Fine root dynamics in broad-leaved deciduous forest stands differing in tree species diversity

摘要: Biodiversity effects on ecosystem functioning in forests have attracted increasing attention only recently. The vast majority of studies in forests focussed above-ground responses to differences tree species diversity, while systematic analyses of the biodiversity root systems are virtually missing. By investigating fine root 12 temperate deciduous forest stands the Hainich National Park (Thuringia, Germany), we tested hypotheses that (i) stand biomass increases with (ii) mixtures result a spatial segregation different tree species, (iii) seasonal changes mass are more pronounced species-poor than species-rich stands, and (iv) productivity and resilience system (i.e. recovery after disturbance) increase species diversity. selected represent gradient diversity similar bedrock from almost pure beech medium-diverse built by beech, ash, lime, highly-diverse stands dominated by maple, hornbeam. We used morphological key identify roots colour, periderm surface structure branching patterns. We investigated fine bio- necromass their spatial distribution patterns at 24 profiles per analysed morphology microscopic analysis. Furthermore, were recorded during 12-month period was estimated with two independent approaches (ingrowth cores, sequential coring). Fine biomass ranged 440 480 g m-2 monospecific 5-species 63-77 % being concentrated upper 20 cm soil. In all present, density (biomass soil volume) decreased exponentially depth very rates. Moreover, indications species-rich not found. showed marked distinctions between but these did lead to significant surface area or tip abundance basis. Moreover, composition alter species. According analysis 360 ingrowth growth into root-free increased 72 g m-2 yr-1 plots 166 5-species plots indicating rapid system after disturbance stands. Fine as approximated coring data also indicated roughly threefold increase stand. found no indication seasonality mass compared stands. conclude "overyielding" terms does occur stands, which is most likely caused absence these late-successional species. Our study produced first evidence support hypothesis more diverse resilient soil disturbance, perhaps productive, forests. Species identification level, conducted here, may open new perspectives further studies focusing dynamics.