Natural grasslands are critical but shrinking habitats for native plants and pollinators, and were historically maintained in the US through fires and grazing. More recently, the introduction of moderate cattle grazing and haying has been proposed as potentially beneficial disturbance regimes that may help maintain high levels of plant species richness and accompanying animal biodiversity in grasslands. Despite this fact, the impacts of these disturbance regimes have only been investigated in a few ecological regions, often at limited spatial and temporal scales, and typically did not quantify effects on critical species interactions, like plant-pollinator interaction networks. In this study, I investigate the impacts of different contemporary and historic disturbance regimes on plant-pollinator network composition and structure, across spatial and temporal scales, focusing on the understudied Blackland Prairie and Edwards Plateau bioregions of Central Texas. These analyses illustrate that historic management, the practices implemented for nearly a century leading up to the present-day management, have a greater effect on current plant and pollinator community composition and network level characteristics than the more recent management techniques of the past 10 years. Specifically, through NMDS analysis and linear modeling, we reveal that the plant-pollinator communities are significantly more similar in sites that were managed similarly historically compared to those that are currently managed similarly. In addition, we found that network nestedness and robustness are significantly driven by landscape level seminatural habitat. This work indicates that historic land management and current habitat can have lasting impacts on plant-pollinator community composition and network dynamics.
