In a landscape with habitat patches, maintaining gene flow helps prevent which risk to small populations?

• A. Inbreeding depression
• B. Habitat expansion
• C. Mutation rate
• D. Dispersal limitation

Answer: (A)

Gene flow between habitat patches keeps small populations genetically connected, which raises heterozygosity and lowers relatedness among individuals. When relatives are less likely to mate, deleterious recessive alleles are less likely to pair up and express themselves, so offspring fitness doesn’t fall as much. That diminished risk is called inbreeding depression, a common threat to small, isolated populations in fragmented landscapes. By maintaining gene flow, populations retain genetic diversity and adaptive potential over time, increasing their chances of surviving environmental changes.

Habitat expansion is about more space, not the genetic risk itself. Mutation rate is about how often new genetic changes arise, which gene flow doesn’t directly control. Dispersal limitation is a constraint gene flow helps overcome, but the specific risk that gene flow most directly mitigates in small populations is inbreeding depression.