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Habitat Modeling. Advanced GIS Workshop April 28-29, 2012 Antioch University New England Chris Brehme , PhD, Keene State College Apollinaire William, Antioch University New England. Habitat Modeling/Mapping.
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Habitat Modeling Advanced GIS Workshop April 28-29, 2012 Antioch University New England Chris Brehme, PhD, Keene State College Apollinaire William, Antioch University New England
Habitat Modeling/Mapping • To translate a species’ requirements to geographic locations on the Earth’s surface • Involves interpretation, quantification, combination and representation
Typical Steps of Habitat Modeling Background Research Sketch out key steps of analysis Prepare GIS Data Layers Analyze GIS Data Produce Final Map Conceptual Stage Implementation Stage
Matching Descriptions to Data • Research species’ habitat requirements • Identify available data that relates to these requirements
Input, Modify and Analyze GIS Data • Input data to GIS • Modify data • Overlay
Habitat Modeling Example American Lobster requires cobble substrates, and seasonal depth ranges (shallow in summer, deep in winter) • Quantify ‘cobble’: boulders and rocks with spaces large enough for lobsters – known as gravel on geology maps. • Quantify depths: < 100’ in summer; > 100’ in winter • Get data on seafloor geology • Get bathymetry data • ‘Gravel’ substrates digitized as a new GIS layer • In GIS, calculate size of geology polygons, eliminate polygons where area < minimum required • Overlay with depth ranges • Create final map of habitats
Habitat Modeling Resources • Scientific Literature • GIS Data resources (State, Federal, NGO, Private) • Metadata! • GIS Tools • Good Map Examples
GIS Tools for Modifying and Overlaying • Clip/Extract • Reclassify • Add Fields, Calculate New Field Values • Buffer • Select (by Attribute, by Rectangle, by Location) • Vector Overlay: Intersect or Union • Raster Overlay: Map Algebra • Terrain: Slope, Aspect
Conceptual Model: Lobster Habitat Reclassify 0-100 = 1 101 – 200 = 2 > 200 -= 3 Select Value = 1 Summer Depths Depth Classes Seafloor Depth Select Value = 2 Winter Depths Summer Depths Intersect Convert to Polygon Summer Habitats Winter Depths Winter Habitats Intersect Select TYPE LIKE ‘Gravel’ Seafloor Geology Gravel Areas
Exercise: Create a Conceptual Model • Characterize the species’ requirements • Quantify qualitative descriptions • Identify potential GIS data • Identify GIS tools and steps for prepping and analyzing the data • Create a diagram of the process