Kushiro Marsh Research Articles

Ecological niche differentiation of two salamanders (Caudata: Hynobiidae) from Hokkaido Island, Japan

AbstractUnderstanding environmental factor determining ecological niche is very important to elucidating the distribution of species, and also revealing how closely related species are able to coexist in a particular region. Here, we applied ecological niche modeling to develop the ecological niches of two hynobiid salamanders: Salamandrella keyserlingii and Hynobius retardatus which are co‐occurring on Hokkaido Island, Japan. We, then, tested hypotheses about ecological niche differentiation between the two species. Our models showed that the potential distribution of S. keyserlingii was strictly limited to a small area at Kushiro Marsh, while the suitable distribution of H. retardatus was covered widely on Hokkaido Island. The results revealed the little geographic range overlap and the differentiation on the requirements of the ecological condition between the two species. We found nonequivalent niches in identity tests and counterintuitive results in background tests, indicating that S. keyserlingii has used a habitat subset of H. retardatus. Overall, our result contributed to understand the ecological niche space, and suggest the historical formation of these species on Hokkaido Island. The models can also be used to aid conservation purposes, such as habitat management, planning and designation of protected areas.

Projection range of eDNA analysis in marshes: a suggestion from the Siberian salamander (Salamandrella keyserlingii) inhabiting the Kushiro marsh, Japan.

BackgroundFreshwater ecosystems are rapidly declining. The Siberian salamander (Salamandrella keyserlingii) which inhabits the Kushiro marsh in Hokkaido, Japan has lost some habitat due to human activity. There are many challenges associated with conventional monitoring methods, including cost, the need for specialist personnel, environmental impact, and ability to detect the presence of this species; thus, we investigated the feasibility of using environmental DNA (eDNA) analysis to detect its presence and identify its breeding grounds.MethodsWe performed tank experiments to confirm eDNA emission from egg sacs, larvae, and adult Siberian salamanders in the water. We also performed water sampling and visual observation of egg sacs in the Kushiro marsh during the end of the breeding season and the larval season.ResultsThe tank experiments found eDNA emission from all growth stages. It also implied concentrated emissions just after spawning and after hatching, and limited emissions during the incubation phase in egg sacs. We also detected eDNA in the field, likely reflecting the distribution of egg sacs or larvae. Combining this data with visual observations, it was determined that the eDNA results from the field were best explained by the number of egg sacs within 7–10 m of the sampling point.ConclusionsThe results of this investigation show that the breeding sites and habitats of marshland species can successfully be monitored using eDNA analysis. They also suggest that the eDNA results from the marshes may reflect the biomass that is in close range to the sampling point. These results support the increased use of eDNA analysis in marshes and provide knowledge that could improve the interpretation of future results.

Inundation analysis using coupling storage function model with a distributed hydrological model in Kushiro marsh, Japan

Inundation analysis using coupling storage function model with a distributed hydrological model in Kushiro marsh, Japan

Heavy Rainfall-induced Displacement of More than 2.5 m in the Kushiro Marsh in 2016, Detected by ALOS-2 SAR

Heavy Rainfall-induced Displacement of More than 2.5 m in the Kushiro Marsh in 2016, Detected by ALOS-2 SAR

Change of Japanese Alder in the permanent quadrat of Kushiro Marsh

Change of Japanese Alder in the permanent quadrat of Kushiro Marsh

Differences in soil nutrients among vegetation types in Kushiro Marsh

Differences in soil nutrients among vegetation types in Kushiro Marsh

Description of a species of Fabaeformiscandona (Ostracoda, Crustacea) from Kushiro Marsh, Hokkaido, Japan, with the nearly complete mitochondrial genomic sequence.

BackgroundSo far, 16 species of non-marine ostracods have been reported from Kushiro Marsh, Kushiro Shitsugen National Park, eastern Hokkaido, Japan (Hiruta and Smith 2001, Smith and Hiruta 2004). Nine of these species are in Candonidae, the second-most diverse family of non-marine ostracods. This family contains ca. 550 species, or around 25% of the total number of non-marine ostracod species (Martens et al. 2008).New informationWe sampled ostracods in Kushiro Marsh on 27 December 2012 and identified an undescribed species in the family Candonidae, herein described as Fabaeformiscandona kushiroensis sp. nov. This species belongs to the F. acuminata species group and is characterized by the shapes of the elongate, dorsally directed medial and outer lobes on the distal end of each hemipenis. We also determined for this species the sequence of the nearly complete mitochondrial genome, the first record from the order Podocopa. The genome (ca. 17 kbp) contains two ribosomal RNA, 22 transfer RNA, and 13 protein-coding genes, as also found in other arthropods for which the mitochondrial genome has been sequenced. The gene arrangement is similar to the pancrustacean ground pattern, except that in the control region there is an approximately 2 kbp tandem repeat region composed of 220-bp motif sequences. We describe the genetic features of the mitochondrial genome, including nucleotide composition and the secondary structures of tRNAs and rRNAs, and compare them with the genome of Vargula hilgendorfii (Myodocopa, Ostracoda).

Depositional facies and sequence of the latest Pleistocene to Holocene incised valley fill in Kushiro Plain, Hokkaido, northern Japan

The development of the latest Pleistocene to Holocene incised valley fill in the Kushiro area, Hokkaido, Japan is investigated in this study. Nine boring core samples drilled in the Kushiro marsh were examined using depositional facies analysis, total sulfur content (TSC) measurement, and radiocarbon dating methods. Based on these methods, 12 depositional facies were recognized including marsh, subaqueous talus, bay-head delta, sand dune, beach, shoreface, barrier sand body, drowned valley-central basin, salt marsh, fluvial, pond, and pyroclastic deposits. The incised valley fill forms a depositional sequence primarily controlled by glacio-eustatic sea-level changes. The lowstand systems tract is composed of river deposits. The transgressive systems tract includes salt marsh, drowned-valley fill central basin, bay-head delta, barrier sand body, central basin, and subaqueous talus deposits. The highstand systems tract is composed of barrier sand body, shoreface, beach, sand dune, central basin bay-head delta, marsh, salt marsh, subaqueous talus, fluvial, and pond facies. Radiocarbon dating analysis indicates that the period of maximum marine flooding was around 7 ka cal. BP.

釧路湿原達古武沼の自然再生に向けて 北海道釧路湿原，特に達古武沼のトビケラ相

2003-2006年に北海道釧路湿原達古武沼とその流入河川でトビケラ相を調べた。16科52種のトビケラ成虫が採集された。このうち21種は釧路湿原初記録であり，他に未記載種1種が新たに採集された。これにより，釧路湿原で確認されたトビケラは74種となり，他に種名の明らかでない7分類群が記録されていることになる。

Cyclocypris diebeli Absolon, 1973 (Ostracoda, Crustacea), extinct in Europe, extant in Japan1

Fossil Cyclocypris diebeli Absolon, 1973 from Europe are redescribed, utilizing material with chitinous preservation of the appendages and carapace. These are compared with living C. diebeli from Kushiro Marsh, Hokkaido, Japan, representing the first living population of this species ever found. The fossil material is associated with strongly calcareous sediments, whereas the living material is found in weakly calcareous to acidic waters. Reasons for the different ecological requirements are discussed. Detailed study of soft parts of both living and fossil material using SEM is compared with other Cyclocypris species and it is shown that C. diebeli is more closely related to the North American Cyclocypris cruciata Furtos, 1935 than to any European congeneric species. Furthermore, the comparison with other Cyclocypris species with left>right valve overlap results in the conclusion that the subgenus Laevicypris Krstić, 1995 is not a useful division of the genus.

人為影響下の湿原におけるトンボ成虫長期モニタリングとその評価_-_釧路湿原，温根内地区を事例に_-_

人為影響下の湿原におけるトンボ成虫長期モニタリングとその評価_-_釧路湿原，温根内地区を事例に_-_

Comparison of image data acquired with AVHRR, MODIS, ETM + and ASTER over Hokkaido, Japan

Comparisons are made from data acquired by four multi-spectral sensors (Landsat/ETM+, Terra/ASTER, Terra/MODIS, and NOAA/AVHRR) over Kushiro Marsh in Hokkaido, Japan, on September 26, 2001. There is good agreement in the spectral characteristics of the Digital Numbers (DNs) between ETM+ and ASTER. Equations relating the Landsat/ETM+ digital number to that of the Terra/ASTER are developed. To eliminate various environmental effects, the Normalized Difference Vegetation Index (NDVI) is computed from the data of the four sensors. Typical values of the NDVI for several land cover types are obtained. The NDVI values for broad-leaf forest indicate the NDVI derived from MODIS is the largest followed by those of ETM, ASTER and AVHRR. The ranges of respective NDVIs reflect the spatial resolution. To reveal the effect of the sensors' spatial resolution, simulated data are generated from the higher spatial resolution (small size pixel) data to match the lower spatial resolution (larger size pixel) data. Comparisons of NDVIs for the simulated pixels indicate that the MODIS NDVI has the largest minimum, mean, and maximum numerical values while the ASTER NDVI indicates the opposite characteristics.

Measuring the Ecological Value of the Forests around the Kushiro Marsh: An Empirical Study of Choice Experiments

This paper estimates the ecological value of the forests around the Kushiro marsh using data from choice experiments (CE). CE is one of the environmental valuation techniques and asks individuals to pick from a set of resource management alternatives. The total sample surveyed was 845. Conditional logit and conditional probit models analyzed the CE data for five management plans of the wetland. The results are as follows: (1) The average willingness to pay is 137 dollars / year / household and the aggregate willingness to pay is 301 million dollars / year, when all the land around the wetland (151,361 ha) is protected for the ecosystem. (2) Cost benefit analysis shows that the optimal protection area is Q4 (91,361 ha). This means that it is important in terms of social welfare to protect not only the wetland itself, but also the forest around the wetland.

Influences of channelization on discharge of suspended sediment and wetland vegetation in Kushiro Marsh, northern Japan

The effects of wetlands on hydrology, water quality, and wildlife habitat are internationally recognized. Protecting the remaining wetlands is one of the most important environmental issues in many countries. However wetlands in Japan have been gradually shrinking due to agricultural development and urbanization, which generally lowers the groundwater level and introduces suspended sediment and sediment-associated nutrients into wetlands. We examined the influences of channelization on discharge of suspended sediment and wetland vegetation in Hokkaido, northern Japan. The impact of river channelization was confirmed not only by the sediment budgets but also by river aggradation or degradation after the channelization and by the resultant vegetational changes. The budgets of suspended sediment demonstrated that wash load was the predominant component accounting for 95% of the total suspended load delivered into the wetland. This suspended sediment was primarily transported into the wetland by flooding associated with heavy rainfall. Twenty-three percent of the wash load and 63% of the suspended bed material load were deposited in the channelized reach, which produced aggradation of about 2 m at the end of the reach. A shorting of the length of the channel, due to channelization of a meandering river, steepened the slope and enhanced the stream power to transport sediment. This steepening shifted the depositional zones of fine sediment 5 km downstream and aggraded the riverbed. Development of the watershed may increase not only the water discharge but also the amount of suspended sediments. The aggradation reduced the carrying capacity of the channel and caused sediment ladened water to flood over the wetlands. The fine sediment accumulated on the wetlands gradually altered the edaphic conditions and wetland vegetation. A low percentage (10 to 15%) of organic contents of wetlands' soil is more evidence indicating that the present condition is far different from normal. Original vegetation such as sedges and Alnus japonica were disappearing from the adjacent areas of the river channel and were being replaced by willow trees ( Salix spp.).

Survival curves and longevity of the leaves of Alnus japonica var. arguta in Kushiro Marsh

The seasonal changes in leaf emergence and leaf-fall in a Japanese alder stand of the fen in Kushiro Marsh were studied, and survival curves for the leaves were drawn. Leaves collected in litter traps were dried and weighed to study the seasonal changes, peaks in mid-August and late September to October suggested a bimodal annual curve. Study of the seasonal changes in the number of emerged and fallen leaves per shoot revealed a third peak about one month before the August peak, showing a trimodal annual curve. First and second leaves had a longevity of about 40 and 50–60 days, respectively. The longevity increased until the fifth leaf. With the sixth and following leaves, longevity decreased. Leaf size increased with leaf rank, with the first leaf being the smallest. The first leaf had only about 10% and the second leaf only 20% of the area of the fifth leaf. On this basis, the early to mid-July peak in number of fallen leaves was composed of first and second leaves which were smaller and short-lived. The early August and September/October peaks were high in both number and mass of fallen leaves. Compared to reports on Japanese alder of other mountainous districts in Hokkaido, the alder trees of Kushiro Marsh had about the same number of leaves per shoot, but had a season of leaf emergence which was about 6 weeks shorter. In addition, the longevity of the longest-lived fifth leaf was about 30–40 days shorter. The short life span of the leaves could be considered as an adaptive strategy of this species to environmental constraints of its habitat.

特集 北海道の風土とランドスケープ 釧路湿原の利用と保護

特集 北海道の風土とランドスケープ 釧路湿原の利用と保護

Estimation of Burned Area in Kushiro Marsh by Using LANDSAT TM Imagery

Estimation of Burned Area in Kushiro Marsh by Using LANDSAT TM Imagery