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Ecological multifunctionality quantifies the functional performance of various important plant traits and increases with growing structural habitat heterogeneity, number of plant functional traits, and species richness. However, the successional changes in multifunctionality have not been traced so far. We use quantitative plant samples of 1 m2 plots from the first 6 years of initial vegetation dynamics in a German created catchment to infer the temporal changes in plant functional trait space and multifunctionality. Multifunctionality at the plot level was in all study years lower than expected from a random sample of the local pool of potential colonizers and was lowest at intermediate states of succession. In each year species containing a specific set of traits occurred with limited but focused functionality. The observed average low degree of multifunctionality contrasts with recent models predicting a tendency towards maximum multifunctionality during plant community development. However, variability in multifunctionality among plots increased during succession and the respective multifunctionality distribution among plots was increasingly right skewed indicating an excess of plots with relatively high multifunctionality. This relative excess of plots with high multifunctionality might act as an important trigger of community development paving the way for new species and functions to become established.
Die zurückliegenden trocken-heißen Sommer haben im Süden Brandenburgs zu zahlreichen Bränden in den dominierenden Kiefernwäldern geführt, einige davon mit katastrophalen Ausmaßen. Dazu gehören die extremen Brandereignisse 2018 bei Treuenbrietzen sowie 2019 bei Jüterbog und Lieberose, die zusammen weit über 1000 ha Waldfläche zerstört und dabei auch Veränderungen der betroffenen Waldböden verursacht haben.
Das seit Mai 2020 von der FNR geförderte Verbundvorhaben Pyrophob befasst sich mit den Auswirkungen von Waldbränden im Süden Brandenburgs auf die Waldökosysteme und mit waldbaulichen Maßnahmen, die mittelfristig zu einer Verringerung der Brandanfälligkeit der Wälder beitragen sollen. Im Rahmen des auf eine fünfjährige Laufzeit ausgelegten Verbundvorhabens finden bodenkundliche Untersuchungen auf zwölf Versuchsflächen bei Treuenbrietzen und Jüterbog statt. An beiden Standorten werden unverbrannte Referenzflächen mit einbezogen. Ergänzend konnten bei Lieberose bereits 2019 nur kurz nach dem Brandgeschehen erste Bodenuntersuchungen durchgeführt werden. Die untersuchten Brandflächen bei Jüterbog und Lieberose sind als Totalreservate ausgewiesen, auf denen auch nach dem Brand waldbauliche Maßnahmen vollständig unterbleiben. Auf den Flächen bei Treuenbrietzen wurden verschiedene Behandlungsvarianten durchgeführt, zu denen auf einem Teil der Flächen die vollständige Entfernung der abgestorbenen Bäume gehörte, während auf anderen Teilflächen Totholz auf der Fläche verblieb.
Ziel der bodenkundlichen Arbeiten in Pyrophob ist zum einen eine Charakterisierung der direkten Auswirkungen des Brandes auf Humus und Mineralboden hinsichtlich des Stoffbestandes und bodenbiologischer Prozesse. Zum anderen wird der Stoffaustrag aus dem Oberboden erfasst. Der etwaige Einfluss der unterschiedlichen waldbaulichen Vorgehensweise auf die Bodenverhältnisse wird dabei als ein Indikator für die Auswahl geeigneter Maßnahmen berücksichtigt.
In den verschiedenen Untersuchungsvarianten des Vorhabens wurden zu diesem Zweck Humus- und Mineralbodenprofile untersucht. Zudem wurden Mischproben aus dem Ober- und Unterboden entnommen und auf ihren Stoffhaushalt hin analysiert. Auf jeder Untersuchungsfläche wurden je drei frei dränende Kleinlysimeter in 10 cm Bodentiefe installiert, um die zeitlichen Veränderungen der Sickerwasserzusammensetzung und die durch den Brand initiierten Stoffausträge aus dem Oberboden zu quantifizieren. Ergänzend finden Untersuchungen zu möglichen Auswirkungen der Brände auf bodenbiologische Prozesse wie Streuabbau und Stickstoffmineralisation statt.
Die Lausitz zählt schon heute zu einer der niederschlagärmsten Regionen in Deutschland. Durch den Klimawandel wird diese Situation noch weiter verstärkt und die Wahrscheinlichkeit von extremen Trockenperioden während der Hauptvegetationsphase wird zunehmen. Einer der zentralen bodenkundlichen Herausforderungen wird es somit sein, die geringe Wasserhaltekapazität der vor allem sandigen Böden der Region zu steigern. In dem Verbundvorhaben StabilOrg wird daher die Entwicklung neuartiger Bodenhilfsstoffe auf der Basis regional in der Lausitz verfügbarer Ressourcen untersucht.
Durch die Tagebauaktivitäten in der Region fallen große Mengen an Eisenhydroxidschlämmen (EHS) an. Hierbei lassen sich 3 Herkunftsschwerpunkte definieren: I) natürliche Eisenhydroxidsedimente aus Fließen, II) EHS aus Grubenwasserbehandlungsanlagen, die durch Kalkung gefällt wurden und III) EHS aus Trinkwassergewinnungsstätten, die gekalkt und zusätzlich durch chemische Flockungsmittel behandelt wurden. Diese sollen mit verschiedenen Tonen und Lehmen als weitere anorganische Komponenten, sowie mit organischem Material (Kompost) gemischt werden. Ziel ist die Herstellung von anorganisch-organische Mischsubstraten, die die bodenphysikalischen Eigenschaften positiv beeinflussen.
Erste Untersuchungsergebnisse zeigen, dass sich die untersuchten EHS je nach Behandlung in ihrer mineralogischen Zusammensetzung, sowie den physikochemischen Parametern deutlich unterscheiden. In ersten Experimenten wird untersucht, wie sich diese Mischungen auf die Wasserhaltekapazität von sandigen Böden auswirken und ob sich dabei Unterschiede zwischen den EHS und in Kombination mit den anderen Ausgangssubstanzen aufzeigen lassen.
Landscapes and ecosystems are complex systems with many feedback mechanisms acting between the various abiotic and biotic components. The knowledge about these interacting processes is mainly derived from mature ecosystems. The initial development of ecosystem complexity may involve state transitions following catastrophic shifts, disturbances or transgression of thresholds. The Chicken Creek catchment was constructed in 2005 to study ecosystem development
of an initial ecosystem at the landscape scale. The world´s largest constructed catchment has a hillslope-shaped 6 ha size with defined boundary conditions and well-documented inner structures1. For 12 years, we have been monitoring the development of different system compartments2,3. The fast formation of patterns and increasing heterogeneity were challenges for the monitoring program. Starting with a regular 20 × 20 m grid in the initially homogeneous system, monitoring installations were continuously complemented by more pattern and patch oriented measurements in order to catch up with both the spatial and temporal dynamics of the catchment. The monitoring program includes both
high-resolution temporal recordings (e.g., groundwater levels, discharge, meteorological data, soil moisture), spatial sampling campaigns (e.g., soil properties) and annual vegetation surveys. In addition, we use drone images to document the site development. The presentation describes the monitoring approach and adaptation with examples from vegetation, soil and hydrological data at different spatial and temporal scales. From the monitoring data we were able to derive different phases during initial development that are characterized by abiotic/biotic feedback mechanisms controlling catchment functioning. Detailed monitoring of the Chicken Creek catchment with known boundary conditions and structure information could help in disentangling general feedback mechanisms between hydrologic, pedogenic, biological and geomorphological processes as well as in gaining a more integrative view of succession and its drivers during the transition from initial, less complex systems to more mature ecosystems. Long-term time series of data are the key for a better understanding of these processes and the effects on ecosystem self-organization and resilience.
Marginal lands are often considered as unfertile and not productive. They are widely excluded from modern land use by conventional agriculture. Assessment of soil fertility usually shows very low productivity potentials at least for growing traditional crops. However, it can be frequently observed that natural succession at different types of marginal lands leads to very diverse and nonetheless productive ecosystems. Examples can be found at abandoned former industrial or transportation sites which were set aside and not further maintained – and also in post-mining landscapes. In one of the lignite open cast mines of the State of Brandenburg in Eastern Germany a landscape observatory was
established in 2005 for observing this natural ecosystem development under marginal site conditions. The site of 6 ha is part of the post-mining landscapes of Lusatia which are often characterized by poor soil conditions and clearly reduced soil fertility. It is named “Hühnerwasser-Quellgebiet” (Chicken Creek Catchment) after a small stream that is restored again after destruction by the mining operations. It is planned to serve as the headwater of this stream and was left to an unrestricted primary succession. A comprehensive scientific monitoring program is carried out since the start of ecosystem development in 2005. The results offer exemplary insights into the establishment of interaction networks between the developing ecosystem compartments. After 10 years a large biodiversity, expressed by a high number of species, can be found at this site as the result of natural recovery processes. A large number of both tree species and individuals have settled here. Even if no economic use of the site and of the woody biomass produced by these trees is planned, an overall assessment of the biomass production was carried out. The results showed that the biomass production from natural succession without any application of fertilizers etc. is directly comparable with yields from adjacent post-mining sites where trees are grown in agroforestry systems for bioenergy production. This reflects the general potentials of marginal lands with regard to biomass production.
The Chicken Creek catchment was constructed in 2005 to study ecosystem development of an initial ecosystem at the landscape scale. The site has an area of 6 ha with defined boundary conditions and known inner structures. Since more than 10 years, we are monitoring the unrestricted development of different system compartments. The fast development, the formation of patterns and increasing heterogeneity were challenges for the monitoring program. Starting with a regular 20 x 20 m grid in the initially homogeneous system, monitoring installations were continuously complemented by more pattern and patch oriented measurements in order to catch up with both the spatial and temporal dynamics of the catchment. The monitoring program includes both high-resolution temporal recordings (e.g. groundwater levels, discharge, meteorological data, soil moisture), spatial sampling campaigns (e.g. soil properties) and annual vegetation
surveys. In addition, we use drone images to document the site development. The presentation describes the monitoring approach and adaptation with examples from vegetation, soil and hydrological data at different spatial and temporal scales.
The constructed Hühnerwasser (“Chicken Creek”) catchment is an ecohydrological system in an initial state of development. The catchment with an area of 6 ha was built up from quaternary sediments in the post-mining landscape of Lusatia in Eastern Germany and serves as a critical zone observatory for detecting ecosystem transition. The soil substrate is characterized as sands to loamy sands with low carbonate contents but significant amounts of gypsum in the sediments of the catchment. The catchment undergoes a strong transition from an abiotic system in the initial years to a system with growing influence of biota. Concerning the hydrology, a regime shift from surface runoff to groundwater flow dominated processes is significant. It is of interest, whether the catchment transition is also reflected by hydrogeochemical indicators. We assume gypsum dissolution as dominant process at the catchment scale. In order to investigate the hydrogeochemical evolution of the catchment we analysed electric conductivity, calcium and sulphate concentrations and pH-values of biweekly composite samples from 2007-2013 of the atmospheric deposition, of runoff and soil water. The two observation points in the flowing water represent surface runoff and groundwater discharge respectively. Soil
water has been analysed at four soil pits in three depths. The monitoring data were provided by the Research
Platform Chicken Creek. From the macroscopic data analysis we found an exponential decay of the electric conductivity, calcium and sulphate concentrations in the flowing waters and some of the soil pits. In the flowing water, the decrease slope of the electric conductivity and the calcium and sulphate concentrations is almost identical. The calcium / sulphate molar ratio as an indicator of gypsum dissolution is almost equal to one up to 2010, afterwards more calcium than sulphate is released. The pH-values in the flowing and soil water are generally higher than in the atmospheric deposition, they do show variabilites but no trend behaviour. The time series analyses showed that the interannual variability of the hydrogeochemical properties is less pronounced in the first years of ecosystem development than in the later years. This leads to the conclusion, that in the first years, gypsum dissolution is the major source for calcium and sulphate in the soil and the flowing waters. The increasing interannual variability and changes in the calcium / sulphate ratio in the later years might be interpreted as hydrogeochemical response to the development of vegetation and acidification due to the development of the rhizosphere.
We studied the role of strutures and processes and their feedbacks during initial ecosystem development in the artificial catchment Chicken Creek. 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.
It is widely acknowledged that increasing complexity is a key attribute of ecosystem genesis. This is particularly true for primary succession on homogeneous substrates. However, a mechanistic understanding of spatial colonisation and pattern formation during primary succession has not been achieved yet. Thus, we studied this topic for 7 years within an experimental catchment (6 ha) established in the post-mining landscape of eastern Germany. Equidistant permanent plots (120 plots à 25m²) allowed for autocorrelation analyses, and thus tracing the spatial development of species cover performance. For each species tested, the “cover balance” first increased due to colonization, while decreasing in the course of succession. Drawing a benefit from these temporal trends, we suggested cover balance levels revealed by autocorrelation analyses to best indicate well-defined phases in primary succession at spatial entities. Hence, with the help of this spatial approach, terrestrial succession can be understood now much better at the most general level of the hierarchy provided by Pickett et al. (1987). In accordance with these authors, at subordinated levels of the causal hierarchy differential species performance might get collectively explained by contributing processes or conditions, such as ecophysiological traits, life history strategies, competition and allelopathy of the occurring plant species. Further research is needed to understand their relative contributions to the pattern formation.