Endemic and invasion dynamics of wild tomato species on the Galápagos Islands, across two centuries of collection records

We aggregated digitized herbarium and other collection records—spanning >225 years since 1795—to assess the biological, geographical, and historical factors shaping distributions of three wild tomato species on the Galápagos Islands, and to infer future threats to the two endemic species ( Solanum cheesmaniae and S. galapagense ) and risks posed by their invasive congener ( S. pimpinellifolium ).

Combining >400 unique geolocated Galápagos records with bioclimate data and species distribution modelling, we quantified the geo-spatial distribution of each species, bracketed the historical timing and location of introductions of the invasive species, characterized species bioclimate envelopes, and projected suitable habitat overlap.

We infer that dispersal limitation and alternative selective histories shape current species distributions, and that anthropogenic change has and will continue to have different impacts on the two endemic species—closely associated with their different geographic and environmental distributions. We also identify plausible avenues for, and limits to, future invasive expansion.

These data vastly extend the temporal and spatial reach of our direct historical inferences, provide a critical complement to genomic analyses of contemporary Galápagos populations, and demonstrate that scientific collections are especially valuable for interpreting factors shaping species distributions on high-endemism islands with recent rapid environmental change.