title: Fragmented environment affects birch leaf endophytes.
abstract: The effect of environmental fragmentation on the species distribution and frequency of horizontally transmitted endophytic fungi in Betula pubescens and Betula pendula leaves was studied in an archipelago in southwestern Finland. The study system consisted of 14 islands, ranging in size and distance to the mainland, and five mainland sites. Endophytic fungi were grown out from surface-sterilized leaves. The frequency of endophytic fungi mainly depended on the size of the island, explaining 32-35% of the variation, and the distance to the mainland explaining 29-35% of the variation. The birch trees on the largest islands near the mainland had the highest endophyte frequencies. Fusicladium betulae, Gnomonia setacea and Melanconium betulinum were the most commonly isolated fungi. Foliar endophytes of birch trees are able to disperse to fairly fragmented areas, but their frequencies seem to depend on environmental isolation and size of the island.
authors.affiliation: Section of Ecology, Department of Biology, University of Turku, FIN-20014 Turku, Finland, and MTT Agrifood Research Finland, Plant Production, FIN-31600 Jokioinen, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Helander
authors.affiliation: Centre for Development and Information in Central Carelia, Centre for Applied Mycology, Kinnulantie 1, FIN-82300 Rääkkylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Ahlholm
authors.affiliation: ETH Zürich, Forest Pathology & Dendrology, Institute of Integrative Biology (IBZ), Universitätsstrasse 16, CH-8092 Zürich, Switzerland.
authors.forename: T N
authors.initials: TN
authors.lastname: Sieber
authors.affiliation: Herbarium, University of Turku, 20014 Turku, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Hinneri
authors.affiliation: MTT Agrifood Research Finland, Environmental Research, FIN-50600 Mikkeli, Finland.|Kevo Subarctic Research Institute, University of Turku, FIN-20014 Turku, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Saikkonen
mesh_terms: D029662:Betula / Q000382:microbiology*; D004777:Environment; D005658:Fungi; D005843:Geography; D018515:Plant Leaves