Decline of ectomycorrhizal fungi in Europe

Changes in this century in the composition of the macromycete flora in the Netherlands were studied by a comparison of excursion reports, mapping of selected species, and repeated mycocoenological studies in permanent plots in forests. The three approaches show similar trends. Among saprotrophic macromycetes of forest litter only a few species show a significant increase or decrease, but most saprotrophic species of grass- and heath-lands are markedly decreasing, due to modern agricultural practice, notably the use of artificial fertilizers. Lignicolous macromycetes are in general increasing, in particular parasitic species, an increase mainly ascribed to the ageing of forests. Among the ectomycorrhizal macromycetes not a single species showed a significant increase, but at least 55 out of 126 species showed a significant decrease. This decline is strongest among species exclusively, or mainly, associated with coniferous trees. At least 15 ectomycorrhizal species seem to have disappeared completely from the Netherlands. Natural forest development, changes in forestry and agriculture and collecting of carpophores are excluded as important factors effecting these changes. The decrease of ectomycorrhizal fungi is mainly attributed to acid precipitation and its effects on soil chemistry and the vitality of trees. However, the exact process is still unknown. Two hypotheses that may explain this phenomenon are discussed.

The changing macromycete flora in the Netherlands

Belowground responses as indicators of environmental change

Acid rain is a serious international environmental problem. Scandinavian forests have suffered especially severe damage, and have been the focus of considerable research on the causes and impacts of atmospheric pollution. This book presents the results of long-term studies on acid rain in Norwegian forests. This research examined soil chemistry and biology; the impacts of acid rain on tree growth and nutrition; and its influence on ground vegetation, fungi, and seedling germination and development. Long-Term Experiments with Acid Rain in Norwegian Forest Ecosystems is a lasting contribution to the literature on acid precipitation, and will be of interest to researchers in ecology, air pollution, forestry and environmental chemistry.

Long-Term Experiments with Acid Rain in Norwegian Forest Ecosystems

Comparative evaluation of the effects of gaseous pollutants, acidic deposition and mineral deficiencies: structural changes in the cells of forest plants

Fine root studies in two old growth spruce forests affected by “Wadsterben” in Bavaria. Fine roots of healthy and declining Norway spruce (Picea abies) were investigated. We observed fewer active myeorrhizac associated with affected spruce in two old growth Forests. It has been hypothesised that air pollution is dimaging the needles resulting in less photosynthate and that the reduction of active mycorrhizae is due to such an initial weakening of the tree.

Von B. Liss

Papers

Vergleichende Feinwurzeluntersuchungen an gesunden und erkrankten Altfichten auf zwei Standorten in Bayernein Beitrag zur Waldsterbensforschung