Over the past few weeks I’ve been thinking a lot about urban pollinators, that is to say bees, hoverflies, butterflies, and other animals, living and foraging in towns and cities. As I recounted in my recent post about the National Pollinator Strategy seminar at Westminster, Jane Memmott presented some of the first data from the Urban Pollinators Initiative which is looking very interesting. At the same time, Muzafar Hussain has submitted the first manuscript from his PhD study of urban solitary bees in Northampton, and will hopefully be defending his thesis early next year. More recently I was asked to examine the PhD thesis of Rob Fowler at the University of Birmingham, whose focus has been on pollinators across an urban-rural gradient. Rob did very well and I look forward to seeing his work published.
Interesting though all this work is, it’s largely being done outside the context of crop pollination per se, focusing mainly on the identity and abundance of these urban pollinators. It’s timely, therefore that a study has just been published by Thebo et al. in the journal Environmental Research Letters entitled “Global assessment of urban and peri-urban agriculture: irrigated and rainfed croplands” which gives the first comprehensive figures on the extent of agriculture in and around the world’s large towns and cities. The paper is open-access so you can read its findings for yourself, but the main message is that urban agriculture is more extensive and important than previously assumed, and there are significant implications for food security and water resources.
The research has (justifiably) received quite a lot of publicity in the media, for example on the BBC News website, and is a great contribution to a still limited field of study. One aspect jumped out at me though; when discussing the limitations of their methods the authors state that: “the scale and methods used……are not structured to capture very small, spatially dispersed areas of urban croplands”. In other words, urban gardens and allotments are not included in this assessment. In the UK at least this is a significant limitation as we know that urban fruit and vegetable growing is widespread, though as far as I’m aware there’s no published figures on the volume and value of this local horticulture of food crops.
Which brings us back to urban pollinators: a significant fraction of these crops (large-scale and local garden) requires pollination by insects. As I reported back in July, in our own urban garden this includes at least 15 crops (strawberries, apples, greengages, cherries, blackcurrants, squashes, courgettes, blackberries, fennel, runner beans, french beans, passion fruit, tomatoes, raspberries, and radish pods). An integrated study of urban agriculture/horticulture in the context of pollinator diversity and abundance would be a great piece of research and is long overdue.