Effects of Hydrological Modifications and Nature Restoration Projects on Ground Beetles Along the Yodo River, Osaka Prefecture, Japan

Jpn. J. Environ. Entomol. Zool. 24（４）：187− 198（2012）環動昆第 24 巻第４号：187 − 198（2012）原著

Effects of hydrological modifications and nature restoration projects on ground beetles along the Yodo River, Osaka Prefecture, Japan

Takahiro Fujisawa and Minoru Ishii

Entomological Laboratory, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan

（Received：October 29, 2012；Accepted：December 14, 2012）

Abstract Hydrological modifications to the Yodo River of Osaka Prefecture, Japan, have been drastically changed the riverine environment, since dam construction and extensive excavation began in 1971. More recently, riverine restoration projects involving excavation of major beds designed to prevent them from drying out have recently been conducted. A field survey of carabid ground beetle assemblages using unbaited pitfall traps was conducted in the Yodo River riverbed from April to December 2009 to elucidate the influence of both hydrological modification and nature restoration activities on the assemblages. Ground beetles were captured for two weeks each month at 13 sites. Also, we measured four environmental parameters, riverbed conditions（minor or major beds）, submergence duration, soil moisture and median soil particle diameter, at each site. A total of 8,697 ground beetles belonging to 65 species were captured during the surveys. Generalized linear mixed model analysis showed that the abundance of nine species, such as Oodes vicarius, Pterostichus eschscholtzii and Pterostichus prolongatus, was positively correlated with the existence of minor beds and submergence duration or soil moisture, while that of 10 other species, such as Carabus yaconinus, Lesticus magnus and Synuchus nitidus, was negatively correlated with existence of minor beds, soil moisture rate and/ or submergence duration. Results of detrended correspondence analysis indicate that most of the former nine species and the latter 10 species were ordered at higher and lower scores of the axis 1, respectively. Also, ground beetle assemblages of major and minor beds were well separated by the ordination along axis 1. The results of this study demonstrate that hygrophilous species and the species preferring less disturbed environments characterize minor and major beds, respectively. Possibly, the nature restoration projects favored hygrophilous species by enlarging minor beds, which resulted in maintenance of heterogeneity of ground beetle habitats in the riverbeds.

Key words：Carabid beetle, Detrended correspondence analysis, Generalized linear mixed model, Major bed, Minor bed, Submergence

channelization and dredging for flood control（Ward, Introduction 1998；Poff et al., 2007）. The habitat homogeneity in river environments has created a major loss of Rivers serve as important landscape features to biodiversity globally（Hauer and Lorang, 2004；Poff et aquatic and terrestrial animals and plants, which al., 2007；Vörösmarty et al., 2010）. provide them with various types of habitats such The Yodo River, the largest river in the northern as intermittently flooded wetlands and floodplains area of Osaka Prefecture, central Japan, has with environmental gradients（Ward, 1998；Ward characteristic landscapes such as a large reed et al., 1999；Bunn and Arthington, 2002）. However, community in the riverbed called locally known human management of river hydrology has caused as “Udono”（Koyama, 1988, Nishino, 2009）. River heterogeneity of these habitats to decline with the regulation works have heavily modified the Yodo River construction of river regulation works such as dams, riverbed since 1971；ground water levels have fallen

Corresponding author：[email protected]

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as major beds dried after extensive excavation and the ground beetles have been decreasing as a result of construction of dams and weirs has been carried out to river regulation works and massive development of stabilize the water level（Koyama, 1999；Aya, 2004； residential zones in and around the river system. Our Nishino, 2009）, and many recreation areas including previous study（Fujisawa et al., 2012）also proved that golf courses have been built on major beds（Aya, the abundance of hygrophilous ground beetles has 2004）. These works probably exerted considerable decreased in the Udono riverbed because of the river influence on riverine terrestrial ecosystems of the regulation works. Yodo River. For example, the reed community declined However, nature restoration projects, involving because terrestrial plants such as kudzu, Pueraria lobata excavation of major beds to prevent them from drying, Ohwi, invaded the riverbeds at Udono（Koyama, 1999）. have recently been carried out at Udono（Koyama, 1999； Ground beetles serve as effective bio-indicators when Aya, 2004；Nishino, 2009）. In this study, we compared used to evaluate environmental changes of terrestrial ground beetle assemblages in the major and minor ecosystems（e.g. Thiele, 1977；Lövei and Sunderland, riverbeds along the Yodo River, to elucidate the influence 1996；Ishitani, 1996；Rainio and Niemelä, 2003）. As of nature restoration projects as well as river regulation for riverbeds, many studies of ground beetles have projects on the characteristics of the assemblages. clarified the influence of human disturbance（Ishii et al., 1996；Lee and Ishii, 2010；Follner et al., 2009）, Study Sites and Methods flood events（Gerisch et al., 2006）, and river restoration （Jähnig et al., 2009）on beetle assemblages. In the Yodo Field surveys using unbaited pitfall traps were River, Yasui et al.（2011）reported that bembidiine made at 13 sites named 1–6, 7a, 7b and 8–12 in the

Fig. 1 Location of 13 study sites（closed circle：major bed, open circle：minor bed）in the Yodo River riverbed, central Japan. Contour interval：200 m.

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Yodo River riverbed in Osaka and Kyoto Prefectures Site 6：A minor bed on the right bank of the Yodo from April to December in 2009（Fig. 1）. Plastic River at Takatsuki City located about 1.9 km upstream cups（7 cm diameter, 10 cm depth）with five 2–3 mm of the Hirakataohashi Bridge where the river was diameter holes in the bottom for drainage were used about 200 m wide. A reed community covered this site, for trapping. Ten traps were placed in a row at about dominated by M. sacchariflorus, P. karka and S. canadensis, 3 m intervals for two weeks a month and emptied which was completely flooded in autumn of 2009；no twice, at one and two weeks after trap placement. traps were placed at Site 6 at that time. Thus ground beetles were sampled a total of 18 times Site 7a：The right bank of the Yodo River at at all the sites except for Sites 7a, 7b and 10. Only 10, Takatsuki City located about 30.6 km upstream of the 16, and 16 samples were collected at Sites 7b, 10 and estuary. This site and Sites 7b, 8 and 9 were located Site 7a, respectively, because of flooding. Also, because in the Udono, the largest reed community in the Yodo some traps were lost during the sampling period, the River, in an area where the river was about 150 m total number of traps collected ranged from 145 to 179 wide. A grassland community dominated by P. australis, at all the sites except for Site 7b, where 91 traps were M. sacchariflorus and P. karka covered this site. This collected. The location and environment of each site site was regarded as a minor bed because a nature follows. restoration project had been completed at this site, Site 1：A minor bed on the right bank of the Yodo where riverbeds had been excavated in 2007 to prevent River at Osaka City located about 0.1 km upstream of drying after which the area became submerged every the Sugawarashirokitaohashi Bridge where the river year. From late July to late August and for a few days was about 200 m wide. A reed community covered this in October 2009, the site was inundated so no traps site, dominated by Phragmites australis（Cav.）Trin. were placed at Site 7a at this time. Also, a prescribed ex Steudel, Phragmites karka（Retz.）Trin. ex Steud, fire burned this site in March 2009. Miscanthus sacchariflorus（Maxim.）Benth. and Bidens Site 7b：This site was added in a minor bed about frondosa L.. 10 m upstream of Site 7a from August 2009 as an Site 2：A major bed on the left bank of the auxiliary to Site 7a. This site on sandy ground had Yodo River at Moriguchi City located about 1.5 km been created by excavation of a major bed and was downstream of the Torigaiohashi Bridge where the poorly covered by Aeschynomene indica L. and Conyza river was about 300 m wide. A reed community canadensis（L.）Cronq.. covered this site, dominated by P. karka, Solidago Site 8：A major bed on the right bank of the canadensis L. and Trichosanthes cucumeroides Maxim.. Yodo River at Takatsuki City located about 31.0 km Site 3：A major bed on the left bank of the Yodo upstream of the estuary where the river was about River at Hirakata City located about 1.3 km upstream 150 m wide. A community dominated by P. australis, of the Yodogawashinbashi Bridge where the river was M. sacchariflorus, P. karka and Humulus japonicus Sieb. et about 200 m wide. A reed community covered this site, Zucc. covered the site. Also, a prescribed fire burned dominated by M. sacchariflorus, P. karka and P. lobata. this site in March 2009. Site 4：A minor bed on the right bank of the Site 9：A major bed on the right bank of the Yodo River at Takatsuki city located about 2.7 km Yodo River at Takatsuki City located about 32.0 km downstream of the Hirakataohashi Bridge where upstream of the estuary where the river was about the river was about 200 m wide. A reed community 150 m wide. A community dominated by P. australis, M. covered this site, dominated by M. sacchariflorus, P. sacchariflorus, P. karka and H. japonicas covered the site. karka and S. canadensis, which was completely flooded Site 10：A minor bed on the left bank of the Yodo in autumn of 2009；no traps were placed at Site 4 at River at Hirakata City located about 32.4 km upstream that time. of the estuary where the river was about 200 m wide. Site 5：A major bed on the left bank of the Yodo This sandy river bed site was dominated by P. australis River at Hirakata City located about 1.3 km upstream and M. sacchariflorus community. From late July to of the Hirakataohashi Bridge. This site was near the early August, this site was flooded and we could not confluence of the Yodo and the Amano Rivers, where access it. the river was about 200 m wide. A reed community Site 11：A minor bed on the left bank of the Yodo covered this site, dominated by M. sacchariflorus and P. River at Hirakata City located about 33.4 km upstream karka. of the estuary where the river was about 200 m wide.

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A reed community covered this site, dominated by M. the entire study, were performed using detrended sacchariflorus and P. karka. This site was near ponds correspondence analysis（DCA）（Hill and Gauch, that had recovered from decline caused by aridification. 1980）with R package“vegan”（Oksanen et al., 2011）. Site 12：A major bed on the right bank of the Yodo To elucidate effects of the environmental parameters River neighboring the confluence of the Yodo and the on the abundance of each ground beetle species, we Katsura River at Oyamazaki Town, Kyoto Prefecture, used a generalized linear mixed model（GLMM）with located about 36.2 km upstream of the estuary where R package “glmmML”（Broström and Holmberg, the river was about 100 m wide. A reed community 2011）, evaluating effects of the environmental covers this site, dominated by M. sacchariflorus, P. karka parameters（fixed model）together with those of sites and S. canadensis. （random factor）on the number of individuals of 38 Four environmental parameters— １）riverbed major species of which more than 20 individuals were condition；major（1）or minor bed（0）；２）submergence captured, totaled from all sites, excluding numbers duration（days）；３）soil water content（%）；and ４） from Site 7b. The natural logarithm of the number median size of soil particles（mm） —were measured of traps was used as an offset to correct for unequal at each site except for Site 7b, which was dealt with trapping effort. All models assumed the Poisson error as auxiliary to Site 7a. The submergence duration distribution in the response variable and used a log was inferred by comparing the elevation of each site link function. Model selection was performed using the （Ministry of Land, Infrastructure and Transport, Akaike’s information criterion（AIC）（Akaike, 1973） Japan, 2002）and the water level of the river, which in the best-subset selection procedure（Johnson and was calculated from cross-section data of the river in Omland, 2004）with R package“MuMIn”（Barto ń, 2009（Yodogawa River Office data）. Soil water content 2012）. was calculated from the mean value of the differences In this survey, we could not identify 16 individuals between wet and dry weights of four soil samples to a particular species. We decided to treat seven taken from 0–10 cm depth at each site on 25 or 26 individuals as Harpalus spp. and nine as Chlaenius spp., August 2009 and dried at 110 ± 5°C for more than but excluded them from comparisons of the number of two days using a natural convection oven（Yamato species and species diversity. Scientific）. In addition, dried soil samples were put through sieves with six different meshes（2.00, 0.85, Results 0.425, 0.250, 0.106, and 0.075 mm）, and the mean of median soil particle size at each site was calculated. A total of 8,697 individual ground beetles belonging Based on field sample data, the Simpson’s index, to 65 carabid species were captured at the 13 sites in 1–λ, was calculated as a species diversity index by the Yodo River riverbed during the study（Table 1）. equation（1）： Sites 3 and 10 supported the largest number of species

1–λ = 1–Σni（ni –1）/ N（N –1）（1）（36 species）and Site 8 had the fewest（22）. Site 1（10.95）

where ni and N are numbers of individuals of the i-th and Site 9（0.48）had the highest and lowest density species and total numbers of individuals, respectively of individuals, respectively. The species diversity index （Simpson, 1949）. （1–λ）was the highest at Site 4（0.91）and the lowest Statistical analyses were performed using R version at Site 2（0.61）（Table 1）. 2.14.1（R Development Core Team, 2011）. To compare The number of the ground beetle species unique to a ground beetle assemblages at major with minor beds, particular site（“unique species”）totaled two at Sites we calculated the mean values and 95% confidence 7a, 7b, 10 and 12, one at Sites 1, 3, 8, 9 and 11, and no intervals of the density（the mean number of unique species were recorded from Sites 2, 4, 5 and 6 individuals per trap per sampling period）, the number （Table 1）. When Sites 7a and 7b are lumped together of species, and the species diversity index（1–λ）using into a single site, five unique species were found— the bootstrap method（1,000 replicates）. Platynus magnus, Amara chalcophaea, Oodes vicarius, Also, to examine the similarity among ground Lachnocrepis prolixa and Apristus cuprascens—and the beetle assemblages at 13 sites, and the relationships total number of individuals of these five species was as between species and sites, ordinations of each of the large as 107. 13 assemblages and each of the 41“major species,” of Dominant species from the entire set of sites were which more than 20 individuals were captured during Pheropsophus jessoensis, Carabus yaconinus, Harpalus

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capito, Dolichus halensis and Chlaenius posticalis in at 11 sites but not Sites 4 and 9, and C. yaconinus descending order, including a total of 3,908 individuals was found at 10 sites but not Sites 7a, 7b and 8. A. of these five species, which accounted 45% of the total cuprascens and Craspedonotus tibialis were dominant only individuals captured in this study（Table 2）. Three of at Site 7b. the five species, H. capito, D. halensis and C. posticalis, Bootstrap analysis shows that mean values of the were recorded from all sites. P. jessoensis was found number of species were significantly different between

Table 1 Mean number of individual ground beetles caught per trap and the total catch（in parentheses）at each of 13 sites in the riverbed of the Yodo River, central Japan from April to December, 2009. Total number of individuals, species richness, species diversity indices（1-λ）, individuals of unique spacies and species richnes of unique species at each site are shown at the bottom.

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sites with major and minor beds, while those of the results showed that major and minor beds supported density and the species diversity index showed no different species compositions. significant differences（Fig. 2）. As the results of model selection using AIC in the DCA shows that eigenvalues for axes 1 and 2 were GLMM, the best-subset was selected for each ground 0.56 and 0.29, respectively, and so axis 1 was considered beetle species except for Harpalus platynotus（Table 3）. to evaluate the quality of the ordination. In ordinations of species, A. cuprascens, C. tibialis, Amara ampliata, H. crates, O. vicarius and Pterostichus eschscholtzii were Discussion ordered with higher scores on axis 1, while Synuchus callitheres, Chlaenius naeviger, S. nitidus, C. yaconinus and In this study, a total of 65 ground beetle species were Lesticus magnus were ordered with lower scores on axis recorded from Yodo River riverbeds. Compared with 1（Fig. 3a）. Moreover, in ordinations of assemblages our previous study（Fujisawa et al., 2012）, in which a and of sites belonging to minor beds were ordered with total of 51 species were recorded from the Yodo River, higher scores on axis 1, while those belonging to major this study reports 20 additional species such as C. beds were ordered at lower scores（Fig. 3b）. The tibialis, Harpalus discrepans and A. cuprascens, although six species previously reported for the Yodo River area such as Agonum chalcomus（Bates）, Amara nipponica Habu and Chlaenius inops Chaudoir were not found in this study. Currently, a total of 71 carabid species have been reported to occur from the Yodo River riverbed by our studies, representing 33.5% of those recorded from northern and central Osaka Prefecture（Osaka Prefecture, 2000）. Three endangered carabid species, Eochlaenius suvorovi, H. crates and O. vicarius, listed on the red data list of Japan（Ministry of Environment, 2012）were found in this study. E. suvorovi was captured at Sites 4, 6 and 11 from minor beds and was a dominant species in the former two sites where reed communities dominated（Table 2）, which shows that E. suvorovi prefers wet grasslands like reed beds. Most or all individuals of the other two endangered species, H. crates and O. vicarius, were captured at Udono. For H. crates, 175 of 184 individuals were captured at Sites 7ab and 8, and all individuals of O. vicarius were captured at Site 7a. Considering Sites 7a and 7b were part of a nature restoration project, it is possible that the project had a favorable effect on these two endangered species. The GLMM analysis shows that the abundance of seven out of the 38 major species, Scarites terricola, Pterostichus versicolor, P. eschscholtzii, D. halensis, Harpalus eous, Harpalus jureceki and O. vicarius, were positively correlated to both existence of minor beds and submergence duration（Table 3）. Two hygrophilous species, P. eschscholtzii and O. vicarius（Habu and Fig. 2 Mean values and 95% confidence intervals Sadanaga, 1971；Ueno et al., 1985）, were found, calculated using bootstrap sampling of each although the abundance of O. vicarius was negatively parameter of ground beetles（density（upper）, the number of species（medium）and species diversity correlated to soil moisture rate in this analysis. The index（below））on minor and major beds in the abundance of two other species, S. terricola and P. Yodo River, respectively. *：P < 0.05 versicolor, was positively correlated with median soil

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Table 2 Five dominant ground beetles in decreasing order and their mean number of individuals caught per trap at each of 13 sites in the riverbed of the Yodo River. Total number of individuals caught at each site is shown in parentheses.

*Percentage of the 5 dominant to all the species caught at each st. in the total number of individuals.

Fig. 3 Results of the detrended correspondence analysis（DCA）of carabid beetles in which more than 20 individuals were captured（a）and of study sites（b）（closed circle: major bed, open circle: minor bed）. Eigenvalues of axes 1 and 2 were 0.56 and 0.29, respectively.

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particle diameter, while the abundance of four species, versicolor prefer humid soil with coarse sand and the P. eschscholtzii, D. halensis, H. eous and H. jureceki, was latter four species prefer humid soil with fine sand in negatively correlated with this parameter. These six the riverbed. species have been recorded from lowland grasslands In addition, GLMM analysis proved that abundance such as crop fields（e.g. Habu and Sadanaga, 1961, of Archipatrobus flavipes, Pterostichus prolongatus and 1969；Ishitani and Yano, 1994；Ishitani, 1996； Chlaenius micans are positively correlated with both Siddiquee et al., 2005；Kagawa et al., 2008）and existence of minor beds and soil moisture rate（Table riverbeds（e.g. Ishii et al., 1996；Ishitani et al., 1997； 3）. These two species are known to be hygrophilous Lee and Ishii, 2010）, but environmental requirements species（Habu and Sadanaga, 1965；Ueno et al., 1985）, of five of these six species are poorly known. The while C. micans has been recorded from various lowland results of GLMM analysis shows that S. terricola and P. environments such as farmlands（Yano et al., 1989；

Table 3 Generalized liner mixed models（GLMM）evaluating the effects of environmental parameter of each site except Site 7b（fixed model）together with those of sites（random factor）on the number of individuals of ground beetles in which more than 20 individuals were captured. The logarithm of the number of traps was used as an offset to correct for unequal trapping effort. All models assumed a Poisson error distribution in the response variable and used a log link function.

* We divided the riverbed of 12 sites into two types of conditions, major（0）or minor（1）beds.

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Ishitani and Yano, 1994；Kagawa et al., 2008）, forests beds in the river. Most of those species were ordered （Suttiprapan and Nakamura, 2007）and river beds at lower scores of axis 1 in the DCA analysis（Fig. 3a）, （Ishii et al., 1996；Ishitani, 1996；Ishitani et al., 1997； which suggests that low scores on axis 1 represent low Lee and Ishii, 2009, 2010）. Also, Inoue（1953）reported levels of disturbance as well as low soil moisture as that C. micans was found abundant in riverine wetlands mentioned above. and shady grasslands in summer, while Tanaka（1991） River regulation works may greatly influence ground observed that this species migrates from forests beetle assemblages through modification of riverbed to riverbeds and/or paddy fields for oviposition in environments. Nevertheless, large sized species summer. In this study, most C. micans individuals were and forest species might survive in riverine areas captured from June to August in riverbeds of the Yodo with river regulation works, because the structures River, which demonstrates that this species shows stabilize riverbed environments, which benefits hygrophilous preference in summer. Thus the above 10 species that prefer low levels of disturbance. In species may all be regarded as hygrophilous species. contrast, hygrophilous species of ground beetles prefer Most of these species were ordered with higher minor beds, but their density was lower in the reed scores on the axis 1 in the DCA analysis（Fig. 3a）, community on major beds, as we reported previously which suggests that higher values on axis 1 represent （Fujisawa et al., 2012）. The results of DCA analysis increasing soil moisture. show that ground beetle assemblages were different The abundance of six of the 38 major species, C. in minor and major beds with axis 1 representing yaconinus, Carabus kumagaii, S. nitidus, Haplochlaenius intensity of disturbance and/or soil moisture（Fig. 3a）. costiger, C. naeviger and Galerita orientalis, was negatively The results of this study demonstrate that the nature correlated with both existence of minor beds and soil restoration project at Udono, where the major bed moisture rate in the GLMM analysis（Table 3）. One was dug down to prevent from aridification（Koyama, of the six species, C. yaconinus, was also negatively 1999；Aya, 2004；Nishino, 2009）, was effective in correlated with median soil particle diameter. Also, conserving species diversity of ground beetles. At the abundance of two of the 38 major species, Carabus Sites 7a and 7b, where the nature restoration project blaptoides and S. callitheres, was negatively correlated was recently carried out, unique species were the with both submergence duration and soil moisture most abundant（Table 1）. Note that three of the five rate, and abundance of L. magnus was negatively dominant species at Sites 7a, P. eschscholtzii, D. halensis correlated with the existence of minor beds and and C. micans, and one of the five unique species at submergence duration（Table 3）. Interestingly, six the sites, O. vicarius, were regarded as hygrophilous of the above nine species, C. yaconinus, C. kumagaii, C. species. As for the remaining two dominant species blaptoides, L. magnus, H. costiger and G. orientalis, belong at the sites, P. jessoensis and P. prolongatus their to the“large-sized species” group（body length > 20 abundance was correlated with submergence duration mm）as defined by Fujita et al.（2008）and Lee and and soil moisture rate, respectively（Table 3）. Also, Ishii（2009, 2010）. Lessel et al.（2011）pointed out that C. tibialis and A. cuprascens, which were abundant at in riverbeds, small carabid beetles such as Bembidion Site 7b, prefer sandy soil in riverbeds（Habu and quadrimaculatum（Linnaeus）or Bembidion lampros Sadanaga, 1965；Matsura et al., 2006）. Thus, the nature （Herbst）are dominant in floodplains, while larger restoration project possibly favored hygrophilous species like Carabus purpurascens Fabricius predominate species or species preferring sandy soil at Sites 7a and in less disturbed environments. Large-sized ground 7b in Udono by enlarging minor beds, which resulted in beetles are found in stable environments in forests（e.g. maintenance of heterogeneity of ground beetle habitats Ishitani et al., 2003；Osawa et al., 2005；Schwerk and in the Yodo River riverbeds, as shown by the DCA Szyszko, 2007）. The results of this study are consistent analysis（Fig. 3b）. with those of previous studies; that is, large-sized ground beetles were found in major beds of the river. Acknowledgments Moreover, previous studies identified the remaining two species, S. nitidus and C. naeviger, as forest species The authors are grateful to Drs. T. Hirowatari （Matsumoto, 2005, 2009；Fujita et al., 2008）, although and N. Hirai of Osaka Prefecture University for their their sizes are not large. The above nine species may useful advice related to the present study, and to Dr. simply prefer less disturbed environments like major T. Kimata of Osaka Prefecture University for allowing

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us to use experimental equipment and for useful beetles（Coleoptera, Carabidae）as indicators of advice related to soil analyses. We are also much hydrological site conditions in floodplain grasslands. indebted to the Yodogawa River Office, Kinki Regional Internat. Rev. Hydrobiol. 91：326 − 340. Development Bureau, Ministry of Land, Infrastructure Habu, A. and Sadanaga, K.（1961）Illustrations for and Transport, for allowing this study and providing identification of larvae of the Carabidae found in us with cross-section data of the Yodo River. We cultivated fields and paddy–fields（I）. Bull. Nat. also thank our laboratory members for their kind Inst. Agr. Sci. C 13：207 − 248（in Japanese with an cooperation and assistance. This study was supported English summary）. partly by JSPS Grants-in-Aid for Scientific Research Habu, A. and Sadanaga, K.（1965）Illustrations for （nos. 20510217 and 23510297）. identification of larvae of the Carabidae found in cultivated fields and paddy-fields（III）. Bull. Nat. References Inst. Agr. Sci. C, 19：81 − 216（in Japanese with an English summary）. Akaike, H.（1973）Information theory as an extension Habu, A. and Sadanaga, K.（1969）Illustrations for of the maximum likelihood principle. In：“Second identification of Larvae of the Carabidae found in International Symposium on Information Theory” cultivated fields and paddy-fields（Suppl. I）. Bull. （Petrov, B. N. and Csaki, F. eds）pp. 267 − 281, Nat. Inst. Agr. Sci. C, 23：113 − 143（in Japanese Akademiai, Kiado. with an English summary）. Aya, S.（2004）Recent changes of ecological Habu, A. and Sadanaga, K.（1971）Discriptions of some environment in the Yodo River. Journal of Urban larvae of the Carabidae found in cultivated fields Living and Health Association 48：334 − 340（in and paddy-fields（III）.Jpn. J. Ent. 39：159− 166（in Japanese）. Japanese with an English summary）. Bartoń, K.（2012）MuMIn: Multi-model inference. R Hauer, F. R. and Lorang, M. S.（2004）River regulation, package version 1.6.6. http://cran.r-project.org/ decline of ecological resources, and potential web/packages/MuMIn/index.html（accessed on for restoration in a semi-arid lands river in the 15 January 2012）. western USA. Aquat. Sci. 66：388 − 401. Broström, G. and Holmberg, H.（2011）glmmML： Hill, M. O. and Gauch, H.（1980）Detrended Generalized linear models with clustering. R correspondence analysis: an improved ordination package version 0.82-1. http://CRAN.R-project.org/ technique. Plant Ecol. 42：47 − 58. package=glmmML（accessed on 15 January 2012）. Inoue, H.（1953）Life history of Chlaenius micans in Bunn, S. E. and Arthington, A. H.（2002）Basic Hokkaido. Sin-Konchu 6：43 − 44（in Japanese）. principles and ecological consequences of altered Ishii, M., Hirowatari, T., Yasuda, T. and Miyake, flow regimes for aquatic biodiversity. Environ. H.（1996）Species diversity of ground beetles in Mgmt. 30：492 − 507. the riverbed of the Yamato River. Jpn. J. Environ. Follner, K., Hofacker, A. and Glaeser, J.（2009） Entomol. Zool. 8：1 − 12. Accurate environmental bioindication in floodplains Ishitani, M.（1996）Ecological studies on ground in spite of an extreme flood event. River. Res. Applic. beetles（Coleoptera：Carabidae, Brachinidae） 26：877 − 886. as environmental indicator. Misc. Rep. Hiwa Mus. Fujisawa, T., Lee, C. M. and Ishii, M.（2012）Species nat. Hist. 34：110pp（in Japanese with an English diversity of ground beetle assemblages in the summary）. distinctive landscapes of the Yodo River flowing Ishitani, M., Tsukamoto, T. and Ikeda, K.（1997） through northern Osaka Prefecture, central Japan. Faunal and biological studies of ground beetles Jpn. J. Environ. Entomol. Zool. 23：89 − 100. （Coleoptera; Carabidae and Brachinidae）:（1） Fujita, A., Maeto, K., Kagawa, Y. and Ito, N.（2008） species compositions on the banks of the same Effects of forest fragmentation on species richness river system. Jpn. J. Ent. 65：704 − 720. and composition of ground beetles（Coleoptera： Ishitani, M. and Yano, K.（1994）Species composition Carabidae and Brachinidae）in urban landscapes. and spatial distribution of ground beetles Entomol. Sci. 11：39 − 48. （Coleoptera）in a forage crop field. Jpn. J. Ent. 62： Gerisch, M., Schanowski, A., Figura, W., Gerken, 201 − 210. B., Dziock, F. and Henle, K.（2006）Carabid Ishitani, M., Kotze, D. J. and Niemelä, J.（2003）

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淀川の地表性甲虫類に及ぼす河川改修と自然再生事業の影響

藤澤貴弘・石井実

大阪府立大学大学院生命環境科学研究科

淀川の河川敷は 1971 年からのダムの建設や河床の掘削などの河川改修工事によって大きく変化したが，一方で乾燥化から河川敷の環境を保全するために，高水敷の切り下げなどの自然再生事業が行われている．このような人為改変の影響を明らかにするため，無餌ピットフォールトラップ法を用いた地表性甲虫類（オサムシ科）の捕獲調査を 2009 年４月から 12 月まで行った．調査地点は 13 地点設定し，トラップは月に２週間設置し，１週間毎に中身を回収した．加えて，環境要因として，各地点の河川敷の状態（高水敷か低水敷か），冠水期間，土壌水分割合，土壌の中央粒径値を計測した．調査の結果全地点から合計 65 種 8,697 個体を捕獲した．一般化線形混合モデル（GLMM）の結果，オオトックリゴミムシ，オオナガゴミムシ，オオクロナガゴムシなどの９種の個体数は低水敷の存在と，冠水期間もしくは土壌水分割合と正の相関を示し，それに対して，ヤコンオサムシ，オオゴミムシ，オオクロツヤヒラタゴミムシなどの 10 種は低水敷の存在や，土壌水分割合もしくは冠水期間に対して負の相関を示した．除歪対応分析（DCA）の結果前者は第１軸の値の高い方に配置されたのに対して，後者は値の低い方に配置された．さらに，各地点の地表性甲虫群集は高水敷と低水敷間で異なっていた．この結果は好湿性の種は低水敷を特徴付けるのに対して，撹乱の少ない環境を好む種は高水敷を特徴づけていることを示している．自然再生事業は低水敷の拡大に伴う地表性甲虫類の生息場所の異質性の維持によって，好湿性種に対して有利に働いたと考えられる．

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