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A slow-fast trait continuum at the whole community level in relation to land-use intensification
(2024)
AbstractOrganismal functional strategies form a continuum from slow- to fast-growing organisms, in response to common drivers such as resource availability and disturbance. However, whether there is synchronisation of these strategies at the entire community level is unclear. Here, we combine trait data for 2800 above- and belowground taxa from 14 trophic guilds spanning a disturbance and resource availability gradient in German grasslands. The results indicate that most guilds consistently respond to these drivers through both direct and trophically mediated effects, resulting in a ‘slow-fast’ axis at the level of the entire community. Using 15 indicators of carbon and nutrient fluxes, biomass production and decomposition, we also show that fast trait communities are associated with faster rates of ecosystem functioning. These findings demonstrate that ‘slow’ and ‘fast’ strategies can be manifested at the level of whole communities, opening new avenues of ecosystem-level functional classification.
Can old organic carbon drive microbial activity in surface waters of a newly created landscape?
(2010)
In initial ecosystems, concentrations of all macro- and micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degrader’s food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this region’s dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, as indicated by its N content, its bioavailability for the degradation process and the development of microbial communities in the detritusphere and soil. The degradation of the L. corniculatus litter, which had a low C / N ratio, was fast and showed pronounced changes in the microbial community structure 1–4 weeks after litter addition. The degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred between 4 and 30 weeks after litter addition to the soil. However, for both litter materials clear indication of the importance of fungi for the degradation process was observed both in terms of fungal abundance and activity (13C incorporation activity).
Ecosystems are characterized as complex systems with abiotic and biotic processes interacting between the various components that have evolved over long-term periods. Most ecosystem studies so far have been carried out in mature systems. Only limited knowledge exists on the very initial phase of ecosystem development. Concepts on the development of ecosystems are often based on assumptions and extrapolations with respect to structure–process interactions in the initial stage. To characterize the effect of this initial phase on structure and functioning of ecosystems in later stages, it is necessary to disentangle the close interaction of spatial and temporal patterns of ecosystem structural assemblages with processes of ecosystem development. The study of initial, less complex systems could help to better identify and characterize coupled patterns and processes. This paper gives an overview of concepts for the initial development of different ecosystem compartments and identifies open questions and research gaps. The artificial catchment site “Chicken Creek” is introduced as a new research approach to investigate these patterns and processes of initial ecosystem development under defined boundary conditions. This approach allows to integrate the relevant processes with related pattern and structure development over temporal and spatial scales and to derive thresholds and stages in state and functioning of ecosystems at the catchment level.