wise use of mires and peatlands - Peatland Ecology Research Group

MIRES AND PEATLANDS43Sieffermann et al. 1988.66Adapted from Joosten 1999. N.B.: these olderdata may not be fully compatible with the newerdata in Tables A1/1 to A1/5 in Appendix 1.67Guesstimate based on production figures correctedfor extraction on already-drained areas.68Immirzi et al. 1992. Additional contemporaryinformation is sought on this figure. It is likelythat the order of magnitude of the combined figureremains valid, given recent large projects in SouthEast Asia.69Additional contemporary information is requiredto verify this figure.70Joosten 1999.71Paavilainen & Päivänen 1995.72Foss 1998.73Bambalov 1996, Belokurov et al 1998.74Based on information from Jukka Turunen.75E.g. Botch et al. 1995; Kauppi et al. 1997; Clymoet al. 1998; Turunen et al. 1999; Vitt et al. 2000;Turunen et al. 2000.76Ingram 1978; Clymo 1984.77Ivanov 1981; Clymo 1984.78Clymo 1984; Gorham 1991; Warner et al. 199379Tolonen et al. 199280Tolonen & Turunen 1996.81Turunen et al. 2000a.82Elina et al 1984.83Vitt et al. 2000.84Turunen et al. 2000b. These data concern oldwatershed ombrotrophic mires in the middle taigazone. New research gives LORCA values for thesouth taiga zone of West Siberia of 41.2±12 (SE)(n= 14), with values ranging from 24.9 to 56.4 gm-2 yr-1 (pers. comm. Elena Lapshina, cf.Lapshina et al. 2001).85These new estimates are lower than earlierestimates of 26-30 g m-2 yr-1 for boreal and subarcticregions, e.g. Gorham 1991; Botch et al.1995; Tolonen & Turunen 1996; Clymo et al.1998. The difference in LORCA estimates ismainly due the fact that shallow mires have beenunder-represented in previous studies. There hasalso been great uncertainty in average dry bulkdensities of peat layers. The bias of data towardsdeeper peat deposits is also evident through theclassification of mires in northern latitudes basedon the minimum thickness of peat deposits, asnoted in Note 13 above. For example, theminimum thickness for geological mires in Finland,Canada and Russia is 30, 40 and 70 cm (Lappalainen& Hänninen 1993, Zoltai et al. 1975, Botch andMasing 1979), respectively.86Summarised by Vardy et al. 2000.87Clymo 1984, Clymo et al. 1998.88Tolonen & Turunen 1996.89Turunen et al. 1999.90Gorham 1991, Clymo et al. 1998, Turunen et al.2000a.91After Clymo et al. 1998.92Turunen et al. 2000a. The large range of these Cstorage estimates reflects the uncertainty in thedepth and dry bulk densities of global peat deposits.93Post et al. 1982.94www.wri.org/climate/carboncy.html, Houghton etal. 1990.95This figure does not include carbon emissions frompeat oxidation in peatlands drained for and byextraction.96Immirzi et al. 1992.97See also Armentano & Menges 1986, Botch et al.1995, Lappalainen 1996, Vompersky et al. 1996,Joosten 1999.98See also §§ 2.2, 2.3, and 2.7. The characteristicsoutlined in this chapter are principally thoserelevant to the functions discussed in Chapter 3.99Undrained peatlands contain between 85% and95% water, making them often “wetter” thanunskimmed milk. Undrained peatlands can oftenbe regarded as “mounds of water kept togetherby some organic material”.100= just below, at, or just above the surface, cf.Edom 2001a.101See §2.2, Ivanov 1981, Koppisch 2001.102Because of erosion and the lack of oxygen andcarbon dioxide, c.f. Ivanov 1981, Ingram & Bragg1984 Alexandrov 1988, Sjörs 1990, Lamers etal. 1999.103Resulting from aeration or input of specific ions(e.g. nitrates, iron, sulfates) (Edom 2001a,Koppisch 2001).104Kløve 2000, Edom 2001a, Stegmann & Zeitz2001, Pozdnyakov et al. 2001. Similar changesalso result from the imposition of weight.105Schmidt et al. 1981.106Moisture contents of undrained peats of 90 - 95% are not uncommon (cf. Segeberg 1960).107Subsidence is the lowering of the peatland surfacelevel as a result of decreased water pressure. Alowering of the moisture content of peat from95% to 90%, for example, halves the volume ofthe water in the peat, and affects substantiallythe height of the mire (Segeberg 1960). Five yearsafter drainage, the height of a bog in Germanyhad already decreased by more than 2 metres(Baden 1939). Construction of a road throughClara Bog (Ireland) lowered the surface in thecentre of the remaining mire by possibly 4 metres(Van der Schaaf 1999).108See Figure 2/2 and §2.3.109Including porosity, storage coefficient, andhydraulic conductivity (Edom 2001a).110Edom 2001b. See also §3.4.3 (o).111Suhardjo & Driessen 1977, Maltby 1986, Stewart1991.112Cf. Brandyk & Skapski 1988.113Stegmann & Zeitz 2001.114See §3.4.3 (m), Tables A2/7 and A2/8 and Fig.A2/2.115Including nitrates and phosphates, which maycause water eutrophication (Gelbrecht et al. 2000).116Maltby 1986.117Long-term observations show height losses of upto 4 metres in 130 years, c.f. Hutchinson 1980,Eggelsmann 1990.118“Teufelskreis der Moornutzung”, c.f. Kuntze 1982.119Gravity drainage becomes increasingly difficultas the water level difference with the maindrainage canal (river, sea) becomes smaller. When