Spatial coexistence of coinvading communities with mutualism and competition

All interactions between multiple species invading together (coinvasion) must
3 be accounted for to predict species coexistence patterns across space. Mutualisms,
particularly, are known to influence species’ population dynamics and
their invasive ability (e.g. mycorrhizal fungi with partner plants). Yet, while
6 modelling coinvasion, their role is mediating coexistence is overlooked. We build
a spatially explicit model of coinvasion of two competing plant species with a
shared fungal mutualist to study how mutualism and competition shape the
9 spatial coexistence of competitors. We find that mutualist presence engenders
regional (spatial) coexistence between competitors even when local coexistence
between them is impossible. Further, increasing mutualist dispersal results in
12 sharp transitions in competitor coexistence outcomes. Finally, differences in
mutualist partner dependence and competitive ability interact to produce a variety
of local and regional coexistence outcomes. Thus, incorporating mutualism
15 dependence and dispersal behaviour into coinvasion models offers new insights
into spatial coexistence and invasive species distributions