Institut für Landschafts- und Pflanzenökologie

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Ableitung von Restitutionspotenzialen als Entscheidungshilfe bei der Umsetzung von Moorschutzprogrammen
(2005) Röhl, Markus; Böcker, Reinhard
As one of the last peatland-rich states of Germany, Baden-Württemberg possesses no self-standing, conservation program to protect its peatlands. Therefore, after consideration of the state administration, a strategy should be created in the next few years for a Baden-Württemberg peatland protection concept. With this in mind, a methodology for the derivation of peatland restitution potential was developed that can direct the future implementation of such a strategy. The exemplary methodology was developed for the nature conservation area ?Schwenninger Moos?, a medium sized former raised bog strongly disturbed by peat digging and agricultural amelioration. The results were applied to the entire surrounding bio-geographical region, the Baar and the Baaralb. Through this verification of the methodology, significant shortfalls in the state-wide dataset could become evident. As the basis of the evaluation of the restitution potential, data concerning the water level, trophy, and species and biotypes in Schwenninger Moos were collected. The water level of Schwenninger Moos was documented through 34 water gauges, the data from which was analysed through various methods. The half-year median and the combined examination of amplitude, average, and minimum values proved especially suitable for the characterisation of the sites. The trophic classifications of the sites were compared through measuring the principal nutrient levels, pH and conductivity values, as well as the C/N ratio. The vegetation of the investigation area was mapped and the results were subsequently compared to the mapping of biotypes of Baden-Württemberg, the mapping performed in the frame of Natura 2000, as well as that of indicator species groups. The mapping of indicator-species groups proved particularly suitable for the appraisal of the current status of a moor complex. The available data on the mires from the peatland register of Baden-Württemberg were somewhat old (40 years). Therefore these data were verified through comparison-boring and continued measurement by means of georadar. Significant differences arose in a number of comparisons between the peatland register and the author?s investigations with respect to the positional accuracy and the stratum sequence. The derivation of the restitution potential was carried out through the combination of three separate assessments: rewetting-possibility, biotic potential, and conversion potential. These three factors were derived through verbal-argument and brought together in a simple, five-step classification. The rewetting-possibility of an area is the main factor determining the restitution, and it depends considerably on drainage systems, topography, condition of the peat, and the water level. The biotic potential consists of the presence of peat-producing plants and the effects of rewetting on populations of endangered species. The conversion potential is essentially dependent on the dominant uses, ownership and social framework. The methodology was applied to altogether 34 peatland complexes of the Baar and Baaralb. The identification of these locations was only possible by a laborious combination of the peatland register, pedological cartography and conservation-oriented publications. It was found that the peatland register exhibited substantial deficits regarding the classification of small and shallow-layered locations in the Baar. Data concerning vegetation and the occurrence of animals and plants were available for the derivation of the restitution potential. However, some of these proved too old and/or too inaccurate or not spatially verified. Little to no data were present as to the water balance and drainage systems. Only three of the 34 locations exhibited a high restitution potential. 23,5% were classified as having moderate restitution potential; most of these sites are already under protection as nature conservation sites. A slight restitution potential was present in a total of 38.2% of the mire complexes, which consist mostly of small-scale spring mires and intensively agriculturally and silviculturally used locations. Likewise, 29.4% of the moorlands exhibited no more restitution potential. For the implementation of a state-wide mire protection program in the context of the investigation, the substantial deficits were pointed out and recommendations for action were formulated. Primarily, an updated and complete peatland register must be available. Furthermore, vegetation and endangered species maps of the entire peatland complexes protected as high conservation value areas should be available. It is in this regard that a system of indicator vegetation units of south German mires is to be aimed for, as is employed in northeast Germany, for example. Lists of priority sites should be made by regional teams of experts for the respective moor regions or administrative districts.
Die Bedeutung städtischer Gliederungsmuster für das Vorkommen von Pflanzenarten unter besonderer Berücksichtigung von Paulownia tomentosa (Thunb.) Steud. - dargestellt am Beispiel Stuttgart
(2002) Richter, Matthias; Böcker, Reinhard
The relevance of urban landuse patterns and ecological factors for the occurrence of spontaneously and subspontaneously growing plant species is the subject of this doctoral thesis. First a model of scales for urban ecological research is introduced in order to structure the different hypotheses. This model distinguishes between the agglomeration Stuttgart, separated in main ?landuse types? (forest, agricultural area, settlement), the central city of Stuttgart, "building structure/free space types" and ?types of soil use?. The types of soil use (e.g. lawns, bushes, flower-beds or pavements) are characterised by the most frequent plant species. Moreover their soils are analysed and they are described climatically. In cities average types of soil use (concerning the chemical characterisation of soils) are wide-spread. Some plant species (e.g. Paulownia tomentosa) are described more in detail, concerning their ecological traits and their preferential occurrence on each spacial scale. The hypothesis is tested: If there is a dependence - of plant species and phytocoenoses on types of soil use - and of types of soil use on building structure/free space types - and of building structure/free space types on their location within the city centre, - then there is a dependence of plant species and their phytocoenoses on the location within the city. To test this hypothesis, some building structure/free space types and types of soil use were selected at random and there vegetation relevés were collected. An attempt is made to construct an improved model of a big city, representing an agglomeration. On the spatial level of the agglomeration Stuttgart Paulownia tomentosa can be found neither in forests nor in agricultural area. It is growing within settlements only, namely within the central built-up areas of Stuttgart, Feuerbach and Bad Cannstatt. The city centre of Stuttgart can be divided into three zones: the central business district with big department stores and banking houses, bordering on old apartment houses and detached houses (especially at the slopes). Other building structure/free space types (like villas, graveyards, parks, or industrial areas) are mingled in these zones. A scheme is outlined which shows how the different building structure/free space types are scattered over the central city. Paulownia tomentosa can be detected most frequently within the zone of old apartment houses. Historical and climatological reasons are important for this result, too. More than 90% of the sites where Paulownia tomentosa is growing are cracks: cracks along the bottom of buildings, gravelled area and urban wasteland. The sites are characterised by a low level of nutrients, high pH-values and soils which extremely dry out in summer. So the occurrence of the species depends on the presence of special types of soil use. A low intensity of gardencare is a further important factor for its presence. Paulownia tomentosa is an exemplification showing how the ecological traits of a species and its dependence from the presence of structural types can be used to find the places where it is growing. In the case of Paulownia this attempt can be used to forecast the expected further spread.
Ecology of alluvial arable land polluted by copper mine tailings : new insights for restoration
(2013) Nikolic, Nina; Böcker, Reinhard
Mining and extraction of metals generates huge amounts of tailings waste (a mixture of water, finely ground ore rock and processing effluents, which remains after removal of mineral concentrate). Unfortunately, accidental release of mine tailings into river systems and their further deposition in floodplains, often over arable land, has been reported from many parts of the world, with environmental implications difficult to predict. Mine tailings from sulphidic metal ores combine high potential for generating soil acidity, and high concentrations of plant available heavy metals, which are the two most intractable issues in restoration of post-mining sites. On the other hand, barren land degraded by mining waste provides an exciting opportunity to reveal some important ecological principles which might not be apparent under ?normal? conditions. Understanding of the process of primary vegetation succession is in particular crucial for the practice of ecological restoration, which is increasingly seen as a preferable alternative to technical reclamation of land degraded by mining. This work addresses the two major issues relevant for ecology and restoration of alluvial arable land polluted by mining waste, which have so far been very poorly understood: Firstly, the long-term fate of contaminants and their actual impact on soil quality and crop production under true field conditions. Secondly, the process of spontaneous revegetation of barren land under the extreme soil conditions and the environmental setup considerably different from the well-studied Central European. The explorative study was undertaken on an exceptional locality created by long-term and large scale-fluvial deposition of sulphidic copper (Cu) tailings over alluvial fields in Eastern Serbia. Comprehensive surveys of spontaneous vegetation, weed assemblages and cereal crops (species cover-abundance; biomass per m2; and foliar mineral analyses), and concomitant surveys of rhizosphere soils (31 physical and chemical parameter) included 297 sampling locations throughout the polluted floodplain (flexible sampling scheme based on visual appearance of vegetation). Data were jointly analysed in a gradient approach framework by different multivariate statistical methods (ordination: NMS, PCA, CCA; classification: agglomerative clustering; group comparisons: MRPP, ISA; habitat modelling: NPMR; and, regression analysis). The results revealed exceptionally strong structure in the vegetation which was highly correlated with the measured soil properties; the regular change of vegetation and soil properties occurred along spatially explicit transects perpendicular to the river channel. The clear gradients observed in this ?field laboratory? research brought forward some new ecological patterns which had not been reported by other relevant studies so far: 1. Severe P deficiency, most likely not amenable by fertilization, is identified as the master limiting soil factor for grains under the multiple abiotic stresses caused by deposition of sulphidic Cu mining waste. Other plausible soil constraints (low pH, excessive concentrations of available Cu and Al, deficiency of N and B; P deficiency-induced increase of As uptake; competition with superior hemicryptophytic weeds), have remained in domain of a ?black-box?. 2. Frequent ploughing accelerates the substitution of high plant available Cu by nutrient deficiency (primarily P and microelements) and excessive exchangeable Al. Thus, agronomic soil quality indicated by crop yield does not improve even when Cu is leached to the background levels. The environmental consequences of intensive land use are however drastic, and increase vulnerability of these soils to further environmental hazards. On the other hand, one type of spontaneously occurring pioneer forests was shown to considerably slow down the oxidative weathering of the tailings deposits and thus prevent Cu leaching via phytostabilization. 3. Although many characteristics of cereal weed assemblages markedly change along the soil pollution gradient, the species? ability to maintain leaf P homeostasis appears to be the key adaptation underlying the observed vegetation structure. The novel associations of unusual species combinations showed a set of functional adaptations which have enabled the leaf N:P homeostasis and thus the uninterrupted survival of weed vegetation along the soil gradient. 4. The proposed conceptual model describes a highly patterned process of spontaneous revegetation of the created barren land under the severe environmental filtering. In this process, the xerothermic surrounding vegetation adapted to calcareous soils has a very limited role. Instead, primary succession relies on novel types of early vegetation which comprise not only novel combinations of species, but also the key role of species which are novel to the affected region, and do not survive outside of the polluted area. We demonstrate for the first time that pollution-induced severe nutrient deficiency can override the well-established importance of both surrounding vegetation and water level gradient for primary succession. Overall, this study implies that severe nutrient deficiency, which is often a neglected issue in studies of metal-polluted sites, can override the effects of Cu toxicity, the role of surrounding vegetation, and even the role of water level gradients, on the process of spontaneous restoration of vegetation cover. It is highly unlikely that spontaneous restoration under the current conditions would allow the reestablishment of the original (or close to original) alluvial vegetation or pre-pollution agricultural land use. Weathering of the substantial residues of sulphides, further acidification and Cu leaching is the major environmental risk; ploughing (or any mechanical soil disturbance with similar effect) of this vast marginalized area should be avoided. Maintenance of the natural flooding regime, which had, bizarrely, caused this vast degradation in the first place, is indicated important for the current spontaneous succession and warrants further research.
Managementauswirkungen auf Reproduktion und Abundanz von Orthopteren in Streuobstwiesen
(2000) Schwabe, Christiane; Böcker, Reinhard
The management of orchards is changing from farmers cutting the grass for their cattle to more timesaving ways of using the grass up to doing nothing at all. The traditional management form as well as alternatives were examined by means of animal ecology in regard to their impact on grasshoppers (Saltatoria, Acrididae). In the years 1994 - 1997 abundance and reproduction of the three species Chorthippus parallelus, Chorthippus dorsatus and Gomphocerus rufus were examined comparing to the management of grass patches. Investigation site was the Limburg (48°36´N / 9°38´E) north of the Swabian Alb (Germany). The management of the patches varied from meadows (two cuts), meadows cut two to four times with grass remaining on the ground, sheep pastures and fallow land. The usable vegetation structures for the three species were investigated in detail. The returning of the grasshoppers on a pasture after intensive sheep grazing was observed. These investigations explain species-dependent habitat preferences. Based on the population data a model was developed to describe the egg density in the soil from given samples of the population density. A method was developed, to determine the management-depending egg mortality. By caging female grasshoppers the number of eggs on defined areas in the soil is increased to simplify finding enough eggs in spring. From the management-depending density of eggs, the rate of fertile eggs in spring and the population densities of the following year a rate of larvae mortality can be calculated, which tells if the population is stable, is a source, or is a sink.
Ökosystem-Funktionen als Kriterium einer Operationalisierung ökologischer Aspekte von Nachhaltigkeit?
(2000) Doppler, Susanne Maria; Böcker, Reinhard
In recent times, against the background of system-theoretical principles, the description of ecosystems as complex, dynamic systems has been strongly promoted. Therefore the capacity of selforganization of ecosystems is strengthened to be integrated into environmental planning processes. The aim of the following work is to point out the limitations and possibilities given by the scientifically-based criterion 'ecosystem-functioning' in the context of sustainability. The investigations are based on a literature-supported analysis and a theoretical argument about the 'function of ecosystems' in relation to the concept of ecosystems. The results of this argument were submitted (1) to a scientific and science-theoretical analysis and criticism as well as considered in the light of (2) environmental protection issues and ethically relevant aspects of the description and observation of the natural world. The aim of this consideration was to establish to what extent the criterion 'ecosystem functioning' is suitable. The central question about limitations and possibilities of the application of the criterion is answered as follows: The criterion 'ecosystem functioning', formulated via system-theoretical principles of dynamic systems does not meet the requirements of both the natural and ethical issues given by the paradigm of sustainability. A possible alternative is to observe ecosystems and the criterion 'ecosystem-functioning' from a utilitarian position of anthroporelativism. The implementation of this perspective in the world of nature through the criterion 'ecosystem functioning' makes it possible (1) to integrate ethical issues of sustainability and (2) to maintain natural values as well as cultural ones in the countryside for this and future generations.

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