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USGS1993

In my experience: Mitochondrial DNA in wildlife taxonomy and conservation biology: Cautionary notes

Several recently published papers discussed the importance of systematics (the study of evolutionary and genetic relationships among organisms) and taxonomy (the naming and classification of organisms) for managing wildlife (Ryder 1986, Avise 1989, Amato 1991, O'Brien and Mayr 1991, Dowling et al. 1992), Often, classification below the species level is needed; for example, the Endangered Species Act of 1973 applies to local populations and subspecies as well as species. Conservation efforts may focus below the species level because of concerns about the fitness, evolutionary potentials, and locally adapted gene pools of natural populations (Soulé 1986, Hedrick and Milller 1992). This can be considered the genetic component of biodiversity. Recent systematic studies with wildlife management applications have used modern molecular genetic methods. Analyses of a specific molecular marker, mitochondrial DNA (mtDNA), have been used in many of these studies (e.g., Shields and Wilson 1987, Avise and Nelson 1989, O'Brien et al. 1990, Wayne and Jenks 1991, Cronin 1992), However, there are limitations to the use of mtDNA in systematics (e.g., Overden et al., 1987, Pamilo and Nei 1988, Dowling et al. 1992). In my experience as a geneticist working with wildlife biologists, I have found a need for clarification of the use and limitations of modern molecular genetics. I specifically discuss the limitations of mtDNA data in systematic assessments of wildlife at and below the species level.

Wildlife Society Bulletin↗
USGS1975

The geologic story of Arches National Park

According to former Superintendent Bates Wilson (1956), Prof. Lawrence M. Gould, of the University of Michigan, was the first to recognize the geologic and scenic values of the Arches area in eastern Utah and to urge its creation as a national monument. Mrs. Faun McConkie Tanner told me that Professor Gould, who had done a thesis problem in the nearby La Sal Mountains, was first taken through the area by Marv Turnbow, third owner of Wolfe cabin. (See p. 12.) When Professor Gould went into ecstasy over the beautiful scenery, Turnbow replied, 'I didn't know there was anything unusual about it.'

Utah↗
USGS1990

The Alaska Mineral Resource Assessment Program: Background information to accompany folio of geologic and resource maps of the Ugashik, Bristol Bay, and western part of Karluk quadrangles, Alaska

The Ugashik, Bristol Bay, and western part of Karluk quadrangles (1:250,000) are a part of the Alaska Peninsula in southwestern Alaska. This circular, in conjunction with a companion folio of MF-series maps, two I-series geologic maps, and three bulletins, represents the results of integrated field and laboratory studies on the geology, geophysics, geochemistry, paleontology, geochronology, and mineral resources of the quadrangles. These studies were undertaken to provide a modern assessment of the mineral and energy resources of the quadrangles. Each map contains descriptive text, explanatory material, tables, diagrams, and pertinent references. This circular provides background information for the mineral resource assessment map (MF-1539-1) and integrates the component M F- and I-series maps. A comprehensive bibliography cites both specific and general references relevant to the geology and resources of the quadrangles.

Alaska↗
USGS2001

Winter distributions of North American Plovers in the Laguna Madre regions of Tamaulipas, Mexico and Texas, USA

To determine the distribution and abundance of wintering plovers in the Laguna Madre of Texas and Tamaulipas, surveys were conducted in December 1997 and February 1998, along a 160 km stretch of barrier islands in Mexico and- 40 km of shoreline on South Padre Island, Texas. Altogether, 5,673 individuals, representing six plover species, were recorded during the surveys. Black-bellied Plovers Pluvialis squatarola were the most numerous (3 ,013 individuals) representing 53% of the total number of plovers observed. Numbers of Piping Charadriusm elodu, Snowy C . alexandrinus, Semipalmated C. semipalmatus and Wilson's Plovers C. wilsonia were 739, 1,345, 561, and 13 birds, respectively. Most individuals (97%) of all species except Wilson's Plovers were observed on bayside flats of the barrier islands. Similar numbers of Piping Plovers were recorded at South Padre Island, Texas, and in the Laguna Madre de Tamaulipas. Over 85% of the individuals of each of the other species were found in the more extensively surveyed Mexico portion of Laguna Madre. In Tamaulipas, most plover species were observed more often on algal flats than any other substrate. These results provide evidence of the value of these systems as wintering areas for plover species and indicate the need for more extensive survey efforts to determine temporal and spatial variation in the distribution of these species within the Laguna ecosystem.

Wader Study Group Bulletin↗
USGS1951

Older Precambrian structure in Arizona

The older Precambrian rocks of Arizona include the Vishnu, Yavapai, and Pinal schists, all overlain unconformably by nonmetamorphosed younger Precambrian rocks. The older Precambrian schists, unnamed gneisses, and associated granitic masses crop out in many of the mountain ranges southwest of the Colorado plateau. The stratigraphy and structure of the schists can be unraveled to some extent by detailed mapping, and work now in progress by the U. S. Geological Survey in the Bagdad, Prescott-Jerome, and Little Dragoon areas, is revealing folded structures trending generally northwest to northeast. Earlier work by Wilson in the Mazatzal Mountains revealed southeastward-dipping, low-angle thrust faults of older Precambrian age. In the Bagdad and Prescott-Jerome areas, a variety of igneous rocks, including rhyolite, alaskite porphyry, diorite, and gabbro, were intruded into the schists prior to the widespread invasion of granite. Only one period of orogeny followed by the intrusion of granitic rocks can be recognized in each area studied to date. The degree of metamorphism is not uniform and some of the pre-intrusive rocks are nonfoliated, whereas others are highly schistose. Some of the intrusive rocks, including granite, show the effect of dynamic metamorphism. The grade of metamorphism is low to intermediate, except near the large masses of granite where coarse-grained sillimanite-bearing schists are found.

Arizona↗
USGS2002

A bibliography of terrain modeling (geomorphometry), the quantitative representation of topography: Supplement 4.0

Terrain modeling, the practice of ground-surface quantification, is an amalgam of Earth science, mathematics, engineering, and computer science. The discipline is known variously as geomorphometry (or simply morphometry), terrain analysis, and quantitative geomorphology. It continues to grow through myriad applications to hydrology, geohazards mapping, tectonics, sea-floor and planetary exploration, and other fields. Dating nominally to the co-founders of academic geography, Alexander von Humboldt (1808, 1817) and Carl Ritter (1826, 1828), the field was revolutionized late in the 20th Century by the computer manipulation of spatial arrays of terrain heights, or digital elevation models (DEMs), which can quantify and portray ground-surface form over large areas (Maune, 2001). Morphometric procedures are implemented routinely by commercial geographic information systems (GIS) as well as specialized software (Harvey and Eash, 1996; Köthe and others, 1996; ESRI, 1997; Drzewiecki et al., 1999; Dikau and Saurer, 1999; Djokic and Maidment, 2000; Wilson and Gallant, 2000; Breuer, 2001; Guth, 2001; Eastman, 2002). The new Earth Surface edition of the Journal of Geophysical Research, specializing in surficial processes, is the latest of many publication venues for terrain modeling. This is the fourth update of a bibliography and introduction to terrain modeling (Pike, 1993, 1995, 1996, 1999) designed to collect the diverse, scattered literature on surface measurement as a resource for the research community. The use of DEMs in science and technology continues to accelerate and diversify (Pike, 2000a). New work appears so frequently that a sampling must suffice to represent the vast literature. This report adds 1636 entries to the 4374 in the four earlier publications1. Forty-eight additional entries correct dead Internet links and other errors found in the prior listings. Chronicling the history of terrain modeling, many entries in this report predate the 1999 supplement. Coverage is representative from about 1800 through early–mid 2002. Papers increasingly are published exclusively or in duplicate on the Internet's World Wide Web; the dates given here for Web addresses (URLs) that lack a print publication indicate a Web site's last update or my last access of it. The bibliography is arranged alphabetically and thus is not readily summarized. This introduction cites about 500 entries, a third of them grouped under 24 morphometric topics, as a guide to the listing's contents. Continuing the practice of previous bibliographies in the series to provide more information on a few applications (see summary of past topics in Pike, 2000a), this report elaborates further on topographic data, putative new parameters, tectonic geomorphology/neo-orometry, biogeography, ice-cap morphometry, results from the Mars Global DEM, landslide-hazard mapping, terrain modeling as physics, Hack's law, and broad-scale computer visualization. The literature of some of these subjects is large, and none of the summaries is intended to more than introduce the topic and comment on some of the current contributions of terrain modeling. Closing the essay is a discussion of pre-1900 papers that trace the evolution of ridge-line and watercourse quantification by descriptive geometry, as well as comments on some new books and an on-line bulletin board.

Open-File Report↗
USGS2018

Late Neogene–Quaternary tephrochronology, stratigraphy, and paleoclimate of Death Valley, California, USA

Sedimentary deposits in midlatitude continental basins often preserve a paleoclimate record complementary to marine-based records. However, deriving that paleoclimate record depends on having well-exposed deposits and establishing a sufficiently robust geochronology. After decades of research, we have been able to correlate 77 tephra beds exposed in multiple stratigraphic sections in the Death Valley area, California, United States. These correlations identify 25 different tephra beds that erupted from at least five different volcanic centers from older than 3.58 Ma to ca. 32 ka. We have informally named and determined the ages for seven previously unrecognized beds: ca. 3.54 Ma tuff of Curry canyon, ca. 3.45 Ma tuff of Furnace Creek, ca. 3.1 Ma tuff of Kit Fox Hills, ca. 3.1 Ma tuff of Mesquite Flat, ca. 3.15 Ma tuff of Texas Spring, 3.117 ± 0.011 Ma tuff of Echo Canyon, and the ca. 1.3 Ma Amargosa ash bed. Several of these tephra beds are found as far northeast as central Utah and could be important marker beds in western North America. Our tephrochronologic data, combined with magnetic polarity data and 40 Ar/ 39 Ar age determinations, redefine Neogene sedimentary deposits exposed across 175 km 2 of the Death Valley area. The alluvial/lacustrine Furnace Creek Formation is a time-transgressive sedimentary sequence ranging from ca. 6.0 to 2.5 Ma in age. The ca. 2.5–1.7 Ma Funeral Formation is typically exposed as a proximal alluvial-fan facies overlying the Furnace Creek Formation. We have correlated deposits in the Kit Fox Hills, Salt Creek, Nova Basin, and southern Death Valley with the informally named ca. 1.3–0.5 Ma Mormon Point formation. In addition, our correlation of the late Pleistocene Wilson Creek ash bed 15 in the Lake Rogers deposits represents the first unambiguous sequences deposited during the Last Glacial Maximum (marine isotope stage [MIS] 2) in Death Valley. Based on this new stratigraphic framework, we show that the Pliocene and Pleistocene climate in Death Valley is consistent with the well-established marine tropical/subtropical record. Pluvial lakes in Death Valley and Searles Valley began to form ca. 3.5–3.4 Ma in the late Pliocene during MIS MG5. Initiation of lakes in these two hydrologically separated valleys at the same time at the beginning of a cooling trend in the marine climate record suggests a link to a cooler, wetter (glacial) regional climate in North America. The Death Valley lake persisted until ca. 3.30 Ma, at the peak of the M2 glaciation, after which there is no evidence of Pliocene lacustrine deposition, even at the peak of the Northern Hemisphere Glaciation (ca. 2.75 Ma). If pluvial lakes in the Pliocene are an indirect record of glacial climate conditions, as they are for the Pleistocene, then a glacial climate was present in western North America for ∼200,000 yr during the Pliocene, encompassing MIS MG5–M2. Pleistocene pluvial lakes in Death Valley that formed ca. 1.98–1.78 Ma, 1.3–1.0 Ma, and ca. 0.6 Ma (MIS 16) are consistent with other regional climate records that indicate a regional glacial climate; however, Death Valley was relatively dry at ca. 0.77 Ma (MIS 19), when large lakes existed in other basins. The limited extent of the MIS 2 marsh/shallow lake in the Lake Rogers basin of northern Death Valley reflects the well-known regional glacial climate at that time; however, Death Valley received relatively lower inflow and rainfall in comparison.

Geological Society of America Bulletin↗
USGS1993

Managing biological diversity

Biological diversity is the variety of life and accompanying ecological processes (Off. Technol. Assess. 1987, Wilcove and Samson 1987, Keystone 1991). Conservation of biological diversity is a major environmental issue (Wilson 1988, Counc. Environ. Quality 1991). The health and future of the earth's ecological systems (Lubchenco et al. 1991), global climate change (Botkin 1990), and an ever-increasing rate in loss of species, communities, and ecological systems (Myers 1990) are among issues drawing biological diversity to the mainstream of conservation worldwide (Int. Union Conserv. Nat. and Nat. Resour. [IUCN] et al. 1991). The legal mandate for conserving biological diversity is now in place (Carlson 1988, Doremus 1991). More than 19 federal laws govern the use of biological resources in the United States (Rein 1991). The proposed National Biological Diversity Conservation and Environmental Research Act (H.R. 585 and S.58) notes the need for a national biological diversity policy, would create a national center for biological diversity research, and recommends a federal interagency strategy for ecosystem conservation. There are, however, hard choices ahead for the conservation of biological diversity, and biologists are grappling with how to set priorities in research and management (Roberts 1988). We sense disillusion among field biologists and managers relative to how to operationally approach the seemingly overwhelming charge of conserving biological diversity. Biologists also need to respond to critics like Hunt (1991) who suggest a tree farm has more biological diversity than an equal area of old-growth forest. At present, science has played only a minor role in the conservation of biological diversity (Weston 1992) with no unified approach available to evaluate strategies and programs that address the quality and quantity of biological diversity (Murphy 1990, Erwin 1992). Although actions to conserve biological diversity need to be clearly defined by viewing issues across biological, spatial, and temporal scales (Knopf and Smith 1992), natural resource managers find much conflicting information in the literature on strategies and programs for the conservation of biological diversity (Ehrlich 1992). Moreover, recommendations provided in much of the published information available for planning or decisions not only can be debated but may prove counterproductive if implemented. Current operational efforts beg for clearer focus on fundamental concepts central to daily decisions that impact native biological diversity. Recognizing that many biologists would provide different council and at the risk of oversimplification, we offer the following 4 topical issues as fundamental guidance to wise conservation action. These recommendations are based on our collective experiences working within conservation agencies since our original, collaborative essay (Samson and Knopf 1982). They are offered as initial, rather than authoritative, steps to better align research and management decisions with what we perceive as the critical issues in conserving biological diversity at the landscape and ecosystem levels of resolution.

Wildlife Society Bulletin↗