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The article presents studies on the vegetation of Nottinghamshire, England. This paper explored the geological structure of the ecology of the Bunter Sandstone and superficial deposits. Different conditions were also taken into account including the climatic and edaphic focusing on the flora of the Sherwood forest. Different plant communities were subjected for thorough investigation recording the botanical information and general account of vegetation. The result of the experiment is discussed in brief.

The article offers information on the prevalence of vivipary on the sea shore. It is cited that one of the features of the mangrove forests is the habit of germination of the seeds on the parent trees. It is said that some refer to vivipary as a relic from the past under the uniform climatic conditions, while others regard it as an adaptation to environment, providing the species with a means for dispersal. It is mentioned that viviparous habit could start the growth of roots in the soil, thus, viviparous seeds should establish themselves on a tidal coast.

The article highlights a report discussing the pleistocene climatic changes and the distribution of life in East Africa. It reports that the present evergreen forest boundaries are generally not natural, noting that they have been reduced by human agency as much as they would have been appreciable drop in rainfall. It discusses the changes that have occurred in the West African forest for a period prior to 400,000 thousand years ago. It also examines the impact of the subsequent dry period in the areas including Elgon, Kilimanjaro, and the highland forms in Southern Tanganyika Territory.

The article presents a study of the charcoals obtained from the recent excavations on the Maiden Castle, England and their significance in relation to the vegetation and climatic conditions in prehistoric period. A few specimens of charcoal collected from the site indicated that the wood was partially decayed before carbonizing. The specimens of charcoals were examined from Neolithic, Early Iron Age and Late Iron Age deposits from the site. It was evident that in Neolithic times, the chalk of Dorset was clothed with a closed plant community of woodland. It was observed that composition of plant species were changing slightly in all the three periods and the soil conditions were becoming less favorable for the growth of oak.

The article focuses on the endemic trees of the British Guiana Peneplain. It describes the situation, climate and topography British Guiana and the distribution of the main climatic associations. It also notes the influence of climate on the distribution of other species and the prevalence of endemism in the Guiana flora through the analysis of the local and general range of forty of the commonest trees. It also states the likelihood of the endemic species of the Guiana flora which have evolved in the highlands that borders the western and southern limits of the peneplain.

The article outlines the research conducted on the vegetation in Mauritius. Researchers found that the mean annual rainfall over the upland climax forest is of the order of 3175 millimeters and the nearest site where records are available over a long period is at Curepipe Gardens. Another important factor that affect the metabolism of the living organism is the intensity of rainfall from day to day. Knowledge of such distribution would enable them to have a better appraisal of the real wetness or dryness of the site. Discussed are the details of the issue.

The article discusses the evolution of modern plant ecology in Great Britain. According to the author, the foundations were laid earlier and the conceptions of plant formations were developed by famous phytogeographers as Humboldt and Grisebach in the first half of the century. Furthermore, its modern meaning was determined by the publication of Warming in 1895 on "Plantesamfund: Grundträk af den ökologiske Plantegeografi." It was translated into German and widely used in England and America which it played as an important part in stimulating fieldwork for both countries. In 1898, A. F. W. Schimper published "Pflanzengeographie auf physiologischer Grundlage," which focus on the types of vegetation throughout the world and discusses the climatic and edaphic factors.

The article discusses the study which assesses the evidence from British hepatics with discontinuous distribution outside the British Isles in relation to the history of the British flora. In this paper, British hepatics showing disjunction in their world distribution are classified in six groups including mediterranean element, disjunct-temperate element and the American element. It is concluded that the hepatics considered do not form a homogeneous group and their distribution patterns all appear to be explicable in terms of post-glacial climatic change without invoking in situ survival through glaciation.

The article discusses the study which aims to set on record results of a phenological survey accomplished in conjunction with a local climatic survey in Bath, England during 1945 and 1946. Bath is situated where Avon lessens the gap in the escarpment of the Cotswold Hills and is the center where six valleys developed on the dip slope of the escarpment. Proximity to water, soil type and vegetation cover are factors in local climatology that may locally be dominant and their effects need specific measurement. It is concluded that local variations of temperature are significant in producing local variations of plant growth.

The article focuses on a study regarding the plant communities on the northern slopes of the island of Pico in the Azores. It mentions the climatic conditions prevailing in the Azores' islands which are characterized by frequent mists, strong winds and a high rate of rainfall. It states that the Pico island is formed entirely of alkali basalt or olivine, and its northern slopes, the Baldios do Conselho, are less steeper than the slopes in the south and are covered with woodland. The assumed dominance of the Pittosporum undulatum tree has affected the vegetation of the northern slopes of Pico which has further resulted in a complex of vegetation.

The article examines the study of vegetational history of post-glacial period in Great Britain. The data from stratigraphy shows that plant remains and the pollen analyses from the site contain lake muds such as Betula, Pinus and Salix. During the Late-glacial period, there was an evidence of a cold climate and of a vegetation of open birch woodland or open vegetation with copses and a rich herbaceous ground flora as well. Thus, the evidence for a climatic oscillation marked a general climatic amelioration of the Post-glacial period.

Examines the impact of climatic variation on leaf development in forage grasses Lolium perenne and Dactylis glomerata. Climatic races of Lolium perenne and Dactylis glomerata; Influence of temperature and supplementary lighting on leaf expansion; Utility of the pattern of climatic variation in the forage grasses in crop improvement.

The article describes the microclimates of the Olokemeji Forest Reserve as a prelude to studies on seasonal changes in the vegetation in Nigeria. This description is based on rainfall and temperature data from Olokemeji and for other climatic elements, on data from Ibadan. The mean length of dry periods is less than 4 days during the wet season and rises to over 50 days during the dry season. The results show that Olokemeji has a climate typical of it area of the country and of the forest/derived savanna boundary area in west Africa.

The article describes the microclimates of forest and savanna sites in the Olokemeji Forest Reserve in Nigeria. This description is based on rainfall and temperature data from Olokemeji and for other climatic elements, on data from Ibadan. The mean length of dry periods is less than 4 days during the wet season and rises to over 50 days during the dry season. The results show that Olokemeji has a climate typical of it area of the country and of the forest/derived savanna boundary area in west Africa.

The article examines some problems of mid-Post-glacial ecology and chronology in the area south and east of the English Lake District in England. The post-glacial increase in pine pollen frequencies is discussed. The stratigraphical evidence for changes in water level during mid-Post-glacial times is detailed. Information on the radiocarbon evidence from Lonsdale is presented. A discussion is presented on the relation of pine maximum in Lonsdale to local habitat factors and the climatic implications of the pine maximum in Lonsdale.

The article presents information about several papers on social history of the Medieval period. Bringing together from the Pergamenos collection of the Archives of the Crown of Aragon 91 documents concerning the Vivas family of Provençals, a neighboring village to Barcelona, Spain between the years 986 and 1084, M. Pierre Bonnassie has been able to follow, with a precise detail very rare for this period and with a considerable insight, the rise of a well-to-do peasant family entering the ranks of the aristocracy. M. Georges Duby, for his part, has studied "Au Xlle siècle: les "jeunes" dans la société aristocratique." He shows that the fate of this horde abandoned to the conquest of glory, profit and female prey by noble houses wishing to relieve the excess of their expansive power, a group very prone to violent death, is not without interest for economic history. In his paper, Mile Emilienne Demougeot has tried to trace a relation between climatic variations and invasions, those invasions at least which occurred in the West up to that of the Cimbrians, Teutons and Goths, at the end of the second century B.C.

Describes environmental requirements for germination and flowering, and the pattern of leaf and tiller development in contrasting light and temperature regimes in collections of forage grass. Materials used in the study conducted on the climatic variation of forage grasses; Description of the effect of temperature on percentage and rate of germination; Genetic variation and effect on flowering behavior.

The article focuses on the utilization of Wilm's method to explain the underlying principles in the collection and statistical treatment of climatic data. It cites that the method is used to determine several chemical elements found in the throughfall data, such as the suspension of bryophyte ground layer in the gauges and approximation of the variance of temperature and humidity data. It also mentions that the changes in the utilization of the method are based on the consideration of the regression line in the data analysis. Further, information on the statistical techniques and methods of computation for the result is also included.

The article reports on the Becium homblei as a plant with high copper soils in Central Africa. Becium homblei is a plant which endure soil copper concentrations of up to 15,000 ppm and endure soil nickel concentrations of about 5,000 ppm. It is found on areas where soil metals are abundant and soil bases specially calcium are low. It is limited by climatic boundaries such as soil pH, soil metal content, and soil calcium bases. It is also widely distributed in Central Africa due to biotype depletion caused by climatic change.

Pollen analysis of three sites on Wilsons Promontory provides a vegetation record from 6000 B.P. to the present day. No extensive changes in the vegetation have been found over this time period, but local and regional variations in the extent of communities may imply small climatic changes. Moister conditions than at present seem to have prevailed earlier than 4500 B.P., followed by a drier phase till less than 2000 B.P., when an increase in moisture gave conditions similar to those of today. Some evidence exists to support the theory of a relatively steady sea level close to the present level over the last 6000 years along the western Wilsons Promontory coastline. [ABSTRACT FROM AUTHOR]

Reports on the description of the seasonal growth characteristics of perennial legumes and annual grass pasture ecosystem in the dry monsoonal region of northern Australia. Identification of phases during which the botanical composition of the ecosystem may change; Presentation of a conceptual model with general applicability for a pasture of perennial and annual species; Examination of the inter-relationships between the identified phases.

This paper investigates whether changes in weather have random effects on crop yields. The data are yield series of several crops for the United States, individual major producing states, and major producing areas. Statistical tests show little evidence of nonrandomness in these series. There is almost no evidence of cycles or bunchiness prior to 1932, none for national average yields or the weighted average for major producing areas. Since 1932 there is some evidence of autocorrelation; however, this appears to reflect the uneven application rate of high yielding inputs, such as fertilizer and hybrid seed. [ABSTRACT FROM AUTHOR]

The concentration of sugar in the nectars of unprotected flowers of several species was measured and did not reach the high values that would be in equilibrium with the daytime humidities recorded outside the corolla, although the sugar concentration was highly correlated with ambient relative humidity. This paper examines features that maintain low nectar sugar concentrations at low ambient humidities. Post-secretory changes in concentration are influenced to a small extent by nectar composition but depend largely on physico-chemical and microclimatic effects. Factors contributing to the maintenance of steep gradients in water activity between the nectar and the ambient air include corolla morphology, sugar concentration gradients and waterproofing lipid monolayers on the nectar surface. This paper considers the relative importance of such features in relation to the pollination syndrome. A simple technique is described for the measurement of intrafloral relative humidity. [ABSTRACT FROM AUTHOR]

The East Anglian Pleistocene succession records eight temperate stages with forest and also interstadials with forest in two of the intervening cold stages. The forest histories of these temperate stages and interstadials are described. The records through the Pleistocene of the tree genera involved are considered. The forest assemblages in each of four substages of the temperate stages (pre-temperate, early-temperate, late-temperate, post-temperate) are compared. The development of heath in the temperate stages is also examined. Floristic and phytogeographic changes indicated by the palaeobotanical evidence give information on Tertiary-relic genera and on extinctions, and have a bearing on the problem of the history of cold stage refugia. The success or failure of particular genera in response to the stress of climatic change is discussed. Finally, comparisons are made with Pleistocene forest history in north-west Europe. [ABSTRACT FROM AUTHOR]

(1) Quantitative changes in the populations of oomycete fungi in the freshwater environment of a small freshwater lake were recorded throughout a period of two years (2) A method of estimating the numbers of fungal propagules by continuous flow centrifugation, pour plating and scanning was tested and the probable losses during processing determined. For zoospores and zoospore cysts the loss of viable propagules was within the range 5-25%. This method was then used on samples from the lake. (3) Zoospores and zoospore cysts were found to be the predominant propagules recovered. (4) There was a seasonal periodicity in propagule numbers, per unit volume, with three, rather than two, maxima early spring, early summer and autumn. (5) There was a diurnal periodicity in numbers, per unit volume, of propagules with two maxima (early afternoon and late evening), the relative importance of which vaned through the year. (6) The changes in the timing of the diurnal maxima are reflected by changes in the relative numbers, per unit volume, of propagules recovered in morning and afternoon samples used to determine the seasonal periodicity. These changes lead to problems in calculating the numbers, per unit volume, of propagules present on any given day from a single time of sampling. (7) Similar diurnal and seasonal fluctuations were found in all the oomycete genera collected, with the possible exception of Phytophthora. (8) Experiments showed that in lakewater zoospores had a short life-span. Thus the number, per unit volume, of zoospores recovered may be indicative of the activity of the fungi. (9) No single factor could be shown to account for the fluctuations observed. [ABSTRACT FROM AUTHOR]

A review of some of the conceptual and methodological progress that has been made in the area of climate research is presented. A discussion of current thinking on the etiology of climates follows, and an integrative conceptual scheme is developed. This perspective is based on Mead's (1934) symbolic interactionism as the process through which individuals come to attach meaning to events. Implications of this approach to the etiology of climates are discussed with respect to measurement issues, the management of climate acquisition in organizations, and the change and development of climates over time. [ABSTRACT FROM AUTHOR]

Analyzes three radiocarbon-dated pollen diagrams from upland peats located northwest of Merthyr Tydfil in Wales. Ecological history of the locality and the initiation of peat deposition on the plateau; Peat initiation at the moisture-shedding sites; Influence of climatic change and soil maturation.

Two factors will determine the rate at which CO[sub2] levels in the atmosphere increase in the future: the rate of input to the atmosphere, primarily from fossil fuel burning, and the way in which this CO[sub2] is partitioned between atmosphere, ocean and biosphere. A brief review is given of the current state of knowledge of these aspects of the CO[sub2] issue prior to a discussion of the changes in climate that might be expected from increased levels of CO[sub2], whenever these might occur. The basis of climate modelling upon which our expectations rest is explained, indicating the nature of the uncertainty that currently exists in the model results. While some of the gross features of the likely climatic change seem reasonably well established qualitatively, considerable model development will be needed before reliable information on the likely regional effects is forthcoming. Observations have yet to confirm the occurrence of temperature change attributable to CO[sub2] increases. Nevertheless, the possibility exists of a change in climate during the coming century that may be substantial relative to past experience. Although direct measures to control CO[sub2] emissions would certainly be premature, long-term planning of infrastructures, closely tuned to present climatic conditions, should ensure their robustness in the face of the uncertain climatic changes that may lie ahead. [ABSTRACT FROM AUTHOR]

Presents a study that supplements the existing climatic analyses for Darwin and the surrounding region in wet-dry tropics. Classification of years in terms of amount and distribution of rainfall; Emphasis on the reliability of rainfall in the wet-dry tropics; Consideration of moisture as the primary limiting factor; Implications of rainfall variability for the design and interpretation of faunal and floristic surveys.

Copyright of Population & Development Review is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

(1) The environment, structure and floristics of four evergreen rainforest sites at 575–800 m altitude in Karnataka, southern India, are described. (2) The mean annual rainfall on the four sites ranges from 5310 to 7670 mm. Most of the rainfall occurs from June to September and there is an intense dry period from December to April. All the sites occur on oxisols overlying hornblendic rocks. (3) The forests at three of the sites are species rich with an important contribution from the Dipterocarpaceae but one site is unusual and has an almost monospecific dominance by Poeciloneuron indicum (Guttiferae). (4) The total aboveground tree biomass was 420–649 t ha-1. The root fraction was 13.9–20.2 t ha-1. (5) Girth increment data over 35 years were available for one site and these were used with biomass estimates to calculate the approximate mean annual increase of above-ground and root (≥5 cm girth) biomass in the four sites. These were 6.4–11.1 t ha-1 for aboveground material and 0.2–0.4 t ha-1 for roots. (6) For small trees (≤5 cm dbh) and herbs, biomass was estimated by destructive sampling in one plot. The combined above ground biomass of these fractions was 7.2 t ha-1. [ABSTRACT FROM AUTHOR]

This article focuses on the study of seasonal changes in numbers and body condition of honeyeaters over 2 years in the New England National Park in New South Wales, Australia. The majority of recent studies dealing with honeyeater communities have considered one of two hypotheses. The first of these is that the abundance of honeyeaters in an area fluctuates in accordance with nectar availability. The second hypothesis is that the larger honeyeater species should aggressively dominate the areas with a high density of energy from nectar, while the displaced smaller species should use the poorer areas.

The natural decline of a virgin high-altitude Pinus sylvestris forest during the Little Ice Age (approximately AD 1300-1850) was studied in the Swedish Scandes. Methods included 14C and cross-dating of wood remnants, soil analyses, year-ring chronologies and age structures. A closed pine forest started a gradual decline in the 11th century or somewhat later, which proceeded until the mid-19th century. Long-term failure of regeneration and premature death of trees are postulated to have caused the forest dieback, mainly owing to a negative shift of the carbon budget, including weather-induced loss of photosynthetic tissue and root disfunction. Temperature measurements on the study site stressed its current marginality. Especially thermal conditions in and close to the ground were deduced to be decisive. The decline of the forest is considered to indicate a long-term lowering during the Little Ice Age of the summer (June-September) mean temperature by 1 °C or more, compared with the 1931-1960 mean. [ABSTRACT FROM AUTHOR]

The Holocene history of the forest-alpine tundra ecotone in Central Sweden (Scandes Mountains) is inferred from radiocarbon analyses of subfossil wood remains. Pinus sylvestris was the dominant subalpine tree species during the early Holocene, when it ascended almost 200 m higher than currently. A short climatic episode (less than 100 years) is postulated to have triggered erosional processes around 6300 B.P., and extinguished the upper part of the subalpine pine woodland. Subsequently, a subalpine belt of Betula pubescens ssp. tortuosa and Alnus incana developed. A Holocene thermal optimum occurred around 6100 B.p., when the birch/alder belt flourished and the tree-limits probably reached their highest levels during the Holocene. Shortly after 6000 B.P., a long-term pine forest retrogression started and the birch/alder belt was disrupted by expanding snow-beds. Pine receded slightly at its tree-limit, but the uppermost belt of closed pine forest (presently dominated by birch) remained intact until c. 3300 B.p., when a severe climatic deterioration occurred. The present-day subalpine belt of pure birch forest developed successively and increased in vertical extent after c. 5300 B.P., when summer temperature declined. The evolution of the birch belt is postulated to have been ultimately a response to decreased seasonality, which favoured birch at the expense of pine. Because of the 'inertia' characterizing the highest pine forest, the birch belt was relatively narrow until a major thermal decline c. 3300 B.P., when it made a massive downslope expansion. The latest phase of pine recession was during the Little Ice Age, 800-300B.P. [ABSTRACT FROM AUTHOR]

Two oolites in the Dinantian (Mississippian⁄Lower Carboniferous) of Glamorgan, SW Britain, were deposited in similar depositional environments but have contrasting diagenetic histories. The Brofiscin and Gully Oolites occur in the upper parts of shallowing-upward sequences, formed through strandplain progradation and sand shoal and barrier growth upon a southward-dipping carbonate ramp. The Brofiscin Oolite is characterized by a first-generation cement of equant calcite spar, preferentially located at grain-contracts and forming non-isopachous fringes around grains, interpreted as meteoric vadose and phreatic in origin. Isopachous fibrous calcite fringes of marine origin are rather rare and occur only at a few horizons. Burial compaction was not important and porosity was occluded by poikilotopic calcite spar. Fitted grain-grain contacts locally occur and could be the results of near-surface vadose dissolution compaction. Syntaxial overgrowth on echinoderm debris are common. Pre-compaction overgrowths are cloudy (inclusion-rich) and probably of meteoric origin, and post-compaction overgrowths are inclusion free. By contrast, the Gully Oolite has little first-generation cement. However, marine fibrous calcite is common in oolitic intraclasts, as isopachous fringes of acicular calcite crystals closely associated with peloidal internal sediment; and early equant, drusy calcite spar occurs in the uppermost part of the Gully, beneath a prominent palaeokarst where pedogenic cements also occur. The major feature of Gully diagenesis is burial compaction, resulting in extensive grain-grain dissolution and microstylolitic grain contacts, and post-compaction poikilotopic spar occluded remaining porosity. The Brofiscin Oolite is pervasively dolomitized up-dip but the Gully Oolite for the most part only contains scattered pre-compaction dolomite rhombs and late veins of baroque dolomite, with less pervasive dolomitization. The difference in diagenetic style if the two... [ABSTRACT FROM AUTHOR]

The Postglacial history of Alnus is of particular relevance to the palaeoecology of wetlands and floodplains. The ecological histories of floodplain sites differ from those on dry-land or from hydroseres. This paper uses pollen percentage and influx data to investigate floodplain succession and woodland development on floodplains in the West Midlands, the primary site being Wilden Marsh near Stourport, Worcestershire. The floodplain at Wilden probably underwent a three-phase succession during the early Postglacial; Betula was replaced by Salix spp. which were out-competed by Alnus. Alnus was present prior to its expansion, which is seen as the result of increasing soil stability, pedogenesis and decreased free drainage related to floodplain development and not necessarily to climatic change or anthropogenic disturbance. During the late Postglacial Alnus declines and Salix frequently increases again due to floodplain deforestation and utilisation, which was partly facilitated by altered soil conditions caused by hydrological change. The advantages of small floodplain sites for the differentiation of vegetation pattern is illustrated by the identification of a non-floodplain pollen component dominated by Tilia. [ABSTRACT FROM AUTHOR]

Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The author reflects on the role of climatic change in the design of biological reserves for conservation biology relative to paleoecology. He remarks that the significance of including climatic change in designing biological reserves is illustrated by the Holocene archeological and paleontological record of the eastern Sahara, in which the concept suggest that individual species respond to environmental changes by migrating in different direction, at different rates, during different times.

The paper describes the application of a numerical model to the prediction of seasonal temperature and moisture content changes in the ground. The results are compared with measured values taken over a two year period at the site of a monitored field experiment. Blind predications have been carried out on the basis of assumed material parameters. It is concluded that the analysis is largely capable of modelling the phenomena observed. Certain limitations are, however, exposed. [ABSTRACT FROM AUTHOR]

Examines the projections of climate changes as simulated by global climate models. Increases in trace gases and global surface temperature; Discussion of the links among the predictions and observations concerning global climate change; Nature and dynamics of global climate change; Response of the public to the problem of global warming.

Provides an economic perspective on global climate changes and agriculture. Role of economics in climate change research; Analysis of climate change effects on U.S. agriculture; Policy implications.

Comments on the lack of economists involved in global climate change research. Reasons for the lack of economists involved in climate change issues; Contributions of economists to the climate change issue; Overview of the economic analysis of global climate change.

Comments on an article about the economic aspects of climate changes. Impacts of climate changes on agriculture; Limitations of the general circulation models of climate change; Future of global warming.

The potential influence of increasing levels of atmospheric carbon dioxide (C02) on water resources includes changes in evapotranspiration that result from control of stomatal resistance by CO2 and changes in precipitation and temperature caused by 'greenhouse' warming. In this study we investigate the potential effects of CO2 change on the hydrological response of a forested catchment in Shenandoah National Park, Virginia. Steady temporal trends are superimposed on stochastically derived time series of precipitation and temperature. These input data, which account for the natural variability of the system and the hypothetical effects of climate change, are then used to drive TOPMODEL, a variable-source-area hydrological model. A variety of climate-change scenarios is simulated and temporal trends in annual average flow, peak flow, and basin yield are detected using Kendall's tau statistic. The direction and magnitude of the runoff trends are dependent on the relative magnitudes of the induced trends in precipitation, temperature, and stomatal resistance. Stochastic variability in temperature and precipitation obscure the runoff trends even when real trends in precipitation, temperature, and stomatal resistance are significant. [ABSTRACT FROM AUTHOR]