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1.1 Setting up the ERS TableSuccessful conservation planning involves risk management. ERS models are aboutcategorizing and ranking potential risks to habitats or features on concern. The first stepin creating an Environmental Risk Surface is to create an intensity value and influencedistance table for all identified risk elements and associated classes. These values can becustomized specifically for the creation of ERS models for terrestrial, freshwater, ormarine realms. Remember that each risk element has to be thought of in terms of itsimpact on the habitats or species in the focal realm (i.e. terrestrial, freshwater, andmarine). A sample Excel spreadsheet risk matrix table is provided with the tutorial data,named “Sample_Intensity_Table.xls.” Open this risk matrix table and you will see sixcolumns that represent the risk element, the associated class for each risk element,followed by the terrestrial and freshwater intensity value and influence distance columns.For instance, the file “risk_quarries.shp” contains two classes, “River Aggregate” and“Limestone”. According to the experts, mining for limestone is more damaging toterrestrial systems than river aggregate mining. Consequently, limestone mining isassigned an intensity value of 40, compared to river aggregate, which is assigned 30.Likewise, the file “risk_roads.shp” has four road class types and corresponding intensityvalues have been assigned based on expert opinion of the degree of potential risk tocritical habitats.TERRESTRIALINFLUENCEDISTANCEFRESHWATERINFLUENCEDISTANCERISK ELEMENTCLASSTERRESTRIALINTENSITYFRESHWATERINTENSITYrisk_ag_small_scale.shp 25 500 25 3000risk_ag_sugarcane.shp 11 1000 11 5000risk_bauxite_mines.shp 50 1000 60 8000risk_quarries.shpRiverAggregate 30 500 10 1000Limestone 40 500 20 1000risk_roads.shp TRACK 5 30 5 30OTHER 10 30 10 30CLASS B 15 60 15 60CLASS A 30 60 60 120risk_urban_areas.shp 95 500 95 1000It is important to remember that when assigning intensity values and influence distances,you are using a relative scale, not a representation of the absolute measure of the impactof activities on biodiversity. These values should be a relative degree to whichbiodiversity is more likely to survive in one place over another based on the presence of agiven activity in comparison to the other risk elements. For this exercise, we use a scaleof 0-100, with 100 being the highest degree of risk to a habitat. It is up to the user todefine the scale, but the user should use whole numbers (integers) for computationalreasons. The influence distance should be in whatever units your input data is in (i.e.projection information). In the sample data, the units are in meters. As with intensityTNC Protected Area Tools (PAT) Version 3.0The Nature Conservancy, August 200915