Code and data: Evidence for the vacated niche hypothesis in parasites of invasive mammals

Species redistribution and invasion are becoming increasingly common due
to climate change and anthropogenic impacts. Understanding the resultant
shifts in host-parasite associations is important for anticipating
disruptions to host communities, disease cycles, and conservation efforts.
In this paper, we bring together the enemy release and vacated niche
hypotheses to relate parasite acquisition and retention, two distinct yet
intertwined processes that play out during host invasion. Using the Global
Mammal Parasite Database, we test for net enemy release based on
differences in parasite species richness, and we develop a novel taxonomic
null modeling approach to demonstrate that parasites fill vacated niches.
We find evidence of net enemy release, and our taxonomic null models
indicate replacement of lost parasites by taxonomically similar acquired
ones, over and above what might be expected by chance. Our work suggests
that both enemy release and vacated niche hypotheses provide valuable
frameworks through which to understand and predict changing host-parasite
associations, which may include insights on how climate change and
anthropogenic influences perturb and reorganize communities and
ecosystems.