Towards a monitoring method and a number of multifaceted and hierarchical biodiversity indicators for urban and suburban parks

In this paper we develop a method for the general monitoring of the biodiversity in (sub)urban parks. The method works along two lines, that of habitat diversity and that of species diversity. On the habitat level we measure the diversity in so called ‘habitat units’. These units are divided in planar, linear and punctual elements. For each category we calculate a Shannon–Wiener diversity index and a saturation index. The latter is the ratio of the diversity index compared to the maximum diversity possible. On the species level we use the species number and diversity index of vascular plants, as measured in random sampling plots of 100 m² (for trees and shrubs) and 4 m² (for herbaceous vegetation). In addition, we also use the species number of butterflies, amphibians and breeding birds. These numbers are compared with the total species number in Flanders, resulting in a saturation index per park for butterflies, amphibians and breeding birds. In this way 20 biodiversity indicators are obtained. The proposed method was applied to the municipal park of Loppem (West-Flanders, Belgium), from which the necessary time budget has been calculated. Since it is the first application of a new method and no reference to other parks is available, the proposed bioindicators have been compared with criteria given in the literature on the selection of biodiversity indicators.