Impact of climate change on the suitable niches of an ornithophilous neotropical orchid (Elleanthus brasiliensis) and its pollen vectors

There is no doubt that climate change not only affects the spatial distribution of organisms but also alters ecological interactions that are crucial for the maintenance and functioning of ecosystems. Much research has been devoted to assessing the impact of global warming on animal-mediated pollination, which is vital for the reproduction of vascular plants. Most analyses have focused on insect pollen vectors, as these are the most common animals involved in pollination. The aim of this study was to investigate the impact of climate change on the distribution of suitable niches of the tropical orchid (Elleanthus brasiliensis) and four hummingbirds reported to serve as pollen vectors for this species (Thalurania glaucopis, Phaethornis pretrei, Phaethornis squalidus, Ramphodon naevius), as well as to estimate the locations of climatic refugia where both orchid and pollinator will co-occur in the future. All species studied will lose suitable niches in different Brazilian biomes as a result of global warming. In the reduced, fragmented potential range of E. brasiliensis, not all orchid populations will have a chance of cross-pollination. Of the birds included in the study, T. glaucopis will be the most important orchid pollinator, being available for basically all of the plant populations. The most endangered populations of E. brasiliensis are located in the southern part of the orchid range where no pollen vectors except of T. glaucopis are predicted to occur in the future. The partial lack of pollen vectors and the fragmentation of geographical ranges will pose serious threats to the long-term survival of the studied orchid. The areas identified in this study as suitable for the occurrence of both the orchid and its pollinator(s) should be considered as climatic refugia and receive additional attention when planning conservation activities.