bluuebunny/crossref_metadata_2025 huggingface dataset:
The Principle of Nested Subsets and Its Implications for Biological Conservation
Authors: PATTERSON BRUCE D.
Published: April 2005

Abstract: The nested subset hypothesis states that the species comprising a depauperate insular biota are a proper subset of those in richer biotas, and that an archipelago of such biotas, ranked by species richness, presents a nested series. The pattern characterizes the distributions of mammals in three different archipelagos, and it appears more strongly developed among faunas in the process of, relaxation (landbridge islands) than in those derived by overwater colonization (oceanic islands). The generality of the nested subset pattern and factors that may produce it are evaluated using distributions of land birds in the New Zealand region. Monte Carlo simulations show that species composition of these insular avifaunas is highly nonrandom, exhibiting significantly nested structure. However, avifaunas on nine oceanic islands lack the structure typical of all islands together or of the 22 landbridge islands. Thus, distinctive patterns of species composition, as well as species number, may distinguish landbridge and oceanic islands.

Because they are isolated fragments of once‐continuous distributions, landbridge islands and their biotas have important implications for long‐term biological conservation in preserves. Real or virtual islands that have undergone faunal relaxation support only a fraction of the species expected in equivalent mainland areas. Furthermore, the species inhabiting fragments are not a random collection of those in the source pool, but are rather nested subsets of the species in richer, more intact biotas. The species preserved in such fragments tend to be the most abundant, generalist species that are least in need of special protection.
Conservation of Stream Fishes: Patterns of Diversity, Rarity, and Risk
Authors: SHELDON ANDREW L.
Published: April 2005

Abstract: North America has a rich fauna of freshwater fishes which attains greatest diversity in the central and southeastern United States. Many stream fishes have limited ranges and are locally rare and patchily distributed. Local diversity increases downstream and total diversity follows typical species‐area relationships. Drainages linked with the large Mississippi system support more species than those of comparable area flowing directly to the sea and rivers isolated by falls have notably few species. The between‐drainage component of diversity is large. Threats to this fauna, which are not addressed by management focused on threatened species, include fragmentation of drainage networks by impoundments and homogenization of faunas by interbasin connections and introductions. Conservation efforts require a biogeographic perspective; they should focus on streams of intermediate size (orders 4–6) plus the upstream portion of each drainage and should attempt to maintain total diversity and, inclusively, populations of rare or threatened species.
Conservation and Distribution of Genetic Variation in a Polytypic Species, the Cutthroat Trout
Authors: ALLENDORF FRED W. , LEARY ROBB F.
Published: April 2005

Abstract: The cutthroat trout (Salmo clarki) presents a series of unusual and difficult problems in conservation biology. As many as 16 subspecies have been recognized in the recent literature. The genetic distance between subspecies based upon 46 enzyme loci ranges from that usually seen between congeneric species to virtual genetic identity. Subspecies from the western portion of the range of the cutthroat trout are genetically more similar to rainbow trout (Salmo gairdneri) than they are to the other subspecies of cutthroat trout. In addition, much of the genetic variation within the west‐slope cutthroat trout (S. c. lewisi) results from alleles found in only one or two local populations, but they often occur at high frequencies in those populations. Thus, preserving the genetic variation in westslope cutthroat trout entails preserving as many local populations as possible.

Captive populations of cutthroat trout present a series of opportunities and genetic problems. A number of management agencies are using captive populations to supplement and reestablish natural populations. Basic genetic principles must be understood and followed in establishing and maintaining captive populations. We describe examples of unsuccessful and successful efforts by management agencies to develop captive populations.

The greatest danger to the conservation of the cutthroat trout is introgressive hybridization among subspecies and with rainbow trout. Several factors make salmonid fishes especially susceptible to problems associated with introgressive hybridization. We conclude that biochemical analysis provides a more reliable and informative means of detecting interbreeding than morphological characters. Interbreeding between westslope and Yellowstone cutthroat trout and nonnative Salmo appears to be common and widespread throughout the natural range of these subspecies.
Threatened Mammals Affected by Human Exploitation of the Female‐Offspring Bond
Authors: OLDFIELD MARGERY L.
Published: April 2005

Abstract: Biologists have implicated human exploitation of the mammalian female‐offspring bond as a causal factor in extinction or depletion. This paper discusses pronounced maternal defense and attachment behavior as a biological attribute of extinction‐prone mammals, and presents scientific and historical evidence of human exploitation or disturbance of the female‐offspring bond of more than 30 threatened species and subspecies Since premodern and traditional whaling practices commonly involved exploitation of the female‐offspring bond a detailed case study is provided for the great baleen whales. Finally, preferential predation of reproductive females with young is addressed in terms of its ecological and evolutionary implications for the long‐tem survival of wild mammal populations.
Ecological Uses of Vertebrate Indicator Species: A Critique
Authors: LANDRES PETER B. , VERNER JARED , THOMAS JACK WARD
Published: April 2005

Abstract: Plant and animal species have been used for decades as indicators of air and water quality and agricultural and range conditions. Increasingly, vertebrates are used to assess population trends and habitat quality for other species. In this paper we review the conceptual bases, assumptions, and published guidelines for selection and use of vertebrates as ecological indicators. We conclude that an absence of precise definitions and procedures, confounded criteria used to select species, and discordance with ecological literature severely weaken the effectiveness and credibility of using vertebrates as ecological indicators. In many cases the use of ecological indicator species is inappropriate, but when necessary, the following recommendations will make their use more rigorous: (1) clearly state assessment goals, (2) use indicators only when other assessment options are unavailable, (3) choose indicator species by explicitly defined criteria that are in accord with assessment goals, (4) include all species that fulfill stated selection criteria (5) know the biology of the indicator in detail, and treat the indicator as a formal estimator in conceptual and statistical models, (6) identify and define sources of subjectivity when selecting monitoring and intetpreting indicator species, (7) submit assessment design, methods of data collection and statistical analysis, interpretations, and recommendations to peer review and (8) direct research at developing an overall strategy for monitoring wildlife that accounts for natural variability in population attributes and incorporates concepts from landscape ecology.
A Long‐Term Monitoring Plan for a Threatened Butterfly
Authors: MURPHY DENNIS D. , WEISS STUART B.
Published: April 2005

Abstract: A long‐term monitoring plan using stratified random sampling of population densities of late instar larvae is presented for a large population of the threatened Bay checkerspot butterfly, Euphydryas editha bayensis. A topographic map of the habitat is analyzed for the distribution of slope exposures and a clear sky insolation model is applied to delineate microclimate strata Sixth and seventh instar larval densities are estimated for square‐meter quadrats on specific slope exposures, and these density samples are then grouped into the microclimate strata for estimating population size. Additionally, samples of larvae from different slopes are weighed to monitor developmental phenology. The larval population increased from 92,000 in 1985 to 783,000 in 1987, and decreased to 319,000 in 1988. The distribution of larvae changed between years, shifting from cool slopes to warmer slopes as the population grew. These shifts affect developmental phenology and the timing of adult emergence. The procedure produces labor‐ and cost‐effective yearly estimates of population densities of larvae in different microclimates and documents within‐habitat responses of the population to a variable climate.
The Impact of Infection and Disease on Animal Populations: Implications for Conservation Biology
Authors: SCOTT MARILYN E.
Published: April 2005

The distinction between infection and disease may be subtle, and detection of disease in wild animal populations depends on the sophistication of sampling design and diagnostic techniques used in examining animal populations. The impact of infection on the host is dependent not only on the pathogenicity of the infection but also on the interactions between infection and other factors such as nutritional status and stress. In this paper I review mechanisms by which parasitic infections can influence the survival, reproduction, and movement patterns of infected individuals. I then discuss the implications for host populations, in particular with reference to the potential of parasites to regulate the abundance of host populations. The implications of infection and disease on host populations are then extended to demonstrate consequences on community structure. Difficulties associated with assessing the level of infection or disease in wild animal populations are discussed and used to account for the frequently held belief that disease rarely occurs in wild animal populations. Finally, the consequences of infection and disease for conservation biology are outlined. Disease is considered with regard to introductions and maintenance of genetic diversity. Emphasis is placed on the dangers associated with forcing animals into high‐density situations. High host densities lead directly to increased disease because of increased transmission rates, and also indirectly increase disease because of synergistic interactions between infection, reduced nutritional status of the host population, and increased stress all associated with high‐density situations. I recommend a surveillance program for monitoring prevalence or intensity in selected indicator age classes as a first step for preventing major disease problems in animal populations. I conclude that infection and disease will be an important determinant of the health and well‐being of animal populations, and as such must be considered in the design of conservation policy.
A Preliminary Assessment of the Status of Major Terrestrial and Wetland Ecosystems on Federal and Indian Lands in the United States
Authors: CRUMPACKER DAVID W. , HODGE STEPHEN W. , FRIEDLEY DALE , GREGG WILLIAM P.
Published: April 2005

Major terrestrial and wetland ecosystems in the United States were described by 135 Küchler potential natural vegetation (PNV) types. Their occurrence on federal and Indian lands was then determined by computer overlay of PNV maps on the National Geographic Society's 1982 map of America's Federal Lands. Based on the map scales used it was determined that at least 33 of 135 PNV types (24%) are inadequately represented on federal and Indian lands. Nine of the 33 have no representation. Eleven others have relatively little representation and are either naturally rare or have been largely converted to nonnatural uses. All federal agencies and the Indian lands have large gaps in their ecosystem coverage. Among agencies with nationwide land management systems and strong conservation mandates, the percentage of major ecosystem types with no apparent representation on these agenlands is: US Forest Service, 27 percent; National Park Service, 33 percent; and U.S. Fish and Wildlife Service, 53 percent. The Bureau of Land Management, Department of Defense, and Indian lands collectively play an important role in supplementing the current coverage of the other agencies.

Because of inaccuracies associated with the small‐scale maps that were analyzed and the nature of PNV types, these results are preliminary and should be used only for general planning. Inclusion of a PNV type within a management unit, based on map overlay, does not ensure that mature vegetation representative of that type actually is present on the ground Additional assessments would have to be made to determine the type and health of existing vegetation within the mil, as well as the amount of future protection that the unit would be expected to provide.

Cooperation among federal, state, and local agencies and private organizations is needed to provide a cost‐effective program of national ecosystem Conservation. More detailed state and regional surveys can be used to improve the accuracy of this preliminary national survey.
Effects of Introduced Plants and Animals on Island Vegetation: Examples from Galápagos Archipelago
Authors: SCHOFIELD EILEEN K
Published: April 2005

Island ecosystems are particularly vulnerable to biological invasions. Since the early 1800s, humans have introduced to the Galápagos Islands animals and plants that threaten the native vegetation Goats are the most abundant and destructive feral animals. Endemic members of the Cactaceae and Asteraceae have been reduced drastically. A control program has completely eradicated goats on several islands, where vegetation has returned but sometimes the species composition differs from the original. Hunting continues on Santiago, where 80,000 goats exist, and fenced quadrats protect some native plants. Cattle damage vegetation, particularly the endemic shrub, Miconia robinsoniana, by trampling and grazing. Ranchers on several islands have been urged to fence in cattle. Wild pigs dig up and eat the roots of woody plants and some rare orchids. Donkeys trample and eat grasses and shrubs. Control of pigs has started; there is no control of donkeys. Between 20 and 50 introduced plants have escaped cultivation and invaded the native vegetation. Guava is the most widespread, covering vast areas on several islands. Its dispersal is aided by free‐roaming cattle, which eat the fruits and excrete the seeds. Quinine trees have spread extensively on one island via windblown seeds. Both species are being cut down, and herbicides are applied to trunks to prevent sprouting. Other aliens that are problems on one or more islands include lantana, hemp, avocado, sweet lime, and forage grasses. None of these is being eliminated yet, because of lack of funds and manpower. To ensure the future of the Galápagos flora, control measures must continue and expand to encompass all dangerous introductions.
Breed Structures of for Conservation of Middle Rare Pigs: Implications the Berkshire, Tamworth, White, Large Black, Gloucester Old Spot, British Saddleback, and British Lop
Authors: HALL S. J. G.
Published: April 2005

Abstract: Registration details of seven rare British breeds of pig w e studied over the period 1978–1986 inclusive. For four breeds, numbers of pigs registered have shown a slight upward trend. About 70% of males and 40% of females that breed, do so in herds other than the natal herd In the breed for which most pedigree data were analysed (the British Lop), 95–100% of recent pig crops were inbred In the rare breeds generally, mean inbreeding at around 6% signifies an inbreeding rate of about 1 % per generation, higher than has been found in commercial breeds. Breeds did not differ greatly in the ways they were structured.

About a third of herds supplied boars to other herds, a relatively high proportion, indicating that the breeds have a structure that is not completely hierarchical, and this is favorable for genetic conservation. Pigs whose parents were from different herds were significantly less inbred than those with both parents from the same herd In some breeds it was clear that pigs sharing the same bloodline name were more closely related than pigs within the same herd but with different bloodline names.

Conservation procedures applied to these pigs have been designed to conform with the customs and procedures of the British pedigree livestock industry. The most important single such procedure is the registration, with a central authority, of breeding stock.
Megafaunal Extinctions: The Conservation Message from 11,000 Years B.P.
Authors: OWEN‐SMITH NORMAN
Published: April 2005

Abstract:At the end of the Pleistocene, the Americas, northern Eurasia: and Australia experienced a vast decline in large mammal diversity, while Africa and tropical Asia were hardly affected. The elimination of the megaberbivores (animals weighing >1000 kg, probably by human predation, removed the vegetation impact of these species. The resultant reduction in habitat mosaic diversity and in forage quality probably precipitated the extinctions of lesser large mammalian species. Surviving megaherbivores in the form of elephants and rhinoceroses are currently being exterminated from many African conservation areas. African savanna ecosystems could prove more resistant to species losses than north temperate ecosystems, because geomorphic factors plus low and erratic rainfall enhance spatial heterogeneity and vegetation quality independently of large herbivore impact Nevertheless, the history of the Hluhluwe Game Reserve in South Africa suggests that certain African ecosystems may become susceptible to an inexorable decline in populations of some large herbivores following the extermination of elephants. If elephants and rhinoceroses cannot be conserved active habitat manipulation will be needed to retain a diverse fauna of large mammals in such regions.
Whither Conservation Ethics?
Authors: CALLICOTT J. BAIRD
Published: April 2005

Abstract: A review of the moral foundations of American conservation provides a historical perspective for formulating a twenty‐first century conservation ethic. Building on the Work of R.W. Emerson and H.D. Thoreau, John Muir formulated a Romantic‐Transcendental Preservation Ethic that pitted the allegedly higher aesthetic and spiritual uses of nature against consumptive and extractive material uses. Gifford Pinchot formulated a more pedestrian and egalitarian Resource Conservation Ethic consistent with utilitarian and democratic ideals. Muir also adumbrated a more radical nonanthropocentric preservation ethic rhetorically cast in Biblical terms Aldo Leopold articulated a similarly nonanthropocentric environmental ethic in evolutionary and ecological terms. A review of Leopold's large literay estate, however, reveals that he continued to advocate active management for a mutually beneficial human‐nature symbiosis, in addition to the passive preservation of “wilderness” As the human population grows and more nations develop, the best hope for conservation biology lies in a generalization of Leopold's ideal of ecosystems which are at once economically productive and ecologically healthy. The principal intellectual challenge raised by such an ideal for conservation biology is the development of criteria of ecological health and integrity in an inherently dynamic, evolving, and human‐saturated biota.
Multi–gene‐pool Surveys in Areas with Rapid Genetic Erosion: An Example from the Aïr Mountains, Northern Niger
Authors: INGRAM GORDON BRENT
Published: April 2005

Abstract:A survey to sample and document wild and cultivated plants with crop and forage genetic resources was carried out in the Aïr Mountains of northern Niger in 1984, 1985, and 1986. This ecogeographical survey was begun in the 1984 drought after considerable desertification had already occurred. Over the last century in this area, there has been progressive alteration and loss of habitat and populations, with probable genetic erosion. The focus was on wild and weedy species in the following gene pools:Pennisetum, Sorghum, Olea, Andropogon, Cenchrus, Brachiaria, Eragrostis, Panicum, Setaria, Acacia, Ziziphus, andGrewia; and on crops from irrigated gardens, including pearl millet, sorghum, and barley. Due to the high degree of environmental heterogeneity and the loss of habitat, relativity small numbers of individuals and clumps were identified a significant portion were probably part of previously contiguous occurrences. In this type of setting, surveys of rapidly diminishing crop and forage genetic resources are especially needed A basis for identifying strategies for sampling and monitoring as species ecology and successional and cultural factors is outlined.
Persistence of Different‐sized Populations: An Empirical Assessment of Rapid Extinctions in Bighorn Sheep
Authors: BERGER JOEL
Published: April 2005

Abstract: Theory and simulation models suggest that small populations are more susceptible to extinction than large populations, yet assessment of this idea has been hampered by lack of an empirical base. I address the problem by asking how long different‐sized populations persist and present demographic and weather data spanning up to 70 years for 122 bighorn sheep (Ovis canadensis) populations in southwestern North America Analyses reveal that: (1) 100 percent of the populations with fewer than 50 individuals went extinct within 50 years; (2) populations with greater than 100 individuals persisted for up to 70 years; and (3) the rapid loss of populations was not likely to be caused by food shortages, severe weather, predation, or interspecific competition These data suggest that population size is a marker of persistence trajectories and they indicate that local extinction cannot be overcome because 50 individuals, even in the short term, are not a minimum viable population size for bighorn sheep.
The Onslaught of Alien Species, and Other Challenges in the Coming Decades *
Authors: SOULÉ MICHAEL E.
Published: April 2005

Abstract: Among the many environmental challenges faced by conservation scientists and managers in the coming decades, the inexorable invasion of alien species from distant land masses and between heretofore isolated regions within continents may be the most revolutionary. Although these invasions will homogenize and impoverish the world's biota, they will lead to a deeper understanding of ecological communities. One consequence of the current biotic interchange is that the public's use of the outdoors will continue to decline as new and alien pathogens and parasites, their distributions and survival enhanced by climate warming and other anthropogenic factors, reduce the safety and enjoyment of hunting fishing and hiking. The forthcoming and massive ecological disruptions are bound to produce misunderstanding and conflict among environmentalists. Attempts by conservation biologists to manage wild and feral animals, including vector species, will be blocked by animal's rights groups. Even within the conservation biology movement there are many real and potential conflicts, especially over turf and resources. Such conflicts are a serious threat to biological diversity. Tolerance and compromise are essential if conservation biology is to accomplish its mission.
Indicators for Monitoring Biodiversity: A Hierarchical Approach
Authors: NOSS REED F.
Published: April 2005

Abstract: Biodiversity is presently a minor consideration in environmental policy. It has been regarded as too broad and vague a concept to be applied to real‐world regulatory and management problems. This problem can be corrected if biodiversity is recognized as an end in itself, and if measurable indicators can be selected to assess the status of biodiversity over time. Biodiversity, as presently understood, encompasses multiple levels of biological organization. In this paper, I expand the three primary attributes of biodiversity recognized by Jerry Franklin — composition, structure, and function—into a nested hierarchy that incorporates elements of each attribute at four levels of organization: regional landscape, community‐ecosystem, population‐species, and genetic. Indicators of each attribute in terrestrial ecosystems, at the four levels of organization, are identified for environmental monitoring purposes. Projects to monitor biodiversity will benefit from a direct linkage to long‐term ecological research and a commitment to test hypotheses relevant to biodiversity conservation. A general guideline is to proceed from the top down, beginning with a coarse‐scale inventory of landscape pattern, vegetation, habitat structure, and species distributions, then overlaying data on stress levels to identify biologically significant areas at high risk of impoverishment. Intensive research and monitoring can be directed to high‐risk ecosystems and elements of biodiversity, while less intensive monitoring is directed to the total landscape (or samples thereof). In any monitoring program, particular attention should be paid to specifying the questions that monitoring is intended to answer and validating the relationships between indicators and the components of biodiversity they represent.
How Many Plants Feed the World?
Authors: PRESCOTT‐ALLEN ROBERT , PRESCOTT‐ALLEN CHRISTINE
Published: April 2005

Abstract: FAO food supply data for 146 countries were analyzed to identify the plant commodities that account for the top 90% of each country's per capita supply of food plants by weighs calories, protein, and fat. The plant commodities were divided into two groups: species commodities, such as “cabbages,” that can be attributed to particular species; and general commodities, such as “hydrogenated oils,” whose species composition is not known. A total of 82 species commodities and 28 general commodities contribute 90% of national per capita supplies of food plants. The 82 species commodities consist of 103 species. Fifty‐six of these commodities, comprising 75 species, individually account for 5% or more of at least one county's supply of a nutritional category (plant weight, plant calories, plant protein, plant fag. These figures are several times higher than previous findings that very few (7–30) plant species feed the world. The new figures are considered more accurate because they derive from national supply rather than global production data and from several separate measures of the importance of a food commodity rather than one. The results suggest that (1) plant species diversity remains a significant factor for world food supply; and (2) a conservation priority is to maintain both this wider away of species and the diversity of genetic variants that comprise each species.
Desert‐dwelling Mountain Sheep: Conservation Implications of a Naturally Fragmented Distribution
Authors: BLEICH V. C. , WEHAUSEN J. D. , HOLL S. A.
Published: April 2005

Abstract:Mountain sheep (Ovis canadensis) are closely associated with steep, mountainous, open terrain. Their habitat consequently occurs in a naturally fragmented pattern, often with substantial expanses of unsuitable habitat between suitable patches; the sheep have been noted to be slow colonizers of vacant suitable habitat. As a result, resource managers have focused on (1) conserving “traditional” mountainous habitats, and (2) forced colonization through reintroduction. Telemetry studies in desert habitats have recorded more intermountain movement by desert sheep than was previously thought to OCCUT. Given the heretofore unrecognized vagility of mountain sheep, we argue that existing corridors of “nontraditional” habitat connecting mountain ranges be given adequate conservation consideration. Additionally, small areas of mountainous habitat that an? not permanently occupied but that may serve as “stepping stones” within such corridors must be recognized for their potential importance to relatively isolated populations of mountain sheep. We discuss the potential importance of such corridors to other large, vagile species.
Use‐Values of Tree Species in a Communal Forest Reserve in Northeast Peru
Authors: PINEDO‐VASQUEZ MIGUEL , ZARIN DANIEL , JIPP PETER , CHOTA‐INUMA JOMBER
Published: April 2005

Abstract: Several rural villages in the department of Loreto, in northeast Peru, have sought to protect local control over access to natural resources by establishing communal reserves. Most of Loreto's villages have heterogeneous populations of detribalized Indians and mestizos, called ribereños (people of the riverbanks). The communal reserves of ribereño villages currently have no legal status, but are regulated by written communal rules and are actively guarded by community members.

An inventory of trees greater than 10 cm in diameter was conducted in one ribereño communal reserve, a fifty‐year‐old secondary forest. A doubly random sampling procedure was used producing a total sample size of 7.5 ha Tree species utilized by community members were found to comprise 60% of the total number of species sampled. Uses were divided into six categories: food construction, crafts remedy, commerce, and other “use‐values” were assigned to each species, based on an ordinal system developed by Prance et al. (1987). The presence or absence of markets for specific forest products was found to be a major determinant of that species' overall use‐value to ribereño populations. Neither the existing markets nor the lack of firm land or resource tenure for ribereño communal reserves encourages sustained management of forest resources.
Endangered Greater One‐horned Rhinoceros Carry High Levels of Genetic Variation
Authors: DINERSTEIN ERIC , MCCRACKEN GARY F.
Published: April 2005

Abstract: The population of Rhinoceros unicornis in the Chitwan Valley, Nepal, was reduced to an estimated effective population size (Ne of 21–28 individuals (60–80 total animals) in 1962. Protein electrophoresis shows that heterozygosity remains very high in this population (Ho= 9.9%) despite its near extinction. We attribute this high heterozygosity to large Ne's prior to the population bottleneck, the recent occurrence of the bottleneck, and long generation time. These results illustrate the importance of considering historical demography and life history parameters when evaluating the possible genetic effects of bottlenecks in wild populations. They also offer support to recent arguments that the erosion of genetic diversity attributed to bottlenecks may be overemphasized.
Forest Canopy Structure at Overwintering Monarch Butterfly Sites: Measurements with Hemispherical Photography
Authors: WEISS STUART B. , RICH PAUL M. , MURPHY DENNIS D. , CALVERT WILLIAM H. , EHRLICH PAUL R.
Published: April 2005

Abstract:Using hemispherical photography and digital image analysis, we have quantifed forest canopy structure and light conditions at monarch butterfly (Danaus plexippus) overwintering sites near Santa Barbara, California Hemispherical photographs were taken from 1.75 m height in more than 30 forest groves, including permanently occupied transient, formerly occupied and unoccupied sites. Analysis of the photographs permitted us to calculate site factors that quantify the proportion of indirect and direct radiation received relative to completely open conditions. The permanently occupied sites exhibited a narrow range of indirect radiation and a slightly wider but still narrow range of annual direct radiation. Transient sites exhibited a wider range of indirect and annual direct radiation than the permanent sites. Within the largest aggregation site, horizontal and vertical variation in site factors was considerable. Changes in monthly direct radiation with height may be unpredictable and reduce confidence in extrapolations from near ground level to the height of butterfly clusters. Sites that formerly supported aggregations and since have had trees removed exhibited high indirect and direct radiation and apparently are now too open to support butterflies. We simulated proposed tree removals at two sites by editing digitized canopy photographs, which enabled us to predict resultant changes in indirect and direct radiation. These results provide quantitative guidelines for silvicultural management to maintain and enhance remaining aggregation sites along the California coast.
Restoration of Coral Reefs in Pacific Costa Rica
Authors: GUZMÁN HÉCTOR M.
Published: April 2005

Abstract: Loss and degradation of coral reef habitats are increasing in the eastern Pacific. Intense, frequent natural and human‐induced disturbances have devastated most reefs in this region during the last decade. Slow recovery combined with intense bioerosion has led to extensive destruction of the reef frameworks. At some reefs along the Pacific coast of Costa Rica, 100% mortality of the dominant coral (Pocillopora spp.) occurred in shallow water. Surviving individuals for some pocilloporid species are extremely small, and reef recovery by sexual or asexual means has been lowered A restoration experiment was conducted in two different shallow habitats inside a marine biological reserve. Coral fragments (n = 110) imported from nearby reefs were transplanted onto dead reef frameworks, and after three years, survivorship was 79%–83%. Furthermore, fragmentation caused a 41%–115% increase in new colonies. These results suggest that coral transplantation for reef management and restoration is a feasible tool in the eastern Pacific region.
Genetic Variation in Running Buffalo Clover (Trifoflium stofoniferum, Fabaceae)
Authors: HICKEY R. JAMES , VINCENT MICHAEL A. , GUTTMAN SHELDON I.
Published: April 2005

Abstract: Starch gel electrophoresis was used to examine the genetic variation in four species of Trifolium Two of these, T. stoloniferum and T. reflexum, are native, and, in Ohio at least, are considered rare. The genetic variation in these species was compared with that of two nonnative taxa, T. hybridum and T. pratense, which have similar life‐history characteristics. The only known Ohio population of T. reflexum was completely homozygous across 14 loci. Three of the 20 loci examined for T. stoloniferum showed variation, with an average of 1. 10 alleles per locus. Trifolium hybridurn and T. pratense showed variation at 53.3% of the loci resolved with an average of 1.73 and 1.93 alleles per locus, respectively. Analyses of genetic structure show considerable differences between T. stoloniferum and the two nonnative species. In T. stoloniferum 33.9% of the genetic variation is partitioned between populations, in contrast to 11.9% and 8.5% for T. hybridum and T. pratense Genetic data suggest that gene flow in the endangered T. stoloniferum is severely limited, even across very short distances, and that conservation efforts should minimally include the preservation of genetic variation residing among various populations.
Greater Yellowstone's Native Ungulates: Myths and Realities
Authors: BERGER JOEL
Published: April 2005

Abstract:At least three North American areas have been compared to Africa's Serengeti, probably because large concentrations of ungulates occur on both continents. Such comparisons are deceiving because the North American ecosystems harbor only about 15 to 25% of the ungulate species diversity found in the Serengeti. Migratory herbivores in both systems are confronted by ecological problems, including conflicts between people and wildlife once the herbivores move beyond park boundaries, and in the North American system, the loss of effective predators. The recent extinction of wolves from the Greater Yellowstone Ecosystem masks any direct effect on large herbivore movements today, although more than half of the Yellowstone Park ungulates migrate regularly to habitats outside park boundaries. If vestiges of ecosystem‐oriented processes are to be preserved, some type of vision coupled with effective, coordinated management must be adopted This paper addresses one component of this issue, migrant ungulates and their habitats. Three specific points are made. (1) Comparisons between the Greater Yellowstone Ecosystem and Serengeti, while questionable ecologically, are heuristic and serve conservation goals. (2) Both the loss of predators and different federally imposed land‐use mandates have altered patterns of herbivore migration, behavior, and habitat use. While consequences of these human‐caused disturbances cannot be predicted precisely, sufficient data from comparable regions allow the development of probable scenarios. (3) Throughout different periods during the last 100 years a variety of plans called for formal interagency cooperation; none has been successful. Until managers and politicians become more cognizant of historical failures stemming from the lack of coordinated ecosystem management during the last century, the same mistakes are likely to plague future generations.
Implications of Global Climate Change for Biogeographic Patterns in the Greater Yellowstone Ecosystem
Authors: ROMME WILLIAM H. , TURNER MONICA G.
Published: April 2005

Abstract: Projected changes in global climate have substantial ramifications for biological diversity and the management of natural areas. We explored the potential implications of global climate change for biogeographic patterns in the Greater Yellowstone Ecosystem by wing a conceptual model to compare three likely climate scenarios: (1) warmer and drier than the present; (2) warmer and drier, but with a compensating increase in plant water use efficiency; and (3) warmer and wetter than the present. The logical consequences of each scenario are projected for several species and community types chosen to represent a range of local climate conditions and biotic responses in the Greater Yellowstone Ecosystem. The upper and lower timberline appear to be particularly sensitive to climate change. The upper timberline is likely to migrate upward in elevation in response to temperature changes, whereas the lower treeline may retreat under drier conditions or move down slope under wetter conditions. In all scenarios, the extent of alpine vegetation in the ecosystem decreased Climate‐induced changes in the fire regime in the Greater Yellowstone Ecosystem would probably have substantial consequences for the extent and age‐class distribution of forest communities. Alterations in the distribution and extent of grassland communities would affect the populations of large ungulates. Our analyses suggest directions for establishing long‐term measurements for the early detection of responses to climate change.
Ecosystem Preservation and the Economy in the Greater Yellowstone Area
Authors: POWER THOMAS MICHAEL
Published: April 2005

Abstract: Because it is usually assumed that the economic health of the counties surrounding Yellowstone National Park is tied almost exclusively to mineral and timber extraction, protection of the Greater Yellowstone ecosystem is seen as inevitably in direct and serious conflict with local economic well‐being. Such a conflict generally does not exist, however, because of the ongoing transformation of these rural economies over the last twenty years. Unpublished federal data on income and employment document the decline in the relative importance of extractive industry and the rise in the importance of service activities. These data also indicate major flows of income into the region that are not associated with current work effort but are at least partially associated with the residential choices of retirees. These income flows dwarf those associated with extractive industry. In addition, in terms of employment, the primary economic activity tied to the Greater Yellowstone Ecosystem is not timber or mining but recreation. The character and quality of the natural and social environments in the region attract both permanent residents and temporary visitors. Both support and stimulate the local economy. These characteristics of the emerging economy suggest that protection of the Greater Yellowstone landscape is consistent with protecting a dominant element in the local economic base that has been a source of stability and expansion. In that sense, protecting the integrity of the Greater Yellowstone Ecosystem is not only not in conflict with local economic well‐being but is a crucial element in any economic development strategy for the region.
Flying Foxes as Strong Interactors in South Pacific Island Ecosystems: A Conservation Hypothesis
Authors: COX PAUL ALAN , ELMQVIST THOMAS , PIERSON ELIZABETH D. , RAINEY WILLIAM E.
Published: April 2005

Abstract: The dependency of highly endemic island floras on few potential pollinators in depauperate island faunas suggests that pollinators and seed dispersers may be crucial in the preservation of biodiversity in isolated oceanic islands. We discuss the hypothesis that flying foxes are “strong interactors” in South Pacific islands where they serve as the principal pollinators and seed dispersers, This suggests that the ongoing decline and ultimate extinction of flying fox species on Pacific islands may lead to a cascade of linked plant extinctions. We propose an empirical test of this hypothesis: comparisons of plant reproductive success in Guam, which has virtually lost its flying fox populations, and Samoa, where significant populations remain.
The Contribution of Variance in Lifetime Reproduction to Effective Population Size in Tigers
Authors: SMITH JAMES L. DAVID , MCDOUGAL CHARLES
Published: April 2005

Abstract: We studied tiger (Panthera tigris) reproduction in Royal Chitwan National Park to examine variance in lifetime reproduction and its contribution to estimates of inbreeding‐effective population size in this species. A total of 36 breeding animals (14 males, 22 females) and 144 young were monitored between 1973 and 1989. Mean litter size was 2.98 and young were born throughout the year. Mortality during the first year was 34%. Loss of entire litters accounted for 73% of first‐year mortality, suggesting that chance events were more important in determining first‐year survival than the quality of a female's territory. Second‐year mortality was 17%, and most (71%) was within‐litter mortality. The number of young that survived to dispersal or 2 years was used as a measure of lifetime reproduction. To calculate the effect of variance in lifetime reproduction on inbreeding‐effective population size, we estimated the distribution of number of offspring that reach breeding age. High variance in lifetime reproduction resulted in an Ne‐to‐N ratio of 0.41 and an Ne, of 26 Because the rate of inbreeding in the Chitwan population is approximately 2% per generation and Chitwan is one of the largest tiger populations on the Indian subcontinent, it is possible that inbreeding depression occurs in many tiger populations. Inbreeding depression may be reflected in many measures of fitness: litter size, birth weight, infant and early survival, and sperm viability. The field data presented here demonstrate the length of time and effort needed to obtain even a single moderate‐sized data set. Were it possible to obtain two such data sets, comparisons between populations or time periods would‐be problematic Because of these difficulties, conservation decision‐makers will need to rely on population viability analysis modeling. Long‐term field data on individual populations and information on the dynamics of metapopulations are needed to build and validate these models.
Nested Faunas and Extinction in Fragmented Habitats
Authors: CUTLER ALAN
Published: April 2005

Abstract: The faunas of habitat islands, such as those produced by fragmentation of formerly continuous habitats, are commonly made up of nonrandom subsets of the total available species pool. Faunas within an archipelago may form a nested series, with depauperate faunas made up of subsets of more species‐rich faunas. The pattern is seldom perfect: widespread species may be absent from otherwise rich faunas (holes), and uncommon species may occur in depauperate faunas (outliers). The “nestedness” of an assemblage of faunas (its fit to the “nested subset model”; Patterson & Atmar 1986) can be measured by summing the holes and outliers.

The distributions of boreal mammals and birds among mountain ranges in the Great Basin of western North America were analyzed by this method Despite differences in their derivation (mammalian faunas are thought to be relicts, isolated since the Pleistocene; bird faunas have probably experienced recurrent colonization throughout their history] both groups show an approximately equal (and highly significant) fit to the nested subset model. They differ, however, in the relative numbers of holes and outliers in their patterns. The mammalian pattern is hole‐rich; the bird pattern is outlier‐rich.

The present‐day composition of the mammalian faunas is the result of selective extinction of species of originally richer faunas. The existence of nested subsets in these faunas suggests that extinction is a highly deterministic process: extinctions occurred in approximately the same sequence throughout the region, despite wide variation in extinction rates Extinction sequence has, in fact, been less variable than extinction rates.
Dynamics of Ventricular Repolarization in Patients with Dilated Cardiomyopathy Versus Healthy Subjects
Authors: Alonso Jose Luis , Martínez Pablo , Vallverdú Montserrat , Cygankiewicz Iwona , Pitzalis Maria Vittoria , Genís Antoni Bayés , Cinca Juan , Rizzon Paolo , Caminal Pere , Zareba Wojciech , De Luna Antoni Bayés
Published: April 2005

Background: Patients with impaired left ventricular function have a high risk of developing ventricular arrhythmias and sudden death. Among different markers of risk, the prolongation and regional heterogeneity of repolarization are of increasing interest. However, there are limited data regarding feasibility of analyzing repolarization parameters and their dynamics in 24‐hour Holter ECG recordings.

Methods: Dynamic behavior of repolarization parameters was studied with a new automatic algorithm in digital 24‐hour Holter recordings of 60 healthy subjects and 55 patients with idiopathic dilated cardiomyopathy (IDC). Repolarization parameters included the mean value of QT and QTc durations, QT dispersion, and peaks of QT duration and QT dispersion above prespecified thresholds.

Results: In comparison to healthy subjects, patients with IDC had lower heart rate variability, longer mean QT and QTc durations, higher content of QTc peaks >500 ms, longer QT dispersion and its standard deviation, and a higher content of peaks >100 ms of QT dispersion (P < 0.01 for all comparisons). These repolarization parameters were significantly higher in IDC patients after adjustment for age, sex, and heart rate variability. The parameters of repolarization dynamics correlated with SDNN in healthy subjects but not in dilated cardiomyopathy patients.

Conclusions: The automatic assessment of repolarization parameters in 24‐hour digital ECG recordings is feasible and differentiates dilated cardiomyopathy patients from healthy subjects. Patients with dilated cardiomyopathy have increased QT duration, QT dispersion, and increased variability of QT dispersion reflecting variations in T‐wave morphology, the factors which might predispose them to the development of arrhythmic events.