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There are two general emphases in the definition of the concept, natural area. One of these views the natural area as a spatial unit limited by natural boundaries enclosing a homogeneous population with a characteristic moral order. The other emphasizes its biotic and community aspects and describes the natural area as a spatial unit inhabited by a population united on the basis of symbiotic relationships. It is the purpose of this paper to examine a series of data with a view to studying whatever natural areas may be present within a larger urban residential district. Rental values range in their block averages from five dollars to one hundred and fifty dollars per month. Many racial, national and religious categories are located here, and the residences have been built at various periods of time. Thus, in the considerable spread in rental value, age of structure, and ethnic background of the population, the basic elements for the production of either functional or homogeneous local units are present.

There is an urgent need to examine the range of ecosystems that is currently protected in national parks and reserves, to point out those examples that are unprotected and to establish a rational programme of priorities for protecting as complete a series as possible. The International Biological Programme has pioneered the field of large-scale survey work for the collection of data of relevance to this need and has contributed to the development of information retrieval techniques for handling the data. The first part of the paper discusses the rationale of the development of the data base and its modus operandi. The system is illustrated by two examples of retrieval and analysis for specific enquiries; the distribution of four species of Pinus, and the occurrence of grazing, logging and burning in national parks and equivalent reserves in the United States. The second part of the paper deals with system design, details of programming for the data base, and retrieval strategy. It is intended as an independent section which may be skipped if the reader has no interest in the finer points of the data base itself. [ABSTRACT FROM AUTHOR]

This paper considers natural animal populations whose members are harvested for their own value, either esthetic or monetary. At the time of the harvest, population members are assumed to be indistinguishable as to sex. Revenue and cost structures are defined for these populations as they relate to the ecosystem. A stochastic description of population growth is used in which a change in the distribution at the growth parameter is described by an associated Markovian distribution process. This associated process describes the changes in environmental conditions. A harvesting policy is described in terms of an optimal population size. This policy maximizes the expected economic gain to be realized for the duration of time over which management of the system is anticipated. [ABSTRACT FROM AUTHOR]

The article describes the habitat and plant communities in the Egyptian desert. The paper explores the potential variations within desert community types over an extensive area. It examines a summary of an ecological survey of the whole Eastern Desert, extending from the Nile valley of the Red Sea mountains and from latitude 30 degrees north and 22 degrees north. It also discussed the features and ecological relationships of plant communities that form the vegetation of a part of the Eastern Desert of Egypt and outlined assumptions of their definition.

The article presents a study about the use analysis of quadrat data in plants. This paper focuses on the point quadrat records applied in the study of vegetation. Interest in computers for the analysis of patterns in vegetation have been rising for the past years to look for data in the absence or presence of species in quadrat. They can be recorded conveniently and associations in plant communities are observed. Methods of analysis in botanical communities are described. Four methods in analization of plant quadrat are presented and explained.

The article presents studies on the organization of animal communities. It states that animal communities may be considered organized if any property of a natural assemblage of species can be predicted. The authors of the research used three observations on the organization of animal communities and from these observations, they deduced that as whole groups, the terrestrial decomposers, producers and predators are limited by their own depletion of their respective resources. The researchers stresses that the aim of this paper is to show that some properties of communities can be deduced from a consideration of groups of species simultaneously.

The article presents a study about the root development of plants in the field using radioactive tracers. This paper focuses on an investigation of the extent of root systems present in plant communities. Some methods employed in the past helped in the creation of the current one used by the author where a method of investigating root distribution of plants in undisturbed communities was applied. Root depths in maximum levels were observed. Absorption capacity in various soil horizons were also investigated.

The article presents several publications that relate to the topic of animal ecology. General papers on particular animal groups include "A List of the Harvest-Spiders of Ireland," by D. R. Pack-Beresford, "The Eisenias of North Wales," by H. Friend, and "A Further List of Species of Coleoptera new to the County of Hertfordshire," by B. S. Williams. Several publications on action of environmental factors are also mentioned including "Local Changes in Distribution," by T. G. Longstaff, "Studies of some Lanarkshire Birds," by W. Stewart, and "The Fauna of Brackish Pools of the Sussex Coast," by W. H. Thorpe.

The pollen content of the organic layers of nine soil profiles in the Forest of Abernethy, Inverness-shire was examined. From a discussion of the process of raw humus formation, it would appear that Mor is a broadly stratified deposit in which favourable conditions exist for the preservation of pollen, although a number of factors which may lead to the deterioration of pollen, or disturbance of stratification are also considered. Pollen diagrams from Mor profiles were interpreted with the aid of surface sample data from Abernethy presented in an earlier paper, 14C-dating of soil material, and documentary evidence. It is concluded that substantial areas of Calluna-dominated heathland have existed in Abernethy since at least AD 400, and that prior to heathland formation, some parts of Abernethy may have contained vegetation consistent with the presence of Mull rather than Mot. [ABSTRACT FROM AUTHOR]

The U.S. IBP is trying to develop a phenology subprogram as part of the Analysis of Ecosystems Program. This paper outlines some of the important objectives of such a program, and why they are thought to be a major contribution to resource management models. It describes the logistic problems of developing an observer network capable of providing the data necessary for mapping purposes and explains the mapping procedure, using the North Carolina Phenology Project as a model. The phenological models developed from our first efforts are presented. [ABSTRACT FROM AUTHOR]

The article focuses on the study of the effects of species number and type of data as a ground for the description of the species. It presented an approach which was based on the proposition that not all species are equally important, and that most detailed data are unnecessary. It explores the effect of species number, and the effect of data. The study suggested that the methods used were proposed as a pilot survey to evaluate the importance of given species, and the given data as description to plant community. Furthermore, the sampling effort was reduced though the information loss was minimal.

The article evaluates the use of Euclidian measures of distance and derivatives of similarity coefficient in simple ordination construction to demonstrate the correlations between vegetation and habitat. Four sets of data were used in the study. Results showed that the use of Euclidian measure is more efficient in the interpretation of the original interstand distances within the ordinations than the use of distances derived from similarity coefficient. However, Euclidian measure seems to obscure gradients of floristic composition and fails to separate dissimilar communities and the resulting ordinations in this regard are less efficient than those using derivatives of similarity coefficient.

The article presents a study on desert plant communities relative to its habitats in the Egyptian desert. It relates that the structure of the desert vegetation is simpler than that of the vegetation in less arid habitat, and desert plant cover is composed of ephemerals and perennials plants. It mentions that stratification in the desert vegetation is more discernible in the root systems, in which the roots of ephemerals are shallowly seated and usually extend no farther than 20 centimeter (cm) from the soil surface and the roots of the perennials are more deeply seated and they exploit the subsoil where some water is reserved throughout the year.

The article presents some facts on the ecology of Bifurcaria brassicaeformis, the only species of the Fucalis genus in South Africa, which forms extensive intertidal communities. B. brassicaeformis is an endemic species with a limited distribution range. It then briefly considers the complex current system off South African coasts and stresses that B. brassicaeformis is most typical of temperatures intermediate between those of the cold waters off the west coast and of the warm waters east of Cape Agulhas. In addition, the plant also occurs as a common rock-pool species especially in the lower half of the intertidal region. Other significant information related to the matter is also provided.

The article offers information on the vegetation of the English chalk. An analysis was made on the bryophytes and lichens in chalk grassland, with comparison of their occurrence in other calcareous grasslands. Principal bryophytes and lichens of chalk grassland had important ecological roles. There are three different types of calcareous grassland, which include Carboniferous Limestone, chalk, and Breckland. The three types features different state of moisture and grazing, which reflects the intermediate characteristics of its bryophytes and lichen vegetation.

The article presents a study that investigates the prevalence and implications of test errors in the use of subjective frequency estimation method in grasslands in Oxford, England. The study was administered by conducting and recording data twice and comparing the differences in its results which could vary on the types of grassland as well as its length. The study reveals that the tests are needed to sustain planning method wherein some of its errors provides startling magnitude, thus it is not suitable to be used on a particular vegetation research. It also offers information on the most commonly used frequency estimation method, symbols used as well as the sources of errors.

The article examines the most known popular poplar found in central Alberta, the Parkland or Grove Belt. The poplar, accordingly, is approximately 20,000 square miles and is mainly covered with trees, shrubs and grasslands. It is allegedly named Parkland or the Grove Belt because the area has once looked like a park. It is believed that the area is formed by climates themselves, composing of long, cold, dry winters, and a growing season of about four months. The area is also marked by low humidity, strong sunlight and frequent high winds. These situations, when taken together, are considered responsible for the development and persistence of the major plant communities. They have been pointed as the main culprit behind the production of the chief classes of soils found in the region.

The article presents an ecological study of the vegetation of West Greenland. With the exception of a strip of land of varying width round the coast, the whole of the country is covered with a continuous ice-field. In the spring, the whole of the smaller deltas, and the central regions of the larger ones, are almost entirely flooded, but during the summer their boulder-strewn surface is baked dry, except where it is intersected by the stream courses. In localities similar to those in which scrub of Salix glauca appears and often bordering on it, one encounters a more or less luxuriant growth of herbaceous plants which are not hardy enough to stand the conditions prevailing in more exposed situations.

The article examines the application of an empirical formula for comparing lists of flora from several districts of different sizes. The researcher collected data from different types of plant associations in the islands of Stockholm, Sweden. The results indicate an increase in the deviation corresponding to increasing area, which depends on the fact that the values of the smaller areas are the average of a greater number of observations than those of the larger. The use of the formula allows one to determine a standard for the relative richness or poorness of a floral district.

Pollen deposition in each of five categories of vegetation in the Forest of Abernethy was examined by collecting surface samples. Qualitative differences in the composition of pollen spectra from category to category were revealed enabling simple distinctions between vegetation categories to be made. Comparison between categories was then placed on a semi-quantitative basis by compiling modal percentage frequencies for each main pollen type recorded in each category, and this data was used to construct surface pollen assemblages characteristic of each vegetation category. The application of these surface pollen assemblages to the paleoecological problems of Scots Pine forest will be considered in detail in a subsequent paper. [ABSTRACT FROM AUTHOR]

A method is described by which the rate of degradation of different kinds of cellulose fibers was determined in aquatic environments. The fiber samples were enclosed in small bags of nylon fabric with a fine mesh and weight losses of bags placed in water or sediments were measured over periods of several months. Newly processed pulp fibers were rapidly degraded in aerobic, nutrient-rich water whereas previously dried pulp and fibers derived from cotton were degraded more slowly. Lignin-containing mechanical pulp was hardly degraded at all. Cellulose decomposition was slow in unpolluted sea water and in the heavily polluted, anaerobic water outside a paper mill but relatively rapid both in the anaerobic water and the sediment of a nutrient-rich lake. The applications and limitations of the bag method in studies of decomposition processes in aquatic ecosystems are discussed. [ABSTRACT FROM AUTHOR]

This paper reports current research concerning Oribatid populations occurring in three ecosystems (an oak forest, a meadow and a poplar plantation). The main criterion used in the faunistic analysis is the relative density; this is expressed as a percentage and conventionally represented by ten classes (Fig. 1). The specific components of each habitat are compared at first wholly (Fig. 2) and then on the more rational basis or the Oribatid mites group peculiar to each milieu or in common with all the habitats (Tab. 1). The study of the relative density sums indicates the interspecifics quantitative connections, but also the similarities and the divergences between the three habitats (Tab. 2, Fig. 3). In the same way, the relationships between the three communities are established on the basis of the species list; those results show not only the connecting species but also the discriminating species (Fig. 4). The conclusions obtained are validated by considering various concepts such as the diversity, the constraint index and the specificity. [ABSTRACT FROM AUTHOR]

A conference paper about the biology and classification of phylum sipuncula and echiura is presented. It includes the study of the anatomical homogeneity, behavior, ecology, development, and physiology of the worms. It also investigates the morphological grounds of both phylums and explains the role of the sipunculans in their biotic communities.

The article focuses on the origin of agriculture in Michigan. David Harris has made a useful distinction between two types of primitive agriculture namely seed-crop cultivation and vegeculture. He considers farming systems as man-modified ecosystems and analyzes in terms of species diversity, productivity and stability. Southwest Asia is one of the first regions of the world to have agriculture and the most intensively investigated area from the standpoint of early cultivation. Seed-cropping is a relatively simple ecosystem since it consists of few species growing in pure stands composed of large numbers of individuals while vegeculture is often a very complex ecosystem since several different species may be grown in a single field.

The phosphorus cycle of microcosms consisting of decomposing plant material and bacteria (with or without bacterial grazers) was studied using a 33P tracer method and compared with computer simulations of a conceptual model of the system. It is shown that (1) The turnover of phosphorus in such systems far exceeds the actual mineralization of phosphorus from the detrital material; (2) Phosphorus cycling is more rapid in systems with protozoa, although excretion by protozoa is minor, with the increase being mainly due to a higher turnover of phosphorus in grazed than in ungrazed bacteria; (3) The mineralization of detritus is stimulated by protozoan grazing; (4) Phosphorus is partly excreted by bacteria in a dissolved, organic form and; (5) A hot-water extractable pool of phosphorus, about 50% of which consists of polyphosphates is found in bacteria, and PO4---taken up by bacteria is first found in this pool. Limited goal modelling of laboratory microcosms is discussed and found useful for the analysis of the functioning of ecosystems. [ABSTRACT FROM AUTHOR]

Information about the topics discussed at the symposium entitled "Ecosystems -- Evolution and Revolution" that was held on June 16-20, 1968 in Madison, Wisconsin is presented. Topics of various sessions focused on giving insights into better ways and means of studying and evaluating some of the biological problems to better understand the ecosystems. Attendees were scientists from different fields of science with a common aim of obtaining a clearer view of the ecological problems.

The article explores the distribution of Empetrum nigrum in the British Isles. The authors discuss the geographical and altitudinal distribution, climatic and topographical limitations as well as the substratum of Empetrum nigrum in the island group. They also tackle the presence of Empetrum nigrum in forest communities, dry heath communities, wet heaths and peatland communities and grasslands. Moreover, they discuss the response of Empetrum nigrum to several biotic factors as well as its performance in various habitats and the impact of frost and drought in its distribution.

The article offers information on the intensity of spatial pattern in plant communities. The said spatial patterns can be standardized to remain constant under random thinning of individuals. The formula for the standardization is presented along with a discussion of the interpretation of spatial pattern, in which the relation between the pattern analysis and the ecological conclusions is assessed. It is cited that there are several alternative measures of pattern, including the spectral analysis and the block-size analysis of variance.

The article offers information on growth rates of species of algae. It is mentioned that fifteen species of algae were the subjects of a study, in which their growth rates were measured at temperatures four degrees Celsius and 36 degrees Celsius. The maximum growth rates of oligotrophic species are smaller than those of eutrophic species. It is cited that the temperature optima for growth under the conditions used did not differ betwen the two groups. Adaptive advantages of low growth rates in infertile waters in relation to maturity of ecosystems are also discussed.

The article discusses the effects of grazing on the structure and productivity of the vegetation on three sites near Pilani, Rajasthan and India. It is said that the sites were exposed to varying degrees of biotic pressure, in which each site is different in variety ratio. The major growth in the area is in August and September, which is the period of maximum rainfall, while in the dry period of October, the community consumption increases over production. The patterns of change of plant pigments and of growth of green biomass are similar, in which correlation coefficients suggest a positive relationship between the green biomass and total chlorophyll.

The article offers information on the numerical classification method of information analysis, which is also an agglomerative polythetic method. Questions are raised concerning issues about the usefulness of the methods when applied to relatively species-poor data. Problems include the relative effectiveness of numerical and traditional methods for eliciting structure from phytosociological data, the efficiency of presence data compared with quantitative data, the differences between normal and inverse analyses and their resolution, and the interpretation of numerical models in terms of the ecological models.

The article presents the results of the pollen analysis of cores of some small bogs in the valley of Dommel River in north Brabant, Netherlands. According to the author, the aim of the pollen analysis is to detect whether an extralocal effect of upland pollen types would be revealed and to what extend the pollen assemblages would differ from those of the Peel raised bogs. The author adds that the sampling point is close to the upland and in the pollen spectra, the pollen types reflect the pollen deposition from the stands surrounding the basin.

The article discusses the ecological and floristic convergence of some plant formations in South America. The author considers certain traits of flora, vegetation and climate as a first approximation to compare corresponding ecosystems. The comparative analysis may be viewed at three different approaches. The first is the assessment of the degree of environmental similarity under which similar types occur. The second concerns the structural and functional convergence of vegetation. The third approach focuses on a morpho-ecological characterization of each of the communities through their main plant components.

The article reports on the phytosociology of Calluna-Arctostaphylos heaths in Scandinavia and Scotland. Calluna-Arctostaphylos heaths' study provides some insight into the nature of the vegetation and its response to factors of the environment. This plant communities' research were conducted using the techniques of association-analysis and ordination. The latter reveals misclassified stands, while the former suggests a basic division of the data on Hypericum pulchrum into two parts, herb-rich heaths in which it is present and herb-poor heaths where it is absent.

The article reports on the cycle of chemical elements in the ecosystem. It notes that in the precipitation and in salt deposit there was an addition of chemical elements, while a loss of chemical elements from the ecosystem occurs through leaching, run-off, and grazing. It gives an account of the chemical element content in a 7½-year-old stand of gorse (Ulex Europaeus L.), the elements' quantities in the annual litter fall and throughfall, and the accession of chemical elements in rain. To present a picture of the circulation of the matter, data on these various facets are combined.

The article offers information on the herb vegetation of an oakwood area on Loch Lomond in the Highlands of Scotland. The oakwood area is comprised of four islands, Inchcailloch, Clairinsh, Creinch and Torrinch. While Torrinch and Clairinsh are underlain by Lower Old Red Sandstone conglomerates, Creinch and Inchcailloch are formed by a band of dolomite fault rock. The soils in the site have ten profile types including podsols, brown earths, and peaty soils. The entry also provides information on Loch Lomond's climate, biotic factors, and history.

The article examines some environmental variables that influences the differentiation and distribution of vegetation in an upland ecosystem. It mentions that vegetation changes in many upland areas have been correlated with variations in soil moisture, soil base status and biotic pressures. Preliminary considerations were directed to those features of slope and regolith which influences the distribution of topo-edaphic or site types. Finer differentiation within the vegetation mosaic is closely related to edaphic gradients of base status and humidity and biotic gradients of sheep grazing and heath burning.

This article presents a study regarding the productivity of a tropical forest and its relation to a world pattern of energy storage. The International Biological Programme aims to estimate existing and potential plant production in the key climatic regions of the world. Ecologists realized the significance of determining the productivity of natural ecosystems, even before this goal was formally proposed for the program. Consequently, there has been in increase in productivity studies in the ecology.

The article highlights a study of the ecology of Hordeum murinum L. in Great Britain. It notes that a punched card technique is described for the analysis of distribution maps. It mentions that the technique allows analysis of complex patterns, the data are amenable to statistical analysis and use is made of negative information. It reports that the distribution of Hordeum murinum and Reseda luteola is shown to be correlated with climate and with the distribution of urban land. It also discusses some of the problems of analysis of distribution patterns using visual comparison and the punched card technique.

This article discusses a study which described gradients of the vegetation and environment at selected locations around the Barbados. The researcher examined the relationships between environmental variations and changes in the coastal vegetation. He used transects of contiguous quadrats orthogonal to the shore to describe vegetation. He found that some species are limited to certain zones within the three ecosystems by reason of aridity, ground and air salinity, sand petrology, soil development and soil grain-size. The study also showed that a few tolerant species are found in all three ecosystems and some zones from different ecosystems have a similar complement of species.

The article focuses on the mire communities of Wybunbury Moss in Cheshire, England and the environmental factors that affect its nature and distribution. It mentions the four major vegetation units in Wybunbury, which includes mixed woodland, reedswamp, pine woodland and Sphagnum lawn. The quantitative investigations of environmental factors show that the distribution of mire communities corresponds to the structure of the deposit of substratum water chemistry and hydrological factors. The peat shrinkage and the edaphic conditions are attributed to the different hydrological conditions controlling peat formation in mires.

The article discusses a system of analysis for the estimation of weight, production and surface relations of trees and shrubs in a forest system. Seven species of trees and shrubs in Brookhaven forest, New York, were used in the estimation. To carry out various computations, a computer program was created. Distributions of biomass and net production among major plant parts are presented as means for sets of sample plants and as regressions. Results showed that regression within species may be used to estimate weight, production and surface relations of shrubland and forests. Findings suggest that the system of analysis has significant usefulness for the study of shrubs, woodland and forest communities.

The article presents the study on the habitat and plant communities of a desert-ecosystem, the wadi beds, in Egypt. It states that the vegetation is comprised of a number of units discernible on grounds for plant growth and their habitats. It is also recognizable in the field and are repeated with reasonable consistency. Each community type of the plants are characterized by one dominant species which is the most abundant perennial and gives character and apparent homogeneity to the plant growth.

The article presents a study that investigates the effect of soil water content on the development and growth of plants in Berkshire, England. The Imperial College of Science and Technology administered the study during summer and winter periods between 1959 and 1960 in their field station through the construction of 28 water tanks that served as water tables that were planted with agrostis tenuis and alopecurus pratensis whose yield and data were analyzed using analysis of variance. The study reveals that the interaction of elements plays an essential factor where the plants are given the capability to regenerate and develop its root system and leave appearance as well as to surpass any adverse situations.

The article presents a study that investigates the biological ecology and distribution rate of Rumex obtusifolius. The study was administered by collecting different samples of species from various countries and location and by comparing its structure through the types of habitat, topographical and climactic restrictions, geography, history and soil types as well as its perianth segment, reproduction rate and hybrid characteristics. The study reveals that the development of the species is not affected by any climactic limitations wherein the result of the survey manifests that rumex does not grow in calcareous soils. It also offers information on the different distinctions and appearance of rumex as well as an analysis on its habitat.

The article presents a study that investigates the mineral nutrient contents of several grass species in England. The study was administered to six different species of grasses that grew in sand culture and placed in an unheated glasshouse from May to June 1959 and had undergone more than eight weeks of observation and estimation of species and nitrogen interaction. The study reveals that the species show different reactions to nitrogen supply which manifest its essential role in the environmental and physiological development of grasses as well as the productivity of plant communities and soil fertility.

The article presents a study that investigates the ecological condition of woodlands that experience seasonal variation and light climate interaction in Salisbury, England. Light variance in different seasons was measured, while the status of actinography and photosite was evaluated. The study reveals that interacting variables cause the different variations in woodland light climate which is essential in biological process, particularly the position of the sun which affects photosynthesis activities, leaf expansion and pattern as well as plant morphogenesis.