釧路泥炭地内の群落更行における残留種について

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(1)Title. 釧路泥炭地内の群落更行における残留種について. Author(s). 田中, 瑞穂. Citation. 北海道学芸大学紀要. 第二部. B, 生物学,地学,農学編, 13(1): 62-68. Issue Date. 1962-09. URL. http://s-ir.sap.hokkyodai.ac.jp/dspace/handle/123456789/5743. Rights. Hokkaido University of Education.

(2) Vol. 13 No. 1 Journal of Hokkaido Gakugei University Dec., 1962. On Resistant Species at the Successive Processes of. the Kushiro Lowland Fen Mizuho TANAKA Biological Laboratory, Hokkaicio Gakugei University, Kushiro. ES^^B : »-^*rt®I¥%M-?;fe9-^®a^-3v^ Introduction At the recent paper') the author reported the ecological characters of f en hummocks and tussocks which spread over the outer part of the comparatively dry fen in the Kushiro Moor, Eastern Hokkaido. He emphasized expressly there that those hummocks carried out a role of stepping stones for invading species from other grounds when the. fen proceeded to be dried naturally or artificially and the vegetation there also changed slowly in proportion to its degree. This report is a description on the life of conservative resistant survivers as Phragmites, Carex and others, remaining still in low and marshy grounds as hollows among hummocks. where lie at a hummock fen. Tatewaki (1942, 1943, 1944),2>-3>.-1) Tatewaki and Tsujii (1956)5) liave already described on the general hydrosere in the moor utilized chiefly for pasturage in North Japan and, moreover, Tatewaki (1928)6) on that of the Horomui Moor and Tanaka (1959)7) on that of the Kushiro Moor. Many of these past studies, however, were chiefly. practised with a view to utilize a fen, and it should be remembered that the vegetational sructnre of the lowland moor in Hokkaido is far from simple and plain compared with that of warmer districts in our country. Even a few changes of some environmental factors may drive and progress it to a direction for the transition moor, whereas resitant species are also abundant and variable, and their ecological studies will give an important suggestion in future for diagnosis and estimation of the ten when and how to utilize it.. Habitat The subject grounds and their extent that he practised field surveys are almost the same of that in the recent paper except the Hokuto region. According to the former report by lizuka (1954),8'1 the peat moss in this lowland moor is chiefly accumulations of Phragmites vulgaris, Carex Th.unbergii, Carex Augustinowiczii, Carex fedia var. Miyabei, Carex Oecleri var. viridula and some other Carex species, including Eqn.isefnm pulustre, and in some places Menyanthes trifoliata, Myrica Gale var. tomentosa, Alnus japonica var. argitta, Schenchzeria Palustris, Chamaedaphne calyculata, Oxycoccus vulgaris, and. Sphagnum sp. Nowadays a thickness of peat depsits differs fairly from spot areas in the fen from about fifty centimetres to more than two hundred centimetres, but these con-. - 62 -.

(3) Mizuho Tanaka. ditlons may be also understood by the following suggestion which Okazaki and Yokohira (1958)9^ have reported — that is, "This Kushiro Moor has tilted a little to the South-East extremity of the moor in recent ages." Accordingly, the present flat lowland has not been proceeded calmly and normally from a swampy marsh of the past, but has experienced many times those stages of the transition moor of which surface grounds were covered with Sphagnnm sp., Clwmaedaphne calyciilata, Care.x Middendorffii and more other species, peculiar to the Sphagnum moor. Headwaters of the Ninishibetsu and many branches of the Setsuri and, moreover, traces of old rivers are found here, too. In order to measure the water table in the subject area, he adopted a method of checking a position of the water table at each hole of about five centimetres in diameter which was digged twenty-four hours before, because the water table should be one of the most important factors in this study except the age of the stand. Results 1. Emerged or swampy species at submerged lowlands Though there is not a marsh in this subject area, there can be seen a large bog at the highland moor of Onnenai, three kilometres north of the Showa region. This is one of. the typical peat bogs in the whole moor, and near its brink, Typha lutifolia, Scirpus lac/isf.ris var. Tabernaeinontani and Equ.isetum limosum emerge at a central part, and Car ex rhynchophysa, Menyanthes trifoliata, and Potent t/la palu.stris at a shore side. Except this bog at Onnenai, the subject lowland which is almost hammock fen too is covered wholly with swampy grasses, but submerged parts in it have different extents according to the season. They are wide enough in spring chiefly because of the remaining of the freezing layer at about tvrenty-five centimetres under the ground even in late spring, then they are reduced slowly near summer, therefore those flooded areas in summer are very shallow and generally not beyond a depth of ten centimetres or so. Plant communities in the submerged portion are shown in Table 1 (A). On the whole, Phragmites vulgaris and Menyanthes trifoli.ata are most dominant, and Ccdtha sibti'ica var. membranacea, Carex lasiocarpa var. occultcms, Naumbtirgia thyrsi flora, Eqiusetuin palustre and Sphagnum sp. are secondly abundant. On the other hand, Sparganium stoloniferiim, Carex dispalata, Biclens radiata, Sium nipponici.im, Comurum palustre and Utricularis intermedir are rather occasional here. At Higashi-Kushiro and Hokuto, Carex Augustmowiczii shows a vigorous development as large hummocks and among them tiny ones can be seen also, but in this paper he omitted and left out a hammock community. 2. Resistant communities at a sedge f en As there have ever been a few main drains at the Showa and Aikoku regions since more than twenty years ago, and moreover many branches added to them for years, the water table has been generally lowered year by year and recently marginal grounds of the fen are so dry in summer even at hollows among hummocks and upheavals that he comes upon few difficulties to walk about, except after rainy diays. -63-.

(4) On Resistant Species at the Successive Processes of the Kushiro Lowland Pen. Distributions of the water table in the sampling plots at hollows, of course, fluctuate from about five centimetres to a hundred centimetres or so in depth. Two groups were conclusively set up here dividing at the thirty centimetres depth of the water table—one is moister for the higher water table and another is drier for the lower one. The sedge communities are shown in Table 1 (B, C). Table 1. Comparison of resistant communities based on the coverage (-, 1~4) and the frequency (I~V). (Tablel 1) Sh(. Sampling area Species. A|]. HigashiKushiro. Aikoku. w;. A. c. B. B. A. c. Hokuto I. A. B. I. Sparganiidii stolonifernm. I'm 2! m 1;D:1 2|1V| 2;V| 1 v 1 v 3;V 1 v 1 v 2; v 2 v 1 v liV| 1 v 1 v 1;IIT| i-: II i; m| +; I +;n 3:1V| +;I +:II 1 :Jlll. Carex sfipata. +:I. Menyun files trifoliatu Pliragmites vnlgaris Equisetiim palustre Ccilflia sibirica var. memhranaceu. Carex iimosa. +;n. +;ltl. 1:111. i;n|. +!I. +;n. Carex laeoirostris CuHa paltistris. +:n|. Carex dispafa. El odes japomca. +!l|. Biclens racliata. +;I. Niimhurgia tliyrsi flora. +;I. +:I. EriophorKin grcicile. +;I. +il. Myrica Gale uar. tomenfosa. 4-im. +;. Sp/iagnmn sp. Utricularis hifermedin Coniarum paltistre Curex uesicaria Cciex canescens. Hosta rectifolia Dryopferis Tlielypferis Onocleu sensibilis. +11. +!. +HI. 4-. I. 1 Ill. I. 1 n. + I + ][[ + Ilf + a +;. I. Scirpiis asiaticns. +;I +; E. -64-. +il. I. +;I. +!U + I. Ccirex hakomnsis. +;I. n. +: u. +;. Carex fedia var. Miyabei. I +-:E]. 1 M. +;]ll. Glyceria ciquatica. Lobelia sessili folio. +. +:I. Siinri nipponicnm. Caex lasiocarpa var. occnlfans. I!E|. +;. I ;+. u. +. I. 1 E. 1 I]. 1 s 1 D I +B. 1 D +. I. + 4-;. 1 +. I I. +. I. 2! TO. 1 sl +. I. 4-!. +. Hi. +:. I. + n. 1 HI. + ]I.

(5) Mizuho Tanaka. Species ~~~~- -—--____. A. B C. A. 2 IV 3;V. Calcnnagrostis Langsclorffii Lafhyrns ezoensis. +Î. Pogonia japonica. 1 B] 3; v + I. +;in. + 1. +; M 1:1\. +! m + ffl. Carex onu'anu Carex psendo-cnra/'cei. A. c. B. +Î. Carex Lyngbei. HigashiKushiro. Aikoku. Show,. Sampling area. Viola verecuncla var. semilunaris. +:s. Sanguisorba tenittfolia var. cilbci. 1 :m. +; I. +. I. B. +;I. Carex accrescens. +. Lycopns piirsiflorus. +;. Moliniopsis japonica. I +!I I +;I. 1. Pcirnassia palKsfris Oxycoccns qiiadripetaltis JimcKs bttfonitis Mentlia arvensis var. piperascens. +;. I. Spirantlies sinensis. + n. Drosera rotimdifolia Lysimachia viilgaris var. ddvnrica TJmltctniin Tlninbergii var. dioaricatnm Cln'ysospleninin alternifoUum var. sihiricum. +;. Anemone debilis. I. Hippuris unlgaris. +:B. +!l +!l. +. I. U]. +;. I. 4-. I. +;[!. +Î. I. +:I. I. +. I. +;u +;TC. +:E. +;I. +;I. Murchuntia sp.. I! m. Artemisia montana. +;I. +:tt +;M. +;I. +:E. +il. +;s. +:m. +;I. +im. +;I. +!i. +Î. +;I +;I. +!i. +;I. +;n. +;I. I. Hypericnm Ascyron. Plntantliera lioiogloftis. +Î. +;I. +!i. +11. Cicnfa uirosa. 2;m 3!V. +:E. 1 s. c. B. +;B +;n. 1 n. +; I +; +. A. i:m 1;IV. +; in. +. c. +il +11 +;I. Fritillciria camfscliafcensis Jnncns Hcienkei. Hokuto. +;I. +il. +;I. +llt +Î +ll[ +!i +Î. +11 +11 +11 +;I +!i +!i. i;m. +;I +;I. +!i. +;I. +!I. +!i. A ; - Swampy commuities. The depth of the water table is from five to ten centimetres or so. B ; - Moister communities. The water table is above thirty centimetres in depth, and the average of thirty samples is eighteen centimetres (from three to twenty-seven). C ; - Drier communities. The water table is below thirty centimetres, and the average of thirty samples is forty-three (from thirty-four to eighty-six).. General Discussion Although most parts of this moor are covered by a sedge fen, they contain numbers of upheavals which are risings of the peat soil with underground stubs. Accordingly, the submerged area is not an aquatic reed swamp, but wide and irregular hollows that fill shallow water, connecting each other. It will be due to the aquatic environment near the. headwaters of the Ninishibetsu that the Hokuto region is especially covered by luxuriant swampy plants as Menyanthes trifoliata, Spargamum, stoloniferum, or Calthn sibiricfi var. -66.

(6) On Resistant Species at the Successive Processes of the Ktishiro Lowland Fen membranaceae.. In a transverse section of the peat soil, the thickness of peat deposits, based on the layer of volcanic ashes under the ground, is different according to the places. The peat is far thicker at the bottom-like place where the ashes layer sinks deeply than at other places, and those thick accumulations make clear that the hollow communities were very flourishing before and their vast crops and products promoted the accumulatios of peat in the hollow, in addition to the inflow of muds and leaves near-by or to the shrinking of the upheaved part. From the foregoing studies, some analyses will be made as follows particularly important to the successional trend of the fen community. 1. Alternation of Car ex species As a general views of the lowland fen in the northern districts of Japan, this moor is abundant in Carex species too, and their alternation may be traced as follows. Besides the hummock and tussock formation by Carex Au.gustmoiviczii, when the MenyanthesPhragmites community in a swamp is alternated subsequently by the Phragmites-Carex community, the first invaders of Carex will be Carex laevirostris, C. vesicaria, C. dispalatci, and C. limosa. Carex limosa is originally and commonly one of the first encroachers to the bog-shore in the transitional or highland moor of this region, but the geographical features of the Kushiro M.oor is so complex that plenty of studded transitional areas are found. In such places, general changes from the wet condition to the dry one proceed, because climatic and other environmental factors enable some wetland to develop into a transitional one led by Sphagnnm, Therefore, Carex limosa often steps in the submerged lowland and grows here and there. Carex sfipata and C. Lyngbei can be recognized as their distinct followers, and up to the moister condition they succeed to Carex lasiocarpa var. occiiltcins, which distributes most widely and extensively throughout the whole moor from moist to dry. Carex omiana, C. fedia var. Miyabei, C. hakonensis, and C. basilata are the coexistent species of C. lasiocarpa var. occiiltans in these moist areas, but at the wetter places wher Carex limosci grows vigorously C. Micldendorffii and C. nemurensis appear with it, and Eriophorum gracile, E. alpnnm and E. vagmatum, too. The dominant Carex species in dry areas is Carex pseudo-cii.raica, and C. accrecens, C. canescens and C. thimbergii are also found there with C. lasiocara var. occultans remaining still. Namely, the main successional course of Carex species may be manifested as C. laeuirostris—'C. stipata->C. lasiocarpa var. occultans—>C. pseudo-cnraica. Such a. direction will branch or turn according to environmental changes. 2. Phragmites versus Calamcigrostis. Phragmites vulgaris and Calamagrostis Langsdorffii take always an opposite situation in the process of the fen succession. On account of the hard freezing of the peat soil in winter and of the low temperature by the dense sea-fog in spring and even in summer, the growing of PhragmHes is slow indeed even in early summer. Therefore, the resistant communities in the lowland seem to be dominated by Ccirex only through such sea-.

(7) Mizuho Tanaka sons, until Phrci.gmi.tes covers ultimately the whole fen in late summer. The rhlzomeg running long under the ground from thirty to seventy centimetres deep, they do not distinctly in proportion to the fall of the water table, and are apt to remain as the delegate species.. On the other hand, Calamagrostis Langsdorffii which grows widely in the inland of Eastern Hokkaido, appears at first in the moist lowlands, and generally spreads out keeping pace with the areal contraction of Phragmites. Therefore, the proportion of Phragmites and Calamagrosis may be supposed to indicate the rate of dryness of the fen ground.. 3. Expanding of the hummock communities At some dry areas in Aikoku where the water table points out eighty centimetres, the grounds are covered equally and uniformly with such communities dominated by Sangiiisorba feiwifolia var. alba, Thalictrum Thtmbegii var. diuancatum, Lobelia sessilifolia, and some others, regardless of hummocks and hollows. They are, of course, typical tussock species on hummocks as described in the recent paper, but it is shown here that the hummock communities step down upheavals and spread out in the neighbourhood and then in even more distant hollows later where the ground is dried well. In these cases, Lobelia sessilifolia and Hosta rectifolia go ahead generally, and are altered gradually to Thcilictrum Thunbergii var. divaricatwn or Sangui.sorba tenuifolia var. alba, and sometimes to Artemi.sia montana later. Therefore, survivers in hollows and hummock invaders mingle together and construct one uniform community at last. This mingled community, however, can be seen only at some limited hollows, and most parts of it remain still dominated by surviving species. Summary 1. Of the fen vegetation in Kushiro where hummocks and hollows are mixed in places, resistant species that survive in wet hollows are chiefly described here, comparing the community structures of three different — submerged, moist, and dry — with each other. 2. The chief current of their successional processes directed to dryness is organized. with the slow diminution of Phragmites viilgaris and with the orderly change among Car ex species. 3. The expanding of hummock species which have grown already on the top-centers of upheavals far before, is observed and it is comparatively slow. They gradually step down to hollows, dried enough, and at last form the complicated grass-complex, being mingled with the survivers such as Phragmites, Carex. and Calamcigrostis. He wishes to express his cordial thanks to Professor M. Numata of Chiba University for his encouragement and for the revision of this manuscript. References 1) Tanaka, M., 1962, .1. Hokkaiclo Gakugei Univ., (in print) 2) Tatewakl, M., 1942, J. Ecol. Rev., Vol. 1. No. 2-3, 87-93 (in Japanese) 67 -.

(8) On Resistant Species at the Successive Processes of the Kushiro Lowland Fell 3) __ , 1943, J. Agr. and For. Sapporo, 35, 1 (in Japanese). 4) _ , 1944, ibid., 36, 4 (in Japanese) 5) _ and Tsujii, T., 1958, Phytosociological Studies of Range and Pasture in Hokkaido. 57-59 (in. Japanese) 6) Tatewaki, M., 1928, J. Agr, and For. Sapporo, 19, 88 (in Japanese) 7) Tanaka, M., 1959, J. Hokkaido Gakugei Univ., Vol. 10, No. 1, 96-111 (in Japanese) 8) lizuka, J., 1954, Distributions and Natures of the peat in the Kushiro Moor. (in Japanese) 9) Okazaki, Y. and Yokohira, H. 1958, Geological Studies of the Kushiro Districts, (in Japanese). - 68.

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