Estimating the adult population size of ground beetles (Carabidae) using the removal method

長野県にある信州大学農学部構内の森林内とその近くの野菜畑において, 除去法を用いた地表徘徊性ゴミムシ類成虫の個体数推定を行った. プラスチック製の境界で区切られた40m²の区画に, 乳酸飲料を入れた15個のプラスチック・トラップをセットし, 10日間毎日ゴミムシを回収した. 調査は森林では2002年の9月末, 野菜畑では2003年の10月初めに行われた. 森林での優占3種はSynuchus cycloderus, Pteroslichus subovatus, Synuchus nitidusで, 野菜畑ではHarpalus griseus, Harpalus sinicus, Amara simplicidensであった. 全ゴミムシ類と優占3種の個体数およびm²当たりの密度は, いくつかある除去法の中で回帰法と最尤法を用いて行われた. 森林内では合計250個体のゴミムシ類が捕獲され, 回帰法による推定値は254個体であった. また野菜畑では176個体の採集で, 推定値は180個体であった. 最尤法による推定値は回帰法とほぼ同じ値で, 10回の実際の採集個体数と推定値がほぼ等しかった. またある時点の捕獲個体数とその時点までの累積捕獲個体数の相関係数は-0.9以下であり, 推定精度も0.12以下の値であった. ゴミムシ類の個体数推定に応用する上での除去法の前提条件や捕獲回数と推定精度の関係が議論された.Adult population sizes of ground beetles (Carabidae) in a forest and vegetable field in Nagano Prefecture, Japan were estimated using the removal method. Removal collections using 15 pitfall traps with a lactic acid beverage were conducted at 40-m² survey sites enclosed by a thick plastic sheet for 10 days in September 2002 in the forest site and October 2003 in the field site. Dominant species were Synuchus cycloderus, Pterostichus subovatus and S. nitidus in the forest, and Harpalus griseus, H. sinicus and Amara simplicidens in the field. Population sizes within the 40-m² sizes and the density(/m²) of total carabid beetles and dominant species were estimated by the regression and maximum likelihood methods. A total of 250 and 176 carabid beetles were caught in the forest and field sites, and estimates by the regression method were 254 and 180 individuals, respectively. Estimates of dominant species and total carabid beetles by the maximum likelihood method were almost equal to those obtained by the regression method. The observed numbers caught from 10 trappings were almost the same as the estimated values. The correlation coefficients between the number of individuals captured during the ith trapping and the total number captured prior to the ith trapping were less than -0.9, and the precision level of the estimations was less than0.12. The prerequisite for the removal method and appropriate number of trappings required for estimating carabid population size were discussed in relation to the precision level of the estimations.Article環動昆 15(4): 239-249 (2004)journal articl

Damage Analysis of Pine Wilt Disease Using GIS in Komagane City Forest, Nagano Prefecture, Japan

The purpose of this study is to detect and analysis of pine wilt damaged area in Komagane City, Nagano Prefecture. The pinewood nematode has introduced pine wilt which is an important non-native disease and causes harmful condition to the red pine tree and the forest. The aim of this study was to make a clear concept of damage and the present status of the red pine tree by applying GIS. This study is based on both primary and secondary data. The result determines the comparison of forest condition before and after the attack of pine beetles.Article信州大学農学部紀要. 46(1-2): 93-98 (2010)departmental bulletin pape

Species composition and forest structure in tropical moist deciduous forest of Bangladesh-a case study in Thakurgaon

This study was conducted in the tropical moist deciduous forest in Bangladesh to describe the species composition, diversity, and the forest structure. There were three plots established in Ranishonkoil, Ruhia, and Baliadangi forest beat in Thakurgaon. A total of 126 tree species, 1,991 stems (663 ha(-1)) of a parts per thousand yen10-cm girth were listed. Tree communities in these forest region differed in dominance, composition, diversity, and structure; and tree stand density varied from 651 to 685 ha(-1). Species diversity (H(1)) ranges from 3.11 to 3.48. Meliaceae, Myrtaceae, and Rubiaceae were the most abundant families within the three plot area. Study site 2 is more diverse at spatial scale and taxonomic levels due to high rainfall and favorable edaphic condition. This study will help the foresters as baseline information for monitoring and sustaining diversity of tropical moist deciduous forests in Bangladesh.ArticleARABIAN JOURNAL OF GEOSCIENCES. 4(7-8):1315-1321 (2011)journal articl

Evaluation of Environments by the Species Composition of Carabid Beetles in Different Husbandry Fields

To clarify whether the species composition of carabid beetles can be used to evaluate the field environments of 3 different husbandry practices(fertilizer(F), tillage(T) and green manure(Gr)), pitfall trappings were taken between June and October 2003 in Nagano Prefecture, Japan. The surveyed field was divided into 8 plots(7.5m X 14m) growing the same kinds of vegetables, and combinations of the 3 husbandry practices were decided using an experimental design based on 3 factors and 2 levels. ANOVA based on a table of orthogonal arrays of the L⁸(2⁷) type was used for the numbers of carabid beetles, species richness and species diversity. A total of 821 carabid beetles of 6 subfamilies representing 31 species were captured during the survey period. The three dominant species were Dolichus halensis, Pterostichus microcephalus and Harpalus tridens. Through cluster analysis using an a index, the 8 plots were classified into a green manure group and a non-green manure group, except for 1 plot. The numbers of captured beetles of Pterostichinae, especially D. halensis, were significantly more abundant in chemical fertilizer plots and non-green manure plots. For Zabrinae and Harpalinae, more individuals were captured in tillage plots and green manure plots. In the tillage plots and green manure plots, the values of the species diversity index(1/λ and H') were significantly higher. These results suggest that carabid assemblages may be used as a bio-indicator for evaluating the field environments of different husbandry practices.ゴミムシ群集を指標種として栽培されている植物は全く同じであるが, 異なった耕作法が実施された圃場環境の評価の可能性を検討するため, 有機肥料と化学肥料, 耕起と不耕起, 緑肥ありと緑肥なしという3要因2水準の実験計画法に沿った8区画を長野県波田町に設け, ゴミムシ群集の調査を2003年の6月から10月まで行った. 結果の解析は, L₈(2⁷）型直交配列表に従った分散分析を用いた. ゴミムシは合計で31種821個体捕獲され, 優占種は多い順にセアカヒラタゴミムシ, コガシラナガゴミムシ, コゴモクムシであった. 類似度指数αをもとにしたクラスター分析では, 8区画は緑肥ありグループとなしグループに分かれた. 分散分析の結果, ナガゴミムシ亜科, 特にセアカヒラタゴミムシでは化学肥料区と緑肥なし区で個体数が多く, 反対にマルガタゴミムシ亜科とゴモクムシ亜科では耕起区と緑肥あり区で個体数が多かった. また耕起区と緑肥あり区では多様度指数(1/λとH')が有意に高くなった. 以上の結果から, ゴミムシ群集を指標種として耕作法が異なった圃場環境を評価できる可能性が示唆された.Article環動昆 16(1): 39-47 (2005)journal articl