Supplementary Data Readme File



Title:

Code for simulating data and calculating CR densities using different approaches to estimate (W)



Instructions: 

This code file allows the user to simulate data on true tiger presences and captures, then run the CR analyses in R Cran to 
estimate density based on the capture history. The results of this analysis provided in Supplementary Figure 4. To run this code 
file, first open R Cran. Then use enter the commands line by line as they are given in the Code file. Commented sections 
(indicated with the hash symbol #) provide brief explantation of each section.  



Explantation of approach: 

Most studies published prior to 2010 that are included in our meta-analysis reported densities based on half MMDM approach, which 
has been shown to be biased. If the true movement of tigers is known (the sigma in an SCR model), then we could use this 
information to improve our older CR estimates of the effective study area. In the code provided, we implement this using a common 
CR analysis to estimate N (the closed-population jackknife estimator). 



Interpreting results: 

The simulations results show half MMDM estimates suffer from a significant positive bias. On the contrary, CR densities that use a 
buffer derived by SCR analyses showed no bias. Thus, we posit that the buffer derived from the sigma in our SCR analyses, which 
comes our large-scale camera trapping fieldwork at three parks in Sumatra, is more accurate than those derived from the half MMDM. 
This assumption is also supported by substantial empirical and other simulation-based evidence (Supplementary refs 7 and 8). 
