Browsing by Subject "Bioindication"

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    Biomonitoring of ammonia deposition by means of higher plants
    (2013) Ilogu Chibuzo Franklin; Fangmeier, Andreas
    Atmospheric nitrogen deposition emanating from oxidized or reduced nitrogen sources has been influenced immensely by human activities. This is as a result of the need to improve and meet the ever changing demands of an increasing growth in global population. The benefits accrued from such activities however, have not been without some negative effects on several ecosystems, plants, air quality and human health. This is due to the emission of reactive nitrogen species and its contribution to the level of atmospheric nitrogen pollution in the environment as well as nitrogen deposition afterwards. Atmospheric ammonia (NH3) arguably is an important source of nitrogen deposition. Its major source is from agricultural activities involving various aspects of crop production including, fertilizer and manure applications among others and also importantly from livestock management. It is pertinent therefore, to conduct continuous monitoring studies in order to ascertain the prevailing ambient NH3 concentration in an area, so as to identify periods when threshold values are exceeded and also to determine how certain plants would respond when exposed to NH3 pollution. This necessitated the need to investigate in this thesis, through active biomonitoring, the interaction of NH3 pollution on selected indicator species namely, Italian ryegrass (Lolium multiflorum L.), barnyard grass (Echinochloa crus-galli L.), stinging nettle (Urtica dioica L.) and common lambsquarters (Chenopodium album L.). The influence of nitrogen deposition, arising from NH3 pollution on the selected indicator species were examined by the responses of the free amino acids and above ground biomass accumulation of the various plants studied, as an indicator of nitrogen accumulation. In order to execute plant and atmospheric NH3 interactions, two different experiments were conducted. The first experiment was a field study carried out around a livestock farm as a source of NH3 pollution and nitrogen deposition. Plant materials were exposed alongside passive diffusion tube samplers at three selected distances from the stable along a transect of 804m. The three different sites were selected with increasing distance from the stable, in order to enable a comparison between the plants exposed in close proximity to the source NH3 emission and those further away. The ambient NH3 concentration at each site was measured with the passive diffusion tube samplers exposed at each location. This measurement was conducted with a view to determine the ambient NH3 concentration exposed to the plant materials at each site and also to observe the influence of increasing distance on NH3 pollution and its exposure on the plants, from a point source of NH3 pollution. Furthermore, two fumigation experiments were conducted under controlled greenhouse conditions. In the fumigation study, only Lolium multiflorum and Echinochloa crus-galli, plants were used for this experiment and exposed to three treatment levels of gaseous NH3 fumigations in different growth chambers. The plants were exposed to the following treatments, non-filtered air (NFA), non-filtered air with low NH3 concentration (NFA+) and non-filtered air with high NH3 concentration (NFA++) in both fumigation experiments. In the field experiment, the ambient NH3 concentration measured at each location from the stable, decreased with increasing distance from the point of NH3 emission. This decrease in concentration of NH3 clearly demonstrates the impact of livestock management as a source of NH3 pollution. The free amino acid concentrations and compositions investigated in the various plants studied in the field experiments showed a significant response to NH3 exposure. Several fold increases in the free amino acid concentrations and changes in composition were observed in plant materials exposed to increasing NH3 concentrations at closer proximity to the stable. Observations made from this study showed that an increase in NH3 concentration with closer distance to the source of NH3 pollution influenced remarkably, the percentage increases of low carbon to nitrogen compounds such as Glutamine (Gln) in Lolium multiflorum and Chenopodium album, Asparagine (Asn) in Echinochloa crus-galli and Arginine (Arg) in Urtica dioica. The increases and alterations observed in the free amino acid compositions of the plants studied, demonstrates the uptake and sensitivity of the various plants to NH3 pollution and nitrogen deposition by inducing changes in its free amino acid metabolism. The effects of nitrogen deposition on the above ground biomass of the plants in the field study, indicated a significant effect of the ambient NH3 concentrations on Lolium multiflorum, Echinochloa crus-galli and Urtica dioica. These findings demonstrate a positive influence of NH3 pollution as a nitrogen source on growth and biomass accumulation in the plants. Considering the results obtained in this study based on the responses of the plants to atmospheric NH3 pollution in the field and in the fumigation studies, it is obvious NH3 had an influence over the growth and metabolism of the plants studied. This influence indicates the plants were able to detect changes in the ambient NH3 concentrations in the environment and responded by exhibiting changes in biomass production and alterations in free amino acid compositions, thus indicating they have good potentials as biomonitors of ammonia deposition.
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    Laufkäfer(Col., Carabidae) in Feldhecken Südwestdeutschlands : Vergesellschaftung und Biodiversität in Abhängigkeit von der Habitatqualität
    (2013) Theves, Florian; Zebitz, Claus P. W.
    The drastic decline of species caused by intensification of farming in the long run reduces the flexibility and productivity of our agroecosystems. One possibility to counter this negative development is the preservation of typical local species compositions in anthropogenic cultivated ecosystems. The conservation of valuable, or the creation of new habitat patches is a way to maintain these requirements. So far, there is too little knowledge yet, which habitat traits are most important for a given group of organisms. As the habitat requirements of many species vary on a regional level, it is necessary to categorize biotopes into types as a precondition for the application of those types on a broader scale. In this study, the zoo-ecological value of hedgerows is categorized by using ground beetles (Carabidae). Using the ?Filderebene? south of Stuttgart as an example, multivariate methods were used to distinguish general types of hedgerows to which regional bioindicators are assigned. Furthermore, the components of ground beetle diversity in hedges are investigated on different spatial scales and a method to estimate functional diversity is tested. It has been demonstrated that hedgerow types can be distinguished by a gradient of ground area size and age. Each of these types contain specific species, suitable for differentiation, established by calculation of species-associatons and indicator-analyses. While richness in species and individuals alone shows no clear dependency, especially forest carabids were positively correlated with hedgerow size. Besides, species-accumulation-curves show that few large hedges contain more species than small ones. Furthermore, it could be proven, that the carabid beetle associations are not only affected by the factors size and age, but also by the coverage of herbaceous vegetation and zonation of the hedgerows. The biodiversity components show a dependency on hedgerow size, too. While alpha-diversity per hedge increases significantly with decreasing area, beta-diversity decreases simultaneously. This relationship can be explained by the immigration of field species into the small hedges, whereas large and old hedges have a greater variety in structure, which results in a large number of microhabitats occupied by carabids. On site-level, the large hedges showed a higher alpha- and gamma-diversity than small hedges, which can be attributed to a higher general species richness of sites with extended hedgerows. In small hedges, biodiversity depends on the surrounding crops, whereas carabid beetle associations of large hedges are less affected by bordering habitats. This was evident, because homogenization of the surrounding crops caused a decline of alpha-diversity and an increase of beta-diversity in the hedges. A comparison between beta-diversities at site- vs. hedgerow-level shows higher heterogeneities inside than between hedges. In order to consider the functional component of biodiversity as well, the carabids of the hedgerows were partitioned into functional groups (guilds) by means of cluster-analysis based on their morphological and ecological traits. The number of guilds in a hedgerow can be used as an estimate for its functional diversity and efficacy of resource use. The average number of three guilds per hedge varies with hedgerow size and age. This results in a shift of species composition of carabid guilds based on hedgerow type and the continuity, of the functional groups occurence during the investigation period. In smaller hedges, the guild of ?forest species? is substituted by less specialized field species and the number of different significant guilds is less stable than in larger hedges.