Countering Insect Habitat Losses and Change in Urban Areas

Abstract

The roles of some of the processes noted in the preceding chapter emphasise the importance of open spaces in urban environments, both as ameliorating influences on threats and as key areas in which the impacts of urbanisation may be prevented or countered through deliberate manipulation or restoration of probable natural features and their close analogues. Most urban conservation depends to large extent on open (‘green’) spaces, the extent of which can be far larger than initially anticipated. Within these, numerous different manipulations and modifications for conservation benefits may be possible. Reflecting many parallel purposes, measures pioneered for use in agroecosystems can sometimes be transferred easily to urban spaces, with similar outcomes of increasing native species diversity and promoting wellbeing of natural enemies of pest arthropods. As examples, ‘beetle banks’ (grassy strips in fields to harbour predators amd protect them from routine agricultural disturbances) and ‘insectary strips’ (linear plantings of nectar-providing plants) are both easily modified in scale for urban uses. Frank and Shrewsbury (2004) combined these, as ‘conservation strips’, as refuges for natural enemies on golf courses, and their presence increased predators, parasitoids and alternative prey abundance on roughs and fairways, suggesting considerable values in conservation biological control (p. xx), perhaps also for turfgrass pests in urban parks and similar places. Manipulation of vegetation has the twin purposes of increasing richness and amount, and increasing structural variety, both with potential to affect availability of seasonal resources for insects and to foster equivalent increases in all guilds of arthropods and to enhance biological communities (Shrewsbury and Leather 2012).