|
| It is widely accepted that the main driver of the observed decline in biological diversity is increasing
human pressure on Earth’s ecosystems. However, the spatial patterns of change in human pressure and their
relation to conservation efforts are less well known. We developed a spatially and temporally explicit map
of global change in human pressure over 2 decades between 1990 and 2010 at a resolution of 10 km2.
We evaluated 22 spatial data sets representing different components of human pressure and used them to
compile a temporal human pressure index (THPI) based on 3 data sets: human population density, land
transformation, and electrical power infrastructure. We investigated how the THPI within protected areas
was correlated to International Union for Conservation of Nature (IUCN) management categories and the
human development index (HDI) and how the THPI was correlated to cumulative pressure on the basis of
the original human footprint index. Since the early 1990s, human pressure increased 64% of the terrestrial
areas; the largest increases were in Southeast Asia. Protected areas also exhibited overall increases in human
pressure, the degree of which varied with location and IUCN management category. Only wilderness areas
and natural monuments (management categories Ib and III) exhibited decreases in pressure. Protected areas
not assigned any category exhibited the greatest increases. High HDI values correlated with greater reductions
in pressure across protected areas, while increasing age of the protected area correlated with increases in
pressure. Our analysis is an initial step toward mapping changes in human pressure on the natural world
over time. That only 3 data sets could be included in our spatio-temporal global pressure map highlights the
challenge to measuring pressure changes over time. | |
|