For the last couple of weeks I have been busy mapping bee colonies in central London. The idea for this topic came from reading news articles expressing concern that the increasingly popular hobby of urban beekeeping is resulting in too many bees in London. How do we know if there are too many bees?
I decided to look at the sustainability of hive locations, based on the type of land and plants that are within the individual bee colonies’ foraging ranges. After getting data about some beehive locations and land type in correct formats, I am happy to report that I have managed to produce the spatial function that calculates the ‘usefulness’ of the land within the bee colonies’ foraging ranges. I have yet to produce the final version of the model in ArcGIS model builder, but I have managed to work out a way to calculate the land type value for bee colonies’ foraging ranges.
I plotted the hive locations on the map, created buffer zones representing the foraging ranges for each hive, gave the land type raster values representing the usefulness of each land type for bees, and then calculated the values in each buffer/foraging range. It would be a very easy task if there were no overlaps in the bees’ foraging ranges. But there are. Lots. And lots.
The challenge was to calculate the correct share of the values for each overlap. Some buffers overlapped with three or four other buffers, creating such complex layers that it took me a couple of days and liters of of tea to figure out how to isolate each buffer intersection with multiple layers and calculate its share of the land value. After that I had to figure out how to ‘reallocate’ that intersect share value to the original buffer (minus the total value of the intersect) so that it would represent the food source value for the hive within that zone.
In the above picture I set the buffer zone to 500m, which in reality is a very small range. I have found research conducted in Sheffield that states that the median distance that a honey bee flies from its hive is 6.1km. That’s just the median! If I set the buffers to that distance, they would all overlap. Of course that is a more realistic representation, but for the purpose of the first phase of my exercise I used small buffers so that it was easier to visually explore the hive locations and overlaps. The beauty of my spatial function (which I will share after the coursework deadline) is that everyone can adjust the parameters for buffer zones and land type values according to their own consideration.
The next step is to figure out some kind of a national bench mark for the land value within a bee colony foraging range, so that I can compare the values from London to the other parts of the country and actually attempt to answer the question whether there are too many hives in London. Stay tuned.
Fortnum and Mason’s bees knees
Meanwhile, here’s a nice video about Fortnum and Mason’s rooftop honey production in central London.
The ‘bee master’ Steve Benbow from the London Honey co mentions in the video that the average foraging range is 3 miles, so I think I shall keep that in mind for future mapping and analysis. If I just got my hands on a more complete dataset about all beehive locations in London…