Les inventaires du patrimoine naturel en milieu urbain

Abstract

Urban and periurban environments do not exert the same attraction to naturalists as wilderness areas. A number of inventories of species or of groups of species (fauna and flora)have been transferred to the urban environment starting in the 19th Century. A revival of interest, be it on the part of the scientific community or of urban managers, has recently been reactivated and has resulted in studies which have revealed some notable faunistic and floristic changes. In current practice, inventory methods utilized to identify, localize and describe the natural heritage reveal that whatever the environment dealt with, there are two types of approaches used : one focusing on species and one on spaces. Concerning species, data are obtained from the occurrence or absence of each taxon, for which both date and locality are given in the most precise manner possible. The quantitati ve or semi-quantitative evaluations, obtained either on the basis of reproductive individuals (vertebrates), or a number of known observation stations (invertebrates, flora), remain limited to a small number of species identified as being "under biological surveillance", of which some are found in urban areas : rare, threatened or protected species, sometimes qualified as "remarkable" or even called "problematical". Currently in French, the inventory of Natural Zones of Ecological, Faunistic and Floristic Interest (ZNIEFF), is the only approach with an objective to conduct inventories, at the national level, of more biologically rich natural spaces. This programme deals with the delimitation of areas harboring the most remarkable biocenosis and environments in a given sector. In urban and periurban environments, it concerns above all the less degraded public green spaces, to which should be added private parks and gardens, unbuilt dry embankments, abandoned industrial and urbanization sites, railway rights of way, cemeteries and industrial zones, as well as certain more specific areas corresponding to a higher diversity-rich sites (e.g., resting placed for bats) . All such inventories open the way to actions of conservation management, destined to preserve remarkable urban natural heritage, while also seeking to limit nuisances.