Absence of distance decay in the similarity of plots at small extent in an urban brownfield

摘要: Similarity in species composition among different areas plays an essential task biodiversity management and conservation since it allows the identification of those environmental gradients that functionally operate determining vari- ation across spatial scale. The decay compositional similarity with increasing or distance derives from: 1) presence constraints which create a physical separation habitats, 2) decrease distance. Even if represents well known pattern characterising all types biological communities, few attempts were made to examine this at small scales respect both grain extent. Aim work was test whether can be observed local scale situations where conditions are relatively homogeneous ecological barriers absent, is dependent on size plant community data recorded. We selected two urban brownfields located Bremen university campus, Germany, 40 m  20 each, systematically divided nested plots 0.25 2 , 1 4 16 . Both soil variables recorded each cell. Linear logarithmic least squares regression models applied order due (calculated as Euclidean pairs plots) PCA-transformed variables). A general lack observed, irrespective type (spatial environmental) size. argue probably random variation important parameters distribution patterns individual species, latter mainly caused by high dispersal abilities majority occurring brownfields.