bluuebunny/crossref_metadata_2025_split huggingface dataset:
A matrix population model analysis for the tropical tree, Araucaria cunninghamii
Authors: ENRIGHT N. J. , WATSON A. D. 
Published: July 2006

AbstractThe temporal stability of estimates of demographic behaviour for a sample population of the tropical rainforest gymnosperm Araucaria cunninghamii was analysed using a stage‐classified (Lefkovitch) matrix model. Previously published life‐table analyses, which used only 2 years of held data (1975–77), were compared with life‐table analysis based on a further 5 years of field data for growth and survival (1977–82). The new analysis calculated the finite rate of natural increase, λ, as 1.009 ± 0.077. This value is closer to the theoretical value of 1.0 for a stable population than is the value calculated on the basis of only 2 years of field data (1.021 ± 0.093). However, the two estimates are not significantly different from each other or from a value of 1.0.Despite the similarity of estimates for λ, the life‐table analysis based on 5 years of data showed some marked differences from the earlier analysis. Revised growth and survival rates imply a slower progression to reproductive maturity and shorter reproductive life for A. cunninghamii. The predicted stable stage distribution (SSD) showed a better fit to the initial stage distribution (ISD), and bulges in the frequency distribution for large trees can be explained by the varying rates at which individuals grow from one stage to the next.The relative contributions of survival, growth and fecundity to the observed population growth rate (elasticity) remained similar for both analyses. Survival rate contributes most significantly to the achieved population growth rate, and this appears typical of long‐lived plant species. However, the pattern of elasticities across size‐classes changed for the new analysis and identified different critical life history stages from those recorded previously.Elasticity is proposed as a measure for classifying species using the competitive (C), stress‐tolerant (S) and ruderal (R) model of plant strategies.
Responses of litter arthropods to major natural or artificial ecological disturbances in mountain ash forest
Authors: NEUMANN FREDERICK G. 
Published: July 2006

AbstractPitfall trapping was used in commercial Mountain Ash (Eucalyptus regnans) regrowth forest to study the effects on epigeal arthropods of high‐intensity wildfire plus salvage logging, and of harvesting by clearfelling plus slash burning, followed by fire‐induced natural or artificially established regeneration respectively. The study, the first of its kind in the Victorian Central Highlands, 60 km east of Melbourne, was based on 146 922 specimens of 30 ordinal or lower level taxa collected over a 3‐year period. The abrupt replacement of the ecologically complex regrowth forest by ecologically much simpler even‐aged regeneration caused appreciable instability among the litter‐frequenting arthropods. An immediate decline in diversity occurred due to short‐term boosts in activity of some common ‘major’ taxa (notably a species of seed‐harvesting ant) and the suppression of other taxa. A broad mix of functionally diverse taxa reappeared within two years of regeneration, and all but three rarely trapped ‘minor’ taxa present in undisturbed 43–46 year old regrowth (‘control’) forest had returned within 5 years. Epigeal arthropods therefore appeared to be affected only over a short period relative to the nominal 80–150 year rotation of the E. regnans ecosystem. Research is needed at the species level to achieve a more precise assessment of arthropod responses to major ecological disturbances.
Survival of saltbush (Atriplex vesicaria) seedlings in heavily grazed experimental plots
Authors: LANGE R. T. , Coleman D. , COWLEY K. R. 
Published: July 2006

Abstract
A grazing experiment in mixed chenopod shrubland near Whyalla, South Australia, is reported, in which the survivorship probabilities of saltbush shoots were measured, contrasting isolated (small seedling) shoots with equivalent shoots in outermost adult plant foliage.Throughout the experiment, measurements showed that seedlings were spared relative to shoots of adult plants. This is in agreement with visual assessments from numerous earlier experiments. When the experiment was terminated, adult root survivorship was 0.035 whereas seedling survivorship was 0.49. This outcome is discussed.
Improvement of environmental impact analysis by application of principles derived from manipulative ecology: Lessons from coastal marine case histories
Authors: PETERSON C. H. 
Published: July 2006

Abstract
I discuss briefly how the basic science of ecology contributed to the resolution of environmental problems in eight different cases in which I have been involved over the past few years. I then draw from 2 decades of experience as an academic marine ecologist and biological oceanographer to extract general lessons from each case on how environmental applications could be improved by better use of the wisdom of the field of ecology. The eight cases respresent four pairs of contrasts covering a spectrum of applications of ecological science to environmental problems: (i) two assessments of the environmental impacts from coastal ocean discharges, one evaluated by data collected under traditionally designed, self‐monitoring programmes largely mandated by the agency granting the discharge permit and the other employing an academically designed programme of explicit impact testing; (ii) two assessments of the effects of offshore oil and gas development, one done before exploration drilling to assess the adequacy of available environmental information on which to base decisions about drilling permits and the other an analysis of natural resource damages after a coastal oil spill had occurred; (iii) two evaluations of environmental problems conducted by special ad hoc panels created to resolve the environmental disputes; and (iv) two examples of how rule‐making commissions employed ecological insights in the establishment of regulations, in one case to preserve environmental quality and in the other to manage natural fishery resources.From the experience of these eight cases, I derive 38 lessons for the future improvement of environmental problem solving by better use of ecological sciences. These lessons fall into four categories: (i) improvements in study design and analysis; (ii) recognition of the importance of the multi‐species, multi‐factor (‘ecosystem’) context in which populations are nested; (iii) acknowledgement of how social concerns constrain environmental decisions; and (iv) identification of common fallacies in environmental assessment.
Short review of selected fish biomarkers of xenobiotic exposure with an example using fish hepatic mixed‐function oxidase
Authors: HOLDWAY D. A. , BRENNAN S. E. , AHOKAS J. T. 
Published: July 2006

Abstract
One group of biological tools that are useful for monitoring exposure to xenobiotics (and hence water quality) have been collectively referred to as biomarkers and are denned in this paper as any biochemical, histological and/or physiological alterations or manifestations of stress. Biomarkers within an aquatic toxicological context generally represent biological responses of individual organisms to xenobiotic exposure (i. e. responses at the whole organism level of biological organization). These include among others, enzyme alterations, bile metabolites, RNA/DNA ratio, adenylate energy charge, skeletal abnormalities, immune dysfunction, behavioural changes and histopathological lesions. Biomarkers can act as effective early warning sentinels to ensure the protection of the integrity of whole ecosystems, including freshwater and marine ecosystems.This paper briefly reviews a selection of fish biomarkers of xenobiotic chemical exposure and discusses their respective strengths and limitations for use in biomonitoring. An example of the application of fish mixed‐function oxidase (MFO) and cytochrome P‐450 as biomarkers of chemical exposure in Port Phillip Bay is provided. It is concluded that judicious application of biomarkers such as MFO in association with an understanding of the underlying causal mechanisms of induction and toxicity, will contribute to the successful prediction of biological effects of xenobiotic exposure on fish population health.
Development and use of a system for predicting the macroinvertebrate fauna in flowing waters
Authors: WRIGHT JOHN F. 
Published: July 2006

Abstract
River InVertebrate Prediction And Classification System (rivpacs) is a software package developed by the Institute of Freshwater Ecology (IFE) for assessing the biological quality of rivers in the United Kingdom. The system can be used to generate site‐specific predictions of the macroinvertebrate fauna to be expected in the absence of major environmental stress. Each prediction is based on a small number of environmental features that are used to characterize the site. The fauna predicted can then be compared with the fauna observed at the same site. This offers a procedure for evaluating biological quality with application in river management both at the local level and for national surveys. Close collaboration between the IFE team and biologists in the water industry during the project had a beneficial influence on the operational development of the system.A second feature of RIVPACS is the national classification of sites, based on the macro‐invertebrate fauna. Although the classification is currently a pre‐requisite for the prediction system, it also has intrinsic value because newly sampled sites of high biological quality can be placed within the national framework, based on their macroinvertebrate fauna. This facility is of interest to the statutory nature conservation bodies as an element in their site appraisal procedures.The predictive component of the current version of the system (RIVPACS n) was used in the 1990 River Quality Survey to assess the biological quality of almost 9000 sites throughout the United Kingdom. Further developmental work is now under way to provide a more comprehensive version of the system for the 1995 survey.
Conservation of arboreal herbivores: The Australian scene
Authors: BRAITHWAITE L. W. 
Published: July 2006

Abstract
A common global issue in biological conservation, that of land use allocation and subsequent management practice, is also at the core of the problem of conserving arboreal herbivores in Australia. The problem is caused by a number of biological and cultural factors. Many populations of Australia's terrestrial vertebrate fauna species of forest and woodland environments, including notably the arboreal herbivores, are concentrated in habitats on soils relatively rich in nutrients. Such habitats are limited due to (i) Australia's general aridity and its naturally poor endowment of soils of reasonable quality, and (ii) the extent to which habitats on the better soils have been cleared to service Australia's social and economic development. Land clearing has focused on these better soils because of cultural traditions in agriculture, and society's recognition of the importance of ‘good’ soils to a nation's development. As a result, Australia has legislation and numerous government policies and programmes that aim to identify and make maximum use of the productive potential of Australia's land. For example, the Crown Lands Alienation Act of 1861 was enacted expressly to transfer land from public to private or leasehold tenure and to develop those lands best suited for agriculture and pastoralism. As a result, from 1861 to the end of the nineteenth century, large areas were extensively cleared and potentially commercial forests were destroyed. The remaining uncleared land in private tenure today carries a major part of the woodland and forest resource on the better soils. Woodland and forest associations on these soils are generally poorly represented in reserves. Furthermore, the Australian constitution, and laws concerning the rights of the private landholder and the use of forest resources on leasehold land, indirectly or implicitly encourage or otherwise act to minimize the constraints on continued land clearing.From the above facts and because human populations are expected to increase, the prognosis for Australia's woodland and forest fauna, including the arboreal herbivores, is one of ongoing loss of important habitats. This paper suggests the following measures for ameliorating this loss: identify strategically important habitats, and encourage private philanthropic purchase or government purchase of timber rights, or subsidize the management of these habitats; examine possible trade‐offs in public expenditures on forest administration and management in return for public purchase of privately held forests; establish educational programmes that encourage a conservation ethic and a better community understanding of the realities and the extent of the difficulties to be addressed.
Ant‐ and termite‐eating in Australian mammals and lizards: a comparison
Authors: ABENSPERG‐TRAUN MAX , STEVEN DION 
Published: July 2006

Abstract
Relative abundance is one factor that influences selection of prey by insectivorous mammals and lizards. Ants and termites are extremely abundant over most of inland Australia. Their patterns of abundance are also broadly similar across climatic gradients, being most and least abundant in seasonally arid (tropic and sub‐tropic) and temperate mesic regions, respectively. All else being equal (e. g. mechanisms of prey defence, palat‐ability, availability), animals that eat many termites should also eat many (adult) ants. The present study asks three questions: (i) What is the diversity of specialized ant‐eaters (>50% volume)?; (ii) Does specialization vary with climate?; and (iii) Are ants and termites eaten in broadly similar proportions (using an earlier study on termites).Of the mammals, only the echidna (Tachyglossus aculeatus) in mesic regions, and probably the marsupial mole (Notoryctes typhlops) in the arid zone and the striped possum (Dactylopsila trivirgata) in mesic regions are ant‐specialized. Ant‐specialization in mammals shows no pattern with regard to climate. Of the lizards, only four agamid lizards are ant‐specialized: Moloch horridus (arid, semi‐arid), Ctenophorus fordi (arid, semi‐arid), Ctenophorus isolepis (arid) and Ctenophorus maculatus (arid). Specialization on ants by lizards is greatest in the arid zone (4 spp.); no lizard species were found to be ant‐specialists in mesic regions.In the arid and semi‐arid zone, two mammals each specialize on termites and one on ants; in mesic regions, two mammals specialize on ants and one on termites. Specialized insectivorous mammals thus demonstrate no marked preference for either termites or ants. Lizards, in contrast, are markedly termite‐specialized (4 ant‐specialist spp., 16 termite‐specialist spp.), and specialization is greatest in the arid zone (16 spp.). Greater specialization on termites than on (adult) ants in lizards is explained with reference to differences in prey defence and palatability between ants and termites. Consumption of ant brood (eggs, larvae, pupae) appears to be associated with a fossorial foraging mode (the marsupial mole N. typhlops; spp. of Aprasia lizards; spp. of blindsnakes Ramphotyphlops).
A MODEL OF URBAN HOUSEHOLD BEHAVIOR WITH LEISURE CHOICE
Authors: DeSalvo Joseph S. 
Published: July 2006

ABSTRACTThis paper provides a complete comparative‐static analysis of the simplest model of urban household behavior that incorporates time explicitly. Results involving the housing‐price function and the effects on housing consumption and location (radial distance from the CBD) of exogenous changes in preferences for housing, housing price, and money costs of transportation are the same as in models not incorporating time explicitly. In addition, it is found that housing consumption and location are negatively related to commuting time, positively related to nonwage income, and ambiguously related (both a priori and empirically, for reasonable values of the relevant variables) to the wage rate.
EMPLOYMENT CYCLES AND PROCESS INNOVATION IN REGIONAL STRUCTURAL CHANGE*
Authors: Seninger Stephen F. 
Published: July 2006

ABSTRACTRegional employment cycles, the demand for skilled and unskilled labor, and process innovations are analyzed in the context of an industry product cycle. Employment fluctuations caused by endogenous technological change lead to spatial decentralization of production facilities through capital relocation and spatial divisions of labor. A capital investment profile suggested by the product cycle scenario is related to employment cycles. A price system for output is outlined in terms of wages and profits over the product cycle.
MEASURES OF DIVERSIFICATION: PREDICTORS OF REGIONAL ECONOMIC INSTABILITY*
Authors: Brewery H. L. 
Published: July 2006

ABSTRACTThis work focuses on determining which measure of regional economic diversification best explains differences in economic instability across regions. One recent article found that a portfolio variance measure had the highest explanatory power. Another researcher found that an entropy measure was best after the model was corrected for heteroscedasticity. Results presented here indicate that, after correction for heteroscedasticity, portfolio variance once again displays the greatest power to explain cross‐sectional variation in observed regional instability.
TESTING THE SPATIAL SCALE AND THE DYNAMIC STRUCTURE IN REGIONAL MODELS (A CONTRIBUTION TO SPATIAL ECONOMETRIC SPECIFICATION ANALYSIS)*
Authors: Blommestein Hans , Nijkamp Peter 
Published: July 2006

ABSTRACTThis article addresses the problem of specification uncertainty in modeling spatial economic theories in stochastic form. It is ascertained that the traditional approach to spatial econometric modeling does not adequately deal with the type and extent of specification uncertainty commonly encountered in spatial economic analyses. Two alternative spatial econometric modeling procedures proposed in the literature are reviewed and shown to be suitable for analyzing systematically two sources of specification uncertainty, viz., the level of aggregation and the spatio‐temporal dynamic structure in multiregional econometric models. The usefulness of one of these specification procedures is illustrated by the construction of a simple multiregional model for The Netherlands.
HAVE CHANGES IN LOCALIZATION ECONOMIES BEEN RESPONSIBLE FOR DECLINING PRODUCTIVITY ADVANTAGES IN LARGE CITIES?*
Authors: Moomaw Ronald L. 
Published: July 2006

ABSTRACTThis paper investigates whether economies of urbanization and localization changed in two‐digit manufacturing industries over the period 1967‐1977. Estimates of changes in such economies indicate that the localization advantages of large industries declined in several industries, but that urbanization advantages increased for a small number of industries and decreased for a small number. Moreover, the absolute change in two‐digit industry employment tends to be negatively correlated with industry size, city size held constant, and positively associated with city size, industry size held constant. These latter findings tend to support the findings regarding changes in external economies.
DEPRECIATION PROFILES AND DEPRECIATION POLICY IN A SPATIAL CONTEXT*
Authors: Lugert Michael I. 
Published: July 2006

ABSTRACTThis paper demonstrates that the treatment of depreciation in the federal tax code is nonneutral not only with respect to assets and industries, as demonstrated in a number of recent studies, but also with respect to location. Using a unique set of data for manufacturing plants in Los Angeles and Philadelphia, the paper shows that the 1981 Tax Act's reduction of equipment lives to five years is likely to create differences in effective tax rates and wedges between the sample metropolitan areas for groups of plants with the same two‐digit industrial classification. These are attributable to spatial differences in corporate tax rates and the type and quality of assets used. The paper concludes by explaining how the results can be generalized to other sectors and metropolitan areas, and by noting some implications for policy.
PUBLIC CAPITAL, REGIONAL OUTPUT, AND DEVELOPMENT: SOME EMPIRICAL EVIDENCE
Authors: Costa Jose da Silva , Ellson Richard W. , Martin Randolph C. 
Published: July 2006

ABSTRACT The goal of our paper is to provide direct estimates of the association between public capital and regional output. This is made possible by the construction of a data series which measures public capital at the state level.The relation between public capital and other productive factors is tested using a translog production function. Our results show that labor and public capital are complementary inputs, and that public capital exhibited diminishing returns. We also consider restrictions on the translog formulation. Linear homogeneity is rejected in all cases, and the Cobb‐Douglas specification is rejected for the manufacturing and all sectors categories.
MULTICOLLINEARITY IN REGRESSION MODELS WITH MULTIPLE DISTANCE MEASURES*
Authors: Heikkila Eric 
Published: July 2006

ABSTRACT. In a polycentric urban context, several urban nodes may exert an influence over land rents. Where this is the case, regression analysis to explain land rents should employ distance variables corresponding to each of the urban nodes. However, these distance measures may be highly intercorrelated, thereby posing a problem of “spatial multicollinearity.”This paper demonstrates that problems arising from spatial multicollinearity can be avoided or substantially lessened by carefully selecting the geographic domain from which observations are drawn.
SOLVING A THREE‐DIMENSIONAL URBAN ACTIVITY MODEL OF LAND USE INTENSITY AND TRANSPORT CONGESTION*
Authors: Rho Jeong Hyun , Kim Tschangcho John 
Published: July 2006

ABSTRACT Recent developments in combining input‐output and transportation planning models have made it possible to construct realistic comprehensive urban and regional activity models of land use intensity. These models form the basis for a rigorous approach to studying the interactions among urban activities. However, efficient computational solution methods for implementing such comprehensive models are still not available.In this paper, an efficient solution method for a nonlinear programming urban systems model is developed by combining Evans's partial linearization technique with Powell's hybrid method. The solution algorithm is applied to a small but realistic urban area with a detailed transportation network.