Plant species response to urbanization: comparison of isolated woodland patches in two cities of North-Western France

Abstract

International audienceThe effect of urbanization on species distribution has been extensively documented, but a main challenge in urban ecology is to better understand the factors causing different distributions among species in response to urbanization. Hence, this paper aims to compare the effects of urbanization on woodland plant assemblages in two cities and to describe species responses by using several indicators. The study was carried out in the cities of Angers and Rennes (North-Western France) where 11 isolated woodlands were surveyed along an urban-rural gradient in each city. Abundance data of spontaneous species were collected from 220 quadrats. The effect of land cover (within a 500 m buffer around each woodland) on species assemblages was investigated by Canonical Correspondence Analysis. Buildings and pavement areas were the most significant predictors of species composition, and the effect of location in Angers or Rennes appeared on the second axis. More than 60% of the most frequent plant specieswere indicator of urban or rural location and their preferences were similar in the two cities. These lists of urban and rural indicator species were compared with Ellenberg's indicator values and two other indicators specific to forest environment. The species which grow preferentially in urban woodlands are species which are already known to be associated with recent forests rather than ancient forests; with hedgerows rather than woodlands. The opposite pattern was observed concerning rural species. Moreover, urban indicator species have higher optima for soil pH and soil nitrogen content than rural indicator species. Different characteristics and history of forest habitat—continuity of the forest land cover, linearity of the habitat, change in adjacent land cover and land use—could select the same species, and the responses of the latter might involve different preferences concerning soil alkalinity and nutrient status

Ellenberg’s indicator values for soil nitrogen concentration and pH in selected swamp forests in the Central Black Sea region of Turkey

“…EIVs for soil N concentration and pH in the present study were similar to those reported for other swamp forests (Slezák et al, 2012). The studied species were indicators of weakly acid to weakly basic and indicated fertile soils with high bioactivity and alkaline and near neutral pH (Vallet et al, 2008).…”

Patterns and Trends in Urban Biodiversity and Landscape Design

“…By comparison, the conifer and oak species were more susceptible to human disturbances than the wind-disseminated species (Rudnicky and McDonnell 1989 ). In addition, and Vallet et al ( 2008 ) report a preponderance of nitrophilic species in remnant forest patches.…”

The effects of urban or rural landscape context and distance from the edge on native woodland plant communities

“…The edge effect on woodland plant communities is also expected to be particularly intense in urban areas, because the surrounding man-modified landscape matrix potentially leads to human disturbance (Matlack 1993b). In addition, urban plant communities are known to be especially rich in non-indigenous species (Deutschewitz et al 2003;Wania et al 2006) while both indigenous and nonindigenous species in urban areas differ in their ecological preferences from those found in rural areas (Godefroid and Koedam 2007;Thompson and McCarthy 2008;Vallet et al 2008). Species preferring fertile, dry, base-rich soils and unshaded habitats are known to be over-represented in urban plant communities (Knapp et al 2009;Thompson and McCarthy 2008).…”