What can we do for urban insect biodiversity? Applying lessons from ecological research

Urban ecosystems are not unique as the ecological processes and anthropological effects they encapsulate can equally be found in a range of human dominated environments. Applying ecological lessons from both within and outside urban areas is important for insect conservation within our expanding towns and cities. The management of urban grasslands, which in many cases is controlled by private individual and corporate landowners, has the potential to make a large difference to the biodiversity they support. Here we report on an investigation of invertebrate biodiversity within a series of small urban grasslands with contrasting frequency of management by mowing. Seven gardens and five other grassland areas were suction sampled for grassland invertebrates in July 2016. Samples were taken in patches that were regularly cut on a 7-14 day cycle (very short), those cut every six weeks (short) and those than had not been cut since the previous year (long). Invertebrates were mostly identified to order level, with the Hemiptera to species or morphospecies. Invertebrate abundance was significantly inversely related to mowing frequency but overall species richness did not differ between short and very short grasslands. Community structure also was most distinct in the long grasslands. The pattern of abundance varied between different taxonomic groups, with the Hemiptera particularly benefiting from very low levels of management. The value to invertebrates, especially Hemiptera, of reduced grassland management is discussed, with reference to how the owners of gardens and other urban grassy areas can make simple changes to benefit biodiversity on their land.