NINJA: An automated calculation system for nematode-based biological monitoring

• NINJA is a tool to perform calculations for nematode-based monitoring of soil quality.
• A taxonomic inventory is the only input; all the indices are calculated automatically.
• The web-interface is accessible at http://spark.rstudio.com/bsierieb/ninja/.
• In future, the system can be linked to molecular-based identification of nematodes.

Monitoring of soil quality and health provides critical insights into the performance of ecosystems. Nematodes are useful indicators of soil condition because they are ubiquitous, represent different trophic levels of a soil food web and are convenient to work with. Several quantitative analyses of nematode assemblages have been developed and used in monitoring programs and by individual researchers. However, the calculations of the metrics involved are quite complicated. Since they are done manually using spreadsheet software, the calculations are time-consuming and error-prone and usually involve a significant learning curve for the user. We have developed an R code to perform these calculations. The code is compiled in html and deployed over the web. It is and will remain freely accessible and has a user-friendly interface. It requires only an input table with taxonomic inventory data and provides output within a few seconds.