Development of a DNA based aging technique for use in fisheries assessments. Final report, Australian Fisheries Research and Development Corporation Project 2007/033.

The productivity of a fisheries resource can be quantified from estimates of recruitment, individual growth and natural and fisheries-related mortality, assuming the spatial extent of the resource has been quantified and there is minimal immigration or emigration. The sustainability of a fisheries resource is facilitated by management controls such as minimum and maximum size limits and total allowable catch. Minimum size limits are often set to allow individuals the opportunity to reproduce at least once before the chance of capture. Total allowable catches are a proportion of the population biomass, which is estimated based on known reproduction, recruitment, mortality and growth rates. In some fisheries, however, management actions are put in place without quantification of the resource through the stock assessment process. This occurs because species-specific information, for example individual growth, may not be available. In these circumstances, management actions need to be precautionary to protect against future resource collapse, but this often means that the resource is lightly exploited. Consequently, the productivity of the resource is not fully realised. Australia’s most valuable fisheries are invertebrate fisheries (Australian Department of Agriculture Fisheries and Forestry, 2008). For example, Australian fisheries (i.e. excluding aquaculture) production of crustaceans (largely prawns, rock lobster and crab) was 41,000 tonnes in 2006/7, worth $778 million. Production from mollusc (largely abalone, scallops, oysters and squid) fisheries was 39,000 tonnes, worth $502 million. Together, in 2006/7 crustacean and mollusc fisheries represented 58% of the total value of Australian wild fisheries production. Sustainable management of Australia’s invertebrate fisheries is frustrated by the lack of data on species-specific growth rates. This project investigated a new method to estimate age, and hence individual growth rates, in invertebrate fisheries species. The principle behind the new aging method was that telomeres (i.e. DNA end-caps of chromosomes) get shorter as an individual gets older. We studied commercial crustacean and molluscan species. A vertebrate fish species (silver perch, Bidyanus bidyanus) was used as a control to standardise our work against the literature. We found a clear relationship between telomere length and shell size for temperate abalone (Haliotis rubra). Further research is recommended before the method can be implemented to assist management of wildharvested abalone populations. Age needs to be substituted for shell size in the relationship and it needs to be studied for abalone from several regions. This project showed that telomere length declined with increasing age in Sydney rock oysters (Saccostrea glomerata) and was affected by regional variation. A relationship was not apparent between telomere length and age (or size as a surrogate for age) for crustacean species (school prawns, Metapenaeus macleayi; eastern rock lobster, Sagmariasus verreauxi; southern rock lobster, Jasus edwardsii; and spanner crabs, Ranina ranina). For school prawns, there was no difference between telomere length in males and females. Further research is recommended, however, as telomeric DNA from crustaceans was difficult to analyse using the terminal restriction fragment (TRF) assay. Telomere lengths of spanner crabs and lobsters were at the upper limit of resolution of the assay used and results were affected by degradation and possible contamination of telomeric DNA. It is possible that telomere length is an indicator of remaining lifespan in molluscan and crustacean individuals, as suggested for some vertebrate species (e.g. Monaghan, 2010). Among abalone of similar shell size and among lobster pueruli, there was evidence of individuals having significantly longer or shorter telomeres than the group average. At a population level, this may be a surrogate for estimates of future natural mortality, which may have usefulness in the management of those populations. The method used to assay telomere length (terminal restriction fragment assay) performed adequately for most species, but it was too expensive and time-consuming to be considered a useful tool for gathering information for fisheries management. Research on alternative methods is strongly recommended.

Suomenlinnan Kustaanmiekan ketokasvillisuus ja siihen vaikuttavat tekijät

Suomenlinna on yksi Helsingin suosituimmista matkailu- ja kulttuurinähtävyyksistä. Kustaanmiekan, samoin kuin koko Suomenlinnan luonto on muodostunut perinteisestä suomalaisesta saaristoluonnosta ja vuosisatojen saatossa paikalle tulleista linnoituksien kasvistosta. Saaren vaihtelevien elinympäristöjen johdosta alueen kasvillisuus on hyvin rikasta. Linnoituksien monet kasvilajit ovat tulleet tulokaskasveina eri puolilta Eurooppaa sekä Venäjältä. Suurin osa Suomenlinnan alueesta on kallioketoa ja tämän lisäksi myös valliketoa, joista molemmat kuuluvat suojeltaviin alueisiin. Kustaanmiekan niityillä kasvaa keto- ja paahdelajeja, kuten harvinaista ketonoidanlukkoa (Botrychium lunaria L.) sekä ketoneilikkaa (Dianthus deltoides L.). Tämän tutkimuksen ensisijaisena tarkoituksena oli kartoittaa Kustaanmiekan alueen kesäkauden 2009 ketokasvilajisto ja eri putkilokasvilajien runsaus. Tutkimuksessa selvitettiin myös maaperätekijöiden ja alueen hoitohistorian mahdollista vaikutusta ketokasvilajistoon. Tutkimuksessa kartoitettiin kymmenen eri kedon kasvillisuus Suomenlinnan Kustaanmiekan linnoitusalueella. Kedot sijaitsivat eri puolilla Kustaanmiekkaa, sellaisilla paikoilla, missä ketokasvillisuus oli runsainta. Maastotyöt suoritettiin kesä- ja heinäkuussa laskemalla jokaisen kedon ruutujen putkilokasvien peittävyydet sekä listaamalla ylös myös ruutujen ulkopuoliset kevät- ja loppukesän kukkijat touko- ja elokuussa. Maaperän ominaisuuksien määrittämiseksi otettiin kultakin kedolta pintamaanäytteet elokuussa. Muita tutkittuja muuttujia olivat maapinnan kaltevuus sekä sammalen, karikkeen, paljaan maan, kenttäkasvillisuuden pohjakerros ja kallion osuus tutkimusruuduilla. Ketojen kasvillisuuden keskimääräinen korkeus mitattiin kesä- ja heinäkuussa. Kasvistossa oli selviä eroavaisuuksia ketojen välillä. Kasvilajien määrä vaihteli ketojen kokonaislajimäärän ollessa 40-60 kasvilajia. Yhteensä kedoilta löytyi 120 eri putkilokasvilajia, joista useimmat kukkivat sekä kesä- että heinäkuussa. Ketojen kasvilajimäärä vaihteli yhdellä neliömetrillä 6,3-13,6 kasvilajiin, minkä lisäksi Shannon-Wienerin diversiteetti-indeksi vaihteli 1,4-2,3 arvon välillä. Yleisimpiä lajeja, joita kedoilla tavattiin, olivat muun muassa siankärsämö (Achillea millefolium L.), koiranheinä (Dactylis glomerata L.), juolavehnä (Elymus repens L.) ja hopeahanhikki (Potentilla argentea L.). Alueella kasvoi myös muutamia sotatulokaslajeja kuten harmiota (Berteroa incana L.), ukonpalkoa (Bunias orientalis L.) ja karvahorsmaa (Epilobium hirsutum L.). Maaperätekijöillä, kuten suurella fosforin pitoisuudella ei ollut vaikutusta kasvilajien määrään kedoilla. Vain maan pH ja johtoluku korreloivat positiivisesti ketojen kasvillisuuden korkeuden kanssa. Vaikka tulosten perusteella ketojen hoidolla ei ollut vaikutusta ketojen kasvillisuuden määrään, voidaan kuitenkin olettaa oikeanlaisen hoidon parantavan tyypillisten ketokasvien kilpailukykyä muita niittykasveja kohtaan.

Efecto de distancias de siembra y frecuencia de control mecánico de malezas, sobre la dinámica de las malezas y el crecimiento y rendimiento del frijol común (Phaseolus vulgaris L.)

Este experimento fue realizado en la época de postrera de 1993, en la estación experimental La Compañía, ubicada en el municipio de San Marcos, Carazo, con el propósito de determinar el efecto de tres distancias de siembra y frecuencias de control mecánico de malezas sobre la cenosis de las malezas y el crecimiento y rendimiento del frijol común (Phaseolus vulgaris L.), variedad Revolución 84. Los factores en estudio fueron: a) distancia de siembra (0.20 m., 0.40 m. y 0.60 m.) y b) frecuencias de control mecánico de malezas (enmalezado, control durante el período crítico (21 días después de la siembra) y limpia periódica (15, 21 y 28 días después de la siembra). En los resultados se presentan los efectos principales de cada uno de los factores, ya que no se encontró interacciones entre factores. Los resultados se resumen de la siguiente manera: referente a abundancia de individuos de malezas a los 28, 42 y 56 días después de la siembra, se observó menor abundancia y biomasa de malezas en el control limpia periódica. Se determinaron como especies más abundantes y dominantes las siguientes: Melanthera aspera (Jacq) Rich, et Spreng. Melampodium divaricatum (Rich.) DC y Bidens pilosa L. En cuanto a los componentes del rendimiento, se determinó mayor número de plantas en el control periodo crítico, y en distanciamiento de 0.40 m., seguido del control limpia periódica y distanciamiento de 0.20 m. El mayor número de vainas por planta, granos por vaina y los mayores rendimientos se presentaron en el control limpia periódica y en la distancia de 0.40 m. El tratamiento con mejor rentabilidad fue el control durante el periodo crítico y la distancia de siembra de 0.40 m.

Composição florística e estrutura da comunidade arbustivo-arbórea de um trecho de floresta submontana na vertente sudeste do Parque Estadual da Ilha Grande, Angra dos Reis / RJ

O estudo objetivou avaliar a composição florística e estrutural dos componentes arbustivo-arbóreo da Floresta Ombrófila Densa submontana em diferentes estágios de regeneração natural, na vertente sudeste do Parque Estadual da Ilha Grande/RJ. Para o inventário florístico foram realizadas coletas assistemáticas em diferentes trechos nessa vertente. A complementação da lista de espécies foi feita a partir, da consulta às exsicatas dos herbários do Rio de Janeiro (FCAB, GUA, HB, HRJ, R, RB, RBR, RFA, RFFP e RUSU) e do inventário fitossociológico. Foi verificado o status de conservação das espécies inventariadas para a Flora Brasileira. Para o inventário fitossociológico foram estabelecidas 34 parcelas amostrais, totalizando 1,02 ha de área amostrada. Todos os indivíduos arbustivo-arbóreos com DAP ≥ 5 cm foram registrados e, após identificação, foram depositados no Herbário da Universidade do Estado do Rio de Janeiro (HRJ). O pacote estatístico FITOPAC 2.1. foi utilizado para a análise dos dados. A similaridade entre o remanescente investigado neste estudo e as outras quatorze áreas distintas do Rio de Janeiro, da própria Ilha Grande ou não, foi avaliada, utilizando-se o coeficiente de Similaridade de Sorensen; pelo critério de agrupamento por ligação média não ponderada (UPGMA) e pelo método de autorreamostragem para a estrutura de grupos; utilizados os programas PAST v1.34 e Multiv 2.4. A partir do levantamento em herbários e dos inventários florístico e fitossociológico realizados neste trabalho, foram analisados 3.470 registros, sendo 1.778 do levantamento de herbários, 1.536 do levantamento fitossociológico e 156 do inventário florístico. Esses registros corresponderam a 606 espécies ou morfo-espécies de Angiospermas e uma de Pteridófita. Os resultados obtidos revelaram a existência de 22 espécies ameaçadas de extinção para a Flora do Brasil. Dentre, as quais, sete são exclusivas da amostragem fitossociológica: Abarema cochliacarpos (Gomes) Barneby & J.W. Grimes, Chrysophyllum flexuosum Mart., Ficus pulchella Schott ex Spreng., Macrotorus utriculatus Perkins, Myrceugenia myrcioides (Cambess.) O.Berg, Rudgea interrupta Benth e Urbanodendron bahiense (Meisn.) Rohwer. No estudo fitossociológico, inventariou-se 1.536 indivíduos de 217 espécies, subordinadas a 53 famílias. O índice de diversidade de Shannon (H) calculado foi de 4,702 nats/ind e equabilidade (J) de 0,874. As 10 famílias com maior riqueza foram: Myrtaceae (31 spp.), Rubiaceae (21), Fabaceae (17), Lauraceae (12), Euphorbiaceae (11), Monimiaceae (8), Melastomataceae (7), Sapindaceae (7), Sapotaceae (6) e Annonaceae (6). Os 10 maiores Valores de Importância das espécies foram para Chrysophyllum flexuosum (3,43%), Lamanonia ternata Vell. (3,40%), Hyeronima alchorneoides Allemão (2,83%), Actinostemon verticillatus (Klotzsch) Baill. (2,55%), Psychotria brasiliensis Vell. (2,55%), Eriotheca pentaphylla (Vell.) A. Robyns (2,28%), Guatteria australis A. St.-Hil. (2,12%), Mabea brasiliensis Müll. Arg. (2,04%), Miconia prasina (Sw.) DC. (1,89%) e Rustia formosa (Cham. & Schltdl. ex DC.) Klotzsch (1,82%). Amostraram-se 27% de espécies representadas por apenas um indivíduo. As análises florísticas avaliadas a partir do Índice de Similaridade de Sorensen indicaram como principais variáveis para a formação dos blocos, os diferentes valores de diversidade para as áreas e a distribuição fitogeográfica das espécies. Os resultados obtidos junto aos dados dos grupos ecológicos, para os indivíduos da fitossociologia, indicaram maior percentual de indivíduos secundários tardios amostrados. Conclui-se que a área de estudo é uma floresta secundária em estágio intermediário de regeneração, com grande riqueza de espécies, muitas das quais de relevante importância ecológica.

On the occurrence of Pithophora oedogonia (Mont.) Wittr. var. polyspora Rendle et West fil (Cladophoraceae) in the pond of the Wroclaw Botanical Garden [Translation from: Fragmenta Floristica et Geobotanica 22 255-260, 1976]

Species of Pithophora occasionally appear in Europe and are associated mostly with the tropical, higher water plants, cultivated in numerous botanical gardens. In June 1973 pale green, branched threads were discovered in the pond of the Wroclaw Botanical Garden, amongst filaments of Spirogyra crassa (Kutz.) Czurda emend. and Cladophora glomerata (L.) Kutz. floating on the water surface. They were maintained for several weeks in crude cultures and produced numerous, dark akinetes tightly packed with reserve material. This collected material was found to be a member of the family Pithophora, Wittr. Further examinations identified the material as Pithophora oedogonia. The findings point out that it is probable, that species of Pithophora Wittr. can become acclimatized in Europe, primarily in ponds of botanical gardens, where consequently they are able to tangle easily with higher tropical plants.

Florística e fitossociologia da Floresta Atlântica montana no Parque Estadual da Ilha Grande, RJ

Este estudo tem por objetivo ampliar o conhecimento sobre a flora da Ilha Grande, Angra dos Reis, RJ, através da avaliação florística e fitossociológica da comunidade arbustivoarbórea, com Circunferência à Altura do Peito ≥ 15,7 cm (CAP ≥ 5,0 cm) em trechos de Floresta Atlântica montana. Foram alocadas 34 parcelas retangulares e permanentes de 10x30 m, totalizando uma área amostral de 1,02 ha. Foram amostrados todos os indivíduos arbustivoarbóreos vivos, que tiveram aferidas a circunferência do caule, estimada a altura total, altura do fuste e realizada a coleta de material botânico. A identificação dos espécimes foi realizada através da análise das estruturas vegetativas e reprodutivas, comparação em herbários, consultas a literatura especializada e, quando possível, com auxílio de especialistas. O material botânico coletado está sendo incorporado à coleção do Herbário da Universidade do Estado do Rio de Janeiro (HRJ). Procedeu-se a avaliação do status de conservação das espécies determinadas para identificar o grau de ameaça. A estrutura da comunidade inventaria foi analisada através do pacote estatístico FITOPAC 2.1. Inventariou-se 1.847 indivíduos arbustivo-arbóreos vivos, subordinados a 225 espécies ou morfo-espécies de 27 gêneros e 53 famílias botânicas. Este estudo constatou que a Ilha Grande é uma nova área de ocorrência para 53 espécies fanerogâmicas. As famílias mais abundantes foram: Myrtaceae (391 indivíduos), Rubiaceae (337), Euphorbiaceae (100), Fabaceae (84) e Sapotaceae (72). Myrtaceae (69 spp.), Rubiaceae (14), Fabaceae (13), Lauraceae e Sapotaceae (11) foram as famílias que apresentaram as maiores riquezas. O índice de diversidade de Shannon & Weaver (H) obtido foi de 4,609 nats/indvs. e o de equabilidade (J) de 0,851. Os parâmetros fitossociológicos calculados indicaram que Amaioua intermedia Mart. (5,17%), Eriotheca pentaphylla (Vell.) A. Robyns (4,84%), Qualea glaziovii Warm. (2,74%), Vochysia bifalcata Warm. (2,69%), Xylopia brasiliensis Spreng. (2,48%), Heisteria silvianii Schwacke (2,43%), Coussarea nodosa (Benth.) Müll. Arg. (2,38%), Guapira opposita (Vell.) Reitz (2,37%), Manilkara subsericea (Mart.) Dubard (2,02%) e Inga lanceifolia Benth. (1,86%) são as espécies com maiores Valores de Importância (VI). Entre as táxons inventariados foi possível identificar 69 espécies raras, representadas na comunidade por um único indivíduo, e nove espécies com problemas de conservação, dais quais Chrysophyllum flexuosum Mart., Micropholis crassipedicellata (Mart. & Eichler ex Miq.) Pierre e Manilkara subsericea (Mart.) Dubard estão categorizadas como dependentes de conservação; Eugenia prasina O. Berg como vulnerável; Myrceugenia myrcioides (Cambess.) O.Berg como futuramente ameaçada de extinção; Ocotea odorifera Rohwer como ameaçada de extinção e/ou vulnerável a extinção; Pradosia kuhlmannii Toledo como ameaçada de extinção; Solanum carautae Carvalho como espécie rara e Urbanodendron bahiense (Meisn.) Rohwer em perigo de extinção. A distribuição dos indivíduos em classes diamétricas apresentou uma tendência exponencial negativa, sugerindo que a comunidade possui capacidade de autoregeneração. Os resultados da composição florística e da estrutura da vegetação montana do PEIG evidenciaram expressiva riqueza e diversidade de espécies arbóreas, cuja preservação é fundamental para o funcionamento e o equilíbrio desta formação. Palavras-chave: Mata Atlântica. Floresta montana. Fitossociologia. Parque Estadual da Ilha Grande.

The History of Oyster Farming in Australia

Aboriginal Australians consumed oysters before settlement by Europeans as shown by the large number of kitchen middens along Australia's coast. Flat oysters, Ostrea angasi, were consumed in southeastern Australia, whereas both flat and Sydney rock oysters, Saccostrea glomerata, are found in kitchen middens in southern New South Wales (NSW), but only Sydney rock oysters are found in northern NSW and southern Queensland. Oyster fisheries began with the exploitation of dredge beds, for the use of oyster shell for lime production and oyster meat for consumption. These natural oyster beds were nealy all exhausted by the late 1800's, and they have not recovered. Oyster farming, one of the oldest aquaculture industries in Australia, began as the oyster fisheries declined in the late 1800's. Early attempts at farming flat oysters in Tasmania, Victoria, and South Australia, which started in the 1880's, were abandoned in the 1890's. However, a thriving Sydney rock oyster industry developed from primitive beginnings in NSW in the 1870's. Sydney rock oysters are farmed in NSW, southern Queensland, and at Albany, Western Australia (WA). Pacific oysters, Crassostrea gigas, are produced in Tasmania, South Australia, and Port Stephens, NSW. FLant oysters currently are farmed only in NSW, and there is also some small-scale harvesting of tropical species, the coarl rock or milky oyster, S. cucullata, and th black-lip oyster, Striostrea mytiloides, in northern Queensland. Despite intra- and interstate rivalries, oyster farmers are gradually realizing that they are all part of one industry, and this is reflected by the establishment of the national Australian Shellfish Quality Assuarance Program and the transfer of farming technology between states. Australia's oyster harvests have remained relatively stable since Sydney rock oyster production peaked in the mid 1970's at 13 million dozen. By the end of the 1990's this had stabilized at around 8 million dozen, and Pacific oyster production reached a total of 6.5 million dozen from Tasmania, South Australia, and Port Stephens, a total of 14.5 million dozen oysters for the whole country. This small increase in production during a time of substantial human population growth shows a smaller per capita consumption and a declining use of oysters as a "side-dish."

外来入侵种紫茎泽兰生理生态学研究

紫茎泽兰(Eupatorium adenophorum Spreng.)种子萌发的温度范围是10-30 ℃，最适宜的萌发温度是25℃，高温显著抑制其萌发，35 ℃恒温即没有种子萌发。紫茎泽兰种子萌发对于光的需求为中等，在黑暗中发芽率为17%。紫茎泽兰种子萌发的pH 范围是5.0-7.0，最高发芽率是以蒸馏水为介质，其pH为5.7。紫茎泽兰种子的萌发率随着水势的加大而逐渐降低，在水势大于-0.7 MPa 条件下，即没有种子萌发。在盐分含量小于100 mM NaCl 条件下，其发芽率均大于65%;在盐分含量小于250 mM条件下，其发芽率仍大于10%，当盐分含量达到300 mM NaCl时，即没有种子萌发。紫茎泽兰种子在土壤表层其发芽率最高，当埋藏深度为1.5 cm时即没有种子萌发。根据我们所得的实验结果，对比其原产地的气候条件并结合我国的气候条件和土壤条件进行分析，我们预测紫茎泽兰未来在中国的分布范围将局限在云贵高原，尽管在某些气候和土壤环境适宜的条件下仍有可能会形成零星分布区。 研究了紫茎泽兰和飞机草(Eupatorium odoratum L.)在三种环境胁迫条件下（高温、低温、干旱）七种抗氧化酶活性的变化。结果表明：这三种环境胁迫都对两种植物的生物膜系统造成了损伤，造成了植物体内丙二醛含量的升高。紫茎泽兰在这三种环境胁迫条件下，DHAR活性都升高;SOD活性也都升高，但是在低温处理时与对照的差别并不明显;POD和GR活性在低温和干旱处理时升高，在高温处理时降低;CAT活性在高温和干旱处理时降低，在低温处理时升高;MDAR活性在在高温和干旱处理时降低，在低温处理时略微上升，但是与对照的差别并不明显;APX活性则在三种环境胁迫下表现各不相同。通过这些结果可以说明：DHAR对紫茎泽兰抵抗不良环境的损伤具有重要作用。 而飞机草的抗氧化酶系统的变化为：SOD、APX和DHAR在三种环境胁迫下酶活性都升高;CAT在高温胁迫下升高，而在低温和干旱胁迫下酶活性降低;POD和MDAR在高温和干旱胁迫下酶活性升高，而在低温胁迫下酶活性降低;GR在高温和干旱胁迫下酶活性升高，而在低温胁迫下保持不变。以上的研究结果说明，SOD、APX和DHAR是飞机草抵御环境胁迫的关键酶。 通过比较两种植物在温度胁迫下抗氧化酶系统的不同响应，我们研究发现：两种植物之所以对温度的忍耐性不同，在一定程度上是由于它们在温度胁迫时抗氧化酶系统所作出的不同响应，抗氧化酶系统很可能在两种植物抵抗温度胁迫过程中扮演重要角色，即通过有效调节抗氧化酶活性来减少植物体内有害物质-活性氧自由基的积累，从而减少对植物细胞膜的损伤。两者的差别主要是：紫茎泽兰在低温胁迫时，清除活性氧的抗氧化酶都增加，这就减轻了活性氧自由基在植物细胞中的积累，从而可以在一定程度上保护植物。但是，在高温胁迫时CAT, POD, APX, GR和MDAR酶活性并没有随着SOD活性的升高而升高，所以很有可能造成对细胞有毒害作用的H2O2累积，其结果就造成了紫茎泽兰在高温胁迫下叶片细胞膜的过氧化程度较强。而飞机草的情况正相反，在低温胁迫下飞机草叶片细胞膜的过氧化程度较强，抗氧化酶的协调上升出现在飞机草遭受高温胁迫时，而当其处于低温胁迫时抗氧化酶间的变化趋势则出现了很大分歧，这说明飞机草在高温胁迫时较低温胁迫时能够较好地保护自身遭受活性氧自由基的伤害。

外来入侵种紫茎泽兰竞争策略与扩散动态

紫茎泽兰（Eupatorium adenophorum Spreng.）作为重要的外来入侵种之一，已严重破坏了入侵地生态系统的结构与功能，同时使当地农林业生产蒙受巨大的损失。因此，明确紫茎泽兰的竞争策略与扩散潜力，对制定合理的控制措施具有重要意义。 土壤氮素增加常常有助于外来种的入侵，那么降氮能否抵制入侵呢？向土壤中添加碳素，增强微生物对氮素的吸收，从而降低土壤中可被植物吸收的氮素是目前常用的降氮方法。为检验这一假说对入侵种紫茎泽兰的适用性，选取入侵种紫茎泽兰和本地种禾本科雀麦（Bromus japonicus）、菊科鱼眼草（Dichrocephala integrifolia），分别单栽或与紫茎泽兰混栽，向各植物组合中添加碳素（按1650克有机质/平方米计）或氮素（按30克氮素/平方米计），并设立对照进行盆栽实验。在碳素添加条件下，紫茎泽兰地上与地下生物量分别比对照降低了71.9% 和 74.9%，而本地种的生物量却没有受到显著影响。同时，碳素添加导致紫茎泽兰对本地种的竞争强度（RII）明显下降。氮素添加则减弱或逆转了上述碳素的作用。因此，向土壤中添加碳素有助于抵抗氮沉降对外来种入侵的促进作用，特别对抵御那些与氮素有亲和力的入侵种更为有效。在不同氮素条件下，紫茎泽兰对本地种竞争中，资源竞争强度均明显大于化感作用。尽管在紫茎泽兰发育早期化感作用较小，但是，碳素添加使紫茎泽兰可利用氮素减少，激发了化感作用在竞争中占有更大的比例，说明资源竞争与化感是相互结合、共同发挥作用的。 去叶作为模拟采食方法之一，至少可以通过两种方式影响植物竞争。一是去叶对目标种生长产生负面影响，二是邻种去叶有利于目标种生长，进而改变种间竞争关系。基于以上假定，对紫茎泽兰与相邻本地种分别单栽、同种合栽和异种混栽，进行去叶处理。结果恰与假定相悖：在整个生长季内，去叶增加目标株生物量的1.0 – 198.9%。对于入侵种而言，当邻居本地种去叶时，紫茎泽兰能完全弥补竞争产生的负面效应，即它与未去叶的单栽紫茎泽兰生长无显著差异;而紫茎泽兰去叶降低了相邻本地种的生长，加剧了原本由于竞争给对本地种带来的负面影响。因此，去叶效应与邻种的存在与否及邻种的类型均有关。在应用生物控制对目标株采食时，特别是在没有造成严重伤害或致死情况下，可以使本来具有竞争优势的入侵种变得更具强势。竞争与去叶之间存在复杂的相互作用，采食带来的间接效应可能比预想的更为复杂。因此，在生物控制措施实施之前，充分地估计生物控制的间接作用至关重要。 为检验反应—扩散模型（reaction–diffusion model）能否正确模拟紫茎泽兰小尺度扩散速率，本研究调查了四川攀枝花山区5个不同的生境的紫茎泽兰群落。对各样地内紫茎泽兰定位和年龄确定，基于克里金插值法做出其入侵格局的等年线图，通过等年线之间的垂直距离即可得到紫茎泽兰扩散速率的经验值。同时，计算内禀增长率和扩散系数，根据模型计算得到扩散速率的预测值。结果表明：紫茎泽兰扩散速率经验值明显小于模型预测值。因此，尽管反应—扩散模型已在大尺度扩散预测方面得到广泛的应用和验证，但在小尺度上，由于没有借助于复杂的生活史模型和分层模型，单凭反应—扩散模型不足以得到准确的预测。另外，在没有遭受干扰的生境中，可以发现紫茎泽兰扩散早期存在明显的时滞期。倘若这种时滞效应在入侵扩散中是频繁发生的，那么在判定物种是否具有入侵性时，很可能由于物种处于时滞期而被误认为非入侵种。 基于紫茎泽兰入侵至中国60年来所收集到的441已知分布记录和23个环境变量，采用GARP模型对其潜在分布范围做出了预测，并通过Kappa和ROC（receiver–operator characteristic）对预测结果进行检验。结果表明紫茎泽兰目前分布以云贵高原为主体，逐渐向四川盆地东部、山东半岛、东南沿海、台湾沿海以及海南岛等地扩散。冷季降水量、年极端低温和年均最高温对分布影响较大。RDA（Redundancy Analysis）分析结果显示温度和降水是限制紫茎泽兰扩散的重要因素。在过去的20年里，紫茎泽兰已经从温度较高、天气波动较小的亚热带气候逐渐向气候温凉、降水减少的高海拔地区扩散。紫茎泽兰可以适应相对较宽的温度和降水梯度，年均温度在10—22 ˚C，年降水量在800—2000 mm区间均有分布。本研究结果为发展早期预警工作、防止紫茎泽兰在中国进一步入侵提供了科学依据。

紫茎泽兰种群补充特征

外来种紫茎泽兰 (Eupatorium adenophorum Spreng.) 对我国西南地区生态系统的危害已长达50~60年之久，我国于20世纪70年代开展紫茎泽兰的研究，但目前仍然没有能力将其限制在一个可控范围之内，随着我国对生物多样性重要性认识的加深，对于紫茎泽兰的研究也越来越深入。本文以四川攀枝花受入侵生态系统为例，通过对该地区植被、土壤种子库以及当地紫茎泽兰无性繁殖和种子萌发特征开展研究，分析受入侵生态系统的特征，结合紫茎泽兰种群补充特征，揭示紫茎泽兰入侵机制，探索管理受害生态系统的方法。 所选实验点为紫茎泽兰危害严重的地带，群落中紫茎泽兰为优势种，伴生种灌木18种，草本植物65种，草本层以紫茎泽兰最为昌盛，种群构成为1～4年生植株与其荫庇下大量的实生幼苗，Drude多度极大，频度达100%。紫茎泽兰与灌木重要值之间极显著负相关 (P<0.01) ，与其他草本重要值之间极显著负相关 (P<0.01) ，灌木与其他草本重要值间的相关性不显著 (P>0.05) 。说明紫茎泽兰的生长与灌木或草本间存在微妙的此消彼长的关联，充分显示了紫茎泽兰与当地物种间的竞争事实。 紫茎泽兰种子雨前的种子库为所研究地区绝大部分物种的长久性土壤种子库，本地区种子库的组成物种共有13种，包括灌木和草本。紫茎泽兰占整个种子库储量的61.3%，在长久种子库中占有明显的优势;种子库与植被间相似度为0.31，虽然种子库中物种均为植被的组成成分，但是植被中绝大多数物种种子未检测出，种子库中出现的物种与该物种本身的生理生态特性密切相关。种子雨是种子库的来源，紫茎泽兰种子雨前表层种子储量只占种子雨后的7.4%，中下层储量占33.8%，共占41.2%，即每年仅58.8%的种子在当年雨季萌发，剩余的在土壤中保持休眠状态。依 目前的研究结果，本地植被仅靠自然恢复的可能性不大。 紫茎泽兰种子最适发芽温度为25℃;储藏1.5 a后的种子萌发率有所下降，25℃下萌发率由77%下降为66%;紫茎泽兰种子有良好的休眠机制，对生境的干扰可以促进紫茎泽兰长久土壤种子库的形成，为紫茎泽兰种群补充奠定了基础。稀疏的植被有利于紫茎泽兰种子萌发及幼苗建植，对原生植被的破坏则促进了紫茎泽兰实生苗的补充。因而保护原始生境、减少对原生态系统的破坏，是减少和抑制紫茎泽兰种群补充的有效途径。 紫茎泽兰 (克隆) 离体无性繁殖的部位为根颈部分，其他离体部分没有无性繁殖能力或很弱;灌丛和路域生境下的离体部分在给予相同培养条件下，克隆繁殖效益有差别，灌丛生境萌芽较早，而主茎和叶生长速度较慢。拔除干扰对于紫茎泽兰萌生新枝具有刺激作用，对紫茎泽兰植株上部的割取类似于给它提供更新复壮的机会，因此在紫茎泽兰防治过程中一定要注意将其拔除干净，以防后患。

不同环境紫茎泽兰幼苗动态和特征

紫茎泽兰（Eupatorium adenophorum Spreng.）入侵我国已有70余年的时间，目前已经对我国西南地区造成了严重危害，却缺少有效的防治方法加以控制。本研究着眼于紫茎泽兰治理效果，在两片大面积综合防治样地的基础上，针对综合防治后样地紫茎泽兰再生长情况展开调查研究，并在野外观测的基础上设计两项置于样地附近的盆栽实验，研究紫茎泽兰在不同环境条件下的存活情况，以及与不同物种混播的种间竞争情况。 对综合治理1年后的样地中4个紫茎泽兰种群调查、分析结果表明，在不同的生境，采取不同的方法治理紫茎泽兰会导致紫茎泽兰采取不同的生长和繁殖对策进行再生长。紫茎泽兰生长速度为：水分充足的环境大于水分不充足的环境，萌生植株大于实生植株。种植替代物种绞股蓝（Gynostmma pentaphyllum）能够抑制紫茎泽兰的高生长，但在绞股蓝的压迫下紫茎泽兰长成L型，反而增加了冠幅、分蘖数目和单位株高的分枝数。在繁殖方式方面：采用拔除方法治理的区域紫茎泽兰以克隆繁殖为主，而采用喷洒化学除草剂治理的区域则以有性繁殖为主。 固定样方调查显示，紫茎泽兰再生长的1年当中，群落随季节变化而变。群落的盖度、密度和物种丰富度均随着旱季的深入而达到最低，第二年雨季到来后上升，紫茎泽兰在群落中处于绝对优势，尤其是在旱季优势更为明显。一年生紫茎泽兰在旱季部分植株死亡（死亡率为53.38±1.55%），少部分（5.66±0.45%）开花，产生种子的密度约为50 000ind∙m-2。与本地优势灌木物种车桑子（Dodonaea viscosa）、台湾相思（Acacia confuse）和马桑（Coriaria nepalensis）相比，紫茎泽兰具有更快的生长速度，更大的高度、密度和盖度。 紫茎泽兰种子的萌发需要充足的水分和遮荫条件。在盆栽实验当中，浇水或遮荫条件下足量紫茎泽兰的种子能够萌发更多的幼苗，而且幼苗的死亡率也比无浇水或无遮荫的处理低。在遮荫或去除其它物种竞争的条件下，紫茎泽兰幼苗生长速度更快。只要水分充足紫茎泽兰幼苗不会因拥挤而死亡，但是个体平均生物量会因拥挤而减小。 紫茎泽兰幼苗与本地3种草本植物比较结果，在未遮荫条件下，紫茎泽兰幼苗数量极少，且个体也非常小，而相同条件下荩草（Arthraxon hispidus）和含羞草决明（Cassia mimosoides）生长良好;在遮荫条件下荩草、含羞草决明和戟叶酸模（Rumex haxtatus ）与紫茎泽兰相比则几乎没有优势。 成株紫茎泽兰生命力强，难以控制，幼苗时期是采用替代控制方法治理紫茎泽兰的最佳时期。在替代控制物种选择方面，可以在根除后播种本地灌木和草本植物，因为草本植物在早期可以抑制紫茎泽兰幼苗的萌发和生长，而同时播种的灌木种类则可以在植被恢复的后期起到控制紫茎泽兰再生长的重要作用。

东湖沿岸带底栖藻类群落的时空变化

武汉东湖是一个浅水富营养湖泊,其沿岸带底栖藻类群落的季节分布特征明显,夏季的优势种群是一些体积很小的硅藻类曲壳藻(Achnanthes spp.),其他大部分季节是绿藻门的团集刚毛藻(Cladophora glomerata)和硅藻门的变异直链藻(Melosira varians)。不同样点间的底栖藻类现存量差异不显著,但优势种类不同,以团集刚毛藻为优势的绿藻在处于中富营养区域的磨山样点比例最高,以变异直链藻为优势种的硅藻在严重富营养化的水果湖样点中比例最高。底栖藻类月平均现存量(以叶绿素a计)的时间变化

The role of plants in channel-dyke and field irrigation systems for domestic wastewater treatment in an integrated eco-engineering system

Eight kinds of plants were tested in channel-dyke and field irrigation systems. The removal rates of TP, phosphate, TN, ammonia, CODcr and BOD, in the channel-dyke system with napiergrass (Pennisetum purpurem Schumach, x Pennisetum alopecuroides (L.) Spreng American) were 83.2, 82.3, 76.3, 96.2, 73.5 and 85.8%, respectively. The field irrigation systems with rice I-yuanyou No.1(88-132) (Oryza sativa L.) and rice II- suakoko8 (Oryza glaberrima) had high efficiency for N removal; the removal rate were 84.7 and 84.3%, respectively. The mass balance data revealed that napiergrass, rice I and II were the most important nutrient sinks, assimilating more than 50% of TP and TN. Plant uptake of N and P as percentage of total removal from wastewater correlated with biomass yield of and planting mode. (C) 2000 Elsevier Science B.V. All rights reserved.

泽兰实蝇的生态学特性及对紫茎泽兰的控制作用

紫茎泽兰(Eupatorium adenophorum Spreng)是一种原产于墨西哥的恶性杂草。近年来已严重妨碍了云南省甚至整个西南地区、林、牧业的发展。自1984年8月引进泽兰实蝇(procecidochares utilis Stone)开展了生物防治研究。已在云南境内七个地州（市）定殖扩散。为了解泽兰实蝇的控制作用，本文从研究泽从实蝇生态学特性入手。分析了泽兰实蝇生态学特性与紫茎泽兰生物防治的关系。定量地评价了泽兰实蝇的控制作用。并且应用灰色系统中局势决策方法比较了不同环境条件下的生防效果。其主要结果如下：1、泽兰实蝇雌性与雄性成虫的存活曲线均近于Deevery I型；雌雄一并来看。则成虫存活曲线为Deevery II型；雌性成虫的寿命比雄性长。产卵峰期多在产卵开始后的第二到第四天。2、泽兰实蝇幼虫与成虫均存在密度制约。在平均每雌占有两枝供试产卵枝条时产卵量最大。同时孕育虫的后代也最多。3、泽兰实蝇的净增殖率R. = 24.365。内禀增长率r_m = 0.055。周限增长值λ = 1.057。种群加倍时间t = 12.603天，世代周期T = 58.371天。4、泽兰实蝇幼虫种群的空间分布呈聚集型且接近于负二项分布。一般来说平均拥挤度大的地区，对紫茎泽兰的控制效果也好。5、利用计算机模拟术对泽兰实蝇的控制作用进行拟合。较之以寄生率来评价生防效果更为科学，也更为符合客观实际。6、对不同环境下的控制作用进行局势决策可知，温度较高。湿度偏低的地区。生防效果优于那些温度较低或温、温度均较高的地区。在本文所进行调查的几个样地中，泽兰实蝇控制效果大小的次序依次为：元江＞宜良＞双柏＞思茅。

Its length polymorphism in oysters and its use in species identification

In an effort to develop genetic markers for oyster identification, we studied length polymorphism in internal transcribed spacers (ITS) between major ribosomal RNA genes in 12 common species of Ostreidae: Crassostrea virginica, C. rhizophorae, C. gigas, C. angulata, C. sikamea, C. ariakensis, C. hongkongensis, Saccostrea echinata, S. glomerata, Ostrea angasi, O. edulis, and O. conchaphila. We designed two pairs of primers and optimized PCR conditions for simultaneous amplification of ITS 1 and ITS2 in a single PCR. Amplification was successful in all 12 species, and PCR products were visualized on high-resolution agarose gels. ITS2 was longer than ITS 1 in all Crassostrea and Saccostrea species, whereas they were about the same size in the three Ostrea species. No intraspecific variation in ITS length was detected. Among species, the length of ITS I and ITS2 was polymorphic and provided unique identification of 8 species or species pairs: C. ariakensis, C. hongkongensis, C. sikamea, O. conchaphila, C. virginica/C. rhizophorae, C. gigas/C. angulata, S. echinata/S. glonzerata, and O. angasi/O. edulis. The ITS assay provides simple, rapid and effective identification of C. ariakensis and several other oyster species. Because the primer sequences are conserved, the ITS assay may be useful in the identification of other bivalve species.