Transition Adjacency Multipliers
The Transition Adjacency Multipliers Property specifies multipliers to be applied to transition probabilities according to primary transition group (note that in the upcoming release of version 3.0 adjacency multipliers will apply to all transition groups) and the condition of a cell's neighborhood. These multipliers can be useful for incorporating spatial processes such as the placement of management actions according to a spatial prioritization scheme (for example, areas with highest habitat values first).
In order to use this property, users must define one record in Transition Adjacency Settings for each Primary Transition Group that the multipliers will be used for. These settings consist of a table outlining the State Attribute used to evaluate the condition of a cell's neighborhood; the neighborhood radius; and the update frequency (in timesteps) for spatial analyses. The condition of a neighborhood is the average state attribute value within the neighborhood radius calculated periodically based on the update frequency. The neighborhood radius includes all cells within the specified radius as determined by the center to center distance of the target cell and its surrounding cells. For attribute calculation purposes, the central target cell is included in the average attribute value calculation. Shorter update frequencies result in more accurate the analyses but longer computation times.
Once the Transition Adjacency Settings are defined for a transition group, users can define multiple records for that group in Transition Adjacency Multipliers.
The fields for the Adjacency Multipliers property are:
Iteration (optional)
The Iteration for which the adjacency multiplier record applies. If left blank then the adjacency multiplier record applies to all iterations.
Timestep (optional)
The Timestep for which the adjacency multiplier applies. If left blank then the adjacency multiplier record applies to all timesteps. A adjacency multiplier continues through time until another Timestep value is encountered by the model for the same transition type in the same stratum, at which point the new adjacency multiplier values for transition type will be applied.
Primary Stratum (optional)
The Primary Stratum for which the adjacency multiplier record applies. If left blank then the adjacency multiplier record applies to all primary strata.
Secondary Stratum (optional)
The Secondary Stratum for which the adjacency multiplier record applies. If left blank then the adjacency multiplier record applies to all secondary strata.
Tertiary Stratum (optional)
The Tertiary Stratum for which the adjacency multiplier record applies. If left blank then the adjacency multiplier record applies to all tertiary strata.
Transition Group
The Transition Group for which the adjacency multiplier applies. Note that in version 2 of ST-Sim adjacency multipliers only apply to primary transition groups but that in version 3.0 and later they apply to all transition groups.
Attribute Value
The Attribute value for which the multiplier record applies, measured as the average value of the attribute across all cells within the neighborhood radius. When determining what multiplier to use, the model will find the record with the attribute value that is less than or equal to and closest to the measured value within a cell's neighborhood. If no records are found that meet this criteria then a multiplier of 1 will be used.
Multiplier
The multiplier value to be used for this transition group and attribute value.
Multiplier Distribution (optional)
When using a probability distribution for multipliers, users must specify a Probability Distribution Type. At the moment either the Normal or Beta distributions are available for setting slope multipliers.
Multiplier Sampling Frequency (optional)
When using a probability distribution for multipliers, users must specify a sampling frequency value that can be used to sample from a specified distribution.
Multiplier SD (optional)
When using a probability distribution for multipliers, users must specify a standard deviation value that can be used to sample from a specified distribution.
Multiplier Min (optional)
When using a probability distribution for multipliers, users can specify a minimum value that can be sampled from a specified distribution.
Multiplier Max (optional)
When using a probability distribution for multipliers, users can specify a maximum value that can be sampled from a specified distribution.