Bees aren’t all alike. Tens of thousands of different bee species exist around the world, and they all like different habitats. Encouraging different species to settle in restored habitat is even more complex. By J.Green
Edinburgh, 17 March 2015- The UK currently has more than 260 bee species, with some 26 of those being social (that is, they live in swarms, nests or hives). There are also 25 native bumblebee species but sadly two have recently become extinct. While there are still many types of bees, research shows bee diversity has significantly decreased in more than 50% of the UK’s landscapes since 1980.
Recent research from the UK-based Centre for Ecology and Hydrology has confirmed that the situation for British bees is pretty dire. Some 75% of the UK is agricultural land. And because of that, researchers estimate around 97% of natural bee habitat - wildflower meadows, small woods, open heather moors – is gone. As a result, “bees have significantly declined over the 20th century,” says the report. That is an understatement.
But bee help is at hand. To combat these trends, the authorities have initiated a program that pays subsidies to landowners for the “intensification of landscape quality.” Farmers chose wildlife-friendly options to qualify for those subsidies, which can total GBP280 a year. One common outcome of this subsidy is natural strip of land left at the edge of existing farmland. There, a mix of agricultural plants and grasses that bees like are added. Bumblebees take to agricultural legumes, while sunflowers are also good for bees.
In one recent project, ecologists tested a few different options. In land where were there simply crops, there was no value for bees. In areas without pesticides, there was likewise a limited response. Where the “natural generation of plant communities” was allowed, there was also only a limited response. The key to making bees feel at home is creating sites that offer pollen and nectar, with a diverse seed mix. This, says the research, results in a “significant response” from bees.
Bees and Seeds
But a single seed mix, no matter how diverse, will “not have sustained benefits,” say researchers. There is also a seasonal component; some plants die off. So flowering plants that offer nectar need to be re-sown every 3-4 years, and a diverse plant mix ensured that includes perennials.
Former mining sites are a surprising potential bee habitat, and are found everywhere in the world. Given all the untapped land, there are lots of opportunities to restore them as habitat for bees. Karen Goodell, an ecology professor at Ohio State University has investigated mining sites as a potential new home for bees.
She says reclaimed mines “can aid bee conservation,” but they will not be as good as remnant or untouched habitat. It’s difficult to restore plant communities that existed in mining areas before. Forests can be re-created, but a full ecosystem is more difficult. Goodell says “floral diversity and abundance will positively affect bee recruitment,” so consequently bees will be less diverse in reclaimed mining sites than in remnant habitats.
In a study of 24 sites at The Wilds, a leading conservation site in Ohio, Goodell netted bee species, counted floral resources, and assessed nest habitat. She looked at sites that were closer and further away from natural habitat, looking specifically at Megachilid bees, which are more solitary than honey bees and nest on or in the ground. Strikingly, she found that the abundance of floral resources wasn’t really important - but restoring nesting substrate was far more critical. The ‘nesting subtrate’ includes stem wood and bare soil but the use of additional artificial nest substitutes didn’t help the bees feel at home. “It’s important that habitats, whether they are restored or not, have ample hollow stem wood lying around, shrubs, dead wood, and bare ground, if you want to attract (Megachilid) bees,” she noted.
Another bee expert, Neal Williams from the University of California, Davis, confirms the transformation of wild areas into agricultural areas is the primary reason for bee habitat loss. Near the Sacramento River in California, a group of farmers and other activists are restoring an 80-kilometer stretch along the river banks from Red Bluff to Chico. Williams’ is studying the community of pollinators in the restored fragments and comparing them to remnant riparian forests while looking for “persistent differences” that stand out between the two areas.
Williams says the sites were successfully restored - a mono-cultural walnut orchard landscape was turned back into a forest - but now there is no understory which meant the bees came back, but not to a thriving overall ecosystem composition.
But bees are essential for both ecosystem health, and for the honey industry too. With around 85% of the world’s flowering plants needing a bee or other pollinator in order to reproduce, these tiny insects are crucial to our survival.
So much so that in California, more than 3,500 truckloads of bees are trucked in every spring from other, less intensively-farmed parts of America to pollinate over 1 million acres of almond trees during their three-week spring bloom.
So it looks like although some dedicated activists are working hard to keep the bees happy with new homes, there is nothing like original, pristine habitat for a happy hive. Farmers in the UK are doing their best, thanks to the government subsidy, but simply describing empty land as a potential bee haven is not realistic. Bees need a complete ecosystem to thrive. The best way to ensure that – and a good supply of honey for us all – is to avoid turning pristine land into mines or wheat fields.
For more information look to : https://eeob.osu.edu/people/goodell.18; http://www.ceh.ac.uk; http://www.helpabee.org