As I’ve frequently reported on this blog, there is growing global concern about declines in pollinator diversity and abundance across many regions, and much research is going on into what is causing those declines, their scale and consequences, and what can be done to reverse pollinator loss. It’s therefore great to see the publication of the European Red List of Bees which provides information on the conservation status of the c. 2000 species of bees in Europe.

The report uses standard IUCN criteria for assessing each species and has been picked up by various media and NGOs, who have typically promoted it with claims such as “Nearly one in 10 of Europe’s wild bee species face extinction“.  However the reality of what the report has found is much more complex and nuanced than the headlines suggest.  Over half of the bee species were classified as Data Deficient, meaning that we don’t have enough information to assess whether they are threatened or not.  Of those that could be classified, 7 species are Critically Endangered, including 3 that are endemic to Europe and found nowhere else in the world; 46 are Endangered including 12 endemics; 24 are Vulnerable, with 7 endemic; 101 are Near Threatened with 17 endemic; 663 are Least Concern (68 endemic), meaning that there are no immediate threats to their survival.

If we turn the “1 in 10” headline around, then a more accurate statement would be “Over 90% of Europe’s bees (for which we have sufficient data) are not immediately threatened by extinction”.  Of course that could change once data for the poorly studied species becomes available.  These are not grounds for complacency; but neither are they grounds for panic.

The scale at which we assess biodiversity is critical if we are to fully understand the threats to species, and when and where limited funds can be prioritised for conservation actions.  Species that are locally endangered or even extinct may actually be quite common when assessed across the whole of their distributional range.  For this reason it’s important to consider the status of species in as wide a geographic region as is possible.  Preferably this would mean a global assessment; but for most species we simply don’t have enough information to be able to undertake such a study, particularly for developing countries where there are limited historical records of species occurrences on which to draw.  Even in a relatively developed region such as Europe, with a long history of natural history observation and monitoring, there are huge gaps in our knowledge – in this case for more than half of Europe’s bees.

With this in mind I looked at the European status of those bee species which are now extinct in the UK, as I discussed in December.  Two of the extinct species are considered Critical (Bombus cullumanus and Andrena tridentata); two are Near Threatened (Dufourea minuta and D. halictula); seven other species are Least Concern; and the remaining two (Andrena lepida and A. lathyri) are Data Deficient.  Clearly some of the UK extinct species are in trouble across Europe, but others are not and may re-colonise the UK in the future, as we believe may have happened in the last couple of years for Andrena vaga.  Or they could be helped to re-colonise via a reintroduction programme, as has been done for Bombus subterraneus

Another way in which to put the findings of this report into a wider context is to consider how the level of threat to bees compares with that of other groups of species.  The authors helpfully provide some comparative data in the summary, which I’ve graphed below (click on it for a better view):

Overall the proportion of threatened bees is identical to that of butterflies, perhaps because they require some similar resources (flowers on which to feed) and tend to be found in broadly similar habitats.  But other taxa are at much greater risk, particularly freshwater fish and molluscs: yet these taxa have not received the same level of publicity about their plight.  Their are no “Save the Mussels” campaigns, or television series about endangered fish in rivers and lakes.  This is surprising: clearly bees have grabbed the public’s attention because of the role they play in crop pollination, but freshwater fish are also suppliers of ecosystem services either directly (fishing) or indirectly (playing a role in maintaining the “health” of these ecosystems, as do the molluscs). Perhaps more importantly for these species, they are also indicators of water quality, an aspect of natural capital that concerns us all.

The authors of the European Red List of Bees are to be congratulated on a fine piece of work that makes a major contribution to our understanding of pollinator conservation, and is timely, coming soon after the publication of the National Pollinator Strategy for England.  However there’s still a lot of work to do to fill in the gaps for species that are Data Deficient and to understand the more detailed population trends, which are unknown for almost 80% of the bee species.

One of the most surprising findings, though, is that the honey bee (Apis mellifera), the most intensively researched pollinating insect on the planet, is considered Data Deficient “until further research enables us to differentiate between wild and non-wild colonies in order to determine the conservation status of the species in the wild.”  That’s an interesting state of affairs!

Full citation:

Nieto, A., Roberts, S.P.M., Kemp, J., Rasmont, P., Kuhlmann, M., García Criado, M., Biesmeijer, J.C., Bogusch, P., Dathe, H.H., De la Rúa, P., De Meulemeester, T., Dehon, M., Dewulf, A., Ortiz-Sánchez, F.J., Lhomme, P., Pauly, A., Potts, S.G., Praz, C., Quaranta, M., Radchenko, V.G., Scheuchl, E., Smit, J., Straka, J., Terzo, M., Tomozii, B., Window, J. and Michez, D. 2014. European Red List of bees. Luxembourg: Publication Office of the European Union.