There’s a thought-provoking essay in Conservation Biology by Hall et al., The city as a refuge for insect pollinators. The authors say that while there’s a lot of conservation outreach in cities there’s less actual conservation. The cities are where people are educated or energised to support conservation efforts, but the conservation happens elsewhere. If you take the view that you’re not going to find nature among the concrete that makes sense, but research shows that’s not the case.
Annals of Botany readers will be familiar with Hanley et al.’s work on pollinators in urban gardens, but Hall et al. point to a much wider range of urban bees. Obviously, urban bee keepers are one source of bees, but there’s a lot more to bees than the honey bee, and there’s a surprisingly large number of bees species, many solitary bees, in the city. It’s not just bees that can benefit from conservation, though.
Honeybees pollinate about a third of the crops in the UK. It’s a massive amount but to put it another way, two-thirds of crops are pollinated by something else. I’d love to pretend this is my wise insight, but it’s something I found on Jeff Ollerton’s site. I was surprised by this, but it is backed by a study showing honeybees are part of a wide range of pollinating insects.
A move from a honeybee-centred conservation to a pollinator-centred conservation would have the benefit of tackling the problems that have been damaging pollinators, including honeybees, for a century. I don’t doubt pesticides are a problem, but removing 98% of wildflower meadows must have had a massive effect on pollinator habitats in the UK.
As an example of what can be found in the city, there’s a study by Sirohi et al who studied bees in Northamption. They found for solitary and primitively eusocial bees the city was a better site for diversity than nature reserves. Baldock et al. also found that the city also beat farmland for diversity.
In their essay Hall et al. emphasise that because of the limited requirements of pollinators, major results for conservation programmes are achievable, concluding:
Attending to the needs of insect pollinators in conjunction with a suite of other conservation measures (e.g., green-infrastructure and environmental quality-of-life provision and climate-change mitigation) can inform current and future generations how to urbanize sustainably. To do so, requires an ecological understanding of the city and a requisite conservation that fits the city: conservation for the city.
The city as a refuge for insect pollinators is Open Access at Conservation Biology.
Another recent article in Annals of Botany about urban ecology. see Ross W. F. Cameron Tijana Blanuša. Green infrastructure and ecosystem services – is the devil in the detail?
Ann Bot (2016) 118 (3): 377-391. DOI: https://doi.org/10.1093/aob/mcw129
Published: 21 July 2016
Their abstract quotes the following scope “Many urban plantings are designed based on aesthetics alone, with limited thought on how plant choice/composition provides other ecosystem services. Research is beginning to demonstrate, however, that landscape plants provide a range of important services, such as helping mitigate floods and alleviating heat islands, but that not all species are equally effective. The paper reviews a number of important services and demonstrates how genotype choice radically affects service delivery.”