The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. ...The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.展开更多
森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特...森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特征进行了对比分析。结果表明:处于森林演替不同阶段的交错带,在由阔叶林、针阔叶混交林到针叶林的演替过程中,Shannon-W e iner多样性指数、M arga lef丰富度指数均表现出单峰变化趋势,在演替中后期的针阔叶混交林阶段,指数值最高。S im pson优势度指数则表现出凹形变化,不同于多样性、丰富度指数,在演替中后期,达到最低值。P ie lou均匀度指数表现出下降趋势。交错带内群落与相邻群落相比,Shannon-W e iner多样性指数较高,具有高的物种多样性,边际效应表现为正效应。M arga lef丰富度指数变化与Shannon-W e iner多样性指数变化不一致,只在一定程度上证明了边际正效应的影响。两指数共同反映出研究地区的森林交错带内群落具有较高的物种多样性。展开更多
Background: Sympatric species adapt to, and temporally or geographically segregate access to similar limiting factors.Methods: We compared nesting habitat and diet affinities of six raptor species in central India bet...Background: Sympatric species adapt to, and temporally or geographically segregate access to similar limiting factors.Methods: We compared nesting habitat and diet affinities of six raptor species in central India between the years 20062015.Results: A large composition of reptiles in the diet was characteristic for Circaetus gallicus, Spilornis cheela and Elanus caeruleus, while Aquila fasciata, Falco chicquera and Nisaetus cirrhatus show a higher proportion of birds. Species with greatest similarity of diet were C. gallicus and S. cheela. Considering the environmental characterization of areas where raptors built the nest, some species were ecologically closer than others. N. cirrhatus and S. cheela were related to the presence of water bodies, dry deciduous forest and evergreen forests, while E. caeruleus and C. gallicus preferred more open habitats. A. fasciata bred either on cliffs or trees, F. chicquera on trees or mobile towers, and the other four species built their nests exclusively in trees.Conclusions: We conclude that although there was overlap in diet and nesting ecology for a number of species, the geographical separation likely limits competition for resources.展开更多
基金the National Natural Science Foundation of China (No. NSFC41476129)the Shanghai Leading Academic Discipline Project (Fisheries Discipline)supported by Shanghai Ocean University International Center for Marine Studies and Shanghai 1000 Talents Program
文摘The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.
文摘森林交错带富于高的生物多样性。应用Shannon-W e iner指数、S im pson指数、M arga lef指数、P ie lou指数,研究了关帝山次生林区森林交错带中处于不同演替阶段的群落物种多样性动态特征,同时对交错带内群落与相邻群落的物种多样性特征进行了对比分析。结果表明:处于森林演替不同阶段的交错带,在由阔叶林、针阔叶混交林到针叶林的演替过程中,Shannon-W e iner多样性指数、M arga lef丰富度指数均表现出单峰变化趋势,在演替中后期的针阔叶混交林阶段,指数值最高。S im pson优势度指数则表现出凹形变化,不同于多样性、丰富度指数,在演替中后期,达到最低值。P ie lou均匀度指数表现出下降趋势。交错带内群落与相邻群落相比,Shannon-W e iner多样性指数较高,具有高的物种多样性,边际效应表现为正效应。M arga lef丰富度指数变化与Shannon-W e iner多样性指数变化不一致,只在一定程度上证明了边际正效应的影响。两指数共同反映出研究地区的森林交错带内群落具有较高的物种多样性。
基金The Advance Postdoc. Mobility fellowship from the Swiss National Science Foundation(SNSF:P300PA-161014 to YS)The Swiss State Secretariat for Education,Research,and Innovation(SERI:13.0146 to HMS)+1 种基金The Swiss National Science Foundation(SNSF:31003A_166448/1 to HMS)the EU COST Action FA1203 ‘Sustainable management of Ambrosia artemisiifolia in Europe(SMA-RTER to HMS)’
文摘Background: Sympatric species adapt to, and temporally or geographically segregate access to similar limiting factors.Methods: We compared nesting habitat and diet affinities of six raptor species in central India between the years 20062015.Results: A large composition of reptiles in the diet was characteristic for Circaetus gallicus, Spilornis cheela and Elanus caeruleus, while Aquila fasciata, Falco chicquera and Nisaetus cirrhatus show a higher proportion of birds. Species with greatest similarity of diet were C. gallicus and S. cheela. Considering the environmental characterization of areas where raptors built the nest, some species were ecologically closer than others. N. cirrhatus and S. cheela were related to the presence of water bodies, dry deciduous forest and evergreen forests, while E. caeruleus and C. gallicus preferred more open habitats. A. fasciata bred either on cliffs or trees, F. chicquera on trees or mobile towers, and the other four species built their nests exclusively in trees.Conclusions: We conclude that although there was overlap in diet and nesting ecology for a number of species, the geographical separation likely limits competition for resources.
