Correct option is A
The correct option is (a)
Beta diversity increases when there is high variation in species composition between different local sites. This often occurs with high habitat heterogeneity (different types of habitats support different species) and strong dispersal limitation (species do not easily move from one site to another, so different sites develop distinct communities).
High gamma diversity means a rich regional species pool, which provides more species to be distributed unevenly across sites, contributing to beta diversity.
Incorrect options-
Option (b) is incorrect because-
Species can move freely and habitats are similar, so species composition will be more uniform across sites, reducing beta diversity.
Option (c) is incorrect because-
Although dispersal limitation is strong, the overall regional species pool is low (low gamma diversity), which limits species turnover and beta diversity.
Option (d) is incorrect because-
Low regional species pool and free movement of species result in low beta diversity.
