The status of pollinator health has been scrutinized closely since at least 2007. There is no agreement on this issue and the data are all over the map. Some show declines, others show increases. Therefore, the folly of making broad and sweeping statements about the health of pollinators. 

Evidence for Pollinator Decline – Pollinators Diversity

In recent years, there are growing concerns over pollinator declines and global pollination crisis (Potts et al. 2010a). However, scarcity of long-term data on the status of domesticated and wild pollinators, in particular bees hampers attempts to evaluate trends in wild pollinators’ abundance and diversity (National Research Council 2007). 

In the last few decades, the number of domesticated honey bee colonies declined in some central European countries, but increased in other countries (Potts et al. 2010b). Overall, the global stock of domesticated honey bees is growing more slowly than the agricultural demand for pollination, stressing the global pollination capacity (Aizen and Harder 2009). 

As for native pollinators, studies have shown declines in populations of some bumble bee (Bombus) species (Cameron et al. 2011; Colla and Packer 2008; Goulson et al. 2006), while other bumble bee species have shown stability or even expansion in range (Williams et al. 2009). Studies on long term trends in the status of pollinator species other than honey bees and bumble bees are scarce. 

Among these few studies are that of Biesmeijer et al. (2006), who demonstrated significant declines in native bee populations, other than bumble bees, in Britain and the Netherlands, and of Burkle et al. (2013) who found an extinction of 50% of the native bee species in Illinois forests, as well as subsequent degradation in bee-plant interactions in these communities. 

However, a comparable study by Bartomeus et al. (2013) did not find such significant declines in other regions of the northeastern United States. The status of wild pollinators in most other regions around the world is largely unknown.

Sapir, Y., Dorchin, A., & Mandelik, Y. (2015). Indicators of Pollinator Decline and Pollen Limitation. In Environmental Indicators (pp. 103-115). Springer Netherlands.

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