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Accueil du site → Doctorat → Allemagne → 2003 → Patterns of arthropod distribution and determinants of arthropod assemblage composition in a natural West African savannah

Bayerischen Julius-Mawimilians-Universität Würzburg (2003)

Patterns of arthropod distribution and determinants of arthropod assemblage composition in a natural West African savannah

Mody, Karsten

Titre : Patterns of arthropod distribution and determinants of arthropod assemblage composition in a natural West African savannah

Verteilungsmuster von Arthropoden und zugrunde liegende Bestimmungsfaktoren in einer naturnahen westafrikanischen Savanne

Auteur : Mody, Karsten

Université de soutenance : Bayerischen Julius-Mawimilians-Universität Würzburg

Grade : Doktor der naturwissenschaftlichen 2003

This study investigated patterns of arthropod community organisation and the processes structuring these communities on a range of different tree species in a natural West African savannah (Comoé National Park, Côte d’Ivoire). It described and analysed patterns of arthropod distribution on the level of whole communities, on the level of multiple-species interactions, and on the level of individual insect species. Community samples were obtained by applying (i) canopy fogging for mature individuals of three tree species (Anogeissus leiocarpa, Burkea africana, Crossopteryx febrifuga) and (ii) a modified beating technique allowing to sample the complete arthropod communities of the respective study plants for medium-sized (up to 3 m) individuals of two other species (Combretum fragrans, Pseudocedrela kotschyi). General information on ant-plant interactions was retrieved from ant community comparisons of the mature savannah trees. In addition, ant-ant, ant-plant and ant-herbivore interactions were studied in more detail considering the ant assemblages on the myrmecophilic tree Pseudocedrela kotschyi. Herbivore-plant interactions were investigated on a multiple-species level (interrelationships between herbivores and Pseudocedrela trees) and on a species level (detailed studies of interrelationships between herbivorous beetles and caterpillars and the host tree Combretum fragrans). The studies on individual herbivore species were complemented by a study on an abundant ant species, clarifying not only the relationship between host plant and associated animal but allowing also to look at interactive (competitive) aspects of community organisation. The study demonstrated for the first time that (i) the structure of beetle communities on tropical trees can be strongly dependent on the host tree species, (ii) individual trees can host specific arthropod communities whose characteristic structure is stable over years and is strongly determined by the individual tree’s attributes, (iii) ants can express a pronounced fidelity to single leaves as foraging area and can thereby determine distribution patterns of other ants, (iv) intraspecifically variable palatability of plants for insect herbivores can be stable over years and can influence the distribution of herbivores that can distinguish between individual hosts according to palatability and (v) intraspecific host plant change can positively affect fitness of herbivores if host plant quality is variable. In general, the present study contributes to our knowledge of anthropogenically unaltered processes affecting community assembly in a natural environment. The fundamental understanding of these processes is crucial for the identification of anthropogenic alterations and the establishment of sustainable management measures. The study points out the important role local factors can play for the distribution of organisms and thereby for community organisation. It emphasises the relevance of small scale heterogeneity of the abiotic and biotic environment to biodiversity and the need to consider these factors for development of effective conservation and restoration strategies

Mots clés : Parc National de la Comoe ? ; Savanne ; Baumkrone ; Gliederfüßer ; arthropod community , animal-plant interactions , ants , diversity , conservation


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Page publiée le 22 mars 2008, mise à jour le 5 janvier 2019