ABSTRACT: Biodiversity in urban areas is affected by a multitude of stressors. In addition to physico-chemical stress factors, the native
regional species pool can be greatly reduced in highly urbanized landscapes due to area loss and fragmentation. In this study,
we investigated how macrophyte composition and diversity in urban water systems are limited by the regional species pool and
local environmental conditions. Canonical correspondence analysis of the macrophyte species composition revealed that urban
and semi-natural water systems differed and differences could be related to local abiotic variables such as pH and iron concentrations.
Macrophytes in the semi-natural area were typical for slightly acid and oligotrophic conditions. In urban water systems, exotic
species characteristic of eutrophic conditions were present. In the semi-natural areas, the number of macrophyte species exceeded
the number of species expected from species–area relationships of artificial water bodies in rural areas. In urban areas,
the number of macrophyte species was similar to artificial water systems in rural areas. Macrophyte species present in the
study areas also were generally found within 20–30km distance to the study area. Macrophyte species composition in urban
water systems and semi-natural water systems appeared to be influenced by the regional species pool within approximately 30km
of the locations. Nevertheless, site limitation ultimately determined the local macrophyte species composition and diversity
in urban water systems and in semi-natural water systems.
KeywordsBiodiversity-Eutrophication-Local and regional processes-Macrophytes-Species–area relationships-Urban water systems-Vegetation
Aquatic Sciences 04/2012; 72(3):379-389. · 2.11 Impact Factor