2040 Future Human Footprint - Current Trends Scenario

The Future Human Footprint (FHF) of the Northern Appalachian/Acadian ecoregion projects the extent and relative intensity of human influence on terrestrial ecosystems over a 20-40 year span at a resolution of 90 m using best available data sets on human settlement (population density, dwelling density, urban areas), access (roads, rail lines), landscape transformation (landuse/landcover, dams, mines, watersheds), and electrical power infrastructure (utility corridors). The Future Human Footprint uses as a basis the Current Human Footprint, and projects forward salient, dynamic features of human infrastructure including residential roads, human settlement, and amenity development. It attempts to capture two dominant land use change processes in North America: 1) exurban growth or incremental expansion in settled landscapes, and 2) instantaneous growth focused on natural amentities (i.e., lakeshores).

Each 90m grid cell is attributed with a Human Footprint score between 0 and 100, where 0 represents minimum human influence and 100 represents maximum human influence at that location. The Human Footprint scores (0-100) may be interpreted as the percent influence.

The Human Footprint is calculated by assigning Human Influence (HI) scores of 0 to 10 to geographic data layers that map features of human activity. Where 0 is no human influence (no conversion from natural state) and 10 is maximum human influence (complete conversion e.g. urban areas, road surfaces). HI scores from assigned to data layers are combined together to calculate the Human Influence Index (HII), that measures total direct human impact.

The Human Footprint is a relative measure of human impact - relative to the ecological context. The Human Footprint is calculated by normalizing the Human Influence Index (HII) within ecological subunits within the study area using the equation HFi = [(HIIi - HIImin_j) * 100] / (HIImax_j - HIImin_j) where i represents the cell and j represents the ecologic subunit of which the cell is a member.

Specifically, the Current Trends FHF casts forward these dyanamic components by 1) an exponential growth model for human population based on 1990's county level growth rates acting as a neighborhood effect on 2000-2001 census units; 2) applying a logit model to explain historical changes in road distribution and then project them to the ecoregion scale (Baldwin et al. 2007), and 3) applying a spatial screening model to identify at risk lakeshores, based on protection level, size of lake, distance to nearest urban area, and predisposition of owners to sell. The Current Trends Human Footprint is based on the following scenario:

The Current Human Footprint is based on the following conditions:

Current Trends: under current trends, the rates of change in human settlement experienced during the 1990's continue to drive new settlement patterns into the future (Process 1). Coupled with this is a modest rise in wilderness development around heretofore undeveloped lakeshores - "instantaneous transition" of forested landscapes to developed ones (Process 2).

Process 1: (a) current trends of population growth projected 40 years
(b) projected 80% probability surface for regular, public roads

Process 2: ownership-weighted risk to wilderness lakeshores, within 100km from major urban areas