wise use of mires and peatlands - Peatland Ecology Research Group

APPENDICES2151Based on information supplied by Heinrich Höper.2Because the concentrations of natural andanthropogenic greenhouse gases are smallcompared to the principal atmosphericconstituents of oxygen and nitrogen, these gasesare also called trace gases.3Crill et al. 2000. All radiation (energy) iseventually transferred back to space but at longerwavelengths. For longer wavelengths a radiatingbody has to be warmer in order to lose the sameamount of energy.4Ivanov 1981, Couwenberg & Joosten 1999.5See §A2.3.6See §A2.2.7Cf. §A2.3.8See §A2.3, A2.4, A2.5, A2.6, A2.7.9Francez & Vasander 1995.10Francez & Vasander 1995.11See §2.5.12Committee on Global Change Research 1999.13The Global Climate Change Task Force Of TheCouncil On Engineering and Council On PublicAffairs, 1998.14Houghton et al. 1990.15Franzén 1994, Franzén et al. 1996. See also Rodhe& Malmer 1997, Franzén 1997.16Scholes et al. 2000.17Reeburgh & Crill 1996.18The most recent estimates indicate that 109·10 12g yr -1 of methane is released by wetlands globally.Tropical regions (20°N to 30°S) are calculated torelease 66 ·10 12 g yr -1 (60.5% of the total),emissions from subtropical and temperatewetlands (20-45°N and 30-50ºS) are only 5 ·10 12g yr -1 (4.5% of the total) but there have beenrelatively few measurements in the tropics andsubtropics, and this figure is therefore currentlyuncertain. Northern wetlands (north of 45ºN)are calculated to release a total of 38 ·10 12 g yr -1(35% of the total) with 34 ·10 12 g yr -1 from wetsoils and 4 ·10 12 g yr -1 from relatively dry tundra(Milich 1999, Scholes et al. 2000).19More recent estimates of the total CH 4emissionfrom rice paddies amount to 50 ± 20 ·10 12 g y -1(Neue 1997).20Aselmann & Crutzen 1990.21Harriss et al. 1985, Bridgeham et al. 1995.22Svensson 1976.23Silvola et al. 1994b, Martikainen et al. 1992,1994, 1995.24Clymo & Reddaway 1971.25Augustin et al. 1996.26Pfeiffer 1993; Meyer 1999.27Crutzen, 1979.28Martikainen et al. 1993.29Hillebrand 1993.30Goodroad & Keeney 1984.31Augustin et al. 1996.32Meyer 1999.33Crill et al. 2000.34Crill et al. 2000.35Scholes et al. 2000.36Charlson et al. 1987, DeMello & Hines 1994,Kiene & Hines 1995, Lomans et al. 1997, 1999,Watson & Liss 1998, Lomans 2001.37Varner et al. 1999.38Daniel et al. 1995.39Roulet 2000b.40Mundel 1976.41Höper 2000.42Mundel 1976.43Wild & Pfadenhauer 1997.44Silvola 1986, Silvola et al. 1994a.45Glenn et al. 1993.46Mundel 1976.47Segeberg & Schröder 1952, Kuntze 1992, Meyer1999.48Hillebrand 1993.49The database for tilled peatlands is small and CO 2emissions have largely to be estimated fromsubsidence measurements (Höper 2000). In thistable the values for fens were calculated using thepeat subsidence in cm year -1 , a bulk density of150 kg m -3 , a C-content of 55%, and assumingthat 80% of peat subsidence is due to peatmineralisation. For bogs a bulk density of 100 kgm -3 was used.50Kuntze 1973, Eggelsmann 1976.51Schuch 1977.52Okruszko 1989.53Glenn et al. 1993.54Svensson 1976.55Lien et al. 1992, Martikainen et al. 1992, 1994,1995.56Augustin et al. 1996.57Meyer et al. 1997.58Personal communication from Heinrich Höper.59Martikainen et al. 1993.60Hillebrand 1993.61Goodroad & Keeney 1984.62Velthof & Oenema 1983.63Flessa & Klemisch 1997.64Augustin et al. 1996.65Tschirsich 1994, Meyer 1999.66As becomes apparent from comparing data fromSegeberg & Schröder 1952 and Kuntze 1992.67Similar results were found by Kasimir-Klemedtsson et al. 1997.68The complexities associated with peatlanddrainage are excellently reviewed for the borealzone in Crill et al. 2000, (cf. also Joosten 2000),on which this subsection is largely based.69See also §3.4.1 (eb).70Stegmann et al. 2001.71In the boreal zone consisting of remains ofconifer needles, branches, rootlets, forest mossesetc.72Provided that the forest management continuesand the peatland remains sufficiently drained.73Cannell et al. 1993; Laine & Minkkinen 1996,Minkkinen & Laine 1998, Minkkinen 1999.74From Laine and Minkkinen 1996. Reproducedby kind permission of the Finnish PeatlandSociety.75See review in Crill et al. 2000 with respect toboreal peatlands. In boreal peatlands the increasedCO 2emissions from the peat carbon store may –temporarily – be overridden by increased CO 2sequestration in the biomass and litter stores. Intemperate Alnus and Betula fens, mineralisation