Vol. 75, No. 2: 157-163, 2006 ACTA SOCIETATIS BOTANICORUM POLONIAE 157 NON-DESTRUCTIVE METHODS FOR PEAT LAYER ASSESSMENT IN OLIGOTROPHIC PEAT BOGS: A CASE STUDY FROM POIANA ªTAMPEI, ROMANIA IULIANA FLORENTINA GHEORGHE1, CRISTINA-MARIA VÂLCU2, ION BARBU3, SORANA ÞOPA4 1 Department of Systems Ecology, University of Bucharest Splaiul Independenþei 91-95, 76201 Bucureºti, Romania 2 Department of Forest Genetics, Technical University of Munich Am Hochanger 13, 85354 Freising, Germany e-mail: [email protected] 3 Research Station for Norway Spruce Sylviculture Câmpulung Moldovenesc Calea Bucovinei 73 bis, Câmpulung Moldovenesc Ro-5950, Romania 4 Petroleum and Gas University of Ploieºti, Environmental Engineering Department B-dul Bucureºti 39, Ploieºti, Romania (Received: July 16, 2005. Accepted: September 28, 2005) ABSTRACT Practices currently employed in the investigation and characterisation of peat deposits are destructive and may irremediable perturb peat bog development even in cases when exploitation is not carried out. We investigated the correlation between vegetation characteristics in the active area of Poiana ªtampei peat bog, Romania, and the underlying peat layer depth, aiming at establishing a non-destructive method of peat layer depth estimation. The presence of the Sphagneto-Eriophoretum vaginati association, dominated by Sphagnum fimbriatum, Eriophorum vaginatum, Andromeda polifolia, Vaccinium oxycoccos, V. myrtillus, V. vitis-idaea, Polytrichum commune, Picea excelsa, Pinus sylvestris and Betula verrucosa was found to predict the existence of the peat layer but not its depth. Out of the seven identified vegetation types, one type was associated with a very thin or no peat layer, one type was characterised by the presence of a thick (over 100 cm) peat layer and five types indicated the presence of variable average depths of the peat layer. pH values correlated with peat layer depth only within the vegetation type associated with thick peat layers. KEY WORDS: classification system, plant community, similarity, Sphagnum fimbriatum. INTRODUCTION Designing sustainable exploitation strategies of peat de- posits depends on the availability of consistent data on qu- Peat bogs are complex ecosystems formed during long antity and quality of the peat deposit. Classical methods term interactions of multiple factors such as topographical, used for this type of investigations involve probing the pe- hydrological and vegetation related factors. at layer. The unavoidable associated risk of such destructi- Excess of humidity is a prerequisite of peat bog genesis ve techniques is the perforation of the impermeable foun- and maintenance, since it greatly influences vegetation dation of the peat bog and the consequent drainage and di- structure as well as peat accumulation and decay. Therefo- sturbance of the peat genesis processes. re, any decline of humidity conditions caused by draining The present study aims at establishing a non-destructive will eventually disturb the bogs equilibrium. Changes in method for the assessment of peat layer depth, based on land use practices of the peat bog or of the catchment area the correlation between vegetation characteristics and the can also result in serious alterations of the vegetation struc- underlying substrate. Conditioning of vegetation patterns ture (Chapman 1991). by stratigraphy and hydrological factors was already inve- 158 NON-DESTRUCTIVE METHODS FOR PEAT LAYER ASSESSMENT Gheorghe I.F. et al. stigated in several studies (Heinselman 1970; Comas cm depth, where the anoxia and acidity strongly limit the 2004), but no such non-invasive method has been reported development of bacterial flora and the intensity of decom- so far, to our knowledge. position processes. The peat environment offers optimal Poiana ªtampei (47°20N, 25°15E) is an oligotrophic conditions for the preservation of spores, pollen and seeds, peat bog formed through the paludification of a spruce fo- storing thus valuable information allowing for the inferen- rest situated on flat terrain with an impermeable clay layer ce of evolutionary scenarios (Glebov 2002). covering the underlying rock. It is one on the largest peat Hence, the development of non-destructive methods for bogs in Romania and part of a scientific reserve. The peat layer depth estimation is of great importance for the marsh forming was conditioned by the local climatic con- preservation of peat bogs. ditions (excessive humidity caused by prolonged heavy ra- in periods) and topologic factors (the area is situated on the terrace of two rivers, at the confluence of Dorna and Dorni- MATERIAL AND METHODS ºoara; its foundation lies above the rivers level). The gene- sis of the peat bog is confirmed by presence of a trunk lay- The field study was performed in August 2003, as part of er at the foundation of the peat deposit (Pop 1960). a more complex analysis of the peat bog. We investigated The peat bog is situated at 910 m altitude, is elliptically the vegetation structure (including identification of plant shaped and occupies 612 ha, 400 ha of which represent its species, classification in vegetation types and associations, active area (Pop 1960). Early studies of the peat deposit vegetation mapping) and also, the existence of correlations (Pop 1950, 1960) revealed its three layered structure: a few between vegetation structure and peat layer depth. meters deep sedge peat covered by 1.5-2 m of old Spha- The study was concentrated on the peat bogs active gnum peat and 2-4 m of new Sphagnum peat. area, which was divided in 86 plots (10 000 m2 each). The The main vegetation association in the peat bog is Spha- peat layer depth was measured in the centre of each plot. gneto-Eriophoretum vaginati, defined by: Sphagnum me- pH, organic substance and the oxygen dissolved in the in- dium, S. fuscus, S. fimbriatum, Eriophorum vaginatum, Em- terstitial water were also determined for each plot. petrum nigrum, Andromeda polifolia, Vaccinium oxycoc- Vegetation types were identified by cluster analyses ba- cos, V. myrtillus, V. vitis-idaea, Polytrichum commune, sed on the species composition of the plots using Jac- Picea excelsa, Pinus sylvestris, Betula pubescens, B. verru- cards coefficient as binary similarity measure and UPGMA cosa (Pop 1960). as clustering algorithm. After assigning the vegetation type Understanding peat bog genesis and evolution is a prere- to each plot, the vegetation and the peat layer depth were quisite for ecological reconstruction of deteriorated peat mapped. bogs (Janssens 1983). The efficiency of peat bogs as infor- To test for differences in the peat layer depth underneath mation storage environment regarding ecological succes- the seven vegetation types, we used a linear model with pe- sion and in situ preservation environment for glacial relicts at layer thickness as dependent variable and vegetation ty- adds to their economic value (Nastac 1973). The extreme pe as predictor while controlling in the full model for phisi- environmental conditions (extreme low pH between 4 and co-chemical parameters (pH, dissolved oxygen and organic 5.2, anoxia and oligotrophy) created by the water over sa- substance). We used single degree of freedom comparisons turation of the Sphagnum layer allowed for a rather redu- (i.e. treatment contrasts, Crawley 2002) to look for diffe- ced and very characteristic vascular flora. These same con- rences among vegetation types. Model simplification was ditions ensured good conservation of detritus below few performed according to Crawley (Crawley 2002). In the 35 PVM 34 91 89 77 90 79 62 27 59 58 26 67 EVM 61 60 96 95 97 SE 86 70 69 45 43 87 78 74 71 SEVI 47 73 72 57 56 55 54 51 50 49 48 46 44 33 32 31 30 29 28 25 24 23 22 21 20 19 92 88 RIC 85 80 41 94 ZUT 37 36 18 16 17 MIXT 15 99 98 52 93 83 82 76 84 75 81 68 65 64 66 63 53 42 40 39 38 14 Fig. 1. Identification of vegetation types by 0.04 0.2 0.36 0.52 0.68 0.84 1 cluster analyses based on the species compo- Jaccards Coefficient sition of the plots. Vol. 75, No. 2: 157-163, 2006 ACTA SOCIETATIS BOTANICORUM POLONIAE 159 TABLE 1. Species composition of the seven vegetation types identified in Poiana ªtampei peat bog. Vegetation type Species MIXT ZUT SE PVM SEVI RIC EVM Tree layer Alnus incana + Betula humilis + Picea excelsa + + + + Pinus sylvestris + + Shrub layer Spirea chamaedryfolia L. + + Viburnum opulus L. + Herbaceous layer Cryptogams Cl. Dicotyledoneae Fam. Asteraceae (Compositae) Aster alpinus L. + Bellis perennis L. + Centaurea kotschyana Heuffel + Cirsium canum L. + Cirsium oleraceum (L.) Scop. + + + Hieracium pilosella L. + + Inula britannica L. + + Senecio nemorensis L. + + + Fam. Boraginaceae Lithospermum officinale L. + Myosotis silvatica (Ehrh.) Hoffm. + + + Symphytum cordatum Waldst. et Kit. + Fam. Caryophyllaceae Stellaria palustris Retz. + Fam. Campanulaceae Campanula abientina Griseb.et Sch. + Campanula glomerata L. + Campanula patula L. + Fam. Droseraceae Drosera rotundifolia L. Fam. Ericaceae Andromeda polifolia L. + Vaccinium myrtillus L. + + + + + + + Vaccinium oxycoccos L. + + Vaccinium vitis-idaea L. + + + + Fam. Hypericaceae Hypericum perforatum L. + + + Fam. Labiatae Galeopsis speciosa Mill. + + Mentha longifolia L. + Prunella vulgaris L. + Fam. Onagraceae Circaea lutetiana L. + Epilobium alpinum L. + + + + Epilobium nutans F.W. Schmidt + Fam. Oxalidaceae Oxalis acetosella L.