General and Theoretical Ecology

Skills & Equipment

Quantification, identification and functional analysis of soil organisms

direct way to modelling

Quantification of soil fauna:

• Emergence traps (Diptera, Hymenoptera), pitfall traps (epigeal fauna), Kempson extractor (macrofauna), Macfadyen High Gradient extractor (microarthropods), wet funnel extractor according to Graefe (Enchytraeidae), Oostenbrink elutriator (Nematoda), density gradient centrifugation (Protozoa), electric earthworm extractor (octett-method according to Thielemann), Berlese-Tullgren extractor (microarthropods)

 

Identification of soil fauna:

• Equipment: High-quality research microscopes (light, phase and interference contrast, fluorescence), dissection microscopes (up to 400x magnification), video camera, image analysis Taxonomic knowhow: Lumbricidae, Isopoda, Gamasina, Collembola, Nematoda, Ciliophora, Ciliates

   

  Soil microorganisms (classical methods):

• Cultivation, enumeration, substrate use differentiation, soil respiration

 

Element cycling:

• Field methods: Litterbags, minicontainers (according to Eisenbeis), bait lamina tests (according to von Törne)-Stäbe
• Laboratory methods: enzyme acivities, several types of microcosms

   

  Molecular biology:

• Gel electrophoresis of DNA and proteines, UV/VIS spectrometry, PCR Gradient cycler, isoelectric focussing, image analysis

Model and test systems:

Interactions and functions of soil organisms: laboratory microcosms (decomposer communities of varying complexity levels), greenhouse microcosms (decomposer communities including living plants), field enclosures (manipulated densities of soil animals under outdoor conditions)

Ecotoxicological tests: Eisenia foetida, Enchytraeus albidus, Folsomia candida, luminescent bacteria, avoidance behaviour, plant growth inhibition test

Selected publications on ecological methods

Filser, J., 1996: Ecological field studies in soil: balancing between space, time, and manpower resour-ces. - Senckenbergiana maritima 27, 109-118

Mommertz, S., Schauer, C., Kösters, N., Lang, A., Filser, J., 1996: A comparison of D-Vac suction, fenced and unfenced pitfall trap sampling of epigeal arthropods in agroecosystems. - Ann. Zool. Fennici 33, 117-124

Mebes, K.-H., Filser, J., 1997: A method for estimating the significance of surface dispersal for popu-lation fluctuations of Collembola in arable land. - Pedobiologia 41, 115-122

Modelling:

The effects of complex processes interacting on different scales often can not be apprehended intuitivly. This refers to the long term behaviour of many ecological systems e.g in ecotoxicology, extrapolation in space and the interactions of many species in food webs. In order to access these themes we need innovative and unconventionell modelling tools in connection with other scientific disziplines such as artificial life. A particular emphasis of the department consists in the representation of complex ecological interactions in individual based models and cellular automata. Individual based models base on the depiction of ecological dynamics as a result of the interactions of basic units on low integration levels. This method allows the representation of spatial, temporal and structural heterogeneities of ecological processes. We use this kind of modells to assess the population dynamics of vertebrates and invertebrates, the dispersal processes of ground living arthropods and for the representation of plant growth including physiological and morphological processes.

Specific topics:

Fish Schools: Reuter, H; Breckling, B; 1994: Selforganization of fish schools: An object-oriented model. Ecological Modelling 75/76: 147 - 159

Predator-Prey-Interaction: Breckling, B. 1985: The changeability of the dynamical behaviour of the Lotka-Voltera-Model basing on the implementation of non linear expansions - Theoretical consequences. Verhandlungen der Gesellschaft für Ökologie 13:295 - 304

Reproduction success of European Robins: Reuter, H.; Breckling, B. 1999: Emerging properties on the individual level - Modelling the reproductive phase of the European Robin (Erithacus rubecula). Ecological Modelling 121: 199 - 219

Foodweb interaction of small mammals: Reuter, H. 2000: Individuum und Umwelt.- Wechselwirkungen und Rückkopplungsprozesse in individuenbasierten tierökologischen Modellen. University of Bremen.

Dispersal of ground arthropods: Breckling, B.; Reuter, H. 1999: Modellierung komplexer bodenökologischer Wechselbeziehungen: Ausbreitungsprozesse uns Strukturbildung. In: Koehler, H.; Mathes, K.; Breckling, B. (ed): Bodenökologie interdisziplinär S.: 27 - 42

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