Ecological Archives A021-148-A2

Cory R. Davis and Andrew J. Hansen. 2011. Trajectories in land-use change around US National Parks and their challenges and opportunities for management. Ecological Applications 21:3298–3315.

Appendix B. A table describing the criteria used to delineate protected-area centered ecosystems and the ecological mechanisms on which they are based, and a table summarizing the known impacts of land-use changes on ecological processes.

TABLE B1. Criteria used to delineate protected-area-centered ecosystem boundaries and the ecological mechanisms on which they are based. The mechanisms are means by which human activities on surrounding lands may alter ecological processes and/or the viability of native species within protected areas as described by Hansen and DeFries (2007).

Mechanism Ecological Effects PACE Delineation criterion PACE data used
in this study
Change in
flows into
and out of
Water, sediment, nutrients, and organisms move with water
flows through watersheds. Land use in upper watersheds
may alter these flows into protected area.
Watershed boundaries: subbasins,
watersheds, or subwatersheds
intersecting protected area.
8, 10, and 12-digit
HUCs intersecting
protected area
(USDA-NRCS 2008)
Disturbances (e.g. fire) may originate outside and move
through a protected area. The condition of the disturbance
initiation zone influences the likelihood of disturbance
moving into the protected area. Both the disturbance
initiation and runout zones may provide important habitat
for organisms in the protected area.
Perimeter around protected area
of potential disturbance initiation
and runout zones based on historic
disturbance size and shape.
Loss of
Seasonal habitats, population source areas, movement paths,
or portions of large home ranges for populations within
protected areas may lie outside the protected areas. Land
use may alter or destroy these crucial habitats.
Migration, source-sink, and
seasonal habitats of
protected-area based organisms.
Change in
size of
Species within a protected area can be lost due to isolation as
the area of surrounding habitats is reduced due to land use.
Habitat types in proportional
representation up to size
specified from species-area
Existing Vegetation
Type layer (U.S.
Department of
Interior 2008)
Human presence on the periphery of protected areas may
cause changes in ecosystem processes and biodiversity that
extend varying distances into the protected area (e.g.,
hunting, poaching, outdoor recreation, pet effects on
wildlife, exotic species).
Private lands within 25-km buffer
around protected area.
All private,
land within
25 km buffer
unpubl. data)

TABLE B2. Known impacts of land-use changes on ecological systems.

Variable Reason for inclusion/effects References
Amount of public land influences the intactness of the larger ecosystem
depending on the level of protection; amount of private land determines
the potential for agriculture or other human development; private land
is susceptible to extractive resource markets such as timber and amenity
driven markets such as housing
Turner et al. 1996
Strongly correlated with adverse effects on species survival due to:
poaching, disease spread and competition from pets or livestock,
increases in exotic species, increases in human-wildlife conflicts,
and loss of habitat from preferential human settlement patterns
Kerr and Currie 1995,
Brashares et al. 2001,
Parks and Harcourt 2002,
Revilla et al. 2001, Packer et al. 1999,
Young et al. 2005, McKinney 2001,
Newmark et al. 1994,
Hansen and Rotella 2002
Recent, rapid increases in housing both at urban fringes and in
rural settings, with particularly high rates around protected areas;
highly correlated with aspects of ecosystem function and biodiversity;
effects include: reduction in the overall size of the effective
ecosystem, intensification of edge effects, interruption of linkages
between habitats used as dispersal or migration routes, introduction
of exotic species, and disruption of flows of energy and disturbance
events; associated with new roads, potentially harmful pets,
recreation, and wildlife-human conflicts
Theobald 2001, Brown et al. 2005,
Wade and Theobald 2010,
Radeloff et al 2010,
Hansen et al. 2005,
Hansen and DeFries 2007,
Crooks and Soule 1999,
Boyle and Samson 1985
Land in
Loss of natural habitat; creates barriers to movement of native
species; creates population sinks along borders of protected areas;
increases spread of invasive plant species; reduces water and air
quality due to pesticides and fertilizers; conversion of former
agricultural land to low density housing may change the available
forage for some species and create more severe barriers to
organism movement
Sinclair et al. 2002,
Pauchard and Alaback 2004,
Kramer and Doran 2010
Expected to double by 2030; measure of water quality; protected
areas located lower in a watershed are dependent on water
quality and quantity from upstream
Allan 2004, Jantz et al. 2005,
Theobald et al. 2009
Area of
Direct mortality to organisms; barriers to species movements;
fragmentation of habitat; noise; spread of invasive
and non-native species
Forman and Alexander 2000,
Ament et al. 2008


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