Lots of (mostly bad) news in pollinator conservation
There has been a flurry of news in the bee conservation world lately. A couple of big papers have been published, one by Laura Burkle et al. in Science and one by Ignasi Bartomeus et al. in PNAS. Laura Burkle’s paper looks at a famous historical dataset from Carlinville Illinois, and adds present day collections and collections from the 1970s to look for declines in bees. They find rather drastic declines in bee species, and while the pollination networks appear stable for now, the loss of pollinator species doesn’t bode well for the future. The tough thing about these data is that the old dataset had no record of sampling intensity or bee abundances besides broad classifications. So comparing to present day data is tough, but the findings of Burkle et al. are still a red light.
The paper by Bartomeus uses museum collections to look at bee populations across the northeastern US, and comes to a different conclusion. While the museum collections agree with other studies (including mine from San Francisco) finding declines in bumble bee species, other bee species are fluctuating, but overall species richness does not appear to be significantly declining. They cite a study stating that human land use has increased in the study area, but there has also been shifts away from farming in the Northeast. Quantifying land use change in their study area would have been very interesting. Perhaps land use change can explain some of the turnover in bee species over time, or perhaps the turn over is just part of the natural variation in bee communities. Bee biologists have known for a long time that bee communities vary greatly from year to year. But perhaps the northeast bee community is not in decline because land use change has not been as drastic in the northeast as in other areas.
The third bit of news is not published, but there have been early media reports of heavy winter losses in honey bee colonies. Colony Collapse Disorder (CCD) attributed colony losses have declined over the previous 2 winters to levels around 20% losses, but it sounds like this winter may have been the worst year yet. There is still no smoking gun as to the cause, but these losses should be another red light. We need to act fast to figure out what we can do, and we need to continue to research the other pollinators out there, as a sort of insurance if commercial honey bee cultivation continues to face these challenges. For CCD, we need more research looking at the newer pesticides out there, especially looking at combinations of pesticides, pathogens and other factors and how that affects bee health. The pesticides undergo some testing on their own, but very little testing for combined effects is done.
Finally, to add to the mostly dreary news, there are alarming reports that monarch butterfly populations at the overwintering grounds in Mexico were at record lows this year. And this loss is being attributed not to logging in Mexico (which has been halted), but to changes in farming practices in the US that has led to fewer milkweed plants, which is the larval food source for monarchs and to harsh weather (also likely our fault). These reports are again in the media and not yet published in peer reviewed journals, but the decline appears to be real. So if you are doing any gardening this year, why not add some native milkweed plants? Milkweed flowers are pretty, they will attract monarchs, and perhaps you will help save one of the marvels of the natural world (the monarch migration). Mexico is doing its part to save the monarchs, and we need to step up as well.