Previous Year Question

For the survival of a species, merely remaining alive is not sufficient; it also requires a natural habitat providing food, water, shelter, breeding sites and suitable environmental conditions. Therefore, destruction of natural habitat directly affects species survival and population size.

When forests, grasslands, wetlands, mangroves and other natural ecosystems are converted into agriculture, urban areas, mines, roads, industries or other land uses, the species living there lose their original habitat and essential resources.

Habitat destruction is frequently accompanied by habitat fragmentation. A large continuous habitat becomes divided into smaller isolated patches. This can reduce movement and gene flow between different populations.

Small and isolated populations can face greater risks of inbreeding, reduction in genetic diversity and local extinction. Fragmentation can also make access to breeding partners and food resources more difficult.

Division of habitats into smaller patches also increases the edge effect. Near habitat boundaries, temperature, light, humidity, predators and invasive species may have different effects compared with the habitat interior, particularly affecting specialised species.

Biodiversity loss is not limited merely to a decline in the number of species. Habitat destruction can also disturb food webs, pollination, seed dispersal, nutrient cycling and ecosystem functioning.

International biodiversity assessments identify land-use change and habitat loss/degradation among the major direct drivers of biodiversity decline. IPBES identifies land-use change as the leading direct driver for terrestrial and freshwater ecosystems.

Among the other options:

Control of predators can alter predator-prey balance within an ecosystem, but it is not the most widespread cause of biodiversity loss.

Pest control through pesticides may affect non-target organisms, but among the given options its impact is not as extensive as habitat destruction.

Genetic assimilation can affect the distinct genetic identity of a population, but it is not the principal global driver of overall biodiversity loss.