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How Did the Squirrel Cross the Highway? Least-Cost Pathway Analysis to Determine Spread of an Introduced Species Author: Emily Kristianne Gonzales 50 Stone Road East Phone: 519-824-4120 ex Spread of an introduced species has traditionally been analyzed in ecology by assuming homogeneous landscapes. Ecologists are quickly learning the value of incorporating geography into spatial analyses. Using least-cost analysis, GIS can be a useful tool in understanding and modeling movement patterns. In the case of the eastern gray squirrel introduced to Canada's west coast, least-cost pathway analysis is used to quantitatively distinguish between two competing expansion hypotheses--expand and fill versus anthropogenic aid. Ecological analyses reciprocally contribute to this GIS analysis using habitat selection indexes to objectively determine the friction values for the cost surface. |