Subproject W06
Prof. Dr. K. Eduard Linsenmair, Department of Animal Ecology and Tropical
Biology. Biozentrum, Am Hubland. D-97074 Wuerzburg, Germany
Determinants of small-scale mosaics of arthropod communities in natural and
anthropogenically disturbed habitats
Introduction
The structure of ecological communities is influenced by many parameters: habitat
characteristics, interactions between organisms, and stochastic events are considered
as especially important local factors. In order to understand the influence
these parameters exert on the structure of species-rich communities, arboricolous
arthropod communities and driver ants (Dorylus nigricans) are investigated
in the presented project.
As study areas, Comoé National Park and adjacent locations in the north-east
of the Republic of Côte d'Ivoire were chosen. They comprise a complex
system of quasi-natural and fire-influenced pasture ecosystems in a dynamic
forest-savanna mosaic, supporting several savanna types, island forests and
gallery forest.
From our own studies we know that clearly distinguishable arthropod communities
occur in seemingly identical, neighboring habitats (conspecific savanna trees
of comparable size). Individual plants were re-colonized by very similar communities
after complete removal of arthropods. This finding demonstrates that deterministic
factors which have not been identified so far are strongly influencing the structure
of these assemblages. Besides, stochastic disturbances are studied as an additional
factor potentially influencing community composition.
Objectives
In this project it is planned to exemplarily investigate the relevance of deterministic
and stochastic factors for maintenance of local biodiversity in two well suited
study systems in West Africa. Factors deterministically acting on the composition
of and differences between individual communities are studied in the arboricolous
arthropod assemblages mentioned above. European willow trees, well known for
their intensively studied phytochemistry, will be included in these investigations
later on for comparative purposes. The abundant driver ants will be used as
a model system to analyze the effects which stochastically occurring disturbances
exert on arthropod communities.
The results of these investigations, in concert with computer simulations and
comparisons with communities in anthropogenically altered habitats, are considered
to provide some deep insights into the understanding of important aspects of
the origin, maintenance and functional properties of biodiversity. They should
also provide a solid basis for the planning of diversity-supporting management
measures, locally applicable to different biomes.
Background
Deterministic habitat heterogeneity and stochastic disturbances are most probably
central mechanisms generating high local and regional diversity in natural environments.
In anthropogenically altered landscapes, however, this small scale ß-diversity
is eliminated in favor of a pronounced monotony. These changes can lead to a
homogenization of species composition (dominance of ubiquists and generalists)
and to a reduction of species diversity and can result in an unwelcome, enhanced
sensitivity of these systems to biotic and abiotic environmental alterations.
Cooperation within BIOTA:
| • |
Dr. Gerald Braun (W01), DLR, description and analysis
of small scale habitat heterogeneity with remote sensing data |
| • |
Dr. Jörg Szarzynski (W02), University
of Mannheim: provision of microclimatic data |
| • |
Prof. Dr. Stefan Porembski (W04), University of Rostock:
habitat characterization and determination of structural diversity by quantification
of vegetation structure; insect herbivory of selected tree species |
The research team:
Prof. Dr. K. Eduard Linsenmair, University of Wuerzburg: project
leader
Karsten Mody (PhD candidate), University of Wuerzburg: arthropod communities
on plants, animal-plant- and animal-animal-interactions
Christian Kost (PhD candidate), University of Wuerzburg: arthropod diversity
and driver ants
External partners of cooperation:
Research museums: Alexander König, Bonn; Humboldt-Museum,
Berlin; Naturkundemuseum, Stuttgart; British Museum, London; Musée National
d'Histoire Naturelle, Paris
Prof. Dr. U. Maschwitz, Frankfurt; Prof. Dr. B. Hölldobler, Wuerzburg (Myrmecology)
Prof. Dr. H.J. Poethke and Dr. T. Hovestadt, Wuerzburg/Fabrikschleichach (Computer
simulation/modelling).
Prof. Dr. J. Grunert, Mainz (Pedology)
Centre de Recherche en Ecologie, Université d'Abobo-Adjamé, Côte
d'Ivoire (local counterparts)
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