Marginalia

One of the most ambitious targets in Biodiversity 2020 (the England Biodiversity Strategy) is the creation of 200,000ha of new priority habitat by 2020. This includes grasslands like lowland meadows, chalk downland and Culm grasslands. And believe me 200,000ha of priority habitat is a great deal of new habitat.

No doubt this ambitious target, along with the “Gold-plated” Habitats Directive, the Nitrates Directive and the Water Framework Directive, feeds into a view within the agricultural industry that the pendulum for too long has swung away from intensive agriculture, towards luxuries like the environment or wildlife. Indeed only last week a conference organised by LEAF heard that “environmentalists couldn’t have it all” and that there needed to be trade-off between food production and the environment. It was reported slightly hysterically in Farmers Weekly. “Having it all”, I would have thought implied that there was total control of the agricultural environment for conservation, resource protection and so on. Which planet are they on?

Back to the 200,000ha ( that’s a shade over 2% of the agricultural land in England). How would we know when it had been achieved? Should we leave it to good-natured landowners, and then do a bit of a survey in 2019 to find out how much had been created. How many extra hectares of lowland meadow should there be? How much extra chalk downland? Should we focus on restoring grasslands which have been damaged or neglected, or is it better to start afresh, with a blank slate, a ploughed field. And what should qualify as priority habitat – should we wait until it’s a top quality habitat full of threatened species, or is it OK to say “yes it’s priority habitat” when the seed has gone into the ground, a ditch has been blocked, or trees have been planted. These are difficult questions.

Priority habitat doesn’t appear overnight, in some cases it can take decades to reach the necessary quality. Given that we only have 8 years to meet the target, if we set the bar too high we will inevitably fail and that would send out all the wrong messages ie that it’s too difficult.

With this in mind I just read a paper  published by the Royal Society where researchers  modelled how climate change might affect interactions between pollinating insects (bumble-bees), essential for crop pollination, and the sources of pollen and nectar on which they feed. The researchers compared a “nectar flower mix” with a “wildflower mix”, as examples of sown field margins. The Nectar mix contained four species, 2 of which were the agricultural fodder plants Alsike clover and Sainfoin. The “wildflower mix” contained 21 species of native wildflower, but only six regularly flowered.

The models simulated the effect of increasing temperatures on the behaviour of the bees and the plants – eg whether the queen bees emerged before any of the plants had started flowering. Although the results were not statistically significant the researchers concluded that the period when the flowers and bees did not overlap was likely to be greater for the nectar mix than the wildflower mix. They recommended that such mixes could be climate-proofed by selecting early (eg white and red dead-nettle) and late flowering (field and devil’s-but scabious) plants and adding them into the mix.

Now this is all interesting but it got me thinking about the agricultural landscape and how people perceive it now and in the future. In theory we can provide the nectar and pollen for some species of (crop) pollinators by engineering the landscape through the widespread provision of sown field margins, sown with nectar mixes or native wildflowers.  It is possible to imagine every rye-grass field or oil seed rape crop, with a 3 or 6 metre margin of nectar crop. Added together this resource might add up to tens of thousands of hectares across the whole of England. It would involve losing a few percent of croppable land for the farmer, but then it would be providing them with an essential service, pollinating crops like oil seed rape and beans.

Of course these sown margins are not grasslands, in the sense that the grassland priority habitats are grasslands (or indeed in any other sense). Nor will the sown margins support the wide range of biodiversity that the priority grasslands (and their semi-improved equivalents) support. Nor will the margins provide all the ecosystem services, the archaeology and the history that the grasslands provide. Certainly a combination of substantially more permanent grazed grasslands, with the perennial nectar/pollen margins will work well together.

Farmers may happily adopt the perennial margin approach because it fits in well with the way they currently manage their land, but will resist the transformation of land to permanent species-rich grassland, because it will require a substantial change in that management. The challenge will be to get farmers to attribute sufficient value to the restoration of field-scale permanent  species-rich grasslands to drive that change in behaviour.

 

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About grasslandstrust

The Grasslands Trust is the only national UK charity that focuses entirely on saving grasslands that are valuable because they are rich in wildlife, history, or for other reasons.
This entry was posted in agriculture, bees, biodiversity, climate change, Ecosystem services, farming, grasslands, Miles King, pollinators and tagged , , , . Bookmark the permalink.

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