Stability and resilience of plant-pollinator networks in an Andean montane community in Southern Ecuador.

Abstract

Mutualistic interactions sustain biodiversity and influence community stability. If there are only a few interactions within a community, or multiple interactions that are weak, the community is more likely to collapse. This research investigated the stability of a plant-pollinator community in the Ecuadorian Andes to understand how vulnerable these interactions are to environmental stressors such as climate change and habitat degradation. To do this, we used two species interaction networks based on foraging fidelity (i.e., consistent returns to a particular plant species) and floral association data from both native and non-native pollinators. We used the network metrics connectance, specialization, and weighted network nestedness to determine the strength of these interactions, and therefore, the resiliency of this montane community. Based on these metrics, we found that our visitation network is relatively robust to ecosystem stressors, however, our larger-scale survey, which may be a more accurate depiction of the community due to sample size and increased diversity, showed a lack of resilience to stressors. Honey bees (Apis mellifera) were much more abundant than native bees in both networks, and may be providing many of the pollination services previously provided by native bees. Honey bees were generalists at the species level, but individuals were faithful to particular plant species. This research can help inform future conservation and non-native species management efforts, and can be used to further understand the nuanced relationships between plants and pollinators, which are essential to agricultural production and ecosystem maintenance on a global scale.