THE BREEDING BIRDS OF THE HULEH SWAMP AND LAKE (NORTHERN ISRAEL).

1. The Huleh swamp and lake, which are now under a draining scheme, are described in relation to their vegetation habitats and the birds breeding in them.
2. Data are presented on the breeding birds, concerning their distribution within Israel, laying season, nest site and clutch size.
3. The Common Heron, White-tailed Eagle, Marsh Harrier, Mallard, Baillon's Crake, Yellow Wagtail, Moustached Warbler and the Great Reed Warbler are here first recorded as breeding in Israel.
4. The relationship between Acrocephalus arundinaceus and A. stentoreus is discussed.
5. Some remarks are made on habitat selection of the warblers breeding in the area.     

Sedimentation in a large lake: the importance of fluctuations in water level

1. A sediment trap study was conducted in the central basin of Lower Lough Erne, Northern Ireland.
2. The material caught was low in organic matter, ash weight was 77% of dry weight on average.
3. Mass deposition of material was shown to be correlated with lake water level. When lake water level fell or rose above the middle range, the amount of material caught by the trap increased markedly. The effect was exaggerated by an unusually dry summer in 1995 which caused abnormally low water levels in the lake.
4. Comparison of Erne data with Windermere shows similar deposition rate of many substances, but the deposition rate of iron is thirteen times higher in Erne than in Windermere, and iron made up 39% of the ash weight in the Erne trap data.
5. Only 17% of the silica removed from the water column during diatom growth was recovered in the trap over the same time period.
6. Trap data are compared with historical data for sediment deposition and the implications of sediment focusing are discussed.     

INVASION OF THE SERENGETI NATIONAL PARK BY ELEPHANTS

1. Elephants were first recorded in the Serengeti in 1955 and were probably absent f or at least the previeras 40 years.
2. Elephant numbers have inereased, mainly through immigration, to their present level of approximately 2,000 and have remained at this level for the last three years.
3. Vegetation changes caused by elephants in the Serengeti include the destruction of the larger trees at the rate of at least six per cent, per year.
4. Recovery of the woodfends from the effeets of elephants is retarded by the inhibiting effeets of bush fires on the regeneration of young trees.
5. The policy and management implications of the elephant invasion are discussed.     

Changes in diatom-inferred pH and add neutralizing capacity in a dilute, high elevation, Sierra Nevada lake since A.D. 1825

SUMMARY. 1. We developed equations which describe relationships between the relative abundance of diatom assemblages in the surface sediments of twenty-seven Sierra Nevada lakes and the present pH and acid neutralizing capacity in these lakes.
2. These equations were employed to reconstruct pH and acid neutralizing capacity at twenty-four depth intervals in a 20 cm long sediment core from Emerald Lake, a dilute, high elevation lake, located in Sequoia National Park, California, U.S.A.
3. The diatom-inferred pH and acid neutralizing capacity values indicated that neither pH nor acid neutralizing capacity exhibited significant trends since about A.D. 1825. We conclude from our diatom analysis that Emerald Lake has not been affected by acidic deposition.     

THE EFFECT OF ADDED NITROGEN ON THE RATE OF DECOMPOSITION OF ORGANIC MATTER

(1) N added to decomposing organic matter often has no effect or a negative effect on microbial activity, at least in the long term. More than 60 papers are cited in support of this statement.
(2) The negative effect of N is mainly found with recalcitrant organic matter with a high C/N ratio (straw, wood, etc.), whereas a positive effect of N is common for easily degradable organic material with low C/N ratio.
(3) The negative effect of N could be explained by: (i) N disturbs the outcome of competition between potent and less potent decomposers; (ii) through 'ammonia metabolite repression', N blocks production of certain enzymes, at least in basidiomycetes, and enhances breakdown of the most available cellulose, whereby recalcitrant lignocellulose accumulates; (iii) amino compounds condense with polyphenols and other decomposition products, forming 'browning precursors' which are toxic or inhibitory.
(4) The effect of adding N may depend on the microflora present.
(5) There are indications that some microorganisms have a 'luxury uptake' of N when it is present in sufficient amounts, thereby delaying N mineralization.
(6) The addition of N seems to increase the formation of water-soluble , brown, recalcitrant compounds, but to decrease the amount of humus formed.     

Gemmules of sponges from a warm lake

1. Two types of gemmules were found, each in a different species of sponge, from the warm monomictic Lake Kinneret: (i) clustered gemmules, sharing the pneumatic layer of the gemmular capsule and resembling gemmules of Eunapius ; (ii) gemmules that develop non-synchronously, containing amphidisc spicules within the gemmular capsule and resembling those of Ephydatia . Algal cells were not detected within either type of gemmule although they exist in the developed sponges.
2. Sponges began producing gemmules in the lake with the onset of lake drawdown and ceased when lake level was minimal. The gemmules hatched when the lake level began to rise.
3. Under experimental conditions gemmules hatched between 13 and 35 °C. Germination was optimal at 20–25 °C. Chilling of young gemmules prior to incubation at 25 °C improved germination rate.
4. The percentage of germinating dry gemmules diminished 4–6 months after their collection from the lake. None germinated after 10 months. Submerged gemmules maintained high viability with ageing (up to 100% germination 18 months after collection). Desiccation influenced gemmule viability over time, by both decreasing the percentage of germinating gemmules and increasing the lag time before onset of germination.
5. Gemmules kept in the dark germinated significantly less than those illuminated for 12 h day     

Gemmules of sponges from a warm lake

1. Two types of gemmules were found, each in a different species of sponge, from the warm monomictic Lake Kinneret: (i) clustered gemmules, sharing the pneumatic layer of the gemmular capsule and resembling gemmules of Eunapius ; (ii) gemmules that develop non-synchronously, containing amphidisc spicules within the gemmular capsule and resembling those of Ephydatia . Algal cells were not detected within either type of gemmule although they exist in the developed sponges.
2. Sponges began producing gemmules in the lake with the onset of lake drawdown and ceased when lake level was minimal. The gemmules hatched when the lake level began to rise.
3. Under experimental conditions gemmules hatched between 13 and 35 °C. Germination was optimal at 20–25 °C. Chilling of young gemmules prior to incubation at 25 °C improved germination rate.
4. The percentage of germinating dry gemmules diminished 4–6 months after their collection from the lake. None germinated after 10 months. Submerged gemmules maintained high viability with ageing (up to 100% germination 18 months after collection). Desiccation influenced gemmule viability over time, by both decreasing the percentage of germinating gemmules and increasing the lag time before onset of germination.
5. Gemmules kept in the dark germinated significantly less than those illuminated for 12 h day     

Unravelling the past 1,000 years of history of human–climate–landscape interactions at the Lindu plain,Sulawesi, Indonesia

The Lindu plain, located in the northern mountainous region of the Lore Lindu National Park in Sulawesi, Indonesia, provides many ecosystem services for the population inhabiting the area and harbours a unique biodiversity. Palynological, charcoal and diatom analyses of a lake sediment core from Lake Lindu (Danau Lindu) reveal that during the last 1,000 years the Lindu plain has been modified by human activities. Evidence of frequent burning and possible shifting cultivation from an earlier phase from ca. ad 1000 to 1200 might be related to the metal age population which erected the megaliths in the province of Central Sulawesi. From ca. ad 1200–1700 there followed 500 years of wetter climate conditions, corresponding to the southward movement of the Intertropical Convergence Zone. At the same time, decreases of macro-charcoal concentrations and pioneer vegetation indicators show that the use of the landscape of Lindu plain had become more permanent. Following a phase of forest recovery from ca. ad 1730 to 1910, the most recent part of the Lake Lindu record shows a trend towards deforestation that started in the late 20th century, lasting until now. The lake level started to fall at the beginning of the 20th century, as shown by the increase of sedimentation rate and supported by low pollen concentration and palaeomagnetic data. Such a change was unprecedented for the last 1,000 years covered by the record, and it has no link to the climate variability as reconstructed for the last hundred years. If deforestation increases and a larger amount of water is channelled away from the lake for irrigation purposes, the lake level will continue to fall. This suggests that there is a need for better management of the forests surrounding the plain and of the irrigation systems in the area open for cultivation.     

THE ROLE OF HETEROCHRONY IN THE EVOLUTION OF CAMBRIAN TRILOBITES

1. Renewed interest in the role of changes to developmental regulation in organisms has highlighted the importance of heterochrony in the evolution of the Metazoa.
2. Beecher's interpretation of the evolution of the Trilobita as having been principally by peramorphosis is examined, as is the view of later workers, principally Stubblefield and Hupé, that paedomorphosis was a dominant factor in trilobite evolution.
3. Both peramorphosis and paedomorphosis are considered to have been important in trilobite evolution.
4. The role of paedomorphosis in the evolution of major morphological novelties is critically examined. Its importance in changes to the structure of the glabella is discussed and new terms proposed to describe the ontogenetic and phylogenetic state of the glabella.
5. The highly variable nature of early Cambrian trilobites, in particular the large degree of ontogenetic change, is considered, along with possible poor developmental control of the growth and moulting hormonal systems, to have been significant in providing a high degree of intrapopulational morphological variability. Selection of these heterochronic variants was responsible for the rapid diversification of the Trilobita during the Cambrian.     

ON FORMS OF THE HOP (HUMULUS LUPULUS L.) RESISTANT TO MILDEW (SPHAEROTHECA HUMULI (DC.) BURR.); III.

SUMMARY.
1. Certain seedlings of the wild hop when grown in the greenhouse are persistently immune to the attacks of the mildew Sphaerotheca Humuli. This immunity has been shown by the same individual seedling for three consecutive years. Under the same cultural conditions other seedlings of the same parentage prove to be very susceptible.
2. Certain seedlings (Group 2) which are immune when grown in the greenhouse are also immune when grown in the open. These seedlings have retained this immunity after four years' residence in a hop-garden under normal conditions of cultivation and manuring.
3. Certain seedlings (Group 3) which are immune when grown in the greenhouse are susceptible when grown in the hop-garden; in some cases the susceptibility shown is of the highest grade.
4. "Cuts" taken from the seedlings of Group 3 in the same year in which the seedling proved to be susceptible in the hop-garden are immune in the greenhouse under cultural conditions in which "cuts" taken from other susceptible seedlings in the hop-garden are very susceptible.
5. Certain seedlings (Group 4) are semi-immune to the attacks of the mildew.
6. One seedling (of American ancestry) grown in the greenhouse was immune throughout the season in 1916 and very susceptible in 1917.     

中国典型湖泊富营养化现状与区域性差异分析

为全面科学地综合评估全国富营养化现状, 以全国五大湖区22个典型湖泊为研究对象, 科学评估了其富营养化状态, 分析了全国湖泊富营养化状态的区域性差异, 并探讨了富营养化状态与总磷的定量关系。结果表明, 2010—2011年, 59.1%的调研湖泊处于不同程度的富营养化状态, 其中云贵湖区的富营养化程度最为严重, 蒙新湖区的富营养化呈两极分化状态, 东北山地-平原湖区与东部湖区的湖泊基本均处于中营养-轻度富营养之间, 青藏高原湖区的富营养化程度最低。通过分析日照数、无霜期、气温、水深、海拔、降雨与湖泊营养状态的关系, 揭示了湖泊所处的地理位置是影响湖泊富营养化的基本因素, 具有区域性的分布规律。综合分析结果表明, 全国范围内湖泊中叶绿素a与总磷浓度存在显著相关性, 其中东部平原湖区、东北平原-山地湖区、青藏高原湖区和云贵高原湖区的叶绿素a与总磷浓度符合三次曲线方程, 蒙新湖区的叶绿素a与总磷浓度符合S型曲线方程; 东部平原湖区、东北平原-山地湖区、青藏高原湖区叶绿素浓度随着总磷浓度的增加, 首先出现1个极小值点, 然后出现1个极大值点, 其中3个湖区极小值点对应的总磷浓度分别为: 0.054、0.089和0.072 mg/L, 可为我国对应湖区的湖泊富营养化控制指标提供借鉴。     

BREEDING OF THE FULMAR FULMARUS GLACIALIS

.1. A study of individually marked Fulmars during three seasons has shown that both sexes can breed in successive years. The evidence for the theory of intermittent breeding is examined and definitions are given of the various categories of birds which compose the population during the breeding season. It is suggested that the supposed non-breeding adults which are seen, often in moult, in July are failed-breeders which have lost their egg or nestling.
2. No marked individual changed its nest-site between years, although the number and identity of sites occupied each July varied considerably.
3. No changes of mate occurred among the six marked pairs which nested in two consecutive years.
4. There is some evidence that both parents remain near the colony during the week before and after hatching.
5. Analysis of the 90 known sites of a colony subject to avian but not wild mammalian predation has revealed a wide range of habitat selection and a strong tendency toward close concentration of nests.
6. There is some evidence that the breeding season, as measured by date of hatching, varies from year to year.     

Lake restoration by reducing external phosphorus loading: the influence of sediment phosphorus release

SUMMARY. 1. This review considers the factors which determine the recovery of eutrophic lakes following a reduction in the external phosphorus loading.
2 The mean phosphorus content of a lake should decrease roughly in proportion to the reduction in phosphorus input. Where the lake phosphorus concentration does not decrease as predicted, then the release of phosphorus from the sediment is implicated.
3. The current understanding of the processes by which sediment phosphorus is mobilized and transported into the photic zone is described. The extent to which phosphorus release can maintain lake phosphorus concentrations following the reduction in external loading is influenced by: lake morphometry, flushing rate, sediment type, trophic state and history of enrichment.
4. A reduction in the phytoplankton biomass of a lake is dependent upon the size of the decrease in lake phosphorus concentration and the degree to which phosphorus limits primary production. The importance of phosphorus in limiting phytoplankton production tends to decrease with increasing lake trophic status.
5. Improvements in the condition of highly eutrophic lakes require very large reductions in external phosphorus loading, whereas in mildly enriched lakes moderate changes in the supply of phosphorus have noticeable effects on phytoplankton biomass.     

洞庭湖区东方田鼠迁移的研究

洞庭湖区东方田鼠以湖滩上的芦苇＋荻或薹草沼泽为最适栖息地,枯水季节,多在其上生长、繁殖。汛期,随着湖水上涨,湖滩面积缩小,东方田鼠在拥挤的的压力下或直接被洪水所迫,越过防洪堤迁入垸内。东方田鼠在湖滩及农田间的迁移主要取决于湖水水位及种群密度,无固定的迁移时间。迁入垸内的东方田鼠主要分布于靠近防洪堤一带,其捕获率随着与防洪堤距离的增加而递减。个体较大的东方田鼠迁移距离较远。在迁移期,迁入垸内的东方田鼠的性比在不同的距离上无显著差异。湖水回落时,东方田鼠随湖滩出露而迁回沼泽草地。回迁时,个体较大的雄性首先回迁的比例较高。迁入垸内的东方田鼠,栖息在荒坡地的种群密度大于在农田中的种群密度;东方田鼠不在农田越冬,小部分可在岗地荒坡中越冬,但少有增殖。按迁移动因看,此种迁移乃洪水逼迫所至,而由逼迫外迁和自动回迁构成循环,保证了种群对湖区特殊环境的适应。     

THE MAIN VICISSITUDES OF THE EUROPEAN AVIFAUNA SINCE THE PLIOCENE

.1. Recent knowledge of the Pleistocene and subsequent ecological changes is summarized. Four glaciations are recognized, each with more than one maximum. The interglacials were all at least as warm as the present day.
2. A map shows the vegetation belts of Europe and the probable limits of permanent sea-ice at the height of the Last Glaciation, about 70,000 years ago. There is reason to believe that the main features of the vegetation-map would apply also to the height of the other glaciations.
3. The avian fossil data are discussed and for the most part of necessity rejected for the present purpose.
4. The main inferences drawn of bird distribution at a glacial maximum are that ( a ) a rich avifauna occupied the treeless (grassy) loess-tundra on the southern edge of the ice, ( b ) practically no arboreal birds could live north of the Pyrenees, the Alps and the Black Sea except in a strip across central Russia, ( c ) the birds of deciduous woodland were confined to part of the three Mediterranean peninsulas, ( d ) "Mediterranean" species were practically expelled from Europe.
5. This implies that the populations of coniferous forest must have been reduced to about one-third of their interglacial extent in Europe and those of deciduous woodlands to one-tenth. Most of the sea-bird species probably suffered less severe fluctuations in numbers, but underwent north-and-south changes in breeding range.
6. The post-glacial recovery of the climate has not been uninterrupted, so that in the last 80,000 years there have probably been only about 8000 during which there have been any arboreal birds north of Germany.
7. The implications of the changes on the details of the migration system are discussed.     

密云水库的浮游植物群落结构与密度

 1998年的调查研究显示,密云水库库区水体的浮游植物群落为硅藻(Bacillariophyta)—绿藻(Chlorophyta)型,细胞密度为358.76×104·L-1。湖泊的营养特征为浮游植物响应型。1988～1998年库区水体总氮增长48.7％,总磷增长31.2％,浮游植物细胞密度增长41.7％,库区水体已为中营养,并出现了富营养型浮游植物指示种类,例如斜生栅藻(Scenedesmus obliquus(Turp)．Kütz．),铜绿微囊藻(Microcystis aeruginosa Kütz．),湖泊色球藻(Chroococcus limneticus Lemm．)。水体向富营养化发展趋势明显。应加强水环境保护,增加密云水库流域植被覆盖度,净化、涵养水源,以保证密云水库向北京市供水的质量和数量。     

THE EFFECT OF PLANT EXTRACTS ON THE GERMINATION OF THE CONIDIA OF VENTURIA INAEQUALIS

Of 1915 flowering plants 23 % gave extracts which completely inhibited the germination of the conidia of Venturia inaequalis under the experimental conditions used. The plants which gave active extracts are distributed throughout the Angiosperms, and there is no correlation with systematic position. The inhibitors were distributed generally in some plants and were localized in others, e.g. to the leaves.
Some extracts appeared merely to inhibit the germination of the conidia while others killed them.
Some inhibitors disappeared when the plants were dried, other dry material was still active when retested several months later.
Hedera Helix contains an inhibitor which is active when the extract is diluted 128 times.