How did the research turn out? What were the findings? Researchers themselves report briefly on the research they have undertaken with funding support from the Formas Research Council.
Editor: Margaretha Nordahl
The importance of ectomycorrhizal fungi for the release of nutrients and retention of nitrogen in forest soil
Håkan Wallander (project leader)
Summary of results with list of publications from Environmental Sciences, Lund University.
Email: Hakan.Wallander@embioekol.lu.se
The forest is fantastic!
Ectomycorrhizal fungi (EM) are a variable group of fungi that live in symbiosis with forest trees and are of great importance for their nutrient uptake. Certain species have the ability to stimulate weathering of minerals in the soil. In this project, a study has been made whether this effect is dependent on the nutritional status of the trees, i.e. can the trees compensate for a deficiency of nutrients by allocating more resources to their EM fungi.
Two large-scale field experiments have been made: spruce forests in south west Sweden and pine forests in west Finland. In the Swedish experiment, the growth of EM fungi was stimulated by adding phosphorus-containing minerals to the soil. The effect of this stimulus was the greater, the lower the phosphorus status of the forest. This indicates that trees are adapted to situations with phosphorus deficiency by sending more resources to the fungi, which in this way can better utilise phosphorus sources in the soil.
The Finnish experiment was more difficult to interpret, and a very large number of samples are therefore needed to ascertain to what extent the addition of phosphorus-containing minerals influences the composition of the EM community.
Increased biodiversity in forests reduces insect damage
Fredrik Schlyter (project leader)
Summary of results from SLU. Jactel, Brockeroff "Tree diversity reduces herbivory by forest insects".
The article is available in pdf format from www.vv.slu.se
Ecologists and nature conservationists have long claimed that there are fewer problems with insects pests in mixed forests, and now evidence is available from experiments with an artificial "mixed odour forest". In the long term, endeavours should therefore be made to establish mixed forests with diverse odours, since landscapes comprising only conifers will not be stable in the climate of the future.
The mechanisms underlying this clear pattern demonstrate that a specialised herbivore has a greater resource availability when all nearby plants are of the right species for its development. On the other hand, predators and parasites benefit from more biodiverse environments, which reduces the numbers of herbivores. One new mechanism for herbivores is "odour diversity", i.e. nonhost volatiles inhibit their orientation.
Responsible for this page: Kerstin Franklin