Step 1: Definition.
Biodiversity conservation refers to the protection, maintenance, and sustainable management of ecosystems, species, and genetic resources to prevent their loss.
Step 2: Strategies for biodiversity conservation. There are two major approaches: \[\begin{array}{rl} 1. & \text{In-situ conservation (On-site): Protects species in their natural habitat.} \\ \bullet & \text{Biosphere reserves: Large areas conserving ecosystems (e.g., Nilgiri, Sundarbans).} \\ \bullet & \text{National parks: Strict protection of wildlife (e.g., Kaziranga, Jim Corbett).} \\ \bullet & \text{Wildlife sanctuaries: Protection of particular species with limited human activities (e.g., Bharatpur Bird Sanctuary).} \\ \bullet & \text{Sacred groves: Forest patches protected by local communities (e.g., Meghalaya).} \\ 2. & \text{Ex-situ conservation (Off-site): Protects species outside their natural habitats.} \\ \bullet & \text{Botanical gardens and zoological parks.} \\ \bullet & \text{Gene banks: Preservation of genetic material (seed banks, cryopreservation, tissue culture).} \\ \bullet & \text{Captive breeding and reintroduction programmes.} \\ \end{array}\]
Step 3: Legal and global efforts.
\[\begin{array}{rl} \bullet & \text{Convention on Biological Diversity (CBD, 1992).} \\ \bullet & \text{Indian Wildlife Protection Act (1972).} \\ \bullet & \text{Project Tiger and Project Elephant in India.} \\ \end{array}\]
Step 4: Conclusion.
A combination of in-situ and ex-situ strategies, along with awareness and legislation, is essential for sustainable conservation of biodiversity.
A biologist surveyed islands of different sizes and consolidated the results in the form of the data given below. Study the data carefully and answer the questions that follow.
Based on data (Birds decline, Plants % decline, Area decline), interpret two reasons for change in the population of migratory birds. 