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Urban habitat – protecting pollinator diversity?

Urban habitat – protecting pollinator diversity?

It may have been my first contact with urban habitat other than gardens: in June 2008 I was in Rome for the first time. Completely overwhelmed as I was by the beauty of the city, I felt some relief arriving at the Roman Forum. It was quiet here, still relatively early in the morning. And: there were some flowering areas. It looked intentional, like a sown wildflower meadow and added splashes of colour to the magnificent monument. I decided to take a look – of course – and see if I could find some bees. And I did.

urban habitat, pollinators, bee diversity

Don’t ask me who this is. From the way she collects pollen, I’d say an Andrena. But in Italy (or any other Mediterranean country), I’m never sure of anything.

At the trefoil, there were some very busy bees, collecting pollen. I had no idea about the species, maybe some Andrena. You may remember that bee diversity hotspots are in Mediterranean areas. There are more than 900 species of bees in Italy and I already struggle with recognizing all 550 in Germany. And it’s not just the number of species, but also additional genera etc. that don’t occur in Germany. However, I was delighted to see bees in the middle of Rome.

At that moment I didn’t give it a name, the term “urban habitat” wasn’t as discussed as it is now. But I realized that in this area of an antique urban structure there was an intentional introduction of some natural space. Perhaps only to embellish the Roman Forum with some flowers and by this attracting also pollinators. Areas like this, however, are becoming more and more popular. “Urban habitat” is a thing, together with “urban beekeeping”, which I will treat in another post. Both became fashionable in the attempt of a broader public to “save bees”. Which makes me cringe…

Urban habitat for bees

I’m not contrary to creating habitat for bees in no place at all, that’s not the issue. What bothers me – you may already imagine – is this simplifying “save the bees with…”. Add any buzzword you’ve heard in this context in the past years. In general, the measures themselves are good but fail to “save bees” because they take only single aspects into account.

Cities formerly were considered part of the problem, and not a solution. They take space and too many people don’t favour wildlife. The general tidiness of parks and gardens may adapt to the aesthetics of humans, but doesn’t comply with the needs of most animal and plant species. Air pollution and too many nutrients further limit biodiversity. Only some species adjust to these conditions, a typical example would be the blackbird or doves; they thrive in human company. Same is true for bees: only some species regularly visit gardens. The Red Mason Bee is a good example, not very picky about its favourite flowers and nesting in trap nests.

urban habitat, non-managed bees, parasites, cleptoparasites, climate change

Red Mason bees don’t mind humans in their habitat. This is Emma, a protagonist of my Master thesis.

But many other species don’t live in parks and gardens, they need special plants that don’t grow there or structures like bare soil or dead wood that don’t fit the image most people have from green spaces in cities. In addition, many gardens recently look more like stone deserts than gardens. In my neighbourhood, the greenest places have a lawn and not much more. My roof terrace and my neighbour’s garden are exceptions to this rule, colourful oasis in the desert.

More nature in urban spaces

On the other hand, nearby there’s a park on a former industrial area with wildflower meadows and quite colourful flower beds. It’s surrounded by newly built houses, all of them with little gardens – most of them looking like the stone deserts described above. I spent some time in the past two years looking what bee species I could see. With some disappointment, to be honest. There were of course only common species, mostly bumblebees. There’s nothing bad to this, they’re beautiful. But these spaces in my experience help only a few species, and, therefore, they don’t “save bees”.

urban habitat, bees, non-managed pollinators

Wildflower verges like this one look pretty and give a feeling of “wilderness” to a former industrial area now turned into a park. The attracted pollinators are common species.

Of course, my personal experience isn’t an objective benchmark. A paper on UK pollinator biodiversity may give a different picture. The authors compared the number of species and pollinator abundance in cities, in farmland and in natural reserves. The largest number of individuals (abundance) occurred in natural reserves, but there actually weren’t significant differences between the three habitat types. Rare species, however, were found mostly in nature reserves and farmed areas. In the cities, there were always the same species, while they varied more in the other habitat types.

Complementary, not exclusive

An interesting aspect mentioned in this paper is about the role urban habitat could play for pollinators:

If high-quality urban areas are able to support good populations of insect pollinators, they could act as important source areas, refuges and corridors of favourable habitat in a hostile matrix habitat such as intensive agricultural landscapes.

This is something I didn’t consider in my reasoning above. Transforming cities in corridors between different pollinator habitats… sounds attractive. However, there’s an important word in this sentence: high-quality. This is something to define carefully and to consider in different conditions.

Reading this paper got me thinking about what really disturbed me about this “let’s save the bees with urban habitat!”-hype. I think that, in addition to my aversion of simplifying, it’s the exclusiveness. Urban habitat doesn’t replace natural spaces. It’s an addition. A corridor. A refuge, perhaps. This doesn’t save us from conserving real, natural habitat.

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