Final answer:
Of the statements provided, 1) increasing edge areas alters species composition, and 2) reducing habitat size causes declines in species diversity, accurately describe the effects of landscape fragmentation. Statements 3 and 4 are incorrect; increased isolation inhibits dispersal and smaller patches typically support fewer species. Option 1 and 2 are correct..
Step-by-step explanation:
The common effects of landscape fragmentation can be understood in the context of habitat change and its impact on species diversity and distribution.
Increasing edge areas (1) often results in altered species composition because edge environments are different from core habitats, sometimes favoring generalist or invasive species over those adapted to interiors of habitats. With respect to the reduction of habitat size (2), it is well-established that smaller fragments support lower species diversity—a concept reflected in the species-area relationship.
Increasing the distance between habitat patches (3) generally hinders species dispersal, as opposed to improving it, by creating more isolated populations. Lastly, reducing the size of each patch (4) does not increase overall species richness; smaller patches sustain fewer species due to factors such as less habitat variety, smaller populations that are more prone to stochastic events, and a smaller sample of the original habitat.