The growing power and accessibility of web-mapping tools and open ecological data create exciting opportunities in data visualization for research and education. We have developed two online animated visualizations of taxon range shifts since the last glacial maximum using data from the Neotoma Paleoecology Database, an open community-curated paleoecological data resource.
The first, Range Mapper (RM), was built using the Neotoma R package and a Javascript library built by Carto, a software-as-service cloud computing platform. To show shifting tree distributions in North America, Europe, and Australia, we downloaded pollen records and temporally interpolated abundance data from 21,000 years BP to present. Then, we used the Carto package to define animation parameters and styling. RM uses proportional symbols to visualize pollen percentages of taxa at sites over time. RM workflows are publicly available on GitHub.
The second visualization, Ice Age Mapper (IAM), is a web application built using open-source tools including the Neotoma APIs, Mapbox-GL and D3 libraries. IAM animates site-level presence/absence data through time, filters data based on percent pollen present, latitude, and investigator, and shares the data of individual sites. Through IAM’s dynamic link to Neotoma, IAM maps are continuously updated as new data are added to Neotoma.
Results/Conclusions
The completed visualizations clearly illustrate major shifts in taxa distribution over the last 21,000 years. In RM and IAM, we can see the northward expansions of Picea, Betula, and Quercus in North America, as well as Tsuga’s well-known decline across the northeastern US at 5,500 years BP. In the European RM, the glacial refugial populations of Quercus on the Iberian Peninsula, Italy, and Turkey/Syria are visible 21,000-15,000 years B.P. The animation also shows the rapid range expansion of Quercus at the onset of Holocene warming and the late Holocene expansions of Picea and Fagus. Despite the sparse but growing Neotoma data for Oceania, RM shows that in Tasmania, warming temperatures from 11,500-9,500 years BP led to first the expansion of Eucalyptus, then, after 9,500 years BP, expansion of Nothofagus forests.
These animated maps of taxa distributions are interactive, with users able to quickly add or remove taxa from pre-built lists. They offer immediately accessible visualizations of species range shifts in response to past environmental change. These visualizations are useful to experts for understanding past patterns and processes and to educators and science communicators. These web-based resources are open to anyone with an internet connection, advancing the goal of open science.