BayCEER Workshop 2008

Testing methods of assessing pollinator diversity

Pollination is a key ecosystem function that is threatened globally. Main drivers of pollinator loss are changing land use practices including agricultural intensification, habitat fragmentation and isolation, agrochemicals, climate change and the introduction of non-native plant species. For the quantification of pollinator diversity and abundance, and long-term monitoring of pollinators across Europe, appropriate methods are needed. Within the framework of the EU-project ALARM (http://www.alarmproject.net) we are testing different methods to develop standardised protocols that will be applicable in semi-natural and agricultural systems at a continental-scale. We focus on bees (Hymenoptera: Apoidea) and hover flies (Diptera: Syrphidae), which represent two important pollinator groups in Europe.   For the method testing we chose six study regions across Europe: Sweden, Poland, Germany, Great Britain, France and Greece. In each region we selected two habitat types (agricultural vs semi-natural). These habitats were located in two different landscape types (structurally complex vs structurally simple landscapes). Each habitat type was replicated two times within the landscape type and region. Following methods were tested: standardised and random transect walks, bee counts in standardised observation plots, white, yellow, and blue UV-reflecting pan traps, and trap nests with reed internodes, and differentially sized paper tubes (Oxford Bee Company Ltd).   The results show that transect walks and pan traps are the most suitable methods to assess pollinator diversity and abundance in agricultural and semi-natural habitat types across Europe. The diversity and abundance of above ground cavity-nesting bees could be adequately assessed using trap nests with reed internodes.     Westphal et. al Ecological Monographs (accepted)