If a graph shows a decrease in the diversity index after a disturbance, what might this indicate about the ecosystem’s resilience?

• A. It may indicate reduced resilience and a slower or incomplete recovery; biodiversity loss can reduce functional redundancy.
• B. It indicates high resilience and rapid recovery.
• C. Biodiversity loss improves recovery.
• D. It has no impact on resilience.

Answer: (A)

Resilience is the ability of an ecosystem to absorb a disturbance and bounce back to its original state. The diversity index tracks how many species are present and how evenly they are represented. If the index drops after a disturbance, it means some species were lost or didn’t recolonize, reducing functional redundancy—the idea that multiple species can fill the same roles. With fewer species available to perform key processes like pollination, decomposition, and nutrient cycling, the system has fewer ways to respond to stress and recover. As a result, recovery tends to be slower and may not return to the pre-disturbance level of diversity, signaling reduced resilience. This pattern does not indicate rapid recovery or no impact; it points to greater vulnerability and a potential shift to a less diverse state if disturbances continue.