lydemapr: an R package to track the spread of the invasive spotted lanternfly (Lycorma delicatula, White 1845) (Hemiptera, Fulgoridae) in the United States

A crucial asset in the management of invasive species is the open-access sharing of data on the range of invaders and the progression of their spread. Such data should be current, comprehensive, consistent and standardised, to support reproducible and comparable forecasting efforts amongst multiple researchers and managers. Here, we present the lydemapr R package containing spatiotemporal data and mapping functions to visualise the current spread of the spotted lanternfly (Lycorma delicatula, White 1841) in the Western Hemisphere. The spotted lanternfly is a forest and agricultural pest in the eastern Mid-Atlantic Region of the U.S., where it was first discovered in 2014. As of 2023, it has been found in 14 states according to State and Federal Departments of Agriculture. However, the lack of easily accessible, finescale data on its spread hampers research and management efforts. We obtained multiple memoranda-of-understanding from several agencies and citizen-science projects, gaining access to their internal data on spotted lanternfly point observations. We then cleaned, harmonised, anonymised and combined the individual data sources into a single comprehensive dataset. The resulting dataset contains spatial data gridded at the 1 km(2) resolution, with yearly information on the presence/absence of spotted lanternflies, establishment status and population density across 658,390 observations. The lydemapr package will aid researchers, managers and the public in their understanding, modelling and managing of the spread of this invasive pest.