Question

The picture shows a pika, a small mammal found in grassland ecosystems. The vast grasslands of the Tibetan plateau are home to the plateau pika. The numerous pikas are prey for many predators of the grasslands, which serve as a major watershed for much of the area. The watershed drains large quantities of groundwater during the rainy season or the monsoon season. Pikas have extensive burrows that help drain groundwater rapidly and are used as nesting sites by many bird species. However, many people advocate the eradication of the plateau pikas because they compete with livestock for grass.

1. The ecosystem will become unstable because predators will have fewer prey, the birds will have fewer nesting sites, and the area downriver will become vulnerable to flooding without the burrows to aerate the soil and provide drainage for monsoon rains.
2. The ecosystem will become more stable because the pika will be replaced by other species of small mammals that can fill the niche, bird species will adapt to nesting aboveground, and the soils will become compacted without the burrows.
3. The ecosystem will become unstable because the predators will migrate to nearby ecosystems, the birds will nest in nearby trees, and the soils will be aerated by other small mammals.
4. The ecosystem will become more stable because the pika will no longer be there to eat the grasses, the birds will migrate to other ecosystems during nesting season, and the soils will be able to absorb more of the monsoon rains without the pika burrows.

Answer 1

Option A is correct

Step-by-step explanation:

Given

Pika are eaten by many animals of the grass land. The burrows of Pika are helpful in draining the ground water rapidly and the burrows also acts as nesting site for many bird species. Pikas consume grass and hence they are competitors of livestock animals.

Removing Pikas from this ecosystem will destabilise the ecosystem as all the grass land predators will not get sufficient food. If Pika will not be there, then their burrows too will not exist and hence the excess ground water cannot be absorbed. Also the bird species will not be able to use burrows as nesting site.

Hence, option A is correct