Local extirpation is pervasive among populations of Galápagos endemic tomatoes

Abstract

The Galápagos Islands are home to incredible endemic biodiversity that 12 is of high conservation interest. Two such endemic species are the Galápagos toma-13 toes: Solanum cheesmaniae and Solanum galapagense. Both are known from histor-14 ical location records, but like many endemic plant species on the Galápagos, their 15 current conservation status is unclear. We revisited previously documented sites 16 of endemic species on San Cristóbal, Santa Cruz, and Isabela, and document the 17 disappearance of >80% of these populations. In contrast, we find that two inva-18 sive relatives (Solanum pimpinellifolium and Solanum lycopersicum ) are now highly 19 abundant, and in some cases-based on morphological observations-might be hy-20 bridizing with endemics. Our findings suggest that expanding human developments 21 and putative interspecific hybridization are among the major factors affecting the 22 prevalence of invasives and the threatened persistence of the endemic populations.23