Predicting the current and future distributions of Australian Loranthaceae mistletoes

Mistletoes are branch parasites of trees and shrubs, occur world-wide, and are considered keystone species in many forest communities. They have complex interactions with seed dispersers, pollinators, and animals that use them for shelter, and contribute to community productivity and biotic diversity. Current understanding of mistletoe occurrence largely attributes host availability and preference to patterns of distribution. Using occurrence records, climate data, and climate modeling, we investigated current distributions and modeled contemporary and future distributions of Australian mistletoes in the Loranthaceae by haustorial type. Although Loranthaceae mistletoes are distributed throughout Australia, our results show distributional differences among haustorial types across biomes and identify their actual and predicted ecological niches based on temperature and precipitation. Epicortical roots, which are considered plesiomorphic in Australia, are mostly associated with mesic ancestral habitats while derived types are associated with drier habitats. Combining the results of all analyses we show that mistletoe distributional patterns, similar to distribution patterns in other angiosperms, are correlated with climate and are susceptible to climate change with expected loss of habitat, primarily in interior arid regions of Australia.