Interaction patterns and specialization in a local and national Norwegian pollination network
Abstract
Pollination is an important ecosystem service that is threatened and not very well studied in Norway. Interaction patterns and specialization is one important aspect of pollination that needs to be studied to better understand pollination networks. This study tries to map pollination interactions and the degree of specialization in a local and a national Norwegian pollination network. In addition, bumblebee tongue length, hoverfly flight length and species abundance, are investigated as possible factors correlated with specialization. The local network was from a hayfield and was sampled with transect walks. The national network was sampled from the user based public internet portal artsobsevasjoner.no and a part goal of this study is to evaluate the usability of this portal. Interactions in the networks where not randomly allocated and species had preferences for interaction partners. For instance bumblebees and Fabaceae plants did as expected interact much. Most species had many interactions, classically seen as generalist, but many species had non opportunistic interaction patterns, seen as specialization. Species varied in how specialized there interaction pattern were. For hoverflies from the national network specialization did as expected significantly increase with shorter flight period. Abundance of plants and pollinators showed a varying relationship with the specialization degree of plants and pollinators. Long tongued bumblebees were the most specialized, but this relationship was not significant. The data from the public internet portal was useful, although there are many problematic biases that one need to be aware of when using such data. That species have preferences for interaction partners and often were specialised should be taken into consideration when evaluating redundancy in pollination networks.