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Helen F. James

Bio: Helen F. James is an academic researcher from National Museum of Natural History. The author has contributed to research in topics: Population & Seabird. The author has an hindex of 33, co-authored 90 publications receiving 4090 citations. Previous affiliations of Helen F. James include University of Maryland, College Park & James Cook University.
Topics: Population, Seabird, Cave, Foraging, Petrel

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Journal ArticleDOI
TL;DR: A new data set of 13 nuclear loci and pyrosequencing of mitochondrial genomes is analyzed that resolves the Hawaiian honeycreeper phylogeny and shows that they are a sister taxon to Eurasian rosefinches and probably came to Hawaii from Asia.
Abstract: Summary Evolutionary theory has gained tremendous insight from studies of adaptive radiations. High rates of speciation, morphological divergence, and hybridization, combined with low sequence variability, however, have prevented phylogenetic reconstruction for many radiations. The Hawaiian honeycreepers are an exceptional adaptive radiation, with high phenotypic diversity and speciation that occurred within the geologically constrained setting of the Hawaiian Islands. Here we analyze a new data set of 13 nuclear loci and pyrosequencing of mitochondrial genomes that resolves the Hawaiian honeycreeper phylogeny. We show that they are a sister taxon to Eurasian rosefinches ( Carpodacus ) and probably came to Hawaii from Asia. We use island ages to calibrate DNA substitution rates, which vary substantially among gene regions, and calculate divergence times, showing that the radiation began roughly when the oldest of the current large Hawaiian Islands (Kauai and Niihau) formed, ∼5.7 million years ago (mya). We show that most of the lineages that gave rise to distinctive morphologies diverged after Oahu emerged (4.0–3.7 mya) but before the formation of Maui and adjacent islands (2.4–1.9 mya). Thus, the formation of Oahu, and subsequent cycles of colonization and speciation between Kauai and Oahu, played key roles in generating the morphological diversity of the extant honeycreepers.

425 citations

Journal ArticleDOI
13 Aug 1982-Science
TL;DR: Thousands of fossil bird bones from the Hawaiian Islands collected since 1971 include remains of at least 39 species of land birds that are not known to have survived into the historic period; this more than doubles the number of endemic species ofLand birds previously known from the main islands.
Abstract: Thousands of fossil bird bones from the Hawaiian Islands collected since 1971 include remains of at least 39 species of land birds that are not known to have survived into the historic period; this more than doubles the number of endemic species of land birds previously known from the main islands. Bones were found in deposits of late Quaternary age; most are Holocene and many are contemporaneous with Polynesian culture. The loss of species of birds appears to be due to predation and destruction of lowland habitats by humans before the arrival of Europeans. Because the historically known fauna and flora of the Hawaiian Islands represent only afraction of natural species diversity, biogeographical inferences about natural processes based only on historically known taxa may be misleading or incorrect.

283 citations

Journal ArticleDOI
TL;DR: It is confirmed that the prehuman lowlands of dry leeward Kaua’i included plants and animals previously known only in wetter and cooler habitats, and efforts to restore lowland areas in the Hawaiian Islands must take into account the evidence from this study.
Abstract: Coring and excavations in a large sinkhole and cave system formed in an eolianite deposit on the south coast of Kaua‘i in the Hawaiian Islands reveal a fossil site with remarkable preservation and diversity of plant and animal remains. Radiocarbon dating and investigations of the sediments and their fossil contents, including diatoms, invertebrate shells, vertebrate bones, pollen, and plant macrofossils, provide a more complete picture of prehuman ecological conditions in the Hawaiian lowlands than has been previously available. The evidence confirms that a highly diverse prehuman landscape has been completely transformed, with the decline or extirpation of most native species and their replacement with introduced species. The stratigraphy documents many late Holocene extinctions, including previously undescribed species, and suggests that the pattern of extirpation for snails occurred in three temporal stages, corresponding to initial settlement, late prehistoric, and historic impacts. The site also records land-use changes of recent centuries, including evidence for deforestation, overgrazing, and soil erosion during the historic period, and biological invasion during both the Polynesian and historic periods. Human artifacts and midden materials demonstrate a high-density human presence near the site for the last four centuries. Earlier evidence for humans includes a bone of the prehistorically introduced Pacific rat (Rattus exulans) dating to 822 yr BP (calendar year [cal yr] AD 1039–1241). Vegetation at the site before human arrival consisted of a herbaceous component with strand plants and graminoids, and a woody component that included trees and shrubs now mostly restricted to a few higher, wetter, and less disturbed parts of the island. Efforts to restore lowland areas in the Hawaiian Islands must take into account the evidence from this study that the prehuman lowlands of dry leeward Kaua‘i included plants and animals previously known only in wetter and cooler habitats. Many species may be restricted to high elevations today primarily because these remote locations have, by virtue of their difficult topography and climate, resisted most human-induced changes more effectively than the coastal lowlands.

225 citations

Journal ArticleDOI
01 Jan 1982
TL;DR: Olson, Storrs, and Prodromus as discussed by the authors discussed the fossil deposits and the physical and biological features of the islands in order to provide background information for future systematic publications on the fossil and modern avifauna of the Hawaiian Islands.
Abstract: Olson, Storrs L., and Helen F. James. Prodromus of the Fossil Avifauna of the Hawaiian Islands. Smithsonian Contributions to Zoology, number 365, 59 pages, 12 figures, 1982.—In the past decade, fossil deposits from five of the main Hawaiian Islands have yielded thousands of bones of extinct and living species of birds. Through these specimens, the number of endemic species of land birds in the avifauna of the main islands has been more than doubled. There are 40 extinct species known only from bones, including 1 petrel (Procellariidae), 2 ibises (Plataleidae), 7 geese (Anatidae), 1 small hawk and 1 eagle (Accipitridae), 7 rails (Rallidae), 3 species of a new genus of owl (Strigidae), 2 large crows (Corvidae), 1 honeyeater (Meliphagidae), and at least 15 species of Hawaiian finches (Fringillidae, Drepanidini). The present report discusses the fossil deposits and the physical and biological features of the islands in order to provide background information for our future systematic publications on the fossil and modern avifauna of the Hawaiian Islands. An informal listing of the species found as fossils permits preliminary analyses of extinction and biogeography. The major fossil "localities are on the islands of Kauai, Oahu, and Molokai, from each of which there are diverse collections of small passerines, as well as many specimens of nonpasserine land birds, shorebirds, and seabirds. Fossils of a few additional extinct species have been found incidentally on Maui and Hawaii. Bones of extinct birds have been found in situations as diverse as sand dunes, sinkholes, and a flooded cavern in a raised coral reef, lava tubes, loess deposits, an ash deposit under a lava flow, and in archeological sites. Although some of the fossil deposits may be from the late Pleistocene epoch, most of the more important ones are probably Holocene, ranging from about 6700 years B.P. to much younger. Evidence is presented to show that the extinct species of birds survived into the period of" Polynesian colonization. We believe that the extinction of half or more of the land birds of the Hawaiian Islands prior to European discovery resulted mainly from the destruction of lowland forest by Polynesians, augmented by predation by man and introduced mammals. This has altered the distribution of species within the archipelago as well as the species composition of individual islands in such a drastic manner as to suggest that the data used in traditional and modern ecological studies of island biogeography may be too incomplete to permit generalizations about any islands that were settled by prehistoric man. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavemosa (Linnaeus). Library of Congress Cataloging in Publication Data Olson, Storrs L. Prodromus of the fossil avifauna of the Hawaiian Islands. (Smithsonian contributions to zoology ; no. 365) Bibliography: p. Supt. of Docs, no.: SI 1.27:365 1. Birds, Fossil. 2. Birds, Extinct. 3. Paleontology—Hawaii. I. James, Helen F. II. Title. III. Scries QL1.S54 no. 365 [QE871] 591s 82-600157 [568'.09969] AACR2

220 citations

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Journal ArticleDOI
24 Feb 2000-Nature
TL;DR: A ‘silver bullet’ strategy on the part of conservation planners, focusing on ‘biodiversity hotspots’ where exceptional concentrations of endemic species are undergoing exceptional loss of habitat, is proposed.
Abstract: Conservationists are far from able to assist all species under threat, if only for lack of funding. This places a premium on priorities: how can we support the most species at the least cost? One way is to identify 'biodiversity hotspots' where exceptional concentrations of endemic species are undergoing exceptional loss of habitat. As many as 44% of all species of vascular plants and 35% of all species in four vertebrate groups are confined to 25 hotspots comprising only 1.4% of the land surface of the Earth. This opens the way for a 'silver bullet' strategy on the part of conservation planners, focusing on these hotspots in proportion to their share of the world's species at risk.

24,867 citations

Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

14,171 citations

23 Apr 2007
TL;DR: In this article, the authors discuss the relationship between Karst and general geomorphology and Hydrogeology and discuss the development of Karst underground systems, and present a detailed analysis of these systems.
Abstract: CHAPTER 1. INTRODUCTION TO KARST. 1.1 Definitions. 1.2 The Relationship Between Karst And General Geomorphology And Hydrogeology. 1.3 The Global Distribution Of Karst. 1.4 The Growth Of Ideas. 1.5 Aims Of The Book. 1.6 Karst Terminology. CHAPTER 2. THE KARST ROCKS. 2.1 Carbonate Rocks And Minerals. 2.2 Limestone Compositions And Depositional Facies. 2.3 Limestone Diagenesis And The Formation Of Dolomite. 2.4 The Evaporite Rocks. 2.5. Quartzites And Siliceous Sandstones. 2.6 Effects Of Lithologic Properties Upon Karst Development. 2.7 Interbedded Clastic Rocks. 2.8 Bedding Planes, Joints, Faults And Fracture Traces. 2.9 Fold Topography. 2.10 Paleokarst Unconformities. CHAPTER 3. DISSOLUTION: CHEMICAL AND KINETIC BEHAVIOUR OF THE KARST ROCKS. 3.1 Introduction. 3.2 Aqueous Solutions And Chemical Equilibria. 3.3 The Dissolution Of Anhydrite, Gypsum And Salt. 3.4 The Dissolution Of Silica. 3.5 Bicarbonate Equilibria And The Dissolution Of Carbonate Rocks In Normal Meteoric Waters. 3.6 The S-O-H System And The Dissolution Of Carbonate Rocks. 3.7 Chemical Complications In Carbonate Dissolution. 3.8 Biokarst Processes. 3.9 Measurements In The Field And Lab Computer Programs. 3.10 Dissolution And Precipitation Kinetics Of Karst Rocks. CHAPTER 4. DISTRIBUTION AND RATE OF KARST DENUDATION. 4.1 Global Variations In The Solutional Denudation Of Carbonate Terrains. 4.2 Measurement And Calculation Of Solutional Denudation Rates. 4.3 Solution Rates In Gypsum, Salt And Other Non-Carbonate Rocks. 4.4 Interpretation Of Measurements. CHAPTER 5. KARST HYDROLOGY. 5.1 Basic Hydrological Concepts, Terms And Definitions. 5.2 Controls On The Development Of Karst Hydrologic Systems. 5.3 Energy Supply And Flow Network Development. 5.4 Development Of The Water Table And Phreatic Zones. 5.5 Development Of The Vadose Zone. 5.6 Classification And Characteristics Of Karst Aquifers. 5.7 Applicability Of Darcy's Law To Karst. 5.8 The Fresh Water/Salt Water Interface. CHAPTER 6. ANALYSIS OF KARST DRAINAGE SYSTEMS. 6.1 The 'Grey Box' Nature Of Karst. 6.2 Surface Exploration And Survey Techniques. 6.3 Investigating Recharge And Percolation In The Vadose Zone. 6.4 Borehole Analysis. 6.5 Spring Hydrograph Analysis. 6.6 Polje Hydrograph Analysis. 6.7 Spring Chemograph Interpretation. 6.8 Storage Volumes And Flow Routing Under Different States Of The Hydrograph. 6.9 Interpreting The Organisation Of A Karst Aquifer. 6.10 Water Tracing Techniques. 6.11 Computer Modelling Of Karst Aquifers. CHAPTER 7. SPELEOGENESIS: THE DEVELOPMENT OF CAVE SYSTEMS. 7.1 Classifying Cave Systems. 7.2 Building The Plan Patterns Of Unconfined Caves. 7.3 Unconfined Cave Development In Length And Depth. 7.4 System Modifications Occurring Within A Single Phase. 7.5 Multi-Phase Cave Systems. 7.6 Meteoric Water Caves Developed Where There Is Confined Circulation Or Basal Injection Of Water. 7.7 Hypogene Caves: (A) Hydrothermal Caves Associated Chiefly With Co2. 7.8 Hypogene Caves: (B) Caves Formed By Waters Containing H2s. 7.9 Sea Coast Eogenetic Caves. 7.10 Passage Cross-Sections And Smaller Features Of Erosional Morphology. 7.11 Condensation, Condensation Corrosion, And Weathering In Caves. 7.12 Breakdown In Caves. CHAPTER 8. CAVE INTERIOR DEPOSITS. 8.1 Introduction. 8.2 Clastic Sediments. 8.3 Calcite, Aragonite And Other Carbonate Precipitates. 8.4 Other Cave Minerals. 8.5 Ice In Caves. 8.6 Dating Of Calcite Speleothems And Other Cave Deposits. 8.7 Paleo-Environmental Analysis Of Calcite Speleothems. 8.8 Mass Flux Through A Cave System: The Example Of Friar's Hole, W.Va. CHAPTER 9. KARST LANDFORM DEVELOPMENT IN HUMID REGIONS. 9.1 Coupled Hydrological And Geochemical Systems. 9.2 Small Scale Solution Sculpture - Microkarren And Karren. 9.3 Dolines - The 'Diagnostic' Karst Landform? 9.4 The Origin And Development Of Solution Dolines. 9.5 The Origin Of Collapse And Subsidence Depressions. 9.6 Polygonal Karst. 9.7 Morphometric Analysis Of Solution Dolines. 9.8 Landforms Associated With Allogenic Inputs. 9.9 Karst Poljes. 9.10 Corrosional Plains And Shifts In Baselevel. 9.11 Residual Hills On Karst Plains. 9.12 Depositional And Constructional Karst Features. 9.13 Special Features Of Evaporite Terrains. 9.14 Karstic Features Of Quartzose And Other Rocks. 9.15 Sequences Of Carbonate Karst Evolution In Humid Terrains. CHAPTER 10.THE INFLUENCE OF CLIMATE, CLIMATIC CHANGE AND OTHER ENVIRONMENTAL FACTORS ON KARST DEVELOPMENT. 10.1 The Precepts Of Climatic Geomorphology. 10.2 The Hot Arid Extreme. 10.3 The Cold Extreme: 1 Karst Development In Glaciated Terrains. 10.4 The Cold Extreme: 2 Karst Development In Permafrozen Terrains. 10.5 Sea Level Changes, Tectonic Movement And Implications For Coastal Karst Development. 10.6 Polycyclic, Polygenetic And Exhumed Karsts. CHAPTER 11. KARST WATER RESOURCES MANAGEMENT. 11.1 Water Resources And Sustainable Yields. 11.2 Determination Of Available Water Resources. 11.3 Karst Hydrogeological Mapping. 11.4 Human Impacts On Karst Water. 11.5 Groundwater Vulnerability, Protection, And Risk Mapping. 11.6 Dam Building, Leakages, Failures And Impacts. CHAPTER 12. HUMAN IMPACTS AND ENVIRONMENTAL REHABILITATION. 12.1 The Inherent Vulnerability Of Karst Systems. 12.2 Deforestation, Agricultural Impacts And Rocky Desertification. 12.3 Sinkholes Induced By De-Watering, Surcharging, Solution Mining And Other Practices On Karst. 12.4 Problems Of Construction On And In The Karst Rocks - Expect The Unexpected! 12.5 Industrial Exploitation Of Karst Rocks And Minerals. 12.6 Restoration Of Karstlands And Rehabilitation Of Limestone Quarries. 12.7 Sustainable Management Of Karst. 12.8 Scientific, Cultural And Recreational Values Of Karstlands.

2,108 citations

Journal Article
TL;DR: In this article, a categorization of weathering characteristics into six stages, recognizable on descriptive criteria, provides a basis for investigation of the weathering rates and processes of recent mammals in the Amboseli Basin.
Abstract: Bones of recent mammals in the Amboseli Basin, southern Kenya, exhibit distinctive weathering characteristics that can be related to the time since death and to the local conditions of temperature, humidity and soil chemistry. A categorization of weathering characteristics into six stages, recognizable on descriptive criteria, provides a basis for investigation of weathering rates and processes. The time necessary to achieve each successive weathering stage has been calibrated using known-age carcasses. Most bones decompose beyond recognition in 10 to 15 yr. Bones of animals under 100 kg and juveniles appear to weather more rapidly than bones of large animals or adults. Small-scale rather than widespread environmental factors seem to have greatest influence on weathering characteristics and rates. Bone weathering is potentially valuable as evidence for the period of time represented in recent or fossil bone assemblages, in- cluding those on archeological sites, and may also be an important tool in censusing populations of animals in modern ecosystems.

2,035 citations

Journal ArticleDOI
01 Oct 1994-Ecology
TL;DR: There are three major causes of global environmental change: increasing carbon dioxide in the atmosphere, alterations in the biogeochemistry of the global nitrogen cycle, and ongoing land use/land cover change as mentioned in this paper.
Abstract: While ecologists involved in management or policy often are advised to learn to deal with uncertainty, there are a number of components of global environmental change of which we are certain–certain that they are going on, and certain that they are human—caused. Some of these are largely ecological changes, and all have important ecological consequences. Three of the well—documented global changes are: increasing concentrations of carbon dioxide in the atmosphere; alterations in the biogeochemistry of the global nitrogen cycle; and ongoing land use/land cover change. Human activity–now primarily fossil fuel combustion– has increased carbon dioxide concentrations from °280 to 355 mL/L since 1800; the increase is unique, at least in the past 160 000 yr, and several lines of evidence demonstrate unequivocally that it is human—caused. This increase is likely to have climatic consequences–and certainly it has direct effects on biota in all Earth's terrestrial ecosystems. The global nitrogen cycle has been altered by human activity to such an extent that more nitrogen is fixed annually by humanity (primarily for nitrogen fertilizer, also by legume crops and as a by product of fossil fuel combustion) than by all natural pathways combined. This added nitrogen alters the chemistry of the atmosphere and of aquatic ecosystems, contributes to eutrophiction of the biosphere, and has substantial regional effects on biological diversity in the most affected areas. Finally, human land use/land cover change has transformed one—their to one—half of Earth's ice—free surface. This in and of itself probably represents the most important component of global change now and will for some decades to come; it has profound effects on biological diversity on land and on ecosystems downwind and downstream of affected areas. Overall, any clear dichotomy between pristine ecosystems and human—altered areas that may have existed in the past has vanished, and ecological research should account for this reality. These three and other equally certain components of global environmental change are the primary causes of anticipated changes in climate, and of ongoing losses of biological diversity. They are caused in turn by the extraordinary growth in size and resource use of the human population. On a broad scale, there is little uncertainty about any of these components of change or their causes. However, much of the public believes the causes–even the existence–of global change to be uncertain and contentious topics. By speaking out effectively, we can help to shift the focus of public discussion towards what can and should be done about global environmental change.

1,781 citations