Final answer:
Habitat corridors have two true roles: providing unique habitats for species and aiding in dispersal between habitat patches, which helps maintain biodiversity across fragmented landscapes.
Step-by-step explanation:
The statement that habitat corridors have two roles is true. One role is providing a unique habitat for certain plant and animal species. Many species benefit from the habitat components that enhance connectivity in a landscape, which includes continuous "corridors" or "stepping stones" of habitat that assist in their activities such as foraging, breeding, and movement. The other role is providing a means of dispersal between larger patches of habitat, helping to reduce the detrimental effects of isolation by promoting movement and genetic exchange between populations.
This is evident in large scale conservation corridors like the "Yellowstone to Yukon" and the Mesoamerican Biological Corridor. However, the implementation of corridors can at times divert conservation resources and potentially increase threats such as the spread of disease or invasive species. Despite these concerns, evidence suggests that habitat corridors benefit biodiversity and serve as critical priorities in maintaining plant and animal assemblages, making them essential elements of landscape-scale conservation efforts. For example, larger fragments or patches of habitat have been correlated with higher species richness, and corridors help to maintain this biodiversity across a fragmented landscape.