Question

Based on data (Birds decline, Plants % decline, Area decline), interpret two reasons for change in the population of migratory birds. 

 

Hint:

In data-based questions, always link your biological reasoning directly to the variables shown in the table columns.

Answer 1

Step 1: Understanding the Concept:
Analysis of the provided table shows a correlation between bird population and environmental factors.

Step 2: Detailed Explanation:
1. Habitat Loss: The total aquatic area decreased from 350 to 220 hectares. Smaller area means less space for nesting and foraging.
2. Food Shortage: Aquatic plant cover dropped from 85% to 45%. Since many migratory birds depend on these plants for food, the decline in vegetation leads to starvation or migration to other areas.

Step 3: Final Answer:
Reasons: Habitat destruction (area reduction) and lack of primary productivity/food (plant decline).