TY - GEN A1 - Schaaf, Wolfgang A1 - Elmer, Michael A1 - Fischer, Anton A1 - Gerwin, Werner A1 - Nenov, Rossen A1 - Pretzsch, Hans A1 - Zaplata, Markus Klemens T1 - Feedbacks between vegetation, surface structures and hydrology during initial development of the artificial catchment 'Chicken Creek' T2 - Procedia Environmental Sciences N2 - Our investigations at the artificial catchment ´Chicken Creek´ in Lusatia/Germany aim to disentangle and understand the feedback mechanisms and interrelationships of processes and their co-development with spatial and temporal structures and patterns by studying this initial, probably less complex ecosystem. Intensive measurements were carried out in the catchment with regard to the development of surface structures, hydrological patterns, and vegetation dynamics. During the first seven years, considerable changes within the catchment were observed. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment. Initial structures formed by the construction process and initial substrate characteristics were decisive for the distribution and flow of water. External factors like episodic events triggered erosion and dissection during this initial phase, promoted by the low vegetation cover and the unconsolidated sandy substrate. The transformation of the initial geo-system into areas with evolving terrestrial or aquatic characteristics and from a very episodic to a more permanent stream network and discharge, together with the observed vegetation dynamics increased site diversity and heterogeneity with respect to water and nutrient availability and transformation processes compared to the more homogenous conditions at point zero. The processes and feedback mechanisms in the initial development of a new landscape may deviate in rates, intensity and dominance from those known from mature ecosystems. It is therefore crucial to understand these early phases of ecosystem development and to disentangle the increasingly complex interactions between the evolving terrestrial and aquatic, biotic and abiotic compartments of the system. Artificially created catchments could be a suitable tool to study these initial developments at the landscape scale under known, designed and defined boundary conditions. Y1 - 2013 U6 - https://doi.org/10.1016/j.proenv.2013.06.010 SN - 1878-0296 VL - 19 SP - 86 EP - 95 ER - TY - GEN A1 - Biber, Peter A1 - Seifert, Stefan A1 - Zaplata, Markus Klemens A1 - Schaaf, Wolfgang A1 - Pretzsch, Hans A1 - Fischer, Anton T1 - Relationships between substrate, surface characteristics, and vegetation in an initial ecosystem T2 - Biogeosciences N2 - We investigated surface and vegetation dynamics in the artificial initial ecosystem “Chicken Creek” (Lusatia, Germany) in the years 2006–2011 across a wide spectrum of empirical data. We scrutinized three overarching hypotheses concerning (1) the relations between initial geomorphological and substrate characteristics with surface structure and terrain properties, (2) the effects of the latter on the occurrence of grouped plant species, and (3) vegetation density effects on terrain surface change. Our data comprise and conflate annual vegetation monitoring results, biennial terrestrial laser scans (starting in 2008), annual groundwater levels, and initially measured soil characteristics. The empirical evidence mostly confirms the hypotheses, revealing statistically significant relations for several goal variables: (1) the surface structure properties, local rill density, local relief energy and terrain surface height change; (2) the cover of different plant groups (annual, herbaceous, grass-like, woody, Fabaceae), and local vegetation height; and (3) terrain surface height change showed significant time-dependent relations with a variable that proxies local plant biomass. Additionally, period specific effects (like a calendar-year optimum effect for the occurrence of Fabaceae) were proven. Further and beyond the hypotheses, our findings on the spatiotemporal dynamics during the system’s early development grasp processes which generally mark the transition from a geo-hydro-system towards a bio-geo-hydro system (weakening geomorphology effects on substrate surface dynamics, while vegetation effects intensify with time), where pure geomorphology or substrate feedbacks are changing into vegetation–substrate feedback processes. Y1 - 2013 U6 - https://doi.org/10.5194/bg-10-8283-2013 VL - 10 SP - 8283 EP - 8303 ER - TY - GEN A1 - Carl, Christin A1 - Biber, Peter A1 - Veste, Maik A1 - Landgraf, Dirk A1 - Pretzsch, Hans T1 - Key drivers of competition and growth partitioning among Robinia pseudoacacia L. trees T2 - Forest Ecology and Management N2 - Competition for above- and below-ground resources depends on their availability and results in varied growth partitioning. This becomes clear as the supply and limitation of the main resources influence the slope of the size-growth relationship in stands. Nevertheless, growth partitioning among trees, especially among black locust (R. pseudoacacia) trees is not understood in sufficient detail. To scrutinize and estimate the mode of competition of R. pseudoacacia, this research analyzed 1333 trees in Germany in 10 study sites, consisting in total 27 sample plots, with similar climate but varying soil conditions. The stand age ranged from 2 to 32 years, with a diameter at breast height ranging from 0.6 to 29.1 cm. The main focus of the study was to evaluate the impact of nitrogen, phosphorus, and water supply on the competition mode of R. pseudoacacia by varying growth partitioning. We applied the size–growth relationship in a mixed-effects model with a random intercept and slope. Fixed effects were the basal area, phosphorus, water, the sunlight competition index, and the interactions between below- and above-ground resources. Site specific effects of the analyzed stands were quantified with the aid of the random effects. Depending on the supply and limitation of phosphorus and water, this study determined how the competition mode as well as the growth partitioning among R. pseudoacacia trees were influenced. Hence, if phosphorus and water availability increased, then the competition for above-ground resources (primarily sunlight) and the slope of the size–growth relationship increased. Large trees grew disproportionately more than smaller trees. If the available phosphorus and water decreased, then the competition for the below-ground resources increased and the slope of the size–growth relationship decreased – to be more flattened. Moreover, it was found that available nitrogen as a below-ground resource had no influence on the mode of competition. In summary, phosphorus was the most important nutrient and, together with water, was the main driver of growth partitioning among R. pseudoacacia trees. Y1 - 2018 U6 - https://doi.org/10.1016/j.foreco.2018.08.002 SN - 0378-1127 VL - 430 SP - 86 EP - 93 ER - TY - GEN A1 - Schaaf, Wolfgang A1 - Elmer, Michael A1 - Fischer, Anton A1 - Gerwin, Werner A1 - Nenov, Rossen A1 - Pretzsch, Hans A1 - Seifert, Stefan A1 - Winter, Susanne A1 - Zaplata, Markus Klemens T1 - Monitoring the formation of structures and patterns during initial development of an artificial catchment T2 - Environmental Monitoring and Assessment N2 - The objective of this paper is to present observations, results from monitoring measurements, and preliminary conclusions about the development of patterns and structures during the first 5 years of development of an artificial catchment starting from point zero. We discuss the high relevance of initial system traits and external events for the system development and draw conclusions for further research. These investigations as part of a Collaborative Research Center, aim to disentangle and understand the feedback mechanisms and interrelationships of processes and their co-development with spatial and temporal structures and patterns by studying an initial, probably less complex ecosystem. Therefore, intensive measurements were carried out in the catchment with regard to the development of surface structures, hydrological patterns, vegetation dynamics, water chemistry, and element budgets. During the first 5 years, considerable changes within the catchment were observed. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment. Initial structures formed by the construction process and initial substrate characteristics were decisive for the distribution and flow of water. External factors like episodic events triggered erosion and dissection during this initial phase, promoted by the low vegetation cover, and the unconsolidated sandy substrate. The transformation of the initial geosystem into areas with evolving terrestrial or aquatic characteristics and from a very episodic to a more permanent stream network and discharge, together with the observed vegetation dynamics increased site diversity and heterogeneity with respect to water and nutrient availability and transformation processes compared with the more homogenous conditions at point zero. The processes and feedback mechanisms in the initial development of a new landscape may deviate in rates, intensity, and dominance from those known from mature ecosystems. It is therefore crucial to understand these early phases of ecosystem development and to disentangle the increasingly complex interactions between the evolving terrestrial and aquatic, biotic, and abiotic compartments of the system. Long-term monitoring of initial ecosystems may provide important data and parameters on processes and the crucial role of spatial and temporal structures and patterns to solve these problems. Artificially created catchments could be a suitable tool to study these initial developments at the landscape scale under known, designed, and defined boundary conditions. KW - ecosystem development Y1 - 2013 U6 - https://doi.org/10.1007/s10661-012-2998-x SN - 0167-6369 VL - Vol. 185 IS - 7 SP - 5965 EP - 5986 ER - TY - CHAP A1 - Hüttl, Reinhard F. A1 - Kögel-Knabner, Ingrid A1 - Zeyer, Josef A1 - Munch, Jean Charles A1 - Grünewald, Uwe A1 - Pretzsch, Hans A1 - Schaaf, Wolfgang A1 - Gerwin, Werner A1 - Veste, Maik T1 - Structures and processes of the initial ecosystem development phase in an artificial water catchment T2 - Plant Life in an Extreme and Changing Environment, Book of Abstracts T2 - Pflanzenleben in extremer und sich ändernder Umwelt Y1 - 2008 UR - http://www.desertconsult.de/PDF/initial_ecosystem2008.pdf N1 - Meeting of the Specialist Groups "Desert Ecology" and "Experimental Ecology" of the Society of Ecology (GfÖ)in Cooperation with German Society of Limnology (DGL) Tharandt, Germany, March 31 – April 2, 2008 SP - 89 EP - 90 ER -