Lichen decline in areas with increased nitrogen deposition might be explained by parasitic fungi : A survey of parasitic fungi on the lichen Alectoria sarmentosa after 4 years of nitrogen fertilisation

• Main Author: Ström, Caspar
• Format: Others
• Language: English
• Published: Umeå universitet, Institutionen för ekologi, miljö och geovetenskap 2011
• Subjects: parasitic fungi; lichen diversity; Alectoria sarmentosa; nitrogen deposition; Biology; Biologi
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-39727

Nitrogen (N) deposition in Europe has recently increased and is expected to continue to increase in the future. There is a well-documented decline in lichen diversity with higher N availability, although the mechanisms behind this are poorly known. In this study, I tested whether attacks by fungal parasites increase with higher N deposition. This pattern has been found in a number of studies on vascular plants, but it has never been investigated for lichens. I surveyed dark lesions and discolourings caused by fungi on the pollution-sensitive lichen Alectoria sarmentosa, after 4 years of increased N deposition in a whole tree fertilisation experiment in a boreal spruce forest. I found two species of fungi growing on the investigated lichen thalli. One of these species responded positively to increased N deposition. The results show that lichens can suffer from increased parasite attacks under a higher N load. Further studies using multiple lichen species and many years of recording are needed to understand the importance of parasites for the response of whole lichen communities to an increased N load.