Small mammals and the dispersal of mycorrhizal spores

Mycorrhizae, the mutualistic symbiosis of mycorrhizal fungi and plants occur in a wide range of habitats and in many plant families all over the world. Mycorrhizal fungi may spread via their external hyphal matrix, rhizomorphs and spores. These spores may be transported by animal vectors (e.g. ground dwelling small mammals, squirrels or ungulates) or by abiotic factors (e. g. water). Most ectomycorrhizal (ECM) fungi form distinct hypogeous fruiting bodies. Fruiting underground is derived from fruiting aboveground, so endozoochory seems to be a successful way of spore dispersal. Major advantages from mycophagy for the fungus are the pelleting of spores in nutrient rich packages and the visit of favourable habitats by fungivorous animals. As most commercially valuable conifers and broadleaf trees form symbioses with ECM- fungi, mycophagy is crucial for sustaining a healthy forest. This mechanism is especially important in forest regeneration, because ECM-fungi (neither spores nor hyphae) can not survive in the soil for longer periods of time without a host plant. So small mammals may play an important role in spreading spores of these fungi into fungi free environments and so also help to maintain a diverse fungal community. The intended project will be the first trying to shed light both on the degree of mycophagy of small mammals (Rodentia, Soricidae) and on the inoculation potential of digested mycorrhiza fungal spores under controlled as well as under natural conditions and thus on more than one part of the tripartite symbiosis of fungi, small mammals and forest trees. The proposed project incorporates new and innovative (especially in the field of molecular genetics) as well as established methods for research into this tripartite interrelationship. Therefore small ground-dwelling mammals will be live trapped and the fecal pellets collected from the traps. These will be examined microscopically and on molecular level and used for inoculation experiments under laboratory conditions. To test the vector potential of small mammals in fungi free environments, sterile substrate will be used (simulating large scale disturbances or early successional habitats) and access for small mammals will be provided, prohibited or simulated (artificial application of small mammal faeces), thus analysing spread of fungal spores. Qualitative and quantitative analyses of seedling roots (macroscopic, microscopic, molecular investigation) will provide results on the amount of mycophagy of different small mammals species, the species of mycorrhizal fungi consumed, on the inoculation potential of small mammals faeces as they occur naturally and on vector function of small mammals in fungi free environments. Soil samples from the study plots will be analysed in a similar way (T- RFLP, cloning and sequencing) and used for interpretation and complementation of these results New insights into the complex role of small mammals in the forest floor community and the "wood wide web" can be obtained and so a considerable gap in the biology of small mammals and their connections to the forest can be filled.

Mycorrhizae, the mutualistic symbiosis of mycorrhizal fungi and plants occur in a wide range of habitats and in many plant families all over the world. Mycorrhizal fungi may spread via their external hyphal matrix, rhizomorphs and spores. These spores may be transported by animal vectors (e.g. ground dwelling small mammals, squirrels or ungulates) or by abiotic factors (e. g. water). Most ectomycorrhizal (ECM) fungi form distinct hypogeous fruiting bodies. Fruiting underground is derived from fruiting aboveground, so endozoochory seems to be a successful way of spore dispersal. Major advantages from mycophagy for the fungus are the pelleting of spores in nutrient rich packages and the visit of favourable habitats by fungivorous animals. As most commercially valuable conifers and broadleaf trees form symbioses with ECM- fungi, mycophagy is crucial for sustaining a healthy forest. This mechanism is especially important in forest regeneration, because ECM-fungi (neither spores nor hyphae) can not survive in the soil for longer periods of time without a host plant. So small mammals may play an important role in spreading spores of these fungi into fungi free environments and so also help to maintain a diverse fungal community. The intended project will be the first trying to shed light both on the degree of mycophagy of small mammals (Rodentia, Soricidae) and on the inoculation potential of digested mycorrhiza fungal spores under controlled as well as under natural conditions and thus on more than one part of the tripartite symbiosis of fungi, small mammals and forest trees. The proposed project incorporates new and innovative (especially in the field of molecular genetics) as well as established methods for research into this tripartite interrelationship. Therefore small ground- dwelling mammals will be live trapped and the fecal pellets collected from the traps. These will be examined microscopically and on molecular level and used for inoculation experiments under laboratory conditions. To test the vector potential of small mammals in fungi free environments, sterile substrate will be used (simulating large scale disturbances or early successional habitats) and access for small mammals will be provided, prohibited or simulated (artificial application of small mammal faeces), thus analysing spread of fungal spores. Qualitative and quantitative analyses of seedling roots (macroscopic, microscopic, molecular investigation) will provide results on the amount of mycophagy of different small mammals species, the species of mycorrhizal fungi consumed, on the inoculation potential of small mammals faeces as they occur naturally and on vector function of small mammals in fungi free environments. Soil samples from the study plots will be analysed in a similar way (T-RFLP, cloning and sequencing) and used for interpretation and complementation of these results New insights into the complex role of small mammals in the forest floor community and the "wood wide web" can be obtained and so a considerable gap in the biology of small mammals and their connections to the forest can be filled.