An important component of understanding the dynamics and stability of communities is to elucidate how species interactions respond to disturbance. We address this issue by experimentally removing a dominant floral resource from an intact subalpine plant community, and exploring its effects on plant-pollinator interaction networks. Our site contained 10 sets of paired plots, in which we removed Helianthella quinquenervis from half. We observed floral visitors throughout the 4-week flowering period of H. quinquenervis to investigate how this removal affected the structure and composition of plant-pollinator interactions. Specifically, we ask the following questions: (1) How does the structure and topology of plant-pollinator interaction networks respond to the removal of H. quinquenervis? And (2) How does the composition of interactions differ between treatments? We hypothesized that the response of structural properties of the networks and the turnover of interactions between treatments would be greatest during peak flowering period of H. quinquenervis. After calculating the structural properties and quantifying interaction turnover, we analyzed differences between treatments using paired t-tests.
Results/Conclusions
Overall, the topological properties of the networks exhibited variation in response to the removal, but only during peak flowering of the dominant plant species. Removing the dominant floral resource resulted in increased network generalization, with removal plots exhibiting higher connectance, higher nestedness, and lower specialization (H2’) compared to control plots during peak flowering which may contribute to greater network stability under some contexts. Interaction turnover was greatest during the peak flowering period of the dominant resource, and species turnover consistently contributed more to interaction turnover than interaction rewiring, indicating that the removal of a dominant floral resource may alter the species composition in the community. These relatively high rates of interaction turnover indicate that this community may be generalized and resilient to various disturbances. Our findings illustrate the complexity of responses that can occur with the removal of a dominant resource, with implications for our understanding of the stability and dynamics of ecological interactions in response to various disturbances.