Step 1: Understanding the Concept:
Ecosystem balance is maintained by native species, while non-native introductions can cause severe ecological disruption.
Step 2: Detailed Explanation:
- Invasive species: Non-native (exotic) species introduced to an ecosystem that rapidly multiply, outcompete native species for food and space, and disrupt food webs. They represent one of the greatest global threats to native biodiversity.
For example, the introduction of Tilapia or African Catfish has severely impacted native fish biodiversity in Indian rivers.
- Keystone species: Species that play a critical, disproportionately large role in maintaining the structure of an ecological community.
- Endemic species: Species confined to a specific geographic area.
Step 3: Final Answer:
The species that pose a threat to biodiversity are invasive species, corresponding to option (C).