Three separate Multi-Criteria Evaluations were conducted in order to represent both the spatial and temporal changes to the suitability of habitat for the Tiger Salamander. This was chosen because the study area (Oliver, BC) has a semi-arid and hot climate with very little precipitation.
The first MCE represents the Early Spring Scenario when the availability of water is relatively high. The second MCE represents the Late Summer Scenario when the availability of water is relatively low. The main differences between these two outputs is the different water body factors used as explained in the methodology. Furthermore, the late summer takes into account greater movement of terrestrial Tiger Salamanders and an increase in the movement of humans through the landscape (agriculture and recreation). This results in a greater weighting on the importance of distance from roads and a decrease in the landusefactor. The last MCE shows the Climate Change and Population Growth Scenario which uses different biogeoclimatic zone constraints than the previous two MCE's. The main difference between the weightings of this output compared to the others is the increase in weight applied to the "distance to urban areas" factor. Increases in population growth will cause outward expansion of roads, recreational activities, and urban development.
In all cases, an analytical hierarchy process (AHP) was used to determine the relative importance of each of the factors to one another by means of a pairwise comparison. The relative importance of any given factor relative to another varies on a continuous scale from 1/9 to 9.
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1/9 = Extremely Less Important
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1 = Equally Important
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9 = Extremely Important
After the MCE produced the suitability outputs, each MCE was reclassified into a more manageable and asthetically pleasing representation. Each output was reclassified in order to show the varying degrees of suitability throughout the landscape. The eight newly produced values ranged from areas of no suitability to excellent suitability.
MCE - Early Spring Scenario
Reclassed MCE (click image to enlarge)
The eigenvector of weights is :
hwyfuzz : 0.0592
landusefactorfuzz : 0.3324
roadfuzz : 0.1145
slopefuzz : 0.0562
urbanfuzz : 0.0939
watergroupedfuzz : 0.3015
watersizedistfuzz : 0.0424
Consistency ratio = 0.05
Consistency is acceptable.
MCE - Early Spring Result for Habitat Suitability (click image to enlarge)
MCE - Late Summer Scenario
Reclassed MCE (click image to enlarge in a new window)
The eigenvector of weights is :
hwyfuzz2 : 0.0545
landusefactorfuzz2 : 0.2591
roadfuzz2 : 0.1670
slopefuzz2 : 0.0578
urbanfuzz2 : 0.0877
watersizedistfuzz2 : 0.0548
watergroupedfuzz2 : 0.3192
Consistency ratio = 0.05
Consistency is acceptable.
MCE - Late Summer Result for Habitat Suitability (click image to enlarge in a new window)
MCE - Climate Change and Population Growth Scenario
Reclassed MCE (click image to enlarge in a new window)
The eigenvector of weights is :
hwy-c1-fuzz : 0.0457
landuse-c1-fuzz : 0.2711
roadfuzz-c1-fuzz : 0.1231
slope-c1-fuzz : 0.0564
urban-c1-fuzz : 0.1229
waterdist-c1-fuzz : 0.0457
waterallsqmeters-c1-fuzz : 0.3352
Consistency ratio = 0.09
Consistency is acceptable.
MCE - Climate Change & Population Growth Result for Habitat Suitability (click image to enlarge in a new window)
Analysis of the first two MCE's suggest that both the amount and quality of suitable habitat deteriorates over the course of the summer (between early spring and late summer). However, an even more important result from the analysis is the amount of habitat fragmentation that occurs between the early spring and late summer. Therefore, the Tiger Salamander is at an increased risk of mortality later in the season. Furthermore, under a climate warming and population growth scenario the amount of suitable habitat and quality decreases even more becoming more fragmented in the process. This is an important scenario to understand in order to develop better management and adaptive strategies for the region if we are to maintain quality habitat for this species.