TROPICS Vol. 16 (1) Issued January 31, 2007

Nutritional ecology of grown in a tropical peat swamp

1) 2) 3) 1) 1,4) Monrawee YANBUABAN , Tanit NUYIM , Takeshi MATSUBARA , Toshihiro WATANABE and Mitsuru OSAKI

1) Research Faculty of Agriculture, Hokkaido University, Sapporo, 060−8589, Japan 2) Princess Sirindhorn Peat Swamp Forest Research and Nature Study Center Narathiwat, 96120, 3) College of Cross-Cultural Communication and Business, Shukutoku University, Japan 4) Corresponding author

ABSTRACT The relationships between and peatland (45, 264 ha), however 60% of the peatland soil in peat swamp forests in two different growth in Thailand is found in Narathiwat Province (Suzuki stages, primary and secondary, were examined and Niyomdham, 1992). Floristic composition of peat by analyzing nutritional characteristics (e.g. N, P, swamp forest is rich, consisting of 124 families and 470 K, Ca, Mg, Na, Fe, Mn, Zn, Cu, Mo, Al, B, and of plants, of which 109 families and 437 species 15 Si concentrations) and natural abundances of N are flowering plants, and 15 families and 33 species of 15 13 13 (δ N) and C (δ C) of plant and soils. Fifty-two fern. Yoshioka et al. (2002) reported that most of the plant species from primary forests and thirty from To Daeng swamp area is a primary swamp forest. Peat secondary forests were randomly sampled. Plants swamp forests in Narathiwat Province are classified as in both forests belonged to the phylogenic groups four types: typical mixed swamp forest on thick peat Euasterids II, Euasterids I, , Eurosids II, layer, Macaranga-dominated swamp on thick peat layer, Eurosids I, , and , which were Melaleuca-dominated forest on thin peat layer or sandy from a newly evolved order. The results showed that soils, and Fagraea-dominated forest on sandy soil with a Eurosids I plants in primary forests accumulated thin peat layer (Suzuki and Niyomdham, 1992). Primary higher P, K, Mg, Fe, and B than those in secondary forests are dominated by Syzygium pyrifolium, Ganua forests. motleyana, Campnossperma coriaceum, Macaranga Other minerals did not limit plant growth at pruinosa, Calophyllum teysmannii, Neesia malayana, either forest type. For Eurosids I plants nutrients Endiandra macrophylla, Syzygium obatum, Sterculia depended on soil K, Mg, and Fe, but for P and B bicolour, Stermonurus secumdiflorus, Syzygium muelleri, they relied on their own nutrient acquisition. This and Baccaurea bracteata (Bunyavajchewin, 1995). Former is similar to other plant phylogenies in both forests destructive anthropogenic use of the peatlands caused the whose nutrient contents reflected their own nutrient disappearance of peat swamp forest, leading to peat soil requirements rather than soil nutrients. Since the degradation and forest type changes or transformation to 15 leaf δ N of plants in both forests is lower than grassland ecosystem (Nagano et al. 1996). 15 soil δ N, N2−fixing microorganism activity may Peat soil is characterized as a nutrient-poor be high. It can be hypothesized that peat swamp ecosystem with very high acidity and loads of organic forests have developed symbiotic systems with N2− matter e.g. lignin (Safford and Maltby, 1998; Paavilaine fixing microorganisms, because of poor N nutrition. and Päivänen, 1995). To Daeng peat swamp is fed by rainfall and by river run-off from mountainous areas in Key words: peat soil, plant phylogeny, primary the west. Ueda et al. (2000) reported that this swamp forest, secondary forest water has low pH, nutrient levels and very low levels of anions and cations in the surface water, even lower than in the ground water. This kind of nutrient-limited INTRODUCTION soil retards plant growth. Therefore, plants growing on The largest areas of peatland in the world are located peat soil must develop some specific mechanisms, such in the Southeast Asian coastal areas along peninsula as organic acid exudation from roots, to accumulate and Indonesian Java, , and . nutrients (Osaki et al. 2003, 1998a, and 1998b, Tuah, Thailand is a country that contains a small area of tropical 2003). In general, plant species that grow and dominate 32 Monrawee YANBUABAN, Tanit NUYIM, Takeshi MATSUBARA, Toshihiro WATANABE and Mitsuru OSAKI in an ecosystem are affected by various environmental parameters, so differences in plant physiology, e.g. seed Soil sampling and analysis germination, relative growth rate, and competition with Soil samples were collected from several points at each other plant species, can also express the changes in the forest type at three depths (0−20, 20−40 and 40−60 environmental development of an ecosystem (Berendse, cm), air-dried and ground prior to chemical analysis. 1990). Soils were analyzed for N content using an MT−6 CHN 15 13 Recently, natural abundances of stable isotopes CORDER (YANAKO). The δ N and δ C were analysed plus N ( δ 15N) and C ( δ 13C) are being used widely in using an isotope mass spectrometer (EA1110-DELTA research on N and C assimilation cycling in organisms Advantage ConFloIII System). Two grams of soil were , and ecosystems (Robinson, 2001; O Lear y, 1981). shaken for 2 hrs, extracted with 1 N HCl and filtrated Measurements of whole plants are inadequate because through Whatman no 42 filtrate paper. Concentrations of , they don t address seasonal life stage differences and P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, Mo, Al, B, and Si in the are limited by time or sample size. Therefore, the extract were determined using ICPS-7000. relative abundance of isotopic assay, which integrates physiological processes over larger temporal and spatial Data analysis scales, is required (Nilsen and Orcutt, 1996). Nitrogen The general tendency of plant mineral element dynamics are fundamental in natural ecosystems and accumulation was explained and comparisons between essential for all plants. However, N cycling in plant and plant phylogenies were made. Phylogenetic classification soil is complex. This study, therefore, aims to highlight was categorized by referring to the orders and families of some aspects of N cycling and other physiological angiosperms and gymnosperms. This classification can mechanisms of plants growing in two growth stages of be accessed at http://biodiverisy.uno.edu.delta. Mineral peat swamp forest. concentration means were compared with a t-test using SPSS 10.0

MATERIALS AND METHODS Study site RESULTS This study was conducted in peat swamp forests of To Vegetation Daeng Peat Swamp Forest, Narathiwat Province Thailand. Fifty-two plant species in primary forests and thirty in This site comprises of primary and secondary forests. secondary forests were observed. These plants were Primary forest is at a climax stage and undisturbed, in classified into 7 phylogenic groups: Ericales, Euasterids contrast to secondary forest, which is dominated by native I, Euasterids II, Eudicots, Eurosids I, Eurosids II, and and those that grow quickly after deforestation by Magnoliids. humans or a natural disaster. Primary forest comprised of Ardisia lanceolata, lanceifolia, Dispyros siamang, and Ganua Plant sampling, preparation, and analysis motleyana for Ericales, Ochreinauclea maingayi, Ixora Mature leaves were randomly sampled from primary and grandifolia, Tarenna wallichii, and Euodia roxburghiana secondary forests. Samples were oven-dried at 80 ˚C to for Euasterids I, Stemonurus secundiflorus for Euasterids constant weight, ground into a fine powder, and weighed II, indica, Crudia caudata, Dialium patens, for subsequent chemical analysis. Archidendron clypearia, Parastemon urophyllus, Baccaurea bracteata, Blumeodendron kurzii, Macaranga griffithiana, Plant analysis Macaranga pruinosa, Garcinia bancana, Cartoxylum Samples were completely digested with a mixture of arborescens, Calophyllum teysmannii, Gynotroches

H2SO4 and H2O2 following Mizuno and Minami (1980). axillaries, griffithii, and Elaeocarpus Leaf N was analysed using a CN analyser (SUMIGRAPH macrocerus for Eurosids I, Neesia malayana, NC-1000). Concentrations of P, K, Ca, Mg, Na, Fe, Mn, Zn, pauciflora, Stercalia bicolour, Eugenia grandis, Eugenia Cu, Mo, Al, B, and Si were determined using inductively tumida, Eugenia spicata, Eugenia caudate, Eugenia coupled plasma emission spectrometry (ICPS-7000, cerasiformis, Eugenia operculata, Eugenia kunstleri, 15 13 SHIMADZU). Leaf δ N and δ C were analysed using Campnosperma coriaceum, Melanochyla bracteata, an isotope mass spectrometer (EA1108-ConfloII-delta-S Sandoricum beccarianum , rubiginosa, Chisocheton system). patens, Aglaia odoratissima, and Nephelium maingayi for Nutritional ecology of plants grown in a tropical peat swamp 33 4 4 . 7 5 . 8 4 . 5 . 3 5 . 1 7 . 5 Mo 11 . 3 12 . 9 11 . 5 11 . 4 12 . 0 13 . 3 12 . 3 11 . 5 12 . 5 12 . 4 13 . 6 10 . 6 11 . 9 12 . 4 11 . 7 13 . 0 13 . 4 13 . 2 11 . 2 13 . 0 13 . 2 12 . 5 13 . 7 13 . 0 12 . 1 12 . 8 12 . 4 11 . 9 13 . 4 12 . 4 11 . 8 12 . 4 13 . 9 11 . 7 13 . 9 11 . 6 12 . 8 13 . 5 11 . 9 14 . 1 12 . 8 12 . 4 12 . 2 12 . 4 13 . 4 8 B 0 . 0 . 3 6 . 2 0 . 0 . 0 . 4 . 2 5 . 0 . 4 . 8 6 . 7 1 . 0 . 1 . 5 8 . 4 2 . 4 . 9 9 . 6 3 . 4 0 . 5 . 8 0 . 0 . 2 . 5 0 . 7 . 5 5 . 9 3 . 7 0 . 1 . 8 5 . 0 2 . 4 0 . 1 0 . 7 . 3 2 . 0 0 . 1 41 . 3 13 . 2 16 . 5 13 . 6 26 . 7 10 . 9 30 . 5 21 . 1 63 . 8 11 . 8 14 . 8 17 . 1 52 . 6 30 . 1 Si 8 . 2 6 . 9 9 . 6 0 . 7 8 . 0 9 . 0 7 . 9 . 3 8 . 5 7 . 5 8 . 3 7 . 2 9 . 1 8 . 6 9 . 9 . 27 . 4 11 . 1 19 . 6 25 . 5 22 . 1 16 . 3 46 . 0 15 . 1 18 . 9 55 . 2 16 . 8 12 . 9 31 . 8 22 . 6 28 . 6 21 . 2 10 . 4 29 . 3 18 . 2 12 . 8 14 . 6 15 . 5 29 . 8 14 . 5 11 . 3 19 . 6 10 . 3 18 . 8 20 . 0 11 . 2 11 . 0 11 . 5 11 . 5 15 . 8 18 . 2 136 . 9 8 . 9 8 . 9 354 338 585 382 120 109 172 106 448 579 118 377 354 113 212 283 234 245 299 127 Mn 77 . 3 14 . 2 11 . 8 17 . 4 27 . 7 35 . 7 83 . 3 18 . 3 52 . 2 29 . 4 12 . 9 25 . 4 43 . 2 37 . 3 71 . 1 12 . 0 16 . 9 17 . 5 11 . 5 35 . 1 13 . 5 15 . 8 18 . 3 25 . 6 90 . 4 11 . 7 16 . 2 29 . 9 84 . 6 2210 − 1 Zn 7 . 1 5 . 9 46 . 8 12 . 7 21 . 6 15 . 8 25 . 3 13 . 1 16 . 4 21 . 3 16 . 0 33 . 5 26 . 2 35 . 9 38 . 6 96 . 1 59 . 8 20 . 9 24 . 3 19 . 2 15 . 2 36 . 2 21 . 5 43 . 2 19 . 1 55 . 4 23 . 9 44 . 5 11 . 0 24 . 2 20 . 1 20 . 1 19 . 0 18 . 0 33 . 8 29 . 0 34 . 7 29 . 6 31 . 2 17 . 6 21 . 2 16 . 6 20 . 5 18 . 4 24 . 3 45 . 0 12 . 3 57 . 9 20 . 8 21 . 1 49 . 3 127 . 1 mg kg 4 . 8 0 . 9 5 . 6 3 . 6 0 . 4 0 . 4 . 7 . 1 4 . 4 . 2 0 . 0 . 8 6 . 0 . 9 0 . 3 . 8 2 . 6 2 . 6 3 . 2 5 . 9 2 . 1 0 . 7 . 3 4 . 7 6 . 5 0 . 0 . 5 . 8 7 . 0 7 . 8 3 . 0 8 . 0 3 . 4 5 . 7 4 . 1 7 . 4 4 . 2 6 . 5 9 . 3 3 . 5 0 . 5 . 0 6 . 2 4 . 5 4 . 2 . 5 4 . 1 7 . 3 4 . 2 7 . 6 Cu 10 . 7 17 . 6 Al 26 28 25 11 36 40 36 35 29 54 26 25 41 24 34 19 24 25 35 44 22 21 35 34 37 49 31 91 35 47 19 32 28 37 32 43 29 55 38 27 32 29 40 20 30 454 236 187 143 252 1112 1016 45 32 37 54 40 76 47 48 84 48 58 94 57 69 43 35 29 80 71 32 37 44 43 54 43 35 54 51 68 30 37 54 45 40 49 38 37 94 44 58 46 51 55 47 47 37 Fe 100 104 280 168 122 137 0 0 0 0 7 8 1 3 0 6 0 70 23 64 86 94 76 15 36 29 73 10 95 28 87 45 50 11 29 33 24 57 19 10 88 51 29 67 Na 153 191 121 200 208 169 121 392 140 236 172 119 159 103 2 . 1 . 2 3 . 0 . 6 0 . 5 1 . 2 1 . 9 1 . 2 . 9 1 . 7 1 . 4 1 . 8 1 . 5 1 . 8 5 . 0 2 . 6 0 . 9 1 . 0 1 . 6 0 . 4 0 . 3 1 . 5 1 . 5 0 . 5 0 . 5 0 . 6 0 . 9 0 . 8 1 . 0 0 . 4 1 . 6 1 . 0 0 . 7 1 . 3 1 . 0 0 . 9 0 . 7 1 . 6 1 . 6 . 5 1 . 3 1 . 0 . 9 0 . 3 0 . 6 0 . 9 0 . 6 0 . 4 1 . 2 1 . 5 0 . 8 1 . Mg N) of some native plants in a primary peat swamp forest 15 Ca 8 . 4 2 . 9 2 . 1 4 . 5 . 4 9 . 5 7 . 2 6 . 8 8 . 0 9 . 5 8 . 6 4 . 7 9 . 8 8 . 7 3 . 3 . 2 7 . 4 9 . 5 3 . 4 1 . 7 6 . 1 4 . 2 5 . 2 3 . 7 5 . 8 5 . 7 9 . 3 5 . 3 6 . 0 2 . 8 3 . 0 7 . 5 9 . 6 6 . 4 5 . 0 2 . 7 5 . 1 6 . 5 5 . 3 9 . 2 2 . 5 6 . 6 . 1 12 . 8 10 . 3 17 . 9 10 . 7 36 . 5 11 . 8 10 . 3 11 . 2 10 . 7 δ N ( 15 K 9 . 6 1 . 4 8 . 0 5 . 0 3 . 8 9 . 2 7 . 9 4 . 6 3 . 5 7 . 9 7 . 0 8 . 4 . 6 5 . 2 3 . 4 . 9 5 . 8 2 . 8 3 . 1 6 . 4 4 . 5 4 . 2 1 . 2 2 . 5 5 . 1 2 . 6 . 0 2 . 9 6 . 3 . 5 6 . 5 8 . 6 4 . 3 6 . 3 6 . 5 3 . 9 4 . 1 3 . 6 5 . 7 5 . 3 4 . 5 8 . 2 4 . 7 3 . 5 8 . 2 5 . 0 3 . 9 6 . 5 27 . 2 10 . 0 20 . 0 10 . 5 − 1 g kg P 0 . 5 0 . 1 0 . 3 0 . 1 0 . 4 0 . 3 0 . 3 0 . 4 0 . 2 0 . 4 0 . 8 0 . 3 0 . 4 0 . 3 1 . 0 . 6 0 . 4 0 . 4 0 . 1 0 . 1 0 . 1 0 . 2 0 . 6 0 . 4 0 . 4 0 . 3 0 . 5 0 . 5 0 . 5 0 . 1 0 . 3 0 . 2 0 . 3 0 . 4 0 . 3 0 . 7 0 . 2 0 . 2 0 . 5 0 . 8 0 . 2 0 . 4 0 . 2 0 . 2 0 . 7 0 . 5 0 . 2 0 . 3 0 . 3 0 . 3 0 . 3 0 . 3 C) and 13 δ N 9 . 6 9 . 7 14 . 4 11 . 2 11 . 5 12 . 4 16 . 9 15 . 8 25 . 6 11 . 5 14 . 3 18 . 9 10 . 9 26 . 4 10 . 2 13 . 4 14 . 8 19 . 2 14 . 9 11 . 6 11 . 6 17 . 4 17 . 5 19 . 1 17 . 0 14 . 9 24 . 4 11 . 3 17 . 9 11 . 1 14 . 1 17 . 9 13 . 6 12 . 4 11 . 7 11 . 4 13 . 9 12 . 5 21 . 6 18 . 6 11 . 9 16 . 3 12 . 3 12 . 5 13 . 4 16 . 4 12 . 0 24 . 0 15 . 5 13 . 1 15 . 7 16 . 8 C ( 13 C 363 368 313 333 354 346 320 330 337 340 357 333 347 323 309 350 336 342 328 355 356 322 341 338 341 359 344 364 356 358 338 341 338 355 334 358 321 342 362 320 362 359 347 363 349 365 361 372 359 334 340 368 N 15 3 0 0 0 4 2 0 2 1 0 2 1 0 2 3 0 4 0 1 1 0 4 0 0 1 2 0 1 0 4 0 3 1 0 0 ‰ − 2 − 1 − 1 − 3 − 1 − 1 − 2 − 1 − 1 − 1 − 1 − 1 − 2 − 2 − 3 − 2 − 1 δ C 13 ‰ − 34 − 33 − 32 − 34 − 30 − 33 − 35 − 34 − 34 − 33 − 33 − 34 − 34 − 32 − 32 − 32 − 32 − 29 − 32 − 33 − 32 − 33 − 33 − 32 − 31 − 33 − 33 − 33 − 34 − 32 − 33 − 32 − 32 − 33 − 34 − 33 − 34 − 33 − 32 − 35 − 35 − 33 − 34 − 34 − 34 − 34 − 33 − 35 − 34 − 35 − 32 − 33 δ Species Diospyros lanceifolia Dispyros siamang Ardisia lanceolata Ganua motleyana Ochreinauclea maingayi Ixora grandifolia wallichii Tarenna Euodia roxburghiana Stemonurus secundiflorus Bhesa indica Crudia caudata Dialium patens Archidendron clypearia Parsatemon urophyllus Baccaurea bracteata Blumeodendron kurzii Macaranga griffithiana Macaranga pruinosa Garcinia bancana Cartoxylum arborescens Calophyllum teysmannii Gynotroches axillaris Elaeocarpus griffithii Elaeocarpus macrocerus Neesia malayana pauciflora Vatica Stercalia bicolor Eugenia grandis Eugenia tumida Eugenia spicata Eugenia caudata Eugenia cerasiformis Eugenia operculata Eugenia kunstleri Campnosperma coriaceum Melanochyla bracteata Sandoricum beccarianum Aglaia rubiginosa Chisocheton patens Aglaia odoratissima Nephelium maingayi Endiandra macrophylla Nothaphoebe coriacca Litsea costata Cinnamomum rhynchophllum Goniothalamus malayanus Polyalthia glauca Polyalthia lateriflora elliptica Horsfieldia crassifolia Horsfieldia irya Myristica iners Family Ebenaceae Myrsinaceae Sapotaceae Rubiaceae Rubiaceae Rutaceae Icacinaceae Celastraceae Leguminosae-Caesalpinioideae Leguminosae-Caesalpinioideae Leguminosae-Mimosoideae Euphorbiaceae Euphorbiaceae Euphorbiaceae Guttiferae Guttiferae Guttiferae Elaeocarpaceae Bombacaceae Sterculiaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Anacardiaceae Meliaceae Meliaceae Meliaceae Sapindaceae Lauraceae Lauraceae Lauraceae Annonaceae Annonaceae Annonaceae Myristicaceae Myristicaceae Myristicaceae Order Ericales Ericales Ericales Ericales Gentianales Gentianales Gentianales Icacinaceae Celastrales Fabales Fabales Malpighiales Malpighiales Malpighiales Malpighiales Malpighiales Malpighiales Malpighiales Malpighiales Oxalidales Malvales Malvales Myrtales Myrtales Myrtales Myrtales Myrtales Myrtales Myrtales Sapindales Sapindales Sapindales Sapindales Sapindales Sapindales Laurales Laurales Laurales Magnoliales Magnoliales Magnoliales Magnoliales Magnoliales Magnoliales Cladistic group Ericales Ericales Ericales Ericales Euasterids I Euasterids I Euasterids I Euasterids I Euasterids II Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids . Nutrient concentrations and natural abundances of stable isotope Table 1 . 34 Monrawee YANBUABAN, Tanit NUYIM, Takeshi MATSUBARA, Toshihiro WATANABE and Mitsuru OSAKI

Eurosids II, and Endiandra macrophylla, 9 . 9 . 7 9 . 0 Mo 10 . 5 14 . 4 14 . 5 15 . 2 12 . 7 14 . 7 13 . 0 10 . 5 13 . 6 13 . 2 15 . 2 12 . 9 12 . 0 16 . 3 13 . 0 14 . 0 14 . 2 12 . 9 10 . 5 16 . 3 16 . 1 15 . 4 13 . 7 14 . 5 13 . 8 15 . 6 16 . 0 Nothaphoebe coriacca, Litsea costata, Cinnamomum rhynchophllum, B 0 . 1 0 . 0 . 0 . 0 . 6 . 0 0 . 2 . 5 0 . 0 . 0 . 0 . 2 . 9 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . 0 . Goniothalamus malayanus, Polyalthia glauca, Polyalthia lateriflora, Myristica Si 9 . 2 . 6 8 . 3 2 . 4 3 . 6 8 . 2 5 . 6 5 . 4 . 6 3 . 8 4 . 7 4 . 0 6 . 1 6 . 3 183 98 . 8 20 . 9 32 . 0 55 . 0 10 . 8 50 . 4 33 . 7 23 . 6 10 . 6 11 . 7 10 . 7 25 . 3 18 . 2 28 . 9 13 . 9 elliptica, crassifolia, , and Myristica iners for 6 . 8 9 . 4 4 . 9 . 6 3 . 7 6 . 2 4 . 7 218 111 Mn 27 . 2 12 . 3 32 . 9 77 . 2 12 . 8 26 . 3 17 . 1 72 . 3 26 . 3 38 . 4 29 . 8 35 . 5 21 . 2 13 . 7 29 . 7 89 . 2 11 . 0 27 . 9 54 . 0 52 . 9 19 . 2 Magnoliids (Table 1). − 1 Zn 9 . 4 5 . 0 Secondary forest comprised 25 . 0 15 . 2 14 . 4 15 . 6 12 . 7 58 . 9 19 . 0 44 . 3 23 . 8 12 . 9 10 . 3 14 . 4 12 . 5 20 . 8 23 . 3 25 . 1 31 . 7 21 . 6 44 . 0 14 . 2 25 . 1 17 . 1 12 . 6 25 . 5 11 . 1 10 . 1 16 . 2 22 . 1 mg kg of Ganua motleyana, and Ardisia 6 . 0 6 . 8 5 . 9 2 . 6 9 . 5 . 6 9 . 6 7 . 1 4 . 7 6 . 7 3 . 6 5 . 3 3 . 2 5 . 6 5 . 8 5 . 1 4 . 9 4 . 7 6 . 9 8 . 9 2 . 6 0 . 3 . 5 2 . 7 3 . 2 4 . 4 . 5 5 . 8 6 . 1 Cu

10 . 1 lanceolata for Ericales, Alstonia spathulata, Fagraea fragrans, Al 37 30 25 72 37 25 30 20 19 35 29 29 24 25 45 59 28 24 39 11 29 17 30 61 27 42 22 108 279 3692 a n d Euodia roxburghiana f o r Euasterids I, Ilex cymosa, Stemonurus 34 31 35 44 85 44 43 61 18 36 36 19 36 53 44 35 31 61 58 38 34 38 15 23 15 31 22 30 32 26 Fe secundiflorus, and Bar ringtonia racemosa for Euasterids II, Helicia 0 0 0 0 5 0 9 79 91 25 10 29 16 59 52 48 71 50 Na 197 324 118 172 126 332 300 101 574 3789 1123 3078 excelsa for Eudicots, Dialium patens, Acacia mangium, 1 . 3 0 . 3 1 . 2 0 . 8 0 . 7 0 . 8 1 . 0 0 . 5 0 . 4 0 . 3 0 . 4 0 . 0 . 8 1 . 4 0 . 6 0 . 3 0 . 9 0 . 8 1 . 0 0 . 8 0 . 4 0 . 3 0 . 4 0 . 4 0 . 3 0 . 4 0 . 1 0 . 5 0 . 8 0 . 7 Mg

N) of some native plants in a secondary peat swamp forest ellipticum, Macaranga griffithiana, 15

δ Baccaurea bracteata, Macaranga Ca 7 . 8 2 . 7 . 0 4 . 5 3 . 5 . 9 6 . 7 3 . 7 1 . 3 1 . 3 3 . 7 4 . 3 3 . 8 3 . 4 5 . 2 4 . 7 5 . 4 . 9 2 . 3 2 . 0 4 . 3 3 . 0 1 . 6 4 . 0 3 . 0 3 . 9 5 . 7 4 . 8 16 . 0 12 . 7

N ( pruinosa, and arborescens 15 for Eurosids I, Sterculia bicolor, K 2 . 4 2 . 0 9 . 3 2 . 6 2 . 6 5 . 2 1 . 7 8 . 5 4 . 2 1 . 7 1 . 2 8 . 3 3 . 4 1 . 6 3 . 8 2 . 3 2 . 7 2 . 5 6 . 4 3 . 1 . 7 2 . 9 5 . 8 5 . 7 4 . 9 7 . 5 4 . 1 5 . 4 0 . 8 10 . 9

− 1 Eugenia oblata, Melaleuca cajuputi, g kg C) and

P Eugenia pseudosubtilis, Eugenia 0 . 1 0 . 1 0 . 5 0 . 1 0 . 3 0 . 1 0 . 0 . 2 0 . 4 0 . 2 0 . 1 0 . 2 0 . 2 0 . 1 0 . 2 0 . 2 0 . 6 0 . 2 0 . 1 0 . 2 0 . 1 0 . 1 0 . 1 0 . 1 0 . 2 0 . 1 0 . 1 0 . 1 0 . 2 0 . 3 13

δ spicata, Campnosperma coriaceum, C ( N

9 . 7 9 . 4 7 . 5 9 . Aglaia rubiginosa, and Sandoricum 11 . 7 12 . 8 15 . 6 14 . 5 17 . 6 11 . 3 10 . 1 18 . 8 18 . 0 10 . 5 17 . 4 22 . 6 14 . 2 10 . 0 11 . 8 12 . 2 17 . 8 10 . 7 16 . 8 10 . 1 10 . 7 14 . 5 11 . 7 14 . 3 11 . 2 10 . 1 13 beccarianum for Eurosids II, and C

343 359 360 351 355 357 347 358 302 360 378 355 328 317 352 361 350 361 360 365 355 348 349 379 355 358 376 375 352 350 Cinnamomum rhynchophyllum, Litsea costata, Polyalthia lateriflora, Horsfieldia ‰ 3 . 7 3 . 2 1 . 2 . 3 2 . 8 0 . 7 2 . 7 1 . 4 1 . 9 1 . 2 2 . 3 0 . 3 . 9 0 . 0 . 3 3 . 8 3 . 8 4 . 1 2 . 5 2 . 5 − 0 . 1 − 1 . 6 − 2 . 1 − 0 . 2 − 5 . 1 − 3 . 4 − 3 . 9 − 3 . 8 − 4 . 0 − 0 . 6 crassifolia, and Horsfieldia irya for d 15 N Magnoliids (Table 2). ‰ − 31 . 9 − 31 . 0 − 31 . 5 − 28 . 2 − 29 . 7 − 31 . 8 − 28 . 7 − 28 . 7 − 29 . 8 − 28 . 9 − 30 . 8 − 30 . 2 − 28 . 6 − 29 . 7 − 29 . 0 − 30 . 4 − 29 . 6 − 31 . 4 − 31 . 0 − 30 . 8 − 30 . 0 − 31 . 0 − 29 . 5 − 30 . 1 − 29 . 9 − 32 . 2 − 31 . 9 − 29 . 6 − 30 . 3 − 28 . 4 d 13 C Nutritional characteristics Plant Concentrations of P, K, Mg, Fe, and B in leaves of Eurosids I, and K and Fe in Magnoliids were significantly higher

Species Ardisia lanceolata Ganua motleyana Alstonia spathulata Fagraea fragrans Euodia roxburghiana Ilex cymosa Stemonurus secundiflorus Barringtonia racemosa Helicia excelsa Dialium patens Acacia mangium Xanthophyllum ellipticum Macaranga griffithiana Baccaurea bracteata Macaranga pruinosa Cratoxylum arborescens Sterculia bicolor Eugenia oblata Eugenia kunstleri Melaleuca cajuputi Eugenia pseudosubtilis Eugenia spicata Campnosperma coriaceum Aglaia rubiginosa Sandoricum beccarianum Cinnamomum rhynchophyllum Litsea costata Polyalthia lateriflora Horsfieldia crassifolia Horsfieldia irya in the primary forests than those in the secondary forests (Figs. 1, 2, and 3). Molybdenum concentrations in leaves of Eurosids I in the secondary forest were significant higher than in the primary forests. However,

Family Myrsinaceae Sapotaceae Apocynaceae Gentianaceae Rutaceae Aquifoliaceae Icacinaceae Lecythidaceae Proteaceae Leguminosae-Caesalpinioideae Leguminosae-Mimosoideae Xanthophyllaceae Euphorbiaceae Euphorbiaceae Euphorbiaceae Guttiferae Sterculiaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Myrtaceae Anacardiaceae Meliaceae Meliaceae Lauraceae Lauraceae Annonaceae Myristicaceae Myristicaceae other mineral concentrations were not significantly different among phylogenic groups and between forest

Order Ericales Ericales Gentianales Gentianales Gentianales Aquifoliales Icacinaceae Lecythidales Proteales Fabales Fabales Fabales Malpighiales Malpighiales Malpighiales Malpighiales Malvales Myrtales Myrtales Myrtales Myrtales Myrtales Sapindales Sapindales Sapindales Laurales Laurales Magnoliales Magnoliales Magnoliales types. In general, concentrations of N, P, Ca, Mg, Fe, Al, Mn, Si, and B in leaves tended to be higher in the primary Cladistic group Ericales Ericales Euasterids I Euasterids I Euasterids I Euasterids II Euasterids II Euasterids II Eudicots Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids I Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Eurosids II Magnoliids Magnoliids Magnoliids Magnoliids Magnoliids

. Nutrient concentrations and natural abundances of stable isotope Table 2 . forests than in the secondary forests, Nutritional ecology of plants grown in a tropical peat swamp 35

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Fig. 1. Concentrations of N, P, K, Ca, Mg (g kg−1), and Na (mg kg−1) in leaves of plants grown in primary and secondary forests. Bars in figure indicate SE. ＊ indicates significant differences at 5% level by t-test.

while concentrations of Na, Cu, Zn, and Mo tended to be higher in the secondary forests (Figs. 1, 2, and 3). δ15N and δ13C values in plants and soils This comparison does not include Eudicots (n=1) and Plant 15 13 Euasterids II (n=1) plants of the primary forests and Average leaf δ N and δ C in the primary forests Ericales (n=2) of the secondary forests, because sample were 0.9 and −33.3 ‰ for Ericales, 1.1 and −33.1 ‰ for sizes were small. Euasterids I, 1.9 and −34.0 ‰ for Euasterids II, 0.5 and −32.4 ‰ for Eurosids I, −0.1 and −33.0 ‰ for Eurosids II, Soil and 0.4 and −33.6 ‰ for Magnoliids, respectively (Table 15 13 Concentrations of N, K, Ca, Mg, Na, Fe, Zn, and Mn 1 and Fig. 4). Average leaf δ N and δ C in secondary seemed to be higher in primary forest soil than secondary forests were 1.8 and −31.4 ‰ for Ericales, 0.2 and −30.3 forest soil, while concentrations of P, Cu, and Si were not ‰ for Euasterids I, 1.0 and −29.7 ‰ for Euasterids II, 0.7 different. Concentrations of Al were higher in secondary and −29.8 ‰ for Eudicots, −1.0 and −29.7 for Eurosids I, forest soil (Table 3). 2.1 and −30.4 ‰ for Eurosids II, and −0.7 and −30.5 ‰ for 36 Monrawee YANBUABAN, Tanit NUYIM, Takeshi MATSUBARA, Toshihiro WATANABE and Mitsuru OSAKI

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Fig. 2. Concentrations of Fe, Al, Cu, Zn and Mn (mg kg−1) in leaves of plants grown in primar y and secondary forests. Bars in figure indicate SE. ＊ indicates significant differences at 5% level by t-test.

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Fig. 3. Concentrations of Fe, Al, Cu, Zn and Mn (mg kg−1) in leaves of plants grown in primar y and secondary forests. Bars in figure indicate SE. ＊ indicates significant differences at 5% level by t-test. Nutritional ecology of plants grown in a tropical peat swamp 37

Table 3. Soil chemical properties in primary and secondary forests Depth N P K Ca Mg Na Fe Al Cu Zn Mn Si B Mo Origin −1 −1 −1 −1 (cm) g kg mg kg g kg mg kg Primary forest 0−20 18.1 54.2 0.39 1.67 0.49 1.17 11440 1946 21.1 13.3 710 23.1 6.3 4.3 20−40 16.8 28.5 0.24 1.40 0.41 1.16 7235 1999 8.6 9.5 568 14.2 6.8 5.4 40−60 12.7 22.9 0.16 n.d. 0.28 0.17 5548 2174 18.9 6.9 412 12.8 6.5 5.3 Secondary forest 0−20 11.5 55.6 0.04 0.67 0.18 0.38 3575 3712 6.6 1.9 111 22.0 6.3 9.8 20−40 6.8 44.4 0.07 0.44 0.13 0.06 3648 4315 27.9 3.0 85 47.9 6.4 8.8 40−60 8.2 37.1 n.d. 0.39 0.15 n.d. 6192 4666 14.9 1.9 83 32.0 6.4 8.9

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Fig. 4. Natural abundances of stable isotope 15N (δ15N) and 13C (δ13C) in leaves of plants grown in primary and secondary forests. Bars in figure indicate SE.

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Fig. 5. Natural abundances of stable isotope 15N (δ15N) and 13C (δ13C) in soils of primary and secondary forests 38 Monrawee YANBUABAN, Tanit NUYIM, Takeshi MATSUBARA, Toshihiro WATANABE and Mitsuru OSAKI

15 15 Magnoliids, respectively (Table 2 and Fig. 4). the small deviation of δ N from 0 ‰ ( δ N of air) 15 in bulk in tissues of vascular plants ( δ N c.a. ± 2 ‰ Soil relative to air) is attributed to enzymic transformations 15 Soil δ N at 0−20, 20−40, and 40−60 cm depths were of N within plants (Yoneyama, 1995). However, leaf 15 3.05, 3.72, and 4.32 ‰ in primary forests, and, 3.17, 3.51, δ N in secondary forests was more specific to the 13 , 2.85 ‰ in secondary forests, respectively. Soil δ C at plant s phylogenic group than that in primary forests, 0−20, 20−40, and 40−60 cm depths were −30.1, −30.0, and indicating that plants in secondary forests had specific −30.1 ‰ in primary forests, and, −29.9, −29.5, and −29.7 ‰ access to N sources. Other researchers have also in secondary forests, respectively (Fig. 5). reported that plant phylogeny has a strongly effect on N acquisition from soil (Högberg, 1997). Robinson 15 (2001) demonstrated that precipitation ( δ N is c.a. DISCUSSION −5 ‰) seemed to be a major N source for plants grown Plant nutritional characteristics in an area where the annual rainfall is over 1,400 mm. In some phylogenetic groups, such as Eurosids I or However, in this study, plants showed the possibility of 15 Magnoliids, differences in the status of some nutrients obtaining N from N2 fixation symbioses ( δ N ranged in plants between primary and secondary forests from −1.0 to 2.1‰), rather than N from precipitation. 15 corresponded to that in soils (Figs. 1, 2, and 3; Table Conclusively, soil δ N ranged from 3.05 to 4.32 3). In many cases, however, the differences in the soil ‰ in primary forests and 2.85 to 3.51 ‰ in secondary 15 nutrient status between two forest types did not affect the forests. However, δ N in leaves were clearly lower than concentrations of these nutrients in the plants, suggesting 2.8 ‰ in both forests. Therefore, it is hypothesized that that plant species growing in a tropical peat swamp have a part of N acquisition in peat swamp forests is derived

mechanisms to acquire nutrients, even under nutrient- form symbiotic systems with N2-fixing microorganisms. limited conditions. Plant phylogeny strongly controlled plant N acquisition from soil, and this phenomenon could be observed δ13C in leaves and soils more clearly in secondary succession forests than in 13 Plants had leaf δ C values between −32.4 and −34.0 ‰ undisturbed, primary forests. in primary forests, and −29.7 and −31.4 ‰ in secondary

forests, indicating that all plant species are C3 plants, ACKNOWLEDGEMENTS We would like to thank according to Nilsen and Orcutt (1996) who reported that all the officers at Pikulthong Silvicultural Research 13 the δ C values of C3 and C4 plants ranged between −20 to Station and Princess Sirindhorn Peat Swamp Forest −35 ‰ and −10 to −12 ‰, respectively. However, different Research and Nature Study Center, Narathiwat, Thailand, 13 leaf δ C values could also be attributed to water who kindly helped us for the duration of this research. availability (Van Nieuwstadt and Douglas, 2005). Since the To Daeng peat swamp is mostly permanently waterlogged (Yoshioka et al. 2002), there may be no difference in REFERENCES water conditions between the primary and secondary Berendse, F. 1990. Organic matter accumulation 13 forests. Therefore, higher leaf δ C in secondary forests and nitrogen mineralization during secondary may be a result of higher photosynthetic activity than in succession in heathland and ecosystems. Journal of primary forests, and light intensity seems to influence Ecology, 78: 413−427. 13 leaf δ C under no water stress conditions, especially, Bunyavajchewin, S. 1995. Canopy structure of Toe-Deng 13 vertical depression of leaf δ C (Matsubara et al. 2000). primary peat swamp forest at Narathiwat Province, Moreover, fast-growing plants grown in secondary forests Southern Thailand. Thai For. Bull. Bot., 23: 1−17. had more exposure to sunlight than plants grown in Matsubara, T., Boontanon, N., Ueda, S., Kanatharana, P. primary forests, where plant density is higher. & Wada, E. 2000. Nitrogen and carbon cycles of peat swamp forests and surrounding areas in Narathiwat, δ15N in leaves and soils Thailand, Inferred from δ13C and δ15N analyses. 15 Plants had leaf δ N values between −0.1 and 1.9 ‰ In Tropical peat land, p. 245−253. Proceedings of for primary forests, and −1.0 and 2.1 ‰ for secondary the international symposium on tropical peatlands, forests, indicating that plants in both forest types have Graduate school of Environmental Earth Science,

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