marApp: An R package and web portal to calculate mutations- and genetic diversity-area relationship for conservation

International conservation policies including the Kunming-Montreal Global Biodiversity Framework now consider genetic diversity of wild species in their targets. However, scalable, theory-driven tools to assess and predict genetic diversity loss are still emerging, limiting their use in conservation planning. Analogous to the species-area relationship, recent work has shown that genetic diversity scales with area, described by the mutations-area relationship (MAR) or genetic-diversity-area relationship (GDAR), can approximate the genetic diversity loss in a species from habitat reduction. To enable application of these insights for conservation practitioners and policy makers, we present the mar R package and marApp web portal, a fast and user-friendly tool for MAR/GDAR analysis. The mar package connects genetic diversity patterns in space to ecological theory, and automates steps from reading genetic and geographic data to simulating various habitat extinction scenarios using MAR/GDAR. The mar package estimates only short-term genetic diversity, providing a lower-limit for the far greater long-term genetic losses, underscoring the need to maximize present-day habitat conservation before it becomes irreversible. As a case example, we showcase predictions of coral (Acropora sp.) genetic diversity loss from reef coverage impacts. We demonstrate the usage of marApp without requirements for prior genetics or coding experiences, and provide downloadable reports for conservation.