Evaluation of floristic diversity in urban areas as a basis for habitat management

Abstract

Questions: How can floristic diversity be evaluated in conser‐vation plans to identify sites of highest interest for biodiversity? What are the mechanisms influencing the distribution of species in human‐dominated environments? What are the best criteria to identify sites where active urban management is most likely to enhance floristic diversity? Location: The Hauts‐de‐Seine district bordering Paris, France. Methods: We described the floristic diversity in one of the most urbanized French districts through the inventory of ca. 1000 sites located in 23 habitats. We built a new index of floristic interest (IFI), integrating information on richness, indigeneity, typicality and rarity of species, to identify sites and habitats of highest interest for conservation. Finally, we explored the relationship between site IFI and land use patterns (LUP). Results: We observed a total of 626 vascular plant species. Habitats with highest IFI were typically situated in seminatural environments or environments with moderate human impact. We also showed that neighbouring (urban) structures had a significant influence on the floristic interest of sites: for example, the presence of collective dwellings around a site had a strong negative impact on IFI. Conclusions: Our approach can be used to optimize management in urban zones; we illustrate such possibilities by defining a ‘Site Potential Value’, which was then compared with the observed IFI, to identify areas (e.g. river banks) where better management could improve the district's biodiversity.

Local gardening practices shape urban lawn floristic communities

“…However it can be compared to studies with similar sampling effort as Thompson, Hodgson, Smith, Warren, and Gaston (2004) who, despite including bryophytes and small trees, observed 159 species (1.5 species/m 2 ) in 52 English lawns, while Stewart et al (2009) found only 127 herbaceous species (0.3 species/m 2 ) in 327 residential lawns in New Zealand. Lawns seem to be relatively poor when compared to other urban vegetal communities, like wastelands (Muratet, Machon, Jiguet, Moret, & Porcher, 2007); but due to their large cumulated surface and their high numbers in cities (Muratet et al, 2008), they could play an important role in the dynamics of urban vegetal communities (Wania, Kuhn, & Klotz, 2006). The lawns we studied had similar communities to temperate semi-natural grasslands.…”

“…To characterize the urban environment around lawns we analyzed the Land Use Pattern (LUP, scale = 1:5000, IAURIF, 2003) within a 200 m buffer radius (previously identified as the best radius to detect the influence of urban activity on floristic diversity: Muratet et al, 2008). We calculated the proportion of area occupied by buildings (vs. unbuilt areas) in the 200 m radius around each lawn.…”

“…Although subject to the consequences of very dense human populations, urban areas are becoming an increasingly important refuge for biodiversity compared to other anthropized land types such as intensively farmed areas (Goddard, Dougill, & Benton, 2009;Von der Lippe & Kowarik, 2008). Among the habitats found in cities, a high proportion of vegetal urban space consists of lawns (Attwell, 2000;Muratet et al, 2008;Stewart et al, 2009;Zipperer & Zipperer, 1992), which therefore share a large part of the urban biodiversity.…”

Does the invasive species Reynoutria japonica have an impact on soil and flora in urban wastelands?

“…This species is one of the ''100 of the world's worst invasive alien species'' (Lowe et al 2000) and is often considered a prominent disturbance by managers of urban green spaces and parks. We focused on urban wastelands, a habitat frequently colonised by R. japonica that plays a major role in urban biodiversity, since they are numerous and widespread, exhibiting the highest floristic richness of all urban plant communities (Muratet et al 2007(Muratet et al , 2008. In its introduced range, R. japonica has been shown to alter plant and invertebrate species diversity in natural riparian habitats (Gerber et al 2008).…”

Use of extensive habitat inventories in biodiversity studies

“…The large number of existing inventory data can however be exploited to address other conservation issues, e.g. to quantify floristic index over a homogeneous region (Muratet et al 2008).…”