Threats to protected areas

Science Center Objects

Land-use intensification poses significant threats to biodiversity both directly through the alteration and fragmentation of ecosystems and habitat loss, and indirectly through the disruption of supporting ecological processes. While protected areas offer refugia for species and ecosystems, they do not function in isolation from surrounding natural, working, or human-dominated landscapes.

Protected areas will likely undergo shifts in ecological composition in coming decades given the coupled threats of land use and climate change. By assessing the land use threats facing species and/or ecosystems we can assist land managers in preserving biodiversity into the future and prioritizing at-risk lands for new protected land acquisition.

Project Description

Study site - land-use impacts on water resources and protected areas

Study site map. Ecoregions of the Pacific Northwest(Public domain.)

We use the LUCAS model to project spatially explicit future land change scenarios to assess land use threats near existing protected areas and priority conservation areas not yet protected. Land use conversion potential is a primary factor in the selection process for prioritizing critical conservation lands.

Our landscape level approach is useful given the magnitude and impact of human landscape alteration in the western United States and the limited time and resources available to enact effective management strategies at broader scales. Species level analyses of land use impacts are extremely useful at the individual level, however they are costly to implement and challenging to integrate into ecosystem level planning efforts. In contrast, landscape level land use scenarios can be used to quickly identify areas with a high probability of land use conversion and subsequent declines in ecosystem reserves and habitat area.

Our goal was to identify, at the ecoregion-level, protected areas in close proximity to lands with a higher likelihood of future land-use conversion. Using a state-and-transition simulation model, we modeled spatially explicit (1 km2) land use from 2000 to 2100 under seven alternative land-use and emission scenarios for ecoregions in the Pacific Northwest.

We analyzed scenario-based land-use conversion threats from logging, agriculture, and development near existing protected areas. A conversion threat index (CTI) was created to identify ecoregions with highest projected land-use conversion potential within closest proximity to existing protected areas.

Our analysis indicated nearly 22% of land area in the Coast Range, over 16% of land area in the Puget Lowland, and nearly 11% of the Cascades had very high CTI values. Broader regional-scale land-use change is projected to impact nearly 40% of the Coast Range, 30% of the Puget Lowland, and 24% of the Cascades (i.e., two highest CTI classes). A landscape level, scenario-based approach to modeling future land use helps identify ecoregions with existing protected areas at greater risk from regional land-use threats and can help prioritize future conservation efforts.

Conversion Threat Index from 2000 to 2100 for ecoregions in the Pacific Northwest

Conversion Threat Index from 2000 to 2100 for ecoregions in the Pacific Northwest (Table 7 in Wilson et al. 2014).(Public domain.)

Findings and Results

  • Our results for the Pacific Northwest indicate >27,081 km2 of land with very high projected CTI values.
  • Approximately 17% of the landscape in the Pacific Northwest fall within the high to very high CTI classes.
  • Lands categorized with medium CTI values comprise ~15% of the total land area in the region. (47,985 km2).
  • While medium CTI land area may not be in closest proximity to protected areas, these land-use conversions do reflect increasing regional land-use pressure over the coming decades which may impact the integrity of existing protected areas.
  • At the ecoregion-scale, nearly 22% of the total land area in the Coast Range and over 16% of the Puget Lowland had very high CTI values (Table 7).
  • Cumulatively, lands categorized with high to very high CTI values comprise nearly 40% (20,992 km2) of the Coast Range, 30% (4943 km2) of the Puget Lowland, and 24% (11,141 km2) of the Cascades.

For more information visit the Land Use and Climate Change Team website.

Land use conversion threat index (CTI) for the Pacific Northwest

Land use conversion threat index (CTI) for conversions into developed, agriculture and harvested forests in the Pacific Northwest from 2000 to 2100 across 7 future land use scenarios. Very high CTI values represent areas where land use conversion was projected to occur within 20 kilometers of an existing protected area across > 5 scenarios (Figure 7 in Wilson et al. 2014).(Public domain.)