Bryophyte vegetation in geothermal areas in Iceland Diplomarbeit zur Erlangung des Grades einer Diplom-Biologin der Mathematisch-Naturwissenschaftlichen Fakultät der Rheinischen-Friedrich-Wilhelms-Universität Bonn vorgelegt von Stefanie Wilberscheid Bonn, den 31. März 2008 Archive for Bryology Special Volume 4 ISSN 0945-3466 Referent: Professor Dr. Jan-Peter Frahm Koreferent: Dr. Bodo Maria Möseler Archive for Bryology Special Volume 4 ISSN 0945-3466 Table of contents 1 Table of contents Table of contents........................................................................................................................I List of Figures and tables........................................................................................................ II 1 Introduction ........................................................................................................................ 1 1.1 State of Knowledge .......................................................................................................1 1.1.1 Geothermal areas as a habitat for plants................................................................. 1 1.1.2 Impact on plants ..................................................................................................... 3 1.1.3 Bryophytes in geothermal areas ............................................................................. 4 1.2 Study area...................................................................................................................... 7 1.2.1 Geology of Iceland................................................................................................. 7 1.2.2 Description of the examined areas ......................................................................... 9 1.2.2.1 Area 1: Mývatn............................................................................................. 9 1.2.2.2 Area 2: Krafla/ Leirhnúkur......................................................................... 10 1.2.2.3 Area 3: Landmannalaugar .......................................................................... 11 1.2.2.4 Area 4: Hveragerði..................................................................................... 12 1.2.2.5 Area 5: Reykjanes ...................................................................................... 13 1.2.2.6 Area 6: Dyngjufjöll .................................................................................... 14 1.2.2.7 Area 7 Haukadalur ..................................................................................... 15 1.2.2.8 Area 8: Hveravellir..................................................................................... 15 2 Material and methods ...................................................................................................... 17 2.1. Material ...................................................................................................................... 17 2.1.1 pH-Meter .............................................................................................................. 17 2.1.2 Infrared thermometer............................................................................................ 17 2.1.3 Soil thermometer.................................................................................................. 17 2.1.4 Statistical treatment.............................................................................................. 18 2.2 Methods....................................................................................................................... 18 2.2.1 Recording methods............................................................................................... 18 2.2.2 Analysis of phytosociological data ...................................................................... 19 2.2.3 Determination of soil pH...................................................................................... 20 2.2.4 Measurement of temperature................................................................................ 20 2.2.5 Humidity............................................................................................................... 21 3 Results ............................................................................................................................... 22 Archive for Bryology Special Volume 4 ISSN 0945-3466 Table of contents 2 3.1 Bryophytes found in geothermal areas........................................................................ 22 3.2 Description of the bryophyte vegetation in the regions .............................................. 24 3.2.1 Mývatn ................................................................................................................. 24 3.2.2 Leirhnúkur............................................................................................................ 27 3.2.3 Landmannalaugar................................................................................................. 28 3.2.4 Hveragerði............................................................................................................ 31 3.2.5 Reykjanes ............................................................................................................. 34 3.2.6 Askja..................................................................................................................... 35 3.2.7 Geysir ................................................................................................................... 35 3.2.8 Hveravellir............................................................................................................ 37 3.3 Correlation between the parameter ............................................................................. 38 3.4 Relation between pH and species occurrence ............................................................. 39 3.5 Relation between temperature and species occurrence ............................................... 41 3.6 Relation between humidity and species occurrence.................................................... 42 3.7 Bryophytes along a warm stream in Reykjadalur ....................................................... 44 3.8 Non-bryophytes on the examined areas ...................................................................... 45 3.9 Areas without vegetation............................................................................................. 46 4 Discussion.......................................................................................................................... 47 4.1 General discussion of the species found ..................................................................... 47 4.1.1 Distribution........................................................................................................... 47 4.1.2 Relation between cold hardiness and thermostability.......................................... 48 4.1.3 Lack of sporophytes ............................................................................................. 48 4.2 Discussion of the vegetation patterns.......................................................................... 49 4.2.1 Relation between vegetation patterns and parameters ......................................... 51 4.2.2 Description of the groups ..................................................................................... 53 4.3 Outlook........................................................................................................................ 62 4.4 Endangering of geothermal vegetation ....................................................................... 63 5 Summary........................................................................................................................... 65 6 References ......................................................................................................................... 67 7 Acknowledgments............................................................................................................. 70 8 Appendix ........................................................................................................................... 71 Distribution maps ................................................................................................................. 71 Icelandic geothermal bryophyte species .............................................................................. 77 Archive for Bryology Special Volume 4 ISSN 0945-3466 List of Figures and tables 1 List of Figures and tables Figure 1-1. Examined areas in Iceland..................................................................................... 9 Figure 1-2. Hills of altered soil in young lavafields at Leirhnúkur........................................ 10 Figure 1-3. One relevé of plot 13 near Hveragerði ................................................................ 12 Figure 1-4. Geothermal field at the south-western cape of Reykjanes ................................... 13 Figure 1-5. Vegetation and hot pools near Geysir................................................................... 15 Figure 2-1. Measurement of the soil temperature in a relevé at Leirhnúkur........................... 18 Figure 2-2. Vegetation assessment at Askja............................................................................ 19 Figure 3-1. Vegetation next to a steam vent in the Mývatn area (Plot 3) ............................... 24 Figure 3-2. Sparse vegetation at Leirhnúkur ........................................................................... 27 Figure