loop: An R package for performing decomposition of weighted directed graphs, food web analysis and flexible network plotting

Demographic loop analysis is one of the basic methods applied in life cycle analysis in population ecology. Here, we developed an R package called “loop” to implement the algorithmic approach of loop analysis developed by a previous work. Additionally, the package can provide flexible network plotting and food web analysis as well. In this paper we illustrated the loop decomposition analysis using the life-cycle graph of a tropical tree species Vouacapoua americana; and performed food web statistics for the two real food webs for illustrating food web plotting and detecting key species in securing food web persistence. The package, including source code and binary versions, is available at the following URL: http://cran.r-project.org/web/packages/loop/.

► We develop an R package “loop” for performing loop decomposition and food web analysis.
► The package provides alternative functions to plot food web structure.
► The package provides statistics to measure basic food web attributes.
► We demonstrate the package using two food webs and a life cycle graph of a species.
► Computing algorithms employed in the package have been presented.