Greenhance - Meadows

Greenhance: Enhancing urban biodiversity: habitat planning and strategic management of urban green areas

Meadows

Grassland habitats can contain rich assemblages of plants and insects. Many of these, such as pollinating insects in particular, are dependent on management regimes that prevent overgrowth and reduce nutrient levels.

The decline of such management practises has resulted in a similar decline in many of the plant and insect species of such habitats. For instance, in Finland, 25% of threatened vascular plant species and 30% of butterfly species are dependent on grazed or mown grasslands. The Helsinki metropolitan region contains a variety of semi-natural grassland habitats, which with appropriate management could provide suitable conditions for these species, and thus contribute to urban biodiversity.

However, grasslands in urban areas tend to be either unmanaged or intensively mown to produce a lawn. The objective of this study is to establish new meadow habitats in urban areas and monitor the development of plant-insect communities in them. The sites used for this study comprise mostly of landfill sites, from which the surface soil is removed, and the underlying surface covered with a bentonite mat. A new layer of nutrient poor sandy soil is then laid onto this and dry meadow plants sown to produce a habitat structure suitable for the development of diverse plant-insect communities. The plant, pollinating insect, and other interacting species assemblages will be monitored prior to the habitat creation and continued for five years subsequently, to investigate the development of these assemblages in comparison to those of established sites.

Similar monitoring will also be conducted at two nearby control sites for each of the habitat creation sites to allow us to determine patterns of dispersal and colonization in the studied taxa. In addition, we will study the trophic complexity and thus the potential contribution of new dry meadow sites to urban biodiversity.