Sunday, 30 July 2017

Why is the world's largest bee hotel like Glasgow's postwar regeneration?

I was in Scotland last weekend to lead a couple of bumblebee ID training events.  As I needed to bring a fair bit of kit with me, I drove, and passed through Glasgow on the M8 motorway on my way to Loch Lomond.  The M8 is strange in that it passes through heavily-populated areas: the splitting of communities caused by the massive new road is one of the many reasons cited for the failure of Glasgow's massive post-war regeneration, where entire neighbourhoods of slum tenements in the centre were demolished and the inhabitants moved out to newly-built flats around the edges of the city.

This, slightly implausibly, came to mind again this morning when I saw a tweet from the BBC's Springwatch about 'the team' at WWT Martin Mere building 'the world's largest bug hotel'.
The thing is huge - 17 cubic metres of bamboo, straw, wood, slate, chicken wire and pine cones that took four weeks to construct.  And I'm rather concerned that it - and the general fashion for building ever-bigger edifices of 'insect habitat' - is repeating very similar mistakes to the planners and builders of post-war Glasgow.

The new developments in Glasgow failed largely because they disrupted families & local communities, and they didn't provide amenities - shops, schools, places to work.  Huge numbers of people were placed in new flats in the middle of nowhere seemingly almost at random.  To see friends or family meant facing long, arduous trips across town; any desire or need to work, visit shops or pubs, or do anything outside their new homes meant difficult trips back to the city centre and their former neighbourhoods.

This is almost exactly what happens with these giant bug hotels.  Usually unaccompanied by any more favourable management - more flower-rich grassland, say - they are giant blocks of just-about-passable accommodation in the middle of nowhere.  Bees - especially the smaller solitary species which are the main targets of 'hotels' - have a fairly limited flight range, especially to forage efficiently and bring back the maximum of pollen & nectar in the minimum time.  The area around a giant 'hotel' is unlikely to be able to support the number of bees which could nest in 17 cubic metres of hotel! Thus most will remain empty... which makes things a bit of a waste of time.

Additionally, any large aggregation of host species will inevitably attract parasites, pests & diseases.  There is already some evidence that 'bee hotels' may potentially do as much harm as good by artificially aggregating solitary bee nests in areas which are easy for parasites and parasitoids to spread between nests: one 'hotel' manufacturer even recommends that the products are cleared out each winter to reduce the parasite load on the bees.

Overall, while these giant 'bug hotels' certainly make a statement to the casual visitor, they almost always remain virtually empty (apart from the inevitable earwigs), and those bees which do set up home are at greater risk of death than those nesting in more natural situations.  I haven't visited the Martin Mere 'hotel': I can't comment on whether they have begun managing the site more for pollinators, or whether their showpiece hotel is accompanied by more natural, more dispersed options for nesting or overwintering.  

But I can virtually guarantee that they don't set out to increase bird numbers on the reserve entirely by putting out more nestboxes, which appears to be essentially what they've done here for insects.

More information on the Glasgow regeneration projects can be found on the University of Warwick website and Buzzfeed has an impressive gallery

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