bluuebunny/crossref_metadata_2025 huggingface dataset:
Perturbational profiling of a cell-line model of tumorigenesis by using metabolic measurements
Authors: Ramanathan Arvind , Wang Connie , Schreiber Stuart L.
Published: April 2005

Weinberg and coworkers have used serial transduction of a human, primary fibroblast cell line with the catalytic domain of human telomerase, large T antigen, small T antigen, and an oncogenic allele of H-ras to study stages leading toward a fully transformed cancerous state. We performed a three-dimensional screening experiment using 4 cell lines, 5 small-molecule perturbagens (2-deoxyglucose, oxamate, oligomycin, rapamycin, and wortmannin), and a large number of metabolic measurements. Hierarchical clustering was performed to obtain signatures of the 4 cell lines, 24 cell states, 5 perturbagens, and a number of metabolic parameters. Analysis of these signatures and sensitivities of the cell lines to the perturbagens provided insights into the bioenergetic states of progressively transformed cell lines, the effect of oncogenes on small-molecule sensitivity, and global physiological responses to modulators of aerobic and anaerobic metabolism. We have gained insight into the relationship between two models of carcinogenesis, one (the Warburg hypothesis) based on increased energy production by glycolysis in cancer cells in response to aberrant respiration, and one based on cancer-causing genes. Rather than being opposing models, the approach described here suggests that these two models are interlinked. The cancer-causing genes used in this study appear to increase progressively the cell's dependence on glycolytic energy production and to decrease its dependence on mitochondrial energy production. However, mitochondrial biogenesis appears to have a more complex dependence, increasing to its greatest extent at an intermediate degree of transduction rather than at the fully transformed state.
Aneuploid colon cancer cells have a robust spindle checkpoint
Authors: Tighe Anthony , Johnson Victoria L , Albertella Mark , Taylor Stephen S
Published: April 2005

Colon cancer cells frequently display minisatellite instability (MIN) or chromosome instability (CIN). While MIN is caused by mismatch repair defects, the lesions responsible for CIN are unknown. The observation that CIN cells fail to undergo mitotic arrest following spindle damage suggested that mutations in spindle checkpoint genes may account for CIN. However, here we show that CIN cells do undergo mitotic arrest in response to spindle damage. Although the maximum mitotic index achieved by CIN lines is diminished relative to MIN lines, CIN cells clearly have a robust spindle checkpoint. Consistently, mutations in spindle checkpoint genes are rare in human tumours. In contrast, the adenomatous polyposis coli (APC) gene is frequently mutated in CIN cells. Significantly, we show here that expression of an APC mutant in MIN cells reduces the mitotic index following spindle damage to a level observed in CIN cells, suggesting that APC dysfunction may contribute to CIN.
A novel mechanism of matrix metalloproteinase‐9 gene expression implies a role for keratinization
Authors: Kobayashi Takashi , Kishimoto Jiro , Ge Yimin , Jin William , Hudson David L , Ouahes Nadia , Ehama Ritsuko , Shinkai Hiroshi , Burgeson Robert E
Published: April 2005

To investigate the pathophysiological role of matrix metalloproteinase (MMP)‐9 in the skin, we analyzed MMP‐9 expression from human keratinocytes in culture. MMP‐9 and the terminal differentiation marker involucrin were co‐localized in the same keratinocytes with a high concentration of Ca2+, a potent stimulator of differentiation. We identified the novel KRE‐M9 element, further downstream to the previously reported TPA responsive element in the MMP‐9 promoter, and both of these two elements were shown to be important for MMP‐9 transcription and Ca2+ induction. The concomitant upregulation of MMP‐9 and involucrin transcripts was probably due to the very similar gene regulatory elements, KRE‐M9 and KRE‐4, in their respective promoters. These results indicate a novel mechanism of transcriptional regulation for MMP‐9 in the process of keratinization, implying the probable association of apoptosis and differentiation of keratinocytes in epidermal skin tissue.
Species‐specific organization of CpG island promoters at mammalian homologous genes
Authors: Cuadrado Myriam , Sacristán María , Antequera Francisco
Published: April 2005

An essential issue derived from the sequencing of the human and other genomes is the identification of gene regulatory elements. Using in vivo footprinting and expression analysis, here we show that mouse and human CpG island promoters at homologous genes have a completely different organization in terms of size and binding of transcription factors. Despite these species‐specific differences, a unifying picture emerges from the precise confinement of protein–DNA interactions between the 5′ boundary of the CpG islands and the transcription initiation site. This finding allows direct localization of promoters on genomic sequences and reveals a very high rate of variation and evolutionary divergence of mammalian regulatory regions. Our results also show that CpG island promoters associated with tissue‐specific genes, such as the human α‐globin, are bound by ubiquitous factors that allow a constitutive low level of expression in many cell types.
Accounting, Valuation and Duration of Football Player Contracts
Authors: Amir Eli , Livne Gilad
Published: April 2005

Abstract:  FRS 10 requires investments in player contracts by football companies to be capitalized and amortized. Given the high degree of uncertainty associated with such contracts, it is not clear that this treatment is consistent with asset capitalization criteria. The evidence provided in this paper does not support inconclusively this capitalization requirement in that it indicates weak association of investment in player contracts with three measures of future benefits. In particular, the duration of this association is at most two years, which is shorter than the duration implied by the amortization period reported by sample companies. Nonetheless, other findings suggest that market participants seem to agree with the treatment prescribed by FRS 10. These results should be of interest to practitioner and standard setters who (axiomatically) regard intangibles acquired in an arm's length transaction as assets.
The Effect of Earnings Management on the Asymmetric Timeliness of Earnings
Authors: García Lara Juan Manuel , García Osma Beatriz , Mora Araceli
Published: April 2005

Abstract:  Is earnings management affecting (driving) the measures of earnings conservatism?Ball et al. (2000) point out that the asymmetry in the recognition of good and bad news in earnings (faster recognition of bad news: earnings conservatism) is more pronounced in common‐law than in code‐law based accounting regimes. However, comparative studies on earnings conservatism in Europe have failed to identify significant differences between common‐law and code‐law based countries. We argue that in code‐law based countries managers have incentives to reduce earnings consistently. This enhances the association between earnings and returns in bad news periods. We find that after controlling for discretionary accruals, the differential earnings response to bad news in Germany and France decreases significantly.
Risk Exposures and International Diversification: Evidence from iShares
Authors: Zhong Maosen , Yang Hui
Published: April 2005

Abstract:  We examine the newly developed international diversification instruments–iShares traded on the American Stock Exchange. Given the fact that iShares can be created and redeemed at will, the daily price of an iShare is expected to be equal to the daily portfolio value of the underlying assets in the home‐country market. Therefore, theoretically, iShare pricing should be influenced by the risk from the iShare's home‐country market and not the risk from the US market, per se. We evaluate the risk exposure of iShare prices to the US market (non‐fundamental effect) as well as the home‐country market (the fundamental effect). We find that most iShare returns are significantly influenced by and sensitive to the US market risk. Moreover, the US market appears to be the key permanent driving factor and the home‐country market is a pronounced transitory driving force for iShare prices. These findings indicate the presence of limits of international arbitrage for iShares. As a result, the international diversification benefits of iShares become questionable.
Callose synthase (CalS5) is required for exine formation during microgametogenesis and for pollen viability in Arabidopsis
Authors: Dong Xiaoyun , Hong Zonglie , Sivaramakrishnan Muthuswamy , Mahfouz Magdy , Verma Desh Pal S.
Published: April 2005

Callose (β‐1,3‐glucan) is produced at different locations in response to biotic and abiotic cues. Arabidopsis contains 12 genes encoding callose synthase (CalS). We demonstrate that one of these genes, CalS5, encodes a callose synthase which is responsible for the synthesis of callose deposited at the primary cell wall of meiocytes, tetrads and microspores, and the expression of this gene is essential for exine formation in pollen wall. CalS5 encodes a transmembrane protein of 1923 amino acid residues with a molecular mass of 220 kDa. Knockout mutations of the CalS5 gene by T‐DNA insertion resulted in a severe reduction in fertility. The reduced fertility in the cals5 mutants is attributed to the degeneration of microspores. However, megagametogenesis is not affected and the female gametes are completely fertile in cals5 mutants. The CalS5 gene is also expressed in other organs with the highest expression in meiocytes, tetrads, microspores and mature pollen. Callose deposition in the cals5 mutant was nearly completely lacking, suggesting that this gene is essential for the synthesis of callose in these tissues. As a result, the pollen exine wall was not formed properly, affecting the baculae and tectum structure and tryphine was deposited randomly as globular structures. These data suggest that callose synthesis has a vital function in building a properly sculpted exine, the integrity of which is essential for pollen viability.
An essential function of phosphatidylinositol phosphates in activation of plant shaker‐type K+ channels
Authors: Liu Kun , Li Legong , Luan Sheng
Published: April 2005

A prominent regulatory property of plant shaker‐type K+ channels is the ‘rundown’ that causes channel closure upon membrane excision from the cell, implicating intracellular factor(s) in maintaining channel activity. One such factor has been identified as hydrolysable ATP‐Mg although the mechanism for ATP function remains unknown. Here we report identification of phosphatidylinositol (PI) phosphates (PIPs) as essential regulators for the voltage‐dependent and ‐independent activation of plant shaker‐type channels such as SKOR, an outward rectifying K+ channel. Inhibition of PI kinase activity abolished the function of ATP‐Mg in restoration of rundown channel activity, demonstrating that PIPs production by PI kinases and ATP‐Mg underlies ATP‐induced activation of the rundown channel. We also identified aluminum block as a common feature of the plant shaker‐type channels and provided evidence that aluminum block of these channels may result from Al interaction with PIPs.
New Perspectives on the Pelagic Stage of Sea Turtle Development
Authors: CARR ARCHIE
Published: April 2005

Abstract: An original difficulty in accepting the idea of a pelagic diwelopmental period for sea turtles was to explain bow food could be found in reliable supply in the open ocean The uncertainty that this introduced was removed when I belatedly came to appreciate the prevalence and diversity of convergences where downwelling gathers and aligns buoyant material, including the dispersed food mources of the surface waters. Thus, it now seems clear that an essential factor in the survival of young sea turtles–and of other elements of the epipelagic; open‐ocean fauna as well–is the accessibility of a front; where inanimate debris and any floating animal or plant will be gathered to.

This new evidence of complexity in the lost‐year ecology of sea turtles has important implications for their conservation and management. It is now obvious that when young cultured sea turtles are released in so‐called bead‐starting projects, the release sites ought to be chosen with the greatest care. Shores located at a distance from any major current or its eddy ought to be avoided. It is also necessary to avoid release localities where the convergence habitat may carry heavy loads of pollutants.

Results of the present work reveal an urgent need for further study of sea turtle life cycles, with special attention to their developmental ecology The growing evidence for a more protracted pelagic stage, during which the juvenile turtles are passive migrants in fronts that are increasingly invaded by debris and toxic wastes, emphasizes the need for a better understanding by marine biologists of the organization of the driftline habitat and the behavioral ecology of its occupants Until these studies of the oceanography and biology of driftlines are done, we are bound to remain peculiarly ignorant of the ecologic organization of three‐fifths of the surface of the earth.
Conservation Lessons from Long‐Term Studies of Checkerspot Butterflies
Authors: EHRLICH PAUL R. , MURPHY DENNIS D.
Published: April 2005

Abstract: Long‐term studies of checkerspot butterflies (Euphydryas spp.) are used to draw conservation lessons with implications for the design and management of reserves for invertebrates We discuss;

The importance of determining the structure of and patterns of mating within demographic units

The lack of congruence between migration and gene flow.

The crucial role of habitat diversity in the protection of species which otherwise require only small areas of habitat

The importance of identaDing and preserving “reservoir” populations within metapopulations

The necessity of identifying subtle habitat requirements

The key role of environmental stochasticity in the extinction of small populations.

The difficulty of protecting metapopulations and of in ‐hoducing populations into “empty” habitat patches

We conclude, among other things, that the size of reserves required to preserve herbivorous insects is often underestimated; that a “minimum viable metapopulation” approach to their conservation may be needed; that long‐term studies of the biology of populations of sample invertebrate groups would greatly aid conservation biologists; and that more effort is needed to inform the public and decision makers about the need to conserve populations as well as species.
Bird Survival in an Isolated Javan Woodland: Island or Mirror?
Authors: DIAMOND JARED M. , BISHOP K. DAVID , VAN BALEN S.
Published: April 2005

Abstract:Differential extinction of forest species following forest fragmentation raises the questions of which populations are most prone to disappeaq and why. Hence we studied an 86–hectare woodland in west Java, the Bogor Botanical Garden (BBG), that became isolated when suwounding woodland was destroyed 50 years ago. Out of 62 bird species breeding in the BBG during 1932–1952, 20 had disappeared by 1980–1985, four were close to extinction, and five more had declined noticeably. The two main variables that identifl extinction‐prone populations in the BBG are 1) small initial population size in the BBG and 2) rareness or absence in the surrounding counttyside. Although the BBG retained wooded habitat, it is evidently too small to retain self‐sustaining populations of many woodland bird species. Small populations at high risk of extinction for stochastic reasons are doomed to disappear permanently unless subsidized by re‐colonization from the surroundings Thus, a too‐small reserve cannot function as a distributional island but comes to mirror the species composition of its surroundings More such case studies documenting species losses from small habitat fragments are required to demonstrate to nonbiologists the need for reserves large enough to support self‐sustaining populations.
Effects of Kenya's Bura Irrigation Settlement Project on Biological Diversity and Other Conservation Concerns
Authors: LEDEC GEORGE
Published: April 2005

Abstract: The Bura Irrigation Settlement Project was designed to settle landless farmers and grow irrigated cotton for export in a remote, semiarid region of Kenya Over $100 million* has been invested by the Kenya government, World Bank, Britain's Overseas Development Administration, Finland's FINNIDA, The Netherlands, Commonwealth Development Corporation, and European Development Fund. The project has been plagued by a wide range of financial, managerial, and technical problems, and has been economically disappointing. Some of the disappointing economic performance is linked to the almost complete lack of concern for forestry, wildlife, and other environmental issues during most stages of project implementation.

The riverine (gallery) forests of the Tana River represent a biologically unique ecosystem in a semiarid region of Kenya The irrigated areas developed under the Bura project have not been situated on riverine forest lands. Nonetheless, the project seriously threatens the long‐term survival of all the nearby riverine forest owing to the acute shortage of fuel‐wood in the region. This shortage has occurred largely because the planned fuelwood plantations have been neglected.
Conservation Genetics in the Management of Desert Fishes
Authors: MEFFE GARY K. , VRIJENHOEK ROBERT C.
Published: April 2005

Abstract: The status and security of fishes in North American deserts have steadily declined in this century due to man's activities in this naturally fragile region. We address genetic aspects of the population structure of desert fishes as applicable to conservation and recovery programs by developing two zoogeographic models of isolation and gene flow. In the Death Valley model populations are isolated, with no chance of natural gene flow among them. Genetic diversity within populations tends to be low, but genetic divergence among populations within a species is high. In the Stream Hierarchy model, a complicated hierarchical genetic structure exists and is a function of geographic proximity and connectivity of habitats. Within‐habitat genetic diversity tends to be higher, and among‐habitat differentiation lower, than in the Death Valley model. These two systems must be recognized as distinct and managed differently. We also suggest three areas of experimentation needed to better understand and manage genetic stocks of desert fishes: relationships between heterozygosity and fitness, experimental mixing of similar stocks to examine effects of increased heterozygosity, and analysis of the relative roles of genetic adaptation and phenotypic plasticity in local differentiation.
Gradient Analysis in Nature Reserve Design: A New Zealand Example
Authors: DeVELICE ROBERT L. , DeVELICE JEAN WARD , PARK GEOFF N.
Published: April 2005

Abstract: Direct and indirect gradient analysis methods were tested to assist in nature reserve design in New Zealand Graphic descriptions were made of community‐environment relationships. Environmental factors considered included altitude, solar radiation, geologic substrate, soil drainage, and landform

Classification identified 21 lowland forest community types in the northwestern South Island study area. These community types and their composite species appear to be arranged along soil fertility, landform, and temperature gradients. Direct gradient analysis was particularly useful in portraying the relationship of the plant communities to perceived environmental gradients.

Comprehensive gradient diagrams for an ecological district may be compared with gradient diagrams depicting the districts current reserves, if any. A representative reserve system may be achieved if “gaps” between the two diagrams are filled in by expanding the reserve system and/or modifying existing reserve boundaries. Based on this technique, a recommendation is made to incorporate a unique coastal forest remnant in a national park proposal for the study area.
Lack of Genic Diversity Within and Among Populations of an Endangered Plant, Howellia aquatilis
Authors: LESICA PETER , LEARY ROBB F. , ALLENDORF FRED W. , BILDERBACK DAVID E.
Published: April 2005

Abstract: Howellia aquatilis (Campanulaceae) is a rare aquatic plant considered endangered throughout its range in the Pacific Northwest. Howellia appears to have a narrow ecological amplitude, occurring only in temporary ponds suwounded by trees. Anatomical observations of developing flowers indicate a restrictive breeding system approaching obligate self‐fertilization. We used protein electrophoresis to examine the genetic structure of four populations from throughout the range of species. Eight enzymes encoded by 18 putative loci showed no variation, either within or among populations. Howellia's small ecological amplitude and lack of genetic variability lead us to believe that the species is prone to extinction A conservation strategy for this species should include protection of ponds that are currently inhabited by Howellia as well as ponds that will become appropriate habitat in the future. To insure against large‐scale environmental perturbations, multiple pond clusters throughout the range of the species should be protected.
Changes in Wildlife Communities Near Edges
Authors: YAHNER RICHARD H.
Published: April 2005

Abstract: Wildlife managers and land managers have traditionally considered edges as beneficial to wildlife because species diversity generally increases near habitat edges. Explanations for this edge effect include greater vegetative complexity at edges or the simultaneous availability of more than one landscape element. However, edges can have negative consequences for wildlife by modifying distribution and dispersal and by increasing incidence of nest predation and parasitism Edges also may be detrimental to species requiring large undisturbed areas because increases in edge generally result in concommitant reductions in size and possible isolation of patches and corridots. Thus, both wildlife and land managers should be cautious when describing the benefits of edges to wildlife: particularly when dealing with species that require forest interiors.

Changes in wildlife communities associated with habitat edges are not easily assessed because defining edge species and measuring edge dimensions can be difficult in field studies Also, there is no general consensus as to how edge effect is best measured. Well‐designed long‐term studies of edges in various landscapes are needed (1) to better understand the positive and negative impacts of edges on wildlife communities, guilds, or key species, and (2) to effectively quantify edge effect and thereby develop management recommendations to improve the quality of edges for wildlife. Additional studies of edge effect are timely because greater amounts of edge will continue to be created in future landscapes due to extensive agriculture and other land‐use‐practices, and because developing knowledge in conservation biology and landscape ecology will facilitate multidisciplinary approaches to edge and landscape management for the benefit of wildlife.
Forests Too Deer: Edge Effects in Northern Wisconsin
Authors: ALVERSON WILLIAM S. , WALLER DONALD M. , SOLHEIM STEPHEN L.
Published: April 2005

Abstract: Browsing by white‐tailed deer (Odocoileus virginianus) can profoundly affect the abundance and population structure of several woody and herbaceous plant species. Enclosure studies and population surveys reveal that past and current deer densities as low as 4 deer/km2 may prevent regeneration of the once common woody species, Canada yew (Taxus canadensis), eastern hemlock (Tsuja canadensis), and white cedar Puja occidentalis), as well as several herbaceous species. Prior to European settlement, forests in northern Wisconsin contained relatively sparse deer populations (<4/km2), but extensive timber cutting in the late nineteenth century boosted deer populations. Continued habitat fragmentation resulting from scattered timber harvests and the creation of “wildlife openings” to improve deer forage maintain these high densities throughout much of the Northeast.

Because deer wander widely, the effects of high deer densities penetrate deeply into remaining stands of old and mature forest, greatly modifying their composition Thus, abundant early successional and “edge” habitat, and the high deer densities they engender, represent significant external threats to these plant communities. We hypothesize that establishing large (200–400 km2) continuous areas of maturing forest, especially in conjunction with increased hunting, could reduce local deer densities and so provide a simple and inexpensive method for retaining species sensitive to the deleterious effects of browsing.
Pollination in Dianthus deltoides (Caryophyllaceae): Effects of Habitat Fragmentation on Visitation and Seed Set
Authors: JENNERSTEN OLA
Published: April 2005

Abstract: I analyse the effects of habitat fragmentation on the pollination success of a perennial, butterfly‐pollinated, caryophyllaceous herb, the maiden pink, Dianthus deltoides L. The study was conducted in July 1986 and July 1987 at two different sites in southwest Sweden, an undisturbed “mainland” site and a fragmented site consisting of “habitat islands” within a heavily utilized agricultural area The fragmented area had a lower diversity and abundance of both flowering plants and flower‐visiting insects. Dianthus flowers received fewer visits in the fragmented area than in the mainland area, and the seed set was much lower. Hand pollination increased seed set up to 4.1 times in the fragmented area, but no significant differences were found between hand‐pollinated and control flowers at the mainland site. There were no differences between the two sites in standing crop of nectar, ovule number per flowers, or seed set of bagged flowers, band‐pollinated flowers, and hand‐pollinated fertilized flowers Thus, the difference in natural seed set between the two sites can be explained by differences in pollinator service.
Tsetse Flies in Africa: Bane or Boon?
Authors: ROGERS DAVID J. , RANDOLPH SARAH E.
Published: April 2005

This paper examines the changing perception of the role of the tsetse fly in the development of tropical Africa. The trypanosomiases transmitted by this group of vector insects historically prevented the establishment of mixed (i.e., arable and livestock) farming and thus the occurrence of an agricultural revolution within the potentially more productive humid zones of the continent. Initially the colonial powers saw the tsetse as the bane of African development, and much of colonial policy was aimed at eradicating the vectors directly or at eliminating the diseases they transmit. The observation of inefficient farming techniques in the fly‐infested areas, coupled with overstocking of cattle in the fly‐free areas, generally led to naive development plans that often exacerbated the very problems they aimed to solve. The presence of the tsetse fly, however, prevented these mistakes from being more widespread and thus now provides a window of opportunity for sensible development that acknowledges the uniqueness of African soils and ecosystems. Ecologists can play a vital role in this process, although the absence of relevant hard data still retards progress.
Estimating the Distribution and Abundance of a Cryptic Species, Dipodomys stephensi(Rodentia: Heteromyidae), and Implications for Management
Authors: PRICE M. V. , ENDO P. R.
Published: April 2005

A common hurdle in developing conservation plans for endangered species threatened by habitat loss is lack of basic information on distribution and factors affecting population densities. Such information is time‐consuming and expensive to obtain for cryptic species, such as nocturnal small mamma whose presence at a site can only be determined through intensive sampling. We illustrate how readily‐available soils maps can be used to estimate the potential distribution of such a species, Stephens' kangaroo rat. In this case, the distribution map accurately predicts presence or absence of this species at 70% of sites. Our maps reveal extensive habitat loss and fragmentation. Data from repeated censuses at several sites indicate that population densities of this species can vary more than 10‐fold in response to rainfall patterns, and that temporal fluctuations in geographically separated populations are correlated. These results suggest that habitat subdivision is unlikely to substantially increase expected time to extinction for the species as a whole; habitat conservation efforts for Stephens’kangaroo rat should therefore be directed at establishing a few large, widely separated reserves, rather than many smaller reserves.
Spatial Structure and Population Extinction: A Study with Drosophila Flies
Authors: FORNEY KARIN A. , GILPIN MICHAEL E.
Published: April 2005

Abstract: The total amount of habitat and also its distribution and subdivision affect the extinction probability of a resident population Two species of Drosophila are studied in spatial configurations of a single large habitat patch, single small habitat patches, and two small but connected habitat patches in which a low rate of migration, roughly one fly per generation, is possible. The single large habitat patch shows the lowest extinction rate lower than the combined rate of two small patches of the same total size. For one of the species, the “corridor” between the pair of small patches seems to produce a “rescue effect” that lowers extinction rates, probably due to a decrease in the coefficient of variation in fluctuations of the population sire in this coupled system. The systems seem to have been influenced by demographic stochasticity, based on the relationship of population size to extinction probability.
Population Estimates of Fruit Bats (Pteropus mariannus) in the Mariana Islands
Authors: WILES GARY J. , LEMKE THOMAS O. , PAYNE NICHOLAS H.
Published: April 2005

Abstract: Populations of Marianas fruit bats, Pteropus mariannus, were surveyed on each of the 15 Mariana Islands in 1983–1984. It is estimated that a minimum of 8,700–9,000 fruit bats occur in the archipelago, with about 8245% of these bats found on the nine northernmost and largely uninhabited islands. The islands of Anatahan, Pagan, and Agrihan had the largest populations, with minimum population estimates of 3,000, 2,500, and 1,000 bats, respectively. Smaller populations of about 400–1,000 fruit bats occurred on Asuncion, Guam, Rota, and Guam. The remaining is‐ands in the archipelago were each estimated to have fewer than 125 bats. Population densities of fruit bats were highest on islands with little bunting but were generally much lower on human‐inhabited islands where bunting was common. Quantity and quality of existing habitat were other important factors regulating the size of fruit bat populations in the Marianas. Increased enforcement of existing laws protecting bats and a public awareness program are important tasks needed to conserve and manage fmit bats in the Marianu Islands. The census techniques used in this study may be applicable to other fypes of colonial, mobile wildlife that inhabit islands.
Use and Misuse of Forest‐harvested Fruits in the Iquitos Area
Authors: VASQUEZ RODOLFO , GENTRY ALWYN H.
Published: April 2005

Abstract: Of 193 fruit species observed to be regularly consumed in the region surrounding Iquitos, Peru, 120 species are exclusively wild‐harvested and 19 more originate from both wild and cultivated sources. The wild‐harvested fruits of 57 species belonging to 24 different plant families are sold in the Iquitos market and are very important in the economy and diets of the area Nearly half of the Iquitos fruit vendors sell wild‐harvested fruits (if fruits used as vegetables or starch sources are excluded), and over half of the fruit species sold are wild‐harvested Many fruit species consumed at Iquitos differ from those consumed in other parts of Amazonia Although some native fruit species are beginning to be grown as crops, the wild populations of these high‐potential species are being rapidly depleted by destructive harvesting techniques as market pressure begins to build In the last few years, the availability of several of the most popular fruit species has decreased markedly. If nondestructive sustained yield harvesting of resources such as wild‐harvested fruits is to play its suggested important role in tropical forest conservation, much stronger efforts will be needed to prevent destructive overharvesting of these potentially significant resources.
Spotted Owls and Old Growth Logging in the Pacific Northwest
Authors: DOAK DANIEL
Published: April 2005

Abstract: Northern Spotted Owls, Strix occidentalis caurina, require large tracts of old‐growth conifer forest to survive and reproduce. Much of this forest has been or is being cut by commercial logging operations, with uncertain consequences for the owls. In this paper I present simulation models of owl population change over the next 100 years, as summing a variety of scenarios for habitat destruction and fragmentation. My analysis differs from previous models by incorporating patchy territory distribution and random environmental fluctuations. Fragmented and patchy habitat distributions are common problems for endangered organisms, but they have received little attention from modelers. My results indicate that yearly fluctuations in breeding success have little impact on owl populations, but that spatial structure is quite important and should be considered in planning forest preservation. The simulations suggest that for all reasonable parameter values the proposed US. Forest Service logging plans will lead to the demise of the owls.
Trends in Landscape Heterogeneity Along the Borders of Great Smoky Mountains National Park
Authors: AMBROSE JONATHAN P. , P.BRATTON SUSAN
Published: April 2005

Border areas of Great Smoky Mountains National Park were examined in a photogrammetric study of temporal trends in landscape heterogeneity. Analysis of data from maps and aerial photographs showed that from 1940 to 1978, most areas outside the park borders experienced an increase in forest patch density and cleared patch density, a decrease in forest patch size and little change in percentage of forest cover Areas inside the park borders showed an increase in forest patch size and percentage of forest cover, and a decrease in density of forested and cleared patches.

Significant differences in spatial continuity of vegetation existed between areas inside and outside the park borders at the time of the park's establishment. Land use changes since 1940 have increased differences in landscape heterogeneity between park and nonpark lands. The areas of greatest change haw generally been those in closest proximity to the legal park border, where relatively sharp gradients in patch size, patch density, and forest cover now exist. Differences in landscape heterogeneity between adjacent lands outside the park have decreased as have differences between adjacent park lands.

Local variations in land use history have influenced the nature and intensity of boundary effects along the park border Different sections of the park border vary greatly in both spatial patterns and temporal trends in landscape heterogeneity. The results of the study point to the limited utility of the island biogeographic model in predicting management problems in this park.
Conservation Genetics of Pacific Salmon I. Temporal Changes in Allele Frequency
Authors: WAPLES ROBIN S. , TEEL DAVID J.
Published: April 2005

Recent reductions in the abundance of all Pacific salmon species (Oncorhynchus spp.), coupled with large increases in artificial productioq demand that careful attention be paid to genetic changes occurring in both wild and cultured populations. Analysis of electrophoretic data for chinook salmon (O. tshawytscha) from the Pacific coast of Oregon revealed substantial allele frequency changes over 24 years in hatchery, but not wild populations. Unfortunately, our understanding of the causes of this result is hampered by a lack of theoretical models designed for organisms with life history features like those of Pacific salmon. We used computer simulations to provide a context for understanding genetic changes observed in the hatchery populations.

Simulation results indicated that annual fluctuations in population allele frequencies due to genetic drift can typically be expected to be several percent, with the absolute magnitude determined primarily by the effective number of spawners each year rather than the age structure. Changes over 10‐ to 25‐year periods were only slightly greater than short‐term changes (1–5 years). The magnitude of allele frequency change over time was different for juvenile and adult samples. The probability of a significant test statistic comparing allele frequencies in temporally spaced samples increased with the ratio of sample size to effective number of breeders per year. This is an important consideration for conservation biologists, who typically are concerned with populations of small effective size.

Simulation results indicate that it is necessary to postulate unrealistically large selection coefficients to explain the genetic changes in the hatchery populations by natural selection. The changes observed are consistent with a pure drift model provided that the effective number of breeders was as small as about 25–50 per year. Analysis of brood stock information for the hatcheries indicates that the effective population number may indeed have been this low, although the number of returning adults was often much larger. This conclusion underlines the importance of monitoring the genetic consequences of the large‐scale artificial propagation program involving Pacific salmon.
The Florida Panther and Private Lands
Authors: MAEHR DAVID S.
Published: April 2005

Intensive efforts to protect Florida panther (Felis concolor coryi) habitat on private lands are essential for this endangered animal to survive. About half of the presently known occupied panther range in south Florida occurs on private lank where agricultural and urban development are increasing rapidly. Panther conservation strategies must go beyond traditional land acquisition by government and include economic programs to preserve critical landscapes on private lank.
Wildlife Conservation Outside Protected Areas—Lessons from an Experiment in Zambia
Authors: LEWIS DALE , KAWECHE GILSON B. , MWENYA ACKIM
Published: April 2005

Managing an area as a national park in Africa often entails dealing with human pressures from regions surrounding the protected area Dealing with these human pressures is the subject of this paper, which goes well beyond mere law enforcement to discuss the realm of traditional leadership in the village, rural socioeconomics, and the services of wildlife management by government in areas surrounding a national park.

This paper describes the results of an experimental project in Zambia that sought to halt the drastic loss of elephants and rhinos to poaching in and around protected areas in the Luangwa Valley. The design of this project was to involve local residents outside national parks in wildlife protection and management activities. In addition, sustained‐yield uses of wildlife were adopted to recycle revenue shares into community development and to make the program of wildlife management financially self‐supporting.

To help carry out the various tasks of protecting and developing wildlife resources, residents were trained and employed as wildlife management staff Village wildlife councils provided advice and assistance. Safari concessions yielded sufficient revenue to meet the recurrent costs of wildlife management and also generated significant earnings for local community benefits. As a result; poaching dropped dramatically, local economies were improve and village attitudes toward wildlife management and conservation became more positive.
Rarity in Neotropical Forest Mammals and Its Ecological Correlates
Authors: ARITA HÉCTOR T. , ROBINSON JOHN G. , H.REDFORD KENT
Published: April 2005

Local density and size of distributional range have been used to characterize rarity, but conclusions are weakened by their possible lack of independence. The usefulness and validity of using these two variables were tested with data on distribution, local density, body size, and feeding habits for a set of 100 Neotropical forest mammals.

In a bivariate plot of distributional range against local density, species clustered according to their trophic or taxonomic groups. This indicates that diet and phylogenetic history have an influence on rarity. A negative correlation was found between distribution and abundance. However this correlation was weaker within trophic or taxonomic groups, and vanished when body size was held constant. These results show that both distribution and abundance are valid and independent estimators of rarity when comparing species with similar sizes and ecological traits. Regression analysis showed that larger animals tend to have lower densities and wider distributional ranges. Rarity is clearly associated with body size.

A dichotomous classification of rarity based on area of distribution and local density is suitable for Neotropical forest mammals. Species in each of four categories created by such a scheme require different conservation and management policies that are determined by the ecological characteristics of the species. Final conservation strategies must also be shaped by political and economic constraints.
Population Viability Analysis for an Endangered Plant
Authors: MENGES ERIC S.
Published: April 2005

Abstract:Demographic modeling is used to understand the population viability of Furbish's lousewort,Pedicularis furbishiae, a perennial plant species endemic to the St. John River Valley in northern Maine. Environment‐specific summaries of demographic parameters (survivorship, growth, and fecundity) over four years, organized into stage‐based projection matrices, provide predictions of future population dynamics given a deterministic extension of past conditions. Stochastic modeling, using (I) empirically observed variation in demographic parameters, and (2) estimated rates of natural catastrophes, leads to predictions of extinction probability.

P. furbishiaeviability has varied widely over the study period Viable populations with finite rates of increase > 1 are found where cover is low, woody plants do not dominate, and disturbance does not occur. Rates of increase vary over time, suggesting that stochastic analyses would be realistic. Stochastic measures of population viability incorporating environmental variation suggest that early successional environments, especially wetter sites, can support viable populations in the absence of disturbance. However; observed rates of natural catastrophe dominate viability estimates of individual populations. Metapopulation dynamics feature extinction rates that are greater than recolonization rates, and may be affected by land use in the watershed Species management needs to consider a large‐scale view of the riverine corridor.
Exotic Organisms: A Dilemma for Conservation Biology
Authors: COBLENTZ BRUCE E.
Published: April 2005

Abstract: Human‐induced problems in resource conservation fall into three categories: (1) inappropriate resource use, (2) pollution, and (3) exotic organisms. Problems of resource use and pollution are correctable; exotic organisms are frequently permanent and may be the most pervasive influence affecting biodiversity in many systems, particularly on oceanic islands. Invasive exotic organisms often have effects far in excess of what might be predicted by equilibrium island biogeographic theory; a single exotic species may cause numerous extinctions in addition to altering the physical environment. Exotic organisms frequently cause environmental crises. In such crises, calls for more research are commonplace, but research results may be an unaffordable luxury, providing information only for the eulogy. Programs to eradicate exotic organisms provide an opportunity to combine good science and good conservation into functioning conservation biology.
Biodiversity Loss in the Temperate Zone: Decline of the Native Fish Fauna of California
Authors: MOYLE PETER B. , WILLIAMS JACK E.
Published: April 2005

In proportion to the entire fauna, loss of species may be as great in temperate regions as in tropical regions. To test the validity of this statement we analyzed the status of the native fish fauna of California, using a methodology that quantifies expert knowledge. Of 113 native taxa, 6 percent are extinct, 12 percent are officially listed as threatened or endangered 6 percent deserve immediate listing I7 percent may need listing soon, 22 percent show declining populations but are not yet in serious trouble, and 36 percent appear to be secure. Much of the faunal decline has taken place in recent years; it has included unexpectedly rapid declines of once abundant species. Fish taxa in serious trouble are most likely to be (1) endemic to California, (2) restricted to a small area, (3) occupants of just one drainage basin, (4) part of a fish assemblage of less than five species, and (5) found in isolated springs, warm water streams, or big rivers. Water diversions and introduced species, acting in concert, seem to be the principal causes of the decline of the native fauna, although other types of habitat degradation have contributed as well. The situation in California, with its high degree of endemism (60 percent), may be regarded as extreme but fish faunas in other temperate regions show signs of being nearly as stressed. It is likely that the situation with fish reflects a more general decline of the biota of temperate regions of the world.
Birds in a Farmland—More Species in Small than in Large Habitat Island
Authors: LOMAN JON , VON SCHANTZ TORBJRN
Published: April 2005

Abstract: Birds were censused on habitat islands to investigate the effect of vegetation, island size, and isolation on the density and species diversity of birds.

The density of birds was highest on small habitat islands and in islands close to other islands, especially large ones. We suggest that this is because birds on small habitat islands utilize resources from surrounding fields. After compensating for sampling effect (the fact that we made more observations and there are more territories on large islands), we analyzed the species richness of different islands. We found that there are more territorial species (i.e., bird species whose territories are readily mapped) on small than on large islands. We discuss different causes for this finding. We also found that a given area comprised of many small islands contains more species than the same area comprised of only a few large islands. This is true for both all observed bird species and for all recorded territorial species. We conclude that, when considering conservation from a local perspective, it is important to protect all nonmatrix land in this type of landscape. This will ensure a high local diversity.