Landscape Ecol Eng (2013) 9:305–309 DOI 10.1007/s11355-012-0193-4

REPORT

Change in distribution of the vascular plant Sasa palmata in Sarobetsu Mire between 1977 and 2003 Yoshiyasu Fujimura • Masayuki Takada Hiroko Fujita • Takashi Inoue

•

Received: 30 November 2011 / Revised: 2 March 2012 / Accepted: 2 May 2012 / Published online: 8 June 2012 Ó International Consortium of Landscape and Ecological Engineering and Springer 2012

Abstract In recent decades, the extent of Sasa palmatadominant communities has increased in Sarobetsu Mire in northern Hokkaido, Japan, replacing the original Sphagnum bog vegetation. However, this marked increase in distribution of Sasa in the mire has not been formally documented or investigated in detail. Using aerial photo-interpretation, the present study updated the distribution maps of Sasa communities, showing the changes that have occurred to these communities between 1977 and 2003. The results revealed that the extent of Sasa communities has increased by 15.8 % from 6.60 km2 in 1977 to 7.64 km2 in 2003. The most marked increase occurred on the ground associated with drainage channels, although the oldest channels were constructed more than half a century ago, suggesting that some responses to the drainage of peat bog ecosystems may take a considerable period of time before becoming particularly evident. Keywords Peat bog  Aerial photograph  Drainage channel  Change in distribution  Broad leaf bamboo Y. Fujimura (&) Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan e-mail: [email protected] M. Takada Faculty of Humanity and Environment, Hosei University, 2-17-1, Fujimi, Chiyoda-ku, Tokyo 102-8160, Japan H. Fujita Botanic Garden, Field Science Centre for Northern Biosphere, Hokkaido University, North 3, West 8, Chuo-ku, Sapporo 060-0003, Japan T. Inoue Graduate School of Agriculture, Hokkaido University, North 9, West 9, Kita-ku, Sapporo 060-8589, Japan

Introduction Peat-forming mires play important roles as hydrological buffers, habitats for rare and endangered species, and sinks for atmospheric carbon dioxide (Breeuwer et al. 2009; Gore 1983; Gorham 1991; Kellner and Halldin 2002). The 2010 Aichi Targets, and decisions of the Convention on Biological Diversity (CBD), explicitly recognize the importance of peatlands as suppliers of key ecosystem services (CBD COP10 website, http://www.cbd.int/ decisions/cop/?m=cop-10). Vegetation type can affect such ecosystem functions (Backstrand et al. 2010; Fujimoto et al. 2006; Takagi et al. 1999) and, consequently, the distribution of vegetation stands represents a useful indicator that can be monitored relatively easily to inform decision makers regarding the effective management of such peat-forming ecosystems. The wetlands of Hokkaido, the northernmost island of Japan, have decreased to 40 % of their original distribution in recent decades due to agricultural and residential development (Geospatial Information Authority of Japan, http://www1.gsi.go.jp/geowww/lake/marsh/part/list_4.html). Although the area of mire vegetation in Sarobetsu Mire in Hokkaido had declined from 13,249 ha in 1923 to 2,773 ha in 1995, it still represents one of the largest areas of Sphagnum bog vegetation in Japan (Fujita et al. 2009). Thus, conserving bog vegetation in Sarobetsu Mire is important for maintaining regional and local biodiversity as well as for other ecosystem services. At present, the mire is bordered by drainage channels, ditches, a river, and pastures (Fig. 1). The artificial ditches and river function as a drainage system for the mire and the adjacent pasture reclaimed from bog, resulting in water table drawdown and subsidence within the mire (Eggelsmann 1972; Hobbs 1986; Ginzler 1997), leading to expansion of the vascular

123

306

Landscape Ecol Eng (2013) 9:305–309

Fig. 1 Aerial photographs of Sarobetsu Mire taken in July 2005. The dotted line denotes the area analyzed in a previous study (Fujita et al. 2003), whereas the area analyzed in this study is shown in Fig. 2. Channels marked A, B, and C were constructed in 1926–1927, 1961–1966, and 1965–1967, respectively, for flood control and pasture development. Channels B and C are sections of the partially straightened Sarobetsu River, indicated by a double-dashed directional line. Drainage ditches were excavated along the white bars marked D and E. The pools were created by peat-mining from 1970 to 2003

plant Sasa palmata (Lat.-Marl. ex Burb.) E.G. Camus across the mire surface. Existing Sasa distribution maps of Sarobetsu Mire show that the extent of Sasa-dominated vegetation increased by 17.4 % from 1977 to 2000 (Fujita et al. 2003). However, these maps do not include the area adjacent to the oldest constructed drainage channel (Channel A in Fig. 1). Clarifying the changes in distribution of Sasa in this area can help understand the long-term effects of channel construction on mire vegetation. Here we update the old Sasa distribution maps by including data on the area adjacent to the oldest constructed channel and discuss the long-term effects of drainage channels on the mire ecosystem. Area studied Sarobetsu Mire—part of the Rishiri Rebun National Park— is located in the lowland coastal plain of northern Hokkaido, Japan (45°50 N, 141°100 E; 3–7 m altitude; Fig. 1). The mire began developing on marine clay approximately 5,000–4,000 years BP (Ohira 1995; Sakaguchi et al. 1985), ultimately achieving an average peat depth of ca. 6 m. The mire was dominated by monocots during most of its development, but Sphagnum was present from the beginning of peat accumulation and has increased in abundance, although the timing of increase has varied from location to location within the site (Hotes et al. 2006; Kito and Hotes 2009). The mire surface is topographically flat with a gentle slope of about 1/3,000 toward the Sarobetsu River. Based on the weather record between 1981 and 2010

123

(Japan Meteorological Agency, http://www.jma.go.jp/jma/ menu/report.html), the annual precipitation in the area is 1,072 mm, while the annual mean temperature is 6.1 °C with monthly mean temperatures ranging from -6.5 °C (February) to 19.6 °C (August). From the end of November until the beginning of April, precipitation is in the form of snow and accounts for ca. 43 % of the annual precipitation. The mire receives water mainly from melted snow and rainfall, but supply of water from fog and artesian groundwater can be negligible in a hydrological simulation (Hokkaido Developmental Bureau 1997; Okada and Inoue 2010). Sphagnum lawn, comprising Sphagnum papillosum Lindb., S. magellanicum Brid., and Carex middendorffii, is the dominant vegetation. The Sasa community accompanied by Myrica gale L. var. tomentosa C.D.C and Ilex crenata Thunb. var. radicans (Nakai ex H. Hara) Murai is also dominant, mainly in western and southern parts of the mire (Takada et al. 2006). The plant height and leaf size of S. palmata growing near ditches and riverbanks are larger than those growing on peat-moss vegetation (Takakuwa and Ito 1986). Emerging macrophytes (helophytes) such as Phragmites australis (Cav.) Trin. Ex Steud., Zizania latifolia (Griseb.) Turcz. Ex Stapf, and Menyanthes trifoliata L. are also found in and around ditches. The scientific name S. senanensis was also used for Sasa species in the Sarobetsu Mire in some previous studies. S. palmata have been distinguished from S. senanensis merely by the hairlessness on the abaxial leaf surface (Suzuki 1996), but the morphological range of the two species is vague because

Landscape Ecol Eng (2013) 9:305–309

307

Fig. 2 Distribution of Sasa in 1977 (left 6.60 km2) and 2003 (right 7.64 km2). Areas dominated by Sasa are shaded. Dotted lines indicate the areas analyzed in this study

the hairiness/hairlessness can be variable in one region. We use S. palmata based on our observation of leaf hairlessness. Drainage channels and ditches bordering the mire were constructed for flood control and pasture development at various times in the past. Channels A, B, and C in Fig. 1 were constructed in 1926–1927, 1961–1966, and 1965–1967, respectively. The depths and widths were 2.4–6.0 and 2.8 m in Channel B and 0.0–6.7 and 8.0–11.0 m in Channel C, respectively, at the time of their construction (Hokkaido Developmental Bureau 1972). The original depth and width of Channel A is not well documented, but it seems to be more than 5 and 15–25 m, respectively (authors’ observation). Ditches marked D and E in Fig. 1 were constructed around 1984 and 1932, respectively (Hokkaido Regional Environment Office, Ministry of the Environment, http://sarobetsu-saisei. jp/data/kyogikai/no09/kyogikai09_keikakusho_shiryo.pdf). The depth and width of the ditches is currently less than 3 and 4 m, respectively. These artificial channels and ditches are intended to function as a drainage system for the pasture and mire. In addition, natural drainage channels (endotelmic streams) formed in the course of peat accumulation also drain the mire (Ivanov 1981; Ingram 1983; Okada 2009).

Methods Sasa distribution maps were produced from color aerial photographs taken in October 1977 (resolution 30 cm) and May 2003 (resolution 50 cm). Spring and fall are better for distinguishing between Sphagnum and/or sedge vegetation and evergreen Sasa community because the former are brown, and the latter are green throughout of the year. The photographs were orthorectified by ERDAS Imagine 2010 (ESRI Inc., USA). Distribution of Sasa was interpreted

based on color, contrast, and texture. Photo interpretation of Sasa distribution in 1977 was performed only for the area adjacent to the oldest constructed channel (Channel A in Fig. 1) because the Sasa distribution maps created by Fujita et al. (2003) was produced from the same series of aerial photographs as used in this study. To summarize and highlight the altered extent of Sasadominated vegetation between the two study dates, 100-m square polygons were produced using ArcGIS 9.3 (ESRI, http://www.esri.com/). Increase in the extent of Sasa was calculated by subtracting the observed extent in 1977 from that in 2003 within each 100-m square (1 ha) polygon.

Results and discussion The extent of Sasa-dominated vegetation in 1977 and in 2003 was 6.60 and 7.64 km2, respectively (Fig. 2), revealing an overall increase of 15.8 % during this period. Tani et al. (2006) showed that the extent of Sasa-dominated vegetation interpreted using the satellite image was smaller than that interpreted in a ground-based investigation because the satellite image could not recognize lowdensity Sasa vegetation. Although, our interpretation based on the aerial photo was not validated by ground-truth surveys, the Sasa-dominated area calculated in this present study might be underestimated. Figure 3 displays the specific 100-m square polygons in which Sasa-dominated vegetation has increased by more than 0.25 or 0.5 ha. Fujita et al. (2003) reported that the distribution of Sasa increased markedly in the vicinity of the Sarobetsu discharge channel (Channel B in Fig. 1), the straightened part of Sarobetsu River (Channel C in Fig. 1), and on the northern side of the eastern end of the roadside ditch (Ditch E in Fig. 1). Our updated Sasa distribution

123

308

Fig. 3 Marked increase in the extent of Sasa communities. The empty and solid squares indicate the 100-m square (1 ha) polygons where the increase in areas of Sasa from 1977 to 2003 exceeded 0.25 and 0.5 ha, respectively

maps show that Sasa increased markedly in the area adjacent to the oldest constructed channel (Channel A in Fig. 1). Drainage affects mire vegetation by altering the hydrology, surface morphology, peat decomposition process, and nutrient availability (Hobbs 1986; Ma¨lson et al. 2008; Talbot et al. 2010; Venterink et al. 2009). Tujii (1968, 1969, 1970, 1971, 1972) documented changes in vegetation along a 2,000 m transect perpendicular to drainage Channel B from 1960 to 1970. He showed that major changes in vegetation occurred within the first 5 years of drainage channel construction. For example, Impatiens noli-tangere L. and Agrostis gigantea Roth probably appeared as a result of transportation by the drainage channel. Meanwhile Sasa species and Calamagrostis purpurea subsp. Langsdorfii (Link) Tzvelev increased whereas Scheuchzeria palustris L. and Rhynchospora alba (L.) Vahl decreased. However, these marked changes were limited to within 35 m of the drainage channel, and no changes were noted in vegetation more than 200 m away from the channel during the 10 years after its construction. Rapid vegetation changes within the first 5 years of construction have also been observed by other workers studying rich fen in Sweden and fen meadow in the Netherlands, although each species responded differently to the increased drainage (Grootjans et al. 2005; Ma¨lson et al. 2008). This initial rapid change in vegetation noted in Sarobetu and other locations probably resulted from the direct effects of the water table drawdown and associated primary consolidation of the peat surface (Hobbs 1986), coupled with consequent peat aeration and nutrient enrichment (Ma¨lson et al. 2008; Pre´vost et al. 1999). Water table drawdown after drainage affects the

123

Landscape Ecol Eng (2013) 9:305–309

peat accumulation/decomposition rate and the extent of peat compaction/subsidence over decades through oxidation and secondary compression in contrast to the effects of primary consolidation, which are generally felt within the first 5–10 years after drainage (Grootjans et al. 2005; Hobbs 1986; Suzumura et al. 2007). The changes in peat properties affect the groundwater flow direction over a broader area than that affected by the properties of the peat. Thus, the long-term effects of channel construction on vegetation will appear slowly over a broader area than the areas where the peat properties were affected directly. Fujimura et al. (2011) suggested that distribution of Sasa is affected not only by groundwater level but also by water movement. In this, Sasa would appear to mimic closely the behavior of Molinia caerulea in the oceanic fringes of Western Europe, where a rise to dominance of M. caerulea on raised and blanket bogs is often an indicator of both lowered water tables and a degree of water movement (Taylor et al. 2001). Although this study did not investigate changes in water flow after construction of channels and peat-excavation pools, the environment of the mire changes abruptly rather than gradually in the vicinity of the Channels A, B, and C in terms of soil, vegetation, topography, and hydrology (Takada 2009). The expansion of Sasadominated vegetation in the vicinity of these channels is therefore considered to be one of the long-term effects of channel construction. Acknowledgments We thank Y. Mishima for the technical assistance regarding orthorectifying aerial photographs. This work was supported financially by the ‘‘Environment Research and Technology Development Fund by the Ministry of the Environment, Japan (D09–08).’’

References Backstrand K, Crill PM, Jackowicz-Korczynski M, Mastepanov M, Christensen TR, Bastviken D (2010) Annual carbon gas budget for a subarctic peatland, Northern Sweden. Biogeosciences 7:95–108 Breeuwer A, Robroek BJM, Limpens J, Heijmans MMPD, Schouten MGC, Berendse F (2009) Decreased summer water table depth affects peatland vegetation. Basic Appl Ecol 10:330–339 Eggelsmann R (1972) Physical effects of drainage in peat soils of the temperate zone and their forecasting. In: Hydrology of marshridden areas. Proceedings of the Minsk symposium 1972. The UNESCO Press, Paris, pp 69–77 Fujimoto T, Iiyama I, Sakai M, Nagata O, Hasegawa S (2006) Comparison of evapotranspiration between indigenous vegetation and invading vegetation in a bog (in Japanese with English abstract). J Jpn Soc Soil Phys 103:39–47 Fujimura Y, Fujita H, Takada M, Inoue T (2011) Relationship between hydrology and vegetation change from Sphagnum lawns to vascular plant Sasa communities. Landsc Ecol Eng. doi: 10.1007/s11355-011-0159-y Fujita H, Kanoh S, Imai H (2003) Kami-Sarobetsu shitugen jikeiretsu Sasa bunnpuzu no sakusei to Sasa no menseki henka (producing

Landscape Ecol Eng (2013) 9:305–309 the temporal distribution map of Sasa and the analysis for change in Sasa distribution area in Kami-Sarobetsu Mire) (in Japanese). Bull Bot Garden Hokkaido Univ 3:43–50 Fujita H, Igarashi Y, Hotes S, Takada M, Inoue T, Kaneko M (2009) An inventory of the mires of Hokkaido, Japan—their development, classification, decline, and conservation. Plant Ecol 200:9– 36 Ginzler C (1997) A hydrological approach to bog management. In: Parkyn L, Stoneman RE, Ingram HAP (eds) Conserving peatlands. CAB International, Wallingford, pp 280–286 Gore AJP (1983) Ecosystem of the world 4B. Mires: swamp, bog, fen and moor. Elsevier, Amsterdam Gorham E (1991) Northern peatlands: role in the carbon cycle and probable responses to climatic warming. Ecol Appl 1:182–195 Grootjans AP, Hunneman H, Verkiel H, Andel JV (2005) Long-term effects of drainage on species richness of a fen meadow at different spatial scales. Basic Appl Ecol 6:185–193 Hobbs NB (1986) Mire morphology and the properties and behavior of some British and foreign peats. Q J Eng Geol 19:7–80 Hokkaido Developmental Bureau (1972) Deitanchi no seitai (Ecology of peat land) (in Japanese). Hokkaido Developmental Bureau, Sapporo Hokkaido Developmental Bureau (1997) Deitanchi no kankyo (Environment of peat land) (in Japanese). Hokkaido Developmental Bureau, Sapporo Hotes S, Poschlod P, Takahashi H (2006) The effect of volcanic activity on mire development: case studies from Hokkaido, northern Japan. Holocene 16:561–573 Ingram HAP (1983) Hydrology. In: Gore AJP (ed) Ecosystem of the world 4A-Mires: swamp, bog, fen and moor-general studies. Elsevier, Oxford, pp 67–158 Ivanov KE (1981) Water movement in mirelands. Academic, London Kellner E, Halldin S (2002) Water budget and surface-layer water storage in a Sphagnum bog in central Sweden. Hydrol Process 16:87–103 Kito N, Hotes S (2009) Sarobetu shitugen-no shokusei keiseikatei (Developmental process of vegetation in Sarobetsu mire). Bulletin of the 56th annual meeting of the Ecological Society of Japan, p 195 Ma¨lson K, Backe´us I, Rydin H (2008) Long-term effects of drainage and initial effects of hydrological restoration on rich fen vegetation. Appl Veg Sci 11:99–106 Ohira A (1995) Kanshinsei ni okeru Sarobetsu genya no deitanchi no keisei to kokankyo henka (Holocene evolution of peatland and paleoenvironmental changes in the Sarobetsu lowland, Hokkaido, northern Japan) (in Japanese with English summary). Chirigaku-hyoron (Geogr Rev Japan) 68 A-10:695–712 Okada M (2009) Formation of bog rills in Sarobetsu Mire: verification using Carex model (in Japanese with English summary). Trans Jpn Geomorphol Union 30:95–111 Okada M, Inoue T (2010) Groundwater flow model considering hydraulic properties of peat (in Japanese with English summary). Wetland Res 1:3–15 Pre´vost M, Plamondon AP, Belleau P (1999) Effects of drainage of a forested peatland on water quality and quantity. J Hydrol 214:130–143

309 Sakaguchi Y, Kashima K, Matsubara A (1985) Holocene marine deposits in Hokkaido and their sedimentary environments, vol 17. Bulletin of the Department of Geography, University of Tokyo, pp 1–17 Suzuki S (ed) (1996) Illustrations of Japanese Bambusaceae, revised edition (in Japanese). Shukai Shorin, Chiba Suzumura T, Inoue T, Takada M (2007) Changes in effective porosity of surface peat layer after drainage. Trans Jpn Soc Irrig Drain Rural Eng 75:640–641 Takada M (2009) Deitanchi-shitsugen no suimon-dojou hendou tokusei to kukan-kozo-hyoka (Evaluation of hydrological and soil properties, and landscape structure analysis in peatland) (in Japanese). Hokkaido University PhD thesis Takada M, Aosier B, Natsume S, Saito K, Kato K (2006) Classifying the vegetation at Sarobetsu Mire, Hokkaido, using satellite remote sensing (in Japanese with English summary). Landsc Ecol Manag 11:3–14 Takagi K, Tsuboya T, Takahashi H, Inoue T (1999) Effect of the invasion of vascular plants on heat and water balance in the Sarobetsu Mire, northern Japan. Wetlands 19:246–254 Takakuwa J, Ito K (1986) Ecological aspects of Sasa in mires (in Japanese with English summary). Memoirs of environmental science, vol 2. Hokkaido University, Sapporo, pp 47–65 Talbot J, Richard PJH, Roulet NT, Booth RK (2010) Assessing longterm hydrological and ecological responses to drainage in a raised bog using paleoecology and a hydrosequence. J Veg Sci 21:143–156 Tani H, Guo Y, Takada M, Takahashi H, Wang X (2006) Study on invasion of Sasa sp. in Sarobetsu mire by satellite data. Environ Inf Sci 20:361–366 Taylor K, Rowland AP, Jones HE (2001) Biological flora of the British Isles: Molinia caerulea (L.) Moench. J Ecol 89:126–144 Tujii T (1968) Showa-44-nendo Sarobetsu sougou chosa hokokusho seibutsu-bumon (Interim report of comprehensive survey on Sarobetsu area for fiscal year 1967, section biology) (in Japanese). Hokkaido Developmental Bureau, Sapporo Tujii T (1969) Showa-45-nendo Sarobetsu sougou chosa hokokusho seibutsu-bumon (Interim report of comprehensive survey on Sarobetsu area for fiscal year 1968, section biology) (in Japanese). Hokkaido Developmental Bureau, Sapporo Tujii T (1970) Showa-46-nendo Sarobetsu sougou chosa hokokusho seibutsu-bumon (Interim report of comprehensive survey on Sarobetsu area for fiscal year 1969, section biology) (in Japanese). Hokkaido Developmental Bureau, Sapporo Tujii T (1971) Showa-47-nendo Sarobetsu sougou chosa hokokusho seibutsu-bumon (Interim report of comprehensive survey on Sarobetsu area for fiscal year 1970, section biology) (in Japanese). Hokkaido Developmental Bureau, Sapporo Tujii T (1972) Deitanchi no seitai, Sarobetsu sougou chosa hokokusho seibutsu-bumon (Ecology of peatland, Report of comprehensive survey on Sarobetsu area, section biology) (in Japanese). Hokkaido Developmental Bureau, Sapporo Venterink HO, Kardel I, Kotowski W, Peeters W, Wassen MJ (2009) Long-term effects of drainage and hay-removal on nutrient dynamics and limitation in the Biebrza mires, Poland. Biogeochemistry 93:235–252

123