What are two situations that would reduce biodiversity?

As lianas become more dense, tree mortality rises, but mortality is not equal among species because lianas preferentially grow on certain species. Because of this biodiversity may be reduced by increased mortality in some species but not others (Phillips, et al., 2002). f. read more

Figure 1. Biodiversity is threatened by a variety of global changes resulting from the combined actions of human society. The most direct threats are overharvesting and loss/disturbance of habitat resulting from conversion of natural ecosystems to human use (thick red arrow). read more