Services Directory Login

SWFL_Modeled_areas (Map Service)


View In:    ArcGIS JavaScript   ArcGIS.com   WMTS  

Current Version: 10.81

Service Description: A variable-width buffer was created for modeling Southwestern Willow Flycatcher (hereafter "flycatcher) habitat across its range in several steps. First, the river/stream reaches and waterbodies nearest known flycatcher territories were identified by overlaying flycatcher sites and the NHDPlus2 stream network. This exploratory analysis indicated that most flycatcher sites were adjacent to stream or river reaches greater than third order (fourth to ninth order) and lakes greater than 1 km2. Second, given that larger-order streams or rivers have larger floodplains, and thus more riparian area that may contain a flycatcher territory, a variable-width buffer was created for modeling. Specifically, the order of the stream or river was multiplied by 100 m, and waterbodies larger than 1 km2 were buffered by 1 km. Thus, for modeling purposes, buffers were 400 m for fourth-order streams , 900 m for ninth-order rivers, and 1 km for waterbodies greater than 1 km2. Third, all areas outside of buffer zones were masked so they would not be considered by the satellite model. These variable-width buffers adjacent to streams, rivers, and waterbodies represent the initial areas considered for modeling, comprising about 6 percent oft he project area (59,887 km2). Pinyon pine (Pinus edulis) and juniper (Juniperus spp.) were masked inside riparian buffer zones with high-resolution imagery because the satellite model commonly confuses them with riparian vegetation above 1,524-m elevation. Creating the modeling mask involved several steps to accomplish. First, all urban and agricultural features identified in the Southwest and South-Central U.S. Geological Survey Gap Analysis Program (GAP) layers were extracted and masked. Second, the urban and agricultural mask was updated by digitizing omitted areas that were clearly visible on high-resolution digital aerial photographs. Omitted areas typically were agricultural fields that had increased in size in the last decade, or urban boundaries. Third, areas that were incorrectly classified as urban or agricultural were identified and the mask in such areas was removed, thereby including them in the modeling arena. The final masking step was an ocular assessment, whereby areas that were not organic in shape (for example, circles, lines, squares) were visually identified with the aid of high-resolution aerial orthophotographs and GIS, and excluded. This was primarily a refinement of the GAP layer because agricultural areas oftentimes become spectrally confused with riparian areas along their interface. Although such areas were difficult to discern with 30-m resolution Landsat imagery, they were visible with 1-m resolution aerial photography, making their identification and digitization possible. Additionally, numerous agricultural fields were excluded from the mask that the Bureau of Reclamation (Reclamation) converted from agricultural plantations to native vegetation in hopes of providing flycatcher habitat; such areas retained a non-organic shape and were initially masked. Finally, all urban footprints that had enlarged since the last GAP assessment were identified and masked because they were not classified as urban at that time; such adjustments were necessary because flycatchers do not breed in urbanized areas.

Map Name: Layers

Legend

All Layers and Tables

Layers: Tables: Description: A variable-width buffer was created for modeling Southwestern Willow Flycatcher (hereafter "flycatcher) habitat across its range in several steps. First, the river/stream reaches and waterbodies nearest known flycatcher territories were identified by overlaying flycatcher sites and the NHDPlus2 stream network. This exploratory analysis indicated that most flycatcher sites were adjacent to stream or river reaches greater than third order (fourth to ninth order) and lakes greater than 1 km2. Second, given that larger-order streams or rivers have larger floodplains, and thus more riparian area that may contain a flycatcher territory, a variable-width buffer was created for modeling. Specifically, the order of the stream or river was multiplied by 100 m, and waterbodies larger than 1 km2 were buffered by 1 km. Thus, for modeling purposes, buffers were 400 m for fourth-order streams , 900 m for ninth-order rivers, and 1 km for waterbodies greater than 1 km2. Third, all areas outside of buffer zones were masked so they would not be considered by the satellite model. These variable-width buffers adjacent to streams, rivers, and waterbodies represent the initial areas considered for modeling, comprising about 6 percent oft he project area (59,887 km2). Pinyon pine (Pinus edulis) and juniper (Juniperus spp.) were masked inside riparian buffer zones with high-resolution imagery because the satellite model commonly confuses them with riparian vegetation above 1,524-m elevation. Creating the modeling mask involved several steps to accomplish. First, all urban and agricultural features identified in the Southwest and South-Central U.S. Geological Survey Gap Analysis Program (GAP) layers were extracted and masked. Second, the urban and agricultural mask was updated by digitizing omitted areas that were clearly visible on high-resolution digital aerial photographs. Omitted areas typically were agricultural fields that had increased in size in the last decade, or urban boundaries. Third, areas that were incorrectly classified as urban or agricultural were identified and the mask in such areas was removed, thereby including them in the modeling arena. The final masking step was an ocular assessment, whereby areas that were not organic in shape (for example, circles, lines, squares) were visually identified with the aid of high-resolution aerial orthophotographs and GIS, and excluded. This was primarily a refinement of the GAP layer because agricultural areas oftentimes become spectrally confused with riparian areas along their interface. Although such areas were difficult to discern with 30-m resolution Landsat imagery, they were visible with 1-m resolution aerial photography, making their identification and digitization possible. Additionally, numerous agricultural fields were excluded from the mask that the Bureau of Reclamation (Reclamation) converted from agricultural plantations to native vegetation in hopes of providing flycatcher habitat; such areas retained a non-organic shape and were initially masked. Finally, all urban footprints that had enlarged since the last GAP assessment were identified and masked because they were not classified as urban at that time; such adjustments were necessary because flycatchers do not breed in urbanized areas.

Copyright Text: James R. Hatten, Research Biogeographer, USGS, WFRC, Columbia River Research Lab,5501A Cook-Underwood Rd. Cook, WA 98605 Voice: 509-538-2932 Cell: 509-439-2276 Fax--509-538-2843 E-mail-- jhatten@usgs.gov http://wfrc.usgs.gov

Spatial Reference:
102100

Single Fused Map Cache: true

Capabilities: Map,TilesOnly

Tile Info:
Initial Extent:
Full Extent:
Min Scale: 5.91657527591555E8
Max Scale: 144447.638572

Min LOD: 0
Max LOD: 12

Units: esriMeters

Supported Image Format Types: PNG

Export Tiles Allowed: false
Max Export Tiles Count: 100000

Document Info: