EaglesOneParam readme.txt The EaglesOneParam .dll file is a custom density dependence function for modeling territorial life histories in RAMAS Metapop or RAMAS GIS. Density dependence arises from the number of territories. For every stage that can hold a territory, referred to as "nesters", there must be an accompanying stage that harbors any excess individuals that do not hold a territory, referred to as "vagrants". This structure allows the user to specify different survival rates for vagrants and nesters and to capture differences in survival or fecundity among classes of nester. The custom density dependence function requires only a single additional parameter not already specified in the stage matrix or density dependence form of the the standard program. This is the survival rate of vagrants, which the user indicates by opening the Populations dialogue and clicking on the "User-Defined" tab. ----------------------- Use and distribtution EaglesOneParam.dll is provided free of charge and can be used and distributed without restriction. The file only has functionality if you have a version of RAMAS GIS or RAMAS Metapop installed, which requires a license from Applied Biomathematics. RAMAS software can be purchased through www.ramas.com. ----------------------- Installation: 1) Users of 32-bit installations of RAMAS GIS or Metapop should use EaglesOneParam32.dll Users of 64-bit installations of RAMAS GIS or Metapop should use EaglesOneParam64.dll 2) Save the .dll file in any folder and note its location. 3) Under Model->Density Dependence, select "All populations use the same density dependence type:" 4) From the dropdown menu of density dependence types, select "User-defined." 5) In the field labeled "Filename for user-defined density dependence function:" type the path to the .dll or click the "..." button to browse to its location. 6) The first time you use the custom density dependence function, you will need to enter the value for vagrant survival in Model->Populations->User-Defined. (For the baseline golden eagle model file, this value is 0.9.) ---------------------- Input: Additional steps need to be taken to ensure the custom function will perform correctly. 1) When defining life stages under the Stages dialogue, be sure to include one vagrant stage for every nester stage. Indicate which are the nesting stages by setting them as the basis for density dependence. Nesting stages should come at the end of the list of stages, after their corresponding vagrant stages and in the same order. 2) Structure the stage matrix (in the Stage Matrix dialogue) as though territories are not limiting. In other words, there should be no transitions into vagrant stages and no probability of remaining in vagrant stages. Use a pre-breeding model (e.g., Fecundity includes first-year survival of young). We note that some consideration should be given to the survival rates indicated for vagrants taking territories. 3) The standard deviation matrix should only have entries where there are values in the stage matrix. 4) Under the Stochasticity dialogue, choose Advanced and select Pooled Variances. This will enable the program to apply information in the standard deviation matrix to vagrants. 5) In the Density Dependence tab of the Populations dialogue, enter a value for K. You can also enter its standard deviation and indicate a trend orlink to a change-in-K file. The context-sensitive help button on that page will guide you if you have questions. Any information entered for Rmax will be ignored. 6) Finally, in the User-Defined tab of the Populations dialogue, be sure to enter a value for vagrant survival. -------------------- What it does: The function modifies the transition matrix to set the proportion of birds that enter (or remain in) vagrant stages versus taking nests. It does this based on stage abundances and expected survival rates as specified in the stage matrix. However, the program does not have access to information about environmental variation, trends in vital rates or K, or catasrophes that affect vital rates. Therefore, the function also performs two checks before calculating the proportion of potential nesters and vagrants. Both checks can result in direct modification of stage abundance. First,if the number of individuals on nests exceeds K, excess nesters are placed in their corresponding vagrant stages. Second, if the number of individuals on nests is below K, any available vagrants are sampled at random to fill the empty nests. These checks imply that the processes determining territory occupancy operate on a subannual time scale. -------------------- Output: The .dll ouputs raw data on the abundance of each stage of each population in each replicate of the simulation. It also indicates how many vagrants became nesters, how many nesters became vagrants, the floater:breeder ratio and the incidence of the youngest nesting stage. This last piece of information can be used to track the incidence of subadults on nests if your model includes such a stage. Output is written to a tab-delimited .txt file called EaglesOut. In Windows XP, the file is written to the same location as the model file. Windows 7 and newer causes EaglesOut.txt to be written to the Roaming folder of the current user (C:/Users/"Current User"/AppData/Roaming/EaglesOut.txt), which is really quite annoying.