
- Help regulate pest populations and disease vectors.
- Act as bioindicators of habitat disturbance.
| [2011] The Himalayan Range is very rich in species diversity. Which one among the following is the most appropriate reason for this phenomenon?Â
(a) It has a high rainfall that supports luxuriant vegetative growth. (b) It is a confluence of different biogeographical zones. (c) Exotic and invasive species have not been introduced in this region. (d) It has less human interference. |
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