Nitrogen dynamics in the hyporheic zone of a forested stream during a small storm, Hokkaido, Japan

Water and dissolved nitrogen flows through the hyporheic zone of a 3rd-order mountain stream in Hokkaido, northern Japan were measured during a small storm in August 1997. A network of wells was established to measure water table elevations and to collect water samples to analyze dissolved nitrogen concentrations. Hydraulic conductivity and the depth to bedrock were surveyed. We parameterized the groundwater flow model, MODFLOW, to quantify subsurface flows of both stream water and soil water through the hyporheic zone. MODFLOW simulations suggest that soil water inflow from the adjacent hill slope increased by 1.7-fold during a small storm. Dissolved organic nitrogen (DON) and ammonium (NH ₄ ⁺ ) in soil water from the hill slope were the dominant nitrogen inputs to the riparian zone. DON was consumed via mineralization to NH ₄ ⁺ in the hyporheic zone. NH ₄ ⁺ was the dominant nitrogen species in the subsurface, and showed a net release during both base and storm flow. Nitrate appeared to be lost to denitrification or immobilized by microorganisms and/or vegetation in the riparian zone. Our results indicated that the riparian and hyporheic system was a net source of NH ₄ ⁺ to the stream.     

Abundance,population structure and vertical distribution of dominant calanoid copepods on the eastern Weddell Sea shelf during a spring phytoplankton bloom

The main emphasis of this study was to analyse the short-term development of abundance, population structure and vertical distribution of the dominant calanoid copepods during a phytoplankton bloom in the coastal area of the eastern Weddell Sea in December 2003. Microcalanus pygmaeus was by far the most abundant calanoid species. Metridia gerlachei, Ctenocalanus citer, Calanoides acutus, Calanus propinquus and the ice-associated Stephos longipes were also present in considerable proportions. The observed changes in the population characteristics and parameters of these species are described in detail and discussed in the context of the spring phytoplankton bloom. A conspicuous event occurring during the final stage of the study was the development of a strong storm. While the results suggest that this storm did not have any considerable influence on the populations of all other investigated copepod species, it very likely caused pronounced changes in the S. longipes population present in the water column. Before the storm, S. longipes was found primarily in the upper 100 m of the water column, and its population was dominated by adults (mean proportion = 41%) and the copepodite stage I (mean proportion = 30%). After the storm, the abundance increased considerably, and the copepodite stage I contributed by far the largest proportion (53%) of the total population indicating that the early copepodite stages probably had been released from the sea ice into the under ice water layer due to ice break-up and ice melt processes caused by the storm.     

Photosynthetic Pathways and Life Form Types for Native Plant Species from Hulunbeier Rangelands,Inner Mongolia,North China

Photosynthetic pathway Types (C₃, C₄, and CAM) and life forms of native species from Hulunbeier rangelands, north China were studied. Of the total 258 species, 216 species in 132 genera and 42 families had C₃ photosynthetic pathway, including dominant herbs, e.g. Stipa baicalensis Roshev. and Leymus chinensis (Trin.) Tzvel., Filifolium sibiricum Kitam. and Arudinella hirta (Thunb.) Koidz. 38 species in 28 genera and 10 families were found with C₄ photosynthesis, and 4 species in 2 genera and 1 family had CAM photosynthetic pathway. The occurrence of C₄ species was common in Gramineae and Chenopodiaceae, and the two families were leading ones within C₄ plants. More than 52 % of the total 258 species were in H form, 21 % in Th form, 19 % in G form; the other life form Types, e.g. Ch, M, N, and HH, formed less than 3 %. 68 % of C₄ species were in Th form and 24 % in H form, indicating that these Types were the dominant life forms for C₄ species in the rangeland region. The occurrence of C₄ species was closely related with plant habitats, disturbed lands had the highest C₄ abundance (55 % of the total C₄ species), followed by grasslands and sandy soil, and forests had the lowest C₄ abundance (8 %). Hence the occurrence of C₄ species could be efficient indicator for rangeland dynamics in Hulunbeier rangelands.     

海南岛次生低地雨林棕榈藤伴生群落优势种生态位研究

以海南岛甘什岭自然保护区次生低地雨林群落优势种及棕榈藤为试验材料,通过重要值筛选群落优势种,利用生态位宽度、相似性比例和生态位重叠探究棕榈藤与各林层优势种对资源的作用机制,为棕榈藤资源保护和利用提供理论参考。结果显示:(1)青梅(Vatica mangachapoi)和铁凌(Hopea reticulata)为群落建群种,5种棕榈藤在整个群落中具有相对较高的重要值,但差异较大,其中杖藤(Calamus rhabdocladus)最大(0.286),小钩叶藤(Plectocomia microstachys)最小(0.053),其排序为:杖藤大白藤(C.faberii)黄藤(Daemonorops jenkinsiana)白藤(C.tetradactylus)小钩叶藤。(2)5种棕榈藤在群落中具有较大的生态位宽度,其中杖藤最大(Bi和Ba分别为2.900和0.612),且明显大于草本层,但与其他林层优势种差异小。(3)棕榈藤种间与优势种均表现出较低的生态位相似性比例,除黄藤与亮叶鸡血藤(Callerya nitida)外,各林层优势种与所有棕榈藤种相似性比例最高的物种相同,为益智(Alpinia oxyphylla)、百足藤(Pothos repens)、铁凌和青梅;藤种间,杖藤与各其它棕榈藤具有较高的生态位相似性比例,小钩叶藤最小。(4)林层优势种和棕榈藤的Lik和Lki值总体较低,均低于0.1,且生态位宽度大的不一定重叠程度越高;其中0~0.023的重叠数量占总数的63.5%,0.023~0.046为36.0%,0.046的仅占0.5%。研究认为,棕榈藤在群落中具有相对较高的资源利用能力,但种间差异较大,棕榈藤种间及其与优势种间均表现为生态位分化,物种间倾向于资源共享。     

Acute toxic impacts of three heavy metals (copper,zinc, and cadmium) on <Emphasis Type="Italic">Diaphanosoma brachyurum</Emphasis> (Cladocera: Sididae)

Diaphanosoma brachyurum (Cladocera: Sididae) is a common limnetic species in summer-temperate and tropical water bodies. Few studies have investigated the sensitivity of D. brachyurum to toxic chemicals despite this species often being dominant in natural lakes and ponds. We performed acute toxicity tests of three heavy metals, copper (Cu), zinc (Zn), and cadmium (Cd), to D. brachyurum. For D. brachyurum, the lethal concentration (LC)₅₀ values of Cu (24-h LC₅₀ = 16.4 μg/L, 48-h LC₅₀ = 10.4 μg/L) and Zn (24-h LC₅₀ = 253.4 μg/L, 48-h LC₅₀ = 174.1 μg/L) were lower than those for D. magna, one of the most used test organisms for toxic chemicals. On the other hand, for D. brachyurum the 24-h LC₅₀ of Cd (166.4 μg/L) was much greater than that for D. magna, and the 48-h LC₅₀ of Cd (69.8 μg/L) was comparable. Our results indicate that D. brachyurum may be more strongly influenced by Zn and Cu than is D. magna. It is likely that the summer plankton community in which Diaphanosoma species is dominant is more sensitive to heavy metals than a community in which Daphnia species are dominant.     

Abundance,diversity and temporal activity of adult Culicoides spp. associated with cattle in West Bengal,India

Relative abundance, species composition and temporal activity of Culicoides midges were studied for a period of 2 years (2012–2014) using suction ultra violet light traps at two sites located in the agriculture heartland of West Bengal, India. Surveillance in close proximity to cattle recorded predominance of five species with C oxystoma and C. peregrinus as the most dominant species followed by C. fulvus, C. innoxius and C. anophelis. The temporal activity of midges was investigated for seven consecutive nights at one site in August-September, 2012 and the predominant species was Culicoides oxystoma followed by Culicoides peregrinus. All of the species exhibited crepuscular activity with their flight activity increasing from dusk to dawn. Engorged adults constituted dominant age group in collections. Studies on population ecology of the adults midges are of considerable importance predicting for the epidemicity of midge-borne diseases in cattle.     

千岛湖次生林优势种植物光合生理生态特性

对千岛湖次生林优势种马尾松(Pinus massoniana)、苦槠(Castanopsis sclerophylla)、石栎(Lithocarpus glaber)、青冈(Cyclobalanopsis glauca)在不同季节的光合作用日变化、光响应、CO2响应以及相对叶绿素含量进行了分析,以期了解群落演替的内在机制。结果表明:(1)马尾松的净光合速率(Pn)日变化在4个季节均呈"单峰"曲线;苦槠在8月呈"双峰"曲线,其他3个月份均呈"单峰"曲线;石栎和青冈在5月、8月和11月的Pn日变化均为"双峰"曲线,有明显的光合"午休"现象,2月为"单峰"曲线。(2)马尾松和苦槠的Pn日积累值为8月最高,石栎和青冈为11月最高,且均与其他3个月均差异显著。4种优势种在4个季节的Pn日积累值的平均值大小为马尾松苦槠青冈石栎,差异显著。(3)4个季节中,光饱和点(LSP)、光补偿点(LCP)、最大净光合速率(Amax)、暗呼吸速率(Rd)、最大羧化速率(Vcmax)、最大电子传递速率(Jmax)均以马尾松最高,表观量子效率(AQY)为马尾松最低。青冈在4个季节中具有最低的LSP、Rd和最高的AQY。苦槠和石栎的光合特性介于马尾松和青冈之间。(4)相对叶绿素含量以青冈最高,马尾松最低。总之,马尾松属强阳性树种,苦槠为阳性树种,石栎具有一定的耐荫性,青冈的耐荫性较强。     

Disturbance events affecting phytoplankton biomass,composition and species diversity in a shallow,eutrophic, temperate lake

The seasonal changes in phytoplankton biomass and species diversity in a shallow, eutrophic Danish lake are described and related to different disturbance events acting on the phytoplankton community.Both the spring diatom maximum and the summer bloom of the filamentous blue-green alga, Aphanizomenon flos-aquae (L.) Ralfs, coincided with low values of phytoplankton species diversity and equitability. Diatom collapse was mainly due to internal modifications as nutrient depletion (Si, P) caused by rapid growth of phytoplankton, and increased grazing activity from zooplankton. A large population of Daphnia longispina O.F. Müller in June effectively removed smaller algal competitors, thus favouring the development of a huge summer bloom (140 mm³ l^–1) of Aphanizomenon flos-aquae. Heavy rainfall and storms in late July increased the loss of Apahnizomenon by out-flow and disturbed the stratification of the lake. These events caused a marked decline in phytoplankton biomass but had no effect on species diversity. A second storm period in late August circulated the lake completely and was followed by a rapid increase in phytoplankton diversity, and a change in the phytoplankton community structure from dominance of large, slow-growing K-selected species (Aphanizomenon) to small, fast-growing r-selected species (cryptomonads).     

28. Andorran high Pyrenees (Perafita Valley,Andorra): SerraMijtana fen

Airborne yeasts were collected with 6‐stage Andersen samplers indoors and outdoors in rural and urban areas in southern Finland in 1982–1983, usually twice a month (but once a month only during the period of snow cover). The predominant yeast genus was Sporobolomyces followed by Rhodotorula and Cryptococcus. The most frequently isolated species were Sporobolomyces roseus, Sp. holsaticus, Rhodotorula minuta, Rh. glutinis, Rh. rubra, Cryptococcus albidus and Cr. laurentii. Ascomycetous yeasts were caught infrequently; for example Candidas occurred in samples only occasionally. Numbers of yeasts indoors were significantly correlated with those out of doors in the country but not in town although numbers outdoors in town and country were correlated. Species found indoors were similar to those found out of doors. Numbers of yeast cells in the air were always small, never exceeding 50 CFU m^‐3 and clearly below estimated threshold values for airborne fungi causing allergic reactions.     

川西亚高山次生林恢复过程中乔木层优势种变化及其影响因子

川西亚高山森林在20世纪下半叶遭受长时期连续砍伐,形成了采伐迹地上天然次生林恢复演替序列。该研究采用空间代替时间方法,以立地条件相似的暗针叶林作为对照,分析川西亚高山暗针叶林采伐迹地上次生林自然恢复过程中乔木层优势种组成及其影响因子。结果表明:(1)研究区亚高山天然次生林恢复演替过程中,不同演替阶段土壤各养分差异显著,其中土壤总氮、土壤总磷、土壤有效磷、土壤有效氮均在针阔混交林阶段最高,土壤pH值的变化在5.42～7.39范围波动,土壤有机碳随恢复的进行而增加,土壤C/N主要集中在15左右,只有针叶林达到18.62。(2)研究区次生林以16个乔木树种为主,针叶树种主要有粗枝云杉、岷江冷杉,阔叶树种主要有红桦、青榨槭等,且不同恢复阶段的群落乔木层优势种差异显著(R_(ANOSINM)=0.439,P0.001)。(3)多元回归树分析发现,次生林乔木层优势种组成主要受林龄、土壤有机碳和总氮的影响,其中在次生林恢复演替后期(80a后),乔木层组成可能主要由于种间竞争导致,在次生林恢复演替前、中期(80a前),环境选择可能是影响乔木层组成差异的主导因素。(4)反向选择筛选结果显示,土壤总氮、海拔高度、土壤有效磷和土壤有机碳是影响乔木层优势种差异的主要因子。     

基于克隆文库法研究古尔班通古特沙漠蓝藻多样性

该研究采用克隆文库法研究古尔班通古特沙漠藻类生物结皮中蓝藻多样性及分布。在古尔班通古特沙漠不同区域采集10份藻类结皮代表性土样,分别构建古尔班通古特沙漠蓝藻16S rRNA和psbA基因克隆文库,并进行系统发育分析,对蓝藻多样性和丰度与环境因子进行关联分析,研究蓝藻分布特点及影响因子。结果显示:(1)16S rRNA基因系统发育树中包括具有明确分类地位的蓝藻有6科10属(占总克隆文库的94.85%)和一个未分类蓝藻属,其中颤藻属(Oscillatoria)和微鞘藻属(Microcoleus)分别占克隆文库的42.54%和37.16%,为古尔班通古特沙漠蓝藻优势属;psbA基因系统发育树中仅鉴定有蓝藻类群4科4属,但优势属与前者结果一致。(2)10个样点藻类结皮中所含蓝藻种类不尽相同,但每个采样点都出现颤藻属和微鞘藻属,证明这二者是古尔班通古特沙漠藻类结皮中的优势属;且样点Gur2和Gur17中蓝藻种类较多,Gur3、Gur5和Gur9中种类较少,但Gur2、Gur3、Gur5和Gur17相对地理位置较近,表明地理位置不是影响蓝藻分布的主要因素。(3)RDA(Redundancy analysis)分析结果显示,微生物量氮(MBN)和土壤有机碳(SOC)对蓝藻多样性影响程度最大,其次是硝态氮(NO~-_3-N)、微生物量碳(MBC),全磷(TP)和全钾(TK)对其影响程度最小。研究表明,古尔班通古特沙漠不同区域沙漠蓝藻多样性和土壤理化性质具有空间异质性,综合分析可得沙漠中南部藻类结皮土壤营养最为丰富,蓝藻多样性较高,而东部和西部土壤营养较为贫瘠,蓝藻丰富度和多样性较低。     

Leaf litter decomposition of canopy trees, bamboo and moss in a montane moist evergreen broad-leaved forest on Ailao Mountain, Yunnan, south-west China

Litter decomposition and nutrient release of selected dominant synusiae in an old-growth, evergreen, broad-leaved mossy forest on Ailao Mountain, Yunnan, south-west China, were studied over a 22-month period. The species studied were three dominant tall tree species, Lithocarpus xylocarpus Markg., Lithocarpus chintungensis Hsu et Qian and Castanopsis wattii A. Camus; one dominant understory species (the bamboo Sinarundinaria nitida Nakai); and a mixture of dominant mosses (including Homaliodendron scalpellifolium Fleisch, Symphyodon perrottetti Mont., Herberta longifolissa Steph. and Bazzania albicans Horik.). Fast initial litter decomposition was followed by lower rates. Decomposition rates of canopy species and bamboo leaf litter appear to be controlled by the initial concentration of lignin, nitrogen (N) and phosphorus (P) more than by morphological features of the leaves. The decay rate of moss litter was less correlated with nutrient composition and lignin concentration in initial mass. The order of decomposition rates was Castanopsis wattii > L. xylocarpus > L. chintungensis > bamboo > moss. The decomposition rate constants (k) of the leaf litter for the canopy species L. xylocarpus, L. chintungensis and Castanopsis wattii were 0.62, 0.50 and 0.64, respectively, and 0.40 and 0.22 for bamboo and moss, respectively. Turnover time (1/k) for the three canopy species was 1.61 years, 2.0 years and 1.55 years, respectively, and 2.50 years and 4.55 years for bamboo and moss, respectively. The N and P concentration in the decomposing leaf litter increased in the first 6 months and then decreased over the remaining period. There was a relatively rapid initial loss of potassium (K), followed by a slight increase. Each of calcium (Ca) and magnesium (Mg) decreased with time whereas iron (Fe) and manganese (Mn) increased with time to some extent. Nutrient release from decomposing leaf litter was in the order of K > Mg > Ca > N > P > Mn > Fe, except for bamboo (Sinarundinaria nitida) K > Ca > P > N > Mg > Mn > Fe.     

鼎湖山南亚热带天然针阔叶混交林臭氧吸收特征

针阔叶混交林是我国南亚热带针叶林向地带性常绿阔叶林演替的中间林分类型,为我国南亚地区主要森林类型,发挥着重要的生态系统服务功能。基于树干液流技术和对臭氧浓度的连续监测,评价该森林类型的臭氧吸收特征和能力有着重要的环境生态学意义。对鼎湖山天然针阔叶混交林优势种马尾松(Pinus manssoniana)、锥栗(Castanopsis chinensis)、木荷(Schima superba)和华润楠(Machilus chinensis)在自然环境条件下的臭氧吸收能力进行了分析研究。结果表明:在日尺度上,4个优势树种的冠层气孔对臭氧导度(GO_3)和臭氧吸收通量(FO_3)均呈单峰型曲线,其最大值的时间在干季(10月至竖年3月)比湿季(4月至9月)滞后;季节尺度上,臭氧浓度在湿季达到最大值48.94 n L/L,湿季GO_3、FO_3和年臭氧吸收累积量(accumulative stomatal O_3flux,AFst)均显著高于干季(P 0.01),华润楠的臭氧吸收能力最强,在干季和湿季可分别达1.11 nmol m~(-2)s~(-1)和1.71nmol m~(-2)s~(-1)。随着水汽压亏缺(VPD)增大,优势种GO_3降低。光合有效辐射(PAR)超过1500 umol m~(-2)s~(-1)时,优势树种GO_3和FO_3呈下降趋势。针阔叶混交林的年臭氧吸收累积量超过了保护森林树木所采用的临界阈值,可认为鼎湖山针阔叶混交林受臭氧危害的潜在风险较高。     

滇西北高原藏区小型兽类体表寄生蚤的生态位特征

为探讨云南西北高原藏区小型兽类体表寄生蚤的生态位特征,根据海拔和地形等自然环境特点,在德钦县选取42个调查样点,划分为5个垂直带,4种生境,采用铗夜法和笼日法捕获小兽,梳捡其体表寄生蚤,运用生态位宽度指数（B_i）和生态位重叠指数（NO）对其生态位特征进行分析。结果：共梳捡寄生蚤1275头,隶属4科9亚科17属33种,其中迪庆额蚤和云南栉眼蚤为优势种,常见种12种,稀有种19种。在海拔资源轴上,B_i值前三分别是特新蚤德钦亚种0.698、棕形额蚤0.690、斯氏新蚤川滇亚种0.667;生境资源轴上,B_i值前三分别是：无值大锥蚤0.630、特新蚤指名亚种0.57、特新蚤德钦亚种0.537;寄主资源轴上,B_i值前三为绒鼠怪蚤0.584、迪庆额蚤0.567、棕形额蚤0.553;多维生态位宽度来看,特新蚤德钦亚种和迪庆额蚤B_i值较大,分别为1.031、1.019。海拔、生境、寄主生态位重叠指数中,有意义的重叠种对分别占比35.6%、39.39%、9.28%;完全不重叠的种对分别占比26.89%、18.56%、51.14%;完全重叠的种对分别占比2.27%、13.26%和0.19%。三种生态因子中,优势种和常见种的生态位宽度值较大,对资源的利用能力和竞争能力较强。不同生态因子的生态位重叠指数格局不同,与资源轴本身有关。有意义的重叠和完全不重叠的种对占比较多,前者多为优势种、常见种、稀有种两两之间重叠,重叠指数越高,竞争关系越激烈;完全不重叠的种对多为稀有种之间,无资源利用竞争关系。总体来说,德钦县小兽体表寄生蚤种类丰富,生态位分化较为均匀,本研究可为该地蚤传疾病的监测防控提供生态学依据。     

The Branchiopoda (Crustacea: Anomopoda, Ctenopoda and Cyclestherida) of the rain forests of Cameroon, West Africa: low abundances, few endemics and a boreal–tropical disjunction

Aim We provide the first in‐depth study of the Branchiopoda of the rain forests of Cameroon and also of the African continent. Location Surface water environments, Cameroon. Methods Qualitative plankton samples were collected in all types of surface water environments present, ranging from big lakes to water collected in rock crevices or fallen fruit cavities. A tow or hand‐held plankton net of mesh size 100 μm was used, and water volumes filtered were at least several m³ in large water bodies, or half to whole water volume in small water bodies. Results We recorded 61 species (53 first records for the country), based on 700+ samples collected between September 1998 and March 2002. Anomopoda (92%) was the dominant order, followed by Ctenopoda (6.5%) and Cyclestherida (1.5%). Chydoridae (67%) was the most speciose family followed by Macrothricidae (6.5%) and Daphniidae (5%). Alona (11%) was the dominant genus followed by Chydorus (10%) and Pleuroxus (8%). Several species of Chydorinae, especially of the genus Pleuroxus, are shared with continental Eurasia–North America, but are absent from the Mediterranean and desert–steppe–savanna zones of Africa (boreal–tropical disjunction). Daphnia was absent, as in most tropical lowlands. No single species was really abundant, and a majority were rare to very rare, and of restricted occurrence within the rain forest patches. Comparing Africa, South America and Southeast Asia, we found a current total of 196 species for the combined rain forest areas, out of a world total of 500+ species. Systematic trends in richness at three taxonomic levels were the same for all continents: Anomopoda–Ctenopoda–Cyclestherida at ordinal level, Chydoridae–Daphniidae–Macrothricidae–Sididae at family level and Alona–Chydorus–Macrothrix–Diaphanosoma at genus level. Southeast Asia was richest (111 species, 14 endemics) with South America a close second (110 species, 27 endemics). Africa was the most species‐poor (95 species, of which only 5 are endemics). Main conclusions We hypothesize that the post‐Miocene cooling and aridization of the world climate hit the freshwater biota of Africa particularly hard, with more extinction here than elsewhere, and little recolonization. Most extinction occurred in the savanna‐desert belt, and eight disjunct boreal species (four Pleuroxus, Picripleuroxus laevis, Kurzia latissima, Alonella exigua, and Monospilus dispar) survive morphologically unchanged since pre‐Pleistocene times in the Cameroon rain forest. Slow evolution thus appears typical of these cyclic parthenogenetic branchiopods in which sexual recombination occurs only at intervals. Illustrative of the same slow evolution is the fact that the two endemic cladocerans of Cameroon (Nicsmirnovius camerounensis and Bryospilus africanus) belong to tropicopolitan genera of Gondwanan age.     

The role of hemiparasitic plants: influencing tallgrass prairie quality,diversity, and structure

Wood betony, Orobanchaceae (Pedicularis canadensis) and bastard toadflax, Santalaceae (Comandra umbellata) are two root‐hemiparasitic plant species found in tallgrass prairie communities. Natural resource managers are interested in utilizing these species as “pseudograzers” in grasslands to reduce competitively dominant grasses and thereby increase ecological diversity and quality in prairie restorations and urban plantings. We performed an observational field study at 5 tallgrass prairie sites to investigate the association of hemiparasite abundance with metrics of phylogenetic and ecological diversity, as well as floristic quality. Although no reduction in C₄ grasses was detected, there was a significant association between hemiparasite abundance and increased floristic quality at all 5 sites. Hemiparasite abundance and species richness were positively correlated at one restoration site. In a greenhouse mesocosm experiment, we investigated response to parasitism by P. canadensis in 6 species representing different plant functional groups of the tallgrass prairie. The annual legume partridge pea, Fabaceae (Chamaecrista fasciculata) had the greatest significant dry biomass reduction among 6 host species, but the C₄ grass big bluestem, Poaceae (Andropogon gerardii) had significantly greater aboveground biomass when grown with the hemiparasite. Overall, host species biomass as a total community was significantly reduced in mesocosms, consistent with other investigations that demonstrate influence on community structure by hemiparasitic plant species. Although hemiparasites were not acting as pseudograzers, they have the potential to influence community structure in grassland restorations and remnants.     

A new model of lateral plate morph inheritance in the threespine stickleback,Gasterosteus aculeatus

The threespine stickleback,Gasterosteus aculeatus, is polymorphic for the arrangement of lateral bony plates. It is confirmed in this paper that four morphs (not three) should be distinguished in this species: low plated, low plated with a keel, partially plated and completely plated. A new model is proposed to explain the inheritance of these morphs which involves one major gene with three alleles displaying a dominance hierarchy withA (completely plated) dominant toa (low plated) which is dominant toa _k (low plated with keel). The dominance of theA allele is modified to semidominance by a dominant alleleC at a second locus. This scheme explains all the results of relevant breeding experiments published so far. Field data also fulfill predictions derived from this model.     

Abundance and Distribution of Pelagic Larvae of Bivalves and Echinoderms in Busse Lagoon (Aniva Bay,Sakhalin Island)

The taxonomic composition and numbers of pelagic larvae of bivalves in Busse Lagoon and the contiguous areas of Aniva Bay (southern Sakhalin) were studied in 2000–2001. In comparison with 1973–1974, the total density of larvae increased 2–3 times, but their taxonomic composition changed and a redistribution of dominant species occurred. Numbers of bivalve larvae increased at the expense of larvae of Musculista senhousia, Crassostrea gigas, and species of the Tellinidae. In 2000–2001, larvae of Ruditapes philippinarum, Mya arenaria, Swiftopecten swifti, and some other species were encountered in plankton very rarely or were not found at all. The drastic decrease in the larval density of some bivalve species was caused by uncontrolled and nearly total harvesting of mollusks. Larval echinoderm numbers in the lagoon were not high in 2000–2001; larvae of the sea cucumber Apostichopus japonicus and the sea urchin Strongylocentrotus intermedius predominated.     

Effects of plant species and soil history on root morphology,arbuscular mycorrhizal colonization of roots,and biomass in four tallgrass prairie species

Although dominant C₄ grasses in tallgrass prairie are highly mycotrophic, for many non-dominant species neither extent of mycorrhizal colonization nor root morphology effects on plant–soil feedback interactions are known. In a laboratory study conducted from November 2013 to February 2014 at Governors State University (University Park, IL), we grew plants of a dominant C₄ grass (Andropogon gerardii) and three non-dominant forbs (Symphyotrichum laeve var. laeve, Symphyotrichum novae-angliae and Parthenium integrifolium) individually in soil collected in the field beneath a conspecific, collected beneath another study species, or in sterilized soil. The study addressed the following questions: (1) Is extent of mycorrhizal colonization of roots related to root structure? (2) How does soil history interact with plant root traits to influence plant–soil feedback? (3) How might plant–soil feedback patterns influence competitive interactions among study species? We found that proportion arbuscular mycorrhizal fungi (AMF) colonization decreased with increasing specific root length. Soil history had a stronger influence than plant species on total biomass of plants, with all species having highest total biomass when grown in Andropogon soil. Consequently, net, or heterospecific, feedback did not differ among pairwise species combinations, and was not different from 0. While these results suggest that no study species should have a competitive advantage in the field, Andropogon might still have an advantage through mechanisms such as competition for light. Future work in the field and including less mycotrophic species is needed to better understand AMF effects on competitive interactions.