Community structure, trophic ecology and reproductive mode of oribatid mites (Oribatida, Acari) in forest ecosystems

• Main Author: Erdmann, Georgia
• Other Authors: Maraun, Mark PD Dr., Scheu, Stefan Prof. Dr., Kreft, Holger Prof. Dr., Rohlfs, Marko PD Dr., Hörandl, Elvira Prof. Dr.
• Format: Other/Unknown Material
• Language: English
• Published: Niedersächsische Staats- und Universitätsbibliothek Göttingen 2013
• Subjects: 333; 577; soil; oribatid mites; biodiversity; trophic structure; stable isotopes; forest management; parthenogenesis; asexuality; thelythoky; Arctic; Mite
• Online Access: http://hdl.handle.net/11858/00-1735-0000-000C-B7E7-7; https://doi.org/10.53846/goediss-3322; https://nbn-resolving.org/urn:nbn:de:gbv:7-11858/00-1735-0000-000C-B7E7-7-8

Oribatid mites are predominantly soil-living organisms reaching densities of up to 400,000 individuals per square meter in forest soils, where they contribute to decomposition processes and nutrient cycling. In acidic forests they are the main decomposer taxon, together with collembolans. Despite their outstanding importance for soil processes knowledge about their trophic ecology and factors structuring their communities is low. About ten percent of the 10,000 described species are thelytokous (i.e., they reproduce via female parthenogenesis); locally up to 80 % of all individuals in temperate forest soils are parthenogens. Oribatid mites likely originated in Cambrian or Precambrian times and include old thelytokous species-rich groups indicating an ancient origin of asexuality as well as parthenogenetic radiations. Sexual and parthenogenetic species coexist in forest soils and in agricultural soils; in temperate, tropical and arctic regions and also on the bark of dead and living trees. This makes oribatid mites a unique group for studying patterns of parthenogenetic reproduction and for studying factors influencing the relative frequency of sexual and parthenogenetic species (see Chapter 1). The present thesis focuses on oribatid mite reproductive mode and ecology and is divided into two parts. The first part investigates the trophic ecology of oribatid mites in soil and on bark analysed with stable isotope measurements (Chapter 2) and abiotic and biotic factors influencing oribatid mite density, diversity and community structure in soils of different forest types (Chapter 3). In the second part oribatid mites were used as model organisms to investigate the distribution of sexual and parthenogenetic individuals in forest soils in two regions in Germany and in different habitats worldwide in relation to food availability (Chapter 4). Further we investigated the effects of nutrient availability on oribatid mite density and the frequency of parthenogenetic individuals on tree trunks (Chapter 5). In Chapter 2 we ...