Human activities alter native habitat. The impact of that activity on a species is determined by three factors: 1) how much area the footprint occupies; 2) how strongly—positively or negatively—the species responds to a footprint; and 3) how much of the footprint is in higher- versus lower-quality habitat for the species. For example, a species that lives in old upland forest may be more affected by the forestry sector than the energy sector, because forestry focuses on those older merchantable stands.