Far from naturalness: how much does spatial ecological structure of European Tree assemblages depart from potential natural vegetation?

Contemporaneous plant communities should retain a clear mark of past disturbances in their ecological patterns. However, unraveling the history of disturbance on natural systems at a large scale is often unfeasible, because of the complexity of the factors involved and to the lack of historical data. Here we aim at demonstrating how comparing observed spatial structure of tree assemblages with that expected in a hypothetical, undisturbed scenario can shed light on how natural European forests are. Borrowing an analytical approach developed in the field of network analysis, we assessed how much the observed ecological patterns of nestedness, segregation (i.e. negative co-occurrence) and modularity in tree assemblages deviate from randomness, and from those projected by PNV geobotanical expert assessments. We found clear evidence that European forests are far from a natural condition, showing only moderate signals (especially at higher latitudes) of the ecological spatial structure typical of undisturbed vegetation. Our results highlight how taking into account spatial structure along with diversity can be a fundamental tool to address this problem and assess the degree of naturalness in species assemblages.

STRONA Giovanni;  MAURI Achille;  VEECH Joseph A.;  SEUFERT Guenther;  SAN-MIGUEL-AYANZ Jesus;  FATTORINI Simone; 

2017-01-02

PUBLIC LIBRARY SCIENCE

JRC102393

1932-6203,   

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165178,    https://publications.jrc.ec.europa.eu/repository/handle/JRC102393,   

10.1371/journal.pone.0165178,