Data from: Novel positive interactions between invasive species: widespread mammals disperse a non-native woody species

Novel ecosystems often emerge from the co-occurrence of species with no
shared evolutionary history, leading to unique and potentially synergistic
interactions. Positive interactions between non-native species can be
crucial for successful invasions. In this study, we investigate the novel
interaction between two invasive mammals (Axis axis and Sus scrofa) and
their role as dispersers of the invasive tree species Gleditsia
triacanthos. We assessed this dispersal mechanism at a local scale in
Entre Ríos, Argentina, by feces sampling. We analyzed the seed content in
feces and performed germination experiments to compare them to
non-consumed seeds. Additionally, using global occurrence data, we mapped
the co-occurrence of both mammal species with G. triacanthos to identify
regions of potential synergistic interactions. We estimated a density of
1917 feces per hectare for A. axis and 267 for S. scrofa. Of the feces
sampled, 56% of A. axis and 37% of S. scrofa feces contained at least one
G. triacanthos seed. The average number of seeds per feces was 6.8 for
deer and 2 for wild boar. Germination experiments confirmed the
germination capacity of seeds consumed by both mammals. Global
co-occurrence analysis revealed widespread spatial overlap, with stronger
co-occurrence between G. triacanthos and S. scrofa. Synthesis and
applications. Our study provides empirical evidence that management plans
should adopt an integrated approach. The movement of invasive animals
significantly influences propagule pressure and given their broad
distribution and widespread use of the landscape, merely reducing plant
density is insufficient. These animals ensure the dispersal of the few
invasive plants that may remain. Therefore, management strategies should
not only focus on controlling plant density but also on regulating animal
populations, especially those that facilitate the spread of non-native
species. Such integrated management is crucial for preventing the
reinforcement of invasive dynamics and improving long-term control
efforts.