The concept of 'edge effect' in ecology refers to:
Correct: A
The edge effect refers to the changes in population or community structures that occur at the boundary of two or more different habitats. It is characterized by an increased biodiversity at habitat edges because species from both adjacent habitats, as well as species specifically adapted to edge conditions, can coexist. This is a well-documented phenomenon in landscape ecology and is relevant in conservation biology for designing nature reserves and wildlife corridors.