Okanogan Highlands Research Articles

First Fossil Record of Trichomanes sensu lato (Hymenophyllaceae) from the Mid-Cretaceous Kachin Amber, Myanmar.

Hymenophyllaceae (filmy ferns), with ca. 430 species, are the most species-rich family of early diverging leptosporangiate ferns but have a poor fossil record dating back to the Late Triassic period. Traditionally, Hymenophyllaceae comprise two species-rich genera or clades: Hymenophyllum (hymenophylloids) and Trichomanes sensu lato (s.l.) (trichomanoids). Unequivocal fossils of Hymenophyllum have been reported from the Early Cretaceous of central Mongolia and the early Eocene of Okanogan Highlands, Washington, USA. However, despite being a highly diversified lineage with an estimated 184 extant species, Trichomanes s.l. lack a definitive fossil record, which severely affects the reliability of the molecular dating of this group. Here, we report the first unequivocal fossil record of Trichomanes s.l. as T. angustum comb. nov. on the basis of fertile material with tubular involucres and long exserted receptacles from the mid-Cretaceous Kachin amber, Myanmar. This species was previously tentatively assigned to Hymenophyllites due to a lack of fertile evidence. Inferred to be an epiphytic fern, T. angustum further enriches the species diversity of the epiphytic palaeocommunities in the mid-Cretaceous Kachin amber, which are mainly composed of Porellalean leafy liverworts and Dicranalean and Hypnodendralean mosses. Fossil records indicate that Hymenophyllaceae probably originated in the tropical Pangea at the latest in the Triassic when all continents were coalesced into a single landmass and had already accumulated some notable diversity in low-middle latitude areas of Laurasia by the mid-Cretaceous period.

The early Eocene flora of Horsefly, British Columbia, Canada and its phytogeographic significance

About forty species, including a bryophyte, ferns, conifers, Ginkgo, and over 35 angiosperms, are recognized based on compression-impression remains from the early Eocene of Horsefly, British Colombia, Canada. This flora is in the north central part of a chain of late early Eocene fossil assemblages known as floras of the “Okanagan Highlands” (= “Okanogan Highlands” in the US). These floras extend from north central British Columbia, Canada southeast to Republic, Washington, USA. The Horsefly flora shows similarities to other Eocene Okanagan Highlands floras, such as McAbee, Falkland, Thomas Ranch and Republic, but with some additional rare taxa. In the broader sense, the Horsefly flora can be compared with early and middle Eocene floras of eastern Asia and midcontinental North America, but shares fewer elements with Europe. Ginkgo, Metasequoia, Pinus, Palaeocarpinus, ulmaceous leaves and Deviacer are shared with northeastern China as well as western North American sites. Fagopsis, Macginitiea, Dipteronia, Florissantia, Sassafras and Lagokarpos also occur in other western North American Eocene floras and Koelreuteria and Jenkinsella with Eocene paleofloras of China. These comparisons demonstrate probable floristic exchange between northwestern North America and northeastern China via a Beringian route during the late early Eocene.

Urticaceae leaves with stinging trichomes were already present in latest early Eocene Okanogan Highlands, British Columbia, Canada.

Paleontologists use tooth form to assess diets of fossil mammals. Plants would also be expected to adapt their morphology to respond to herbivory. Fossil nettle leaves with definitive stinging trichomes (tribe Urticeae, family Urticaceae) are described from the early Eocene upland lacustrine floras of the Okanogan Highlands, British Columbia, Canada. This is the first report of stinging trichomes in the fossil record. Their occurrence in western North America at a time of major large herbivorous mammal radiation suggests they acted, as they do today, as a deterrent for mammal herbivory. Fossil leaf compressions and extant leaves were photographed with standard methods. Focus-shift stacking was used to layer photos of the fossil leaves. Urticaceous fossil leaves from the Okanogan Highlands greatly resemble their modern relatives in leaf morphology and particularly in both stinging and nonstinging trichomes. Nettles are common components of the flora of the Volcanoes National Park in Rwanda. This region is used as a modern analogue for the Okanogan Highlands, based on comparable elevation, equable conditions that host both similar floras and large folivores. Nettles in tribe Urticeae (Urticaceae) producing leaves with stinging and nonstinging trichomes were already present in the early Eocene of western North America at a pivotal time during the early radiation of modern mammalian herbivore groups. They offer tantalizing evidence of a selective response that plants may have developed to protect themselves from the evolving mammalian herbivores of that time.

Newly Recognized Diversity in Trochodendraceae from the Eocene of Western North America

The Eocene flora of the Okanogan Highlands in the Pacific Northwest of North America has been recognized previously to include extinct species of both extant genera of the Trochodendraceae. Here, u...

A multicentury dendrochronological reconstruction of western spruce budworm outbreaks in the Okanogan Highlands, northeastern Washington

The western spruce budworm (Choristoneura occidentalis occidentalis Freeman) is recognized as the most ecologically and economically damaging defoliator in western North America. Synchronous western spruce budworm outbreaks can occur over much of a host species’ range, causing widespread limb and tree mortality, regeneration delays, and reduction in tree growth rates. Observational outbreak records in northern Washington State extend back only to the mid-20th century, limiting our understanding of this species’ long-term population dynamics. In this study, we used dendrochronological methods to reconstruct multicentury outbreak records at four sites in the Okanogan Highlands of northeastern Washington State. We assessed long-term changes in outbreak patterns and tested moisture availability as a potential driving factor of western spruce budworm population dynamics. Outbreak synchrony was found to increase after the late 19th century, especially for high-intensity outbreaks, possibly due to anthropogenic ...

Nuphar carlquistiisp. nov. (Nymphaeaceae): A Water Lily from the Latest Early Eocene, Republic, Washington

Premise of research. Fossil remains of a water lily, Nuphar carlquistii DeVore, Taylor & Pigg sp. nov. (Nymphaeaceae), are described from the latest early Eocene Republic flora of north-central Washington. Specimens include several fruits, one with in situ seeds, others with remnants of stamens and stamen attachment scars, and dispersed seeds found both within a mucilaginous dispersal matrix and separately. Associated structures, including a stigmatic disk, isolated tepals, and several rhizome segments bearing nested clusters of roots and leaf scars, are included in N. cf. carlquistii.Methodology. Fossils preserved in a lacustrine shale were dégaged to reveal details, photographed with LM, and compared morphologically with extant material of related plants.Pivotal results. The study documents the most complete fossil Nuphar known to date. The combination of multiple organs, including fruits, seeds, stamens, and rhizomes with leaf scars and clustered root scars, demonstrates that Eocene Nuphar had vegetative morphology and dispersal methods comparable to those of today. The fossil fruits share morphological features with extant members of section Astylus, establishing the presence of this New World lineage in the latest early Eocene Republic flora in northwestern North America. One specimen, a short rhizome fragment with attached roots that was previously attributed informally to Ensete (Musaceae), is shown to belong to this genus, underscoring the need for complete study of fossils prior to their use as climatic indicators.Conclusions. Nuphar carlquistii is rare among fossil remains of water lilies in having multiple reproductive structures present, including fruit peduncles, characteristic laminate anthers, seed masses in several stages of dispersal, and individual seeds. Associated Nuphar rhizomes with attached roots, tepals, and a stigmatic disk are assigned to N. cf. carlquistii and interpreted as representing the same plant. The presence of N. carlquistii in the Republic flora demonstrates that Nuphar section Astylus had established its present-day structure, plant habit, mode of seed dispersal, and aquatic niche by the early Eocene in the Okanogan Highlands of northwestern North America.

Temporal carbon dynamics of forests in Washington, US: Implications for ecological theory and carbon management

We quantified carbon (C) dynamics of forests in Washington, US using theoretical models of C dynamics as a function of forest age. We fit empirical models to chronosequences of forest inventory data at two scales: a coarse-scale ecosystem classification (ecosections) and forest types (potential vegetation) within ecosections. We hypothesized that analysis at the finer scale of forest types would reduce variability, yielding better fitting models. We fit models for three temporal dynamics: accumulation of live biomass, accumulation of dead biomass, and net primary productivity (NPP). We compared fitted model parameters among ecosections and among forest types to determine differences in potential C storage and uptake.Models of live biomass C accumulation and NPP fit the data better at the scale of forest types, suggesting this finer scale is important for reducing variability. Model fit for dead biomass C accumulation depended more on the region than on the scale of analysis. Dead biomass C was highly variable and a relationship with forest age was found only in some forest types of the eastern Cascades and Okanogan Highlands. Indicators of C storage potential differed between forest types and differences were consistent with expectations based on spatial variability in climate. Across the study area, maximum live biomass C varied from 6.5 to 38.6kgCm−2 and the range of ages at which 90% of maximum is reached varied from 57 to 838years. Maximum NPP varied from 0.37 to 0.94kgCm−2yr−1 and the age of maximum NPP varied from 65 to 543yrs. Forests with the greatest C storage potential are wet forests of the western Cascades. Forests with the greatest potential NPP are 65–100-year-old mesic western redcedar-western hemlock forests and riparian forests, although limited data suggest maximum NPP of coastal sitka spruce forests may be even greater. The observed relationship between the ages at which maximum NPP and maximum live biomass are reached for a given forest type suggests that there is a trade-off between managing for maximum live biomass (storage) vs. NPP (uptake) in some forest types but an optimal age for C management in others. The empirical models of C dynamics in this study can be used to quantify the effects of age-class distributions on C storage and NPP for large areas composed of different forest types. Also, the models can be used to test the effects of current or future natural and anthropogenic disturbance regimes on C sequestration, providing an alternative to biogeochemical process models and stand-scale methods.

Paleobotanical Evidence for the Origins of Temperate Hardwoods

Premise of research. Several key morphological and anatomical features are found in temperate deciduous hardwood taxa that undergo seasonal dormancy, including long-shoot/short-shoot differentiation, heterophylly, and diffuse-porous wood. These features, when found together in the fossil record, can serve as indicators suggesting that fossil plants had physiological responses to changing photoperiod and chilling similar to those present today in temperate deciduous forests. We measured heterophyllous leaves on branches of extant Cercidiphyllum trees and used these data as a profile with which to compare fossil leaves of the family Trochodendraceae. Methodology. We recorded frequency distributions of L∶W ratios of leaves from short and long shoots on branches of live Cercidiphyllum japonicum (Cercidiphyllaceae) trees and compared them with fossil leaves of late Paleocene Zizyphoides flabellum of Almont, North Dakota, of Zizyphoides type 1 from the late early Eocene “upland” Okanogan Highlands locality at Republic, Washington, and Trochodendron nastae, also from Republic. We reviewed the literature on seasonal dormancy and on the correlative distribution of leaf phenology and wood porosity type. Pivotal results. Extant Cercidiphyllum and Z. flabellum both showed a bimodal distribution of frequency distribution of L∶W ratios in leaves; Trochodendron did not. Zizyphoides sp. also showed a trend toward bimodality but had less conclusive results. Conclusions. We suggest that on the basis of morphological features, temperate deciduous forest trees demonstrating seasonal heterophylly can be detected in the fossil record. We suggest that triggers such as photoperiod and changing temperature that today influence these plants were pivotal to the evolution of modern temperate deciduous trees. This response may have been first to the trigger of photoperiod change in high-latitude plants and later combined with lower-temperature regimes of upland regions such as the Okanogan Highlands. The development of preformed leaves on plants with diffuse-porous wood allowed for early leaf emergence in the temperate environment.

Carbon dynamics of forests in Washington, USA: 21st century projections based on climate-driven changes in fire regimes

During the 21st century, climate-driven changes in fire regimes will be a key agent of change in forests of the U.S. Pacific Northwest (PNW). Understanding the response of forest carbon (C) dynamics to increases in fire will help quantify limits on the contribution of forest C storage to climate change mitigation and prioritize forest types for monitoring C storage and fire management to minimize C loss. In this study, we used projections of 21st century area burned to explore the consequences of changes in fire regimes on C dynamics in forests of Washington State. We used a novel empirical approach that takes advantage of chronosequences of C pools and fluxes and statistical properties of fire regimes to explore the effects of shifting age class distributions on C dynamics. Forests of the western Cascades are projected to be more sensitive to climate-driven increases in fire, and thus projected changes in C dynamics, than forests of the eastern Cascades. In the western Cascades, mean live biomass C is projected to decrease by 24–37%, and coarse woody debris (CWD) biomass C by 15–25% for the 2040s. Loss of live biomass C is projected to be lower for forests of the eastern Cascades and Okanogan Highlands (17–26%), and CWD biomass is projected to increase. Landscape mean net primary productivity is projected to increase in wet low-elevation forests of the western Cascades, but decrease elsewhere. These forests, and moist forests of the Okanogan Highlands, are projected to have the greatest percentage increases in consumption of live biomass. Percentage increases in consumption of CWD biomass are greater than 50% for all regions and up to four times greater than increases in consumption of live biomass. Carbon sequestration in PNW forests will be highly sensitive to increases in fire, suggesting a cautious approach to managing these forests for C sequestration to mitigate anthropogenic CO2 emissions.

Carbon dynamics of forests in Washington, USA: 21st century projections based on climate‐driven changes in fire regimes

During the 21st century, climate-driven changes in fire regimes will be a key agent of change in forests of the U.S. Pacific Northwest (PNW). Understanding the response of forest carbon (C) dynamics to increases in fire will help quantify limits on the contribution of forest C storage to climate change mitigation and prioritize forest types for monitoring C storage and fire management to minimize C loss. In this study, we used projections of 21st century area burned to explore the consequences of changes in fire regimes on C dynamics in forests of Washington State. We used a novel empirical approach that takes advantage of chronosequences of C pools and fluxes and statistical properties of fire regimes to explore the effects of shifting age class distributions on C dynamics. Forests of the western Cascades are projected to be more sensitive to climate-driven increases in fire, and thus projected changes in C dynamics, than forests of the eastern Cascades. In the western Cascades, mean live biomass C is projected to decrease by 24-37%, and coarse woody debris (CWD) biomass C by 15-25% for the 2040s. Loss of live biomass C is projected to be lower for forests of the eastern Cascades and Okanogan Highlands (17-26%), and CWD biomass is projected to increase. Landscape mean net primary productivity is projected to increase in wet low-elevation forests of the western Cascades, but decrease elsewhere. These forests, and moist forests of the Okanogan Highlands, are projected to have the greatest percentage increases in consumption of live biomass. Percentage increases in consumption of CWD biomass are greater than 50% for all regions and up to four times greater than increases in consumption of live biomass. Carbon sequestration in PNW forests will be highly sensitive to increases in fire, suggesting a cautious approach to managing these forests for C sequestration to mitigate anthropogenic CO2 emissions.

096 New studies of fossil Rosaceae from the upland early-middle Eocene Okanogan Highlands floras of British Columbia, Canada and Republic, Washington, USA

096 New studies of fossil Rosaceae from the upland early-middle Eocene Okanogan Highlands floras of British Columbia, Canada and Republic, Washington, USA

PrunusandOemleria(Rosaceae) Flowers from the Late Early Eocene Republic Flora of Northeastern Washington State, U.S.A.

Two genera of Rosaceae are described from the latest early Eocene Republic flora of northeastern Washington State, United States. Prunus cathybrownae sp. nov. (Rosaceae: subfamily Spiraeoideae, tribe Amygdaleae sensu Potter et al.) is based on eight flowers, including one containing in situ pollen and two immature fruits. Flowers are actinomorphic, perigynous, and pentamerous, with a campanulate hypanthium bearing five sepals. The gynoecium is unicarpellate and consists of a distally flared, bilobed stigma; an elongate style; and an ellipsoid, bilaterally asymmetric ovary. Two whorls of stamens—an inner one in which stamens are reflexed and an outer whorl of extended stamens—are both inserted into the hypanthium. Pollen from the outer whorl is 20 μm in diameter and tricolporate with a striately ornamented exine; clusters of smaller, presumably immature grains 7 μm long and 4 μm wide lacking distinctive ornamentation were recovered from the inner whorl. Immature fruits differ from the flowers in either having a senescent style or lacking one entirely and having fewer remnants of perianth parts and a larger and more symmetrical ovary. A second flower, Oemleria janhartfordae sp. nov. (Rosaceae: subfamily Spiraeoideae, tribe Osmaronieae sensu Potter et al.) is actinomorphic and perigynous and has five free pistils that each resemble the solitary pistil of Prunus. These include a flattened, bilobed stigma and an ellipsoid, bilaterally asymmetric ovary. The fossil has the laterally fixed, elongate style characteristic of the genus. These fossils are the oldest known floral examples of these two genera and demonstrate that both Prunus and Oemleria were present in the latest early Eocene in western North America. The Okanogan Highlands floristic province provides the earliest fossil evidence to date for the first major radiation of the Rosaceae, an important mostly temperate, mostly Northern Hemisphere family.

Attenuation of Lg in the western US using the USArray

The unprecedented breadth and density of the USArray allows us to resolve lateral variations of 1‐Hz Lg attenuation to 0.5 degrees over much of the western United States. We collected over 31,000 Lg amplitudes from 547 events and 408 stations of the initial USArray footprint. Two‐dimensional tomographic inversion yielded Q ranging from 60 to 550, with a variance reduction of 47% relative to the best‐fit constant Q model (Q = 155). Q is low over most of the region, with lowest values associated with recent volcanic activity, and active shear zones. High Q is found in older, stable crust, notably the Colorado and Columbia plateaus, while smaller islands of high Q are associated with batholiths, including the Sierra Nevada, Peninsular, and Bitterroot Ranges, the western Mojave, and Okanogan Highlands, as well as other areas of competent crust such as the Harcuvar range, and two topographically bounded blocks in the Basin and Range.

Stable isotope paleoaltimetry of Eocene core complexes in the North American Cordillera

The hydrogen isotope composition of Eocene muscovite in mylonitic quartzite from the Kettle and Shuswap metamorphic core complexes (Washington and British Columbia) permits estimates of paleoaltimetry of the North American Cordillera at the onset of post‐collisional lithospheric extension. Coupled oxygen, hydrogen, and 40Ar/39Ar isotope data indicate that meteoric water penetrated to significant depths during normal faulting along the Columbia River Detachment bounding both Kettle and Shuswap metamorphic core complexes. Synkinematic muscovite attains δDmuscovite values as low as −135‰ and −157‰, respectively, consistent with δDwater values of −115 ± 5‰ and −135 ± 5‰. In context with stable isotope data from Eocene sedimentary basins of continental North America, these data constrain the isotopic composition of precipitation from which paleoelevation estimates can be made. Stable isotope paleoaltimetry indicates that during detachment formation (49–47 Ma), orogen‐parallel variations in topography existed, and mean elevations decreased from ≥4000 m at the latitude of the Shuswap core complex to ≥3000 m in the Kettle core complex. In addition, these data indicate a net decrease in mean surface elevation by ∼1000 m since the Eocene. Our results for the Kettle core complex are consistent with paleoelevation estimates based on fossil floral physiognomy in the Eocene Republic basin (Washington), indicating that high elevations characterized not only the frontal escarpment near the crustal‐scale detachment but continued into the Okanogan highlands further west. Collectively, the stable isotope, geochronological, and paleofloral data support tectonic models of high Eocene surface elevations contemporaneous with magmatism and lithospheric extension.

A brief review of the fossil history of the family Rosaceae with a focus on the Eocene Okanogan Highlands of eastern Washington State, USA, and British Columbia, Canada

Many of the oldest definitive members of the Rosaceae are present in the Eocene upland floras of the Okanogan Highlands of northeastern Washington State and British Columbia, Canada. Over a dozen rosaceous taxa representing extant and extinct genera of all four traditionally recognized subfamilies are known from flowers, fruits, wood, pollen, and especially leaves. The complexity seen in Eocene Rosaceae suggests that hybridization and polyploidy may have played a pivotal role in the early evolution of the family. Increased species diversity and the first appearance of additional modern taxa occur during the Late Paleogene in North America and Europe. The Rosaceae become increasingly important components of fossil floras during the Neogene, with taxa adapted to many habitats.

New Diversity among the Trochodendraceae from the Early/Middle Eocene Okanogan Highlands of British Columbia, Canada, and Northeastern Washington State, United States

Newly recognized fossil infructescences and leaves of the Trochodendraceae are described from the Early/Middle Eocene McAbee and One Mile Creek sites of British Columbia, Canada, and Republic, eastern Washington State, United States. Trochodendron drachukii Pigg, Dillhoff, DeVore, & Wehr sp. nov., from McAbee, is an infructescence similar to that of extant Trochodendron aralioides Sieb. & Zucc. but strongly paniculate rather than racemose. This new species is larger and more robust than those of the Eocene flora of Republic, Washington, and has attached fruits quite similar to both extant Trochodendron Sieb. & Zucc. and Miocene fossils from Asia and western North America. Associated leaves are similar to those of extant Trochodendron except for sometimes bearing short basal auriculate extensions of the lamina. They differ from Trochodendron nastae Pigg, Wehr, & Ickert‐Bond leaves from Republic that have palmate rather than pinnate venation. Tetracentron hopkinsii Pigg, Dillhoff, DeVore, & Wehr sp. nov. from One Mile Creek and Tetracentron sp. from Republic have leaves remarkably like those of extant Tetracentron Oliver, firmly establishing the presence of this genus in the Eocene. This study demonstrates that within the Trochodendraceae, a poorly understood group within the eudicot grade, both extinct forms as well as plants with quite modern‐appearing fruits and leaves were present by the Eocene in northwestern North America.

Corylus, Carpinus, and Palaeocarpinus (Betulaceae) from the Middle Eocene Klondike Mountain and Allenby Formations of Northwestern North America

Coryloid reproductive remains (Betulaceae, subfamily Coryloideae) are documented from the middle Eocene Republic flora of northeastern Washington State and the Princeton flora of southern British Columbia. The oldest confirmed examples of two modern genera, Corylus johnsonii Pigg, Manchester & Wehr sp. nov., and Carpinus perryae Pigg, Manchester & Wehr sp. nov., are reported from the Republic flora, and three new species of the extinct genus Palaeocarpinus, Palaeocarpinus barksdaleae Pigg, Manchester & Wehr sp. nov., Palaeocarpinus stonebergae Pigg, Manchester & Wehr sp. nov., and Palaeocarpinus dentatus (Penhallow) Pigg, Manchester & Wehr comb. nov., are described from Republic, Washington; Princeton, British Columbia; and Stump Lake, British Columbia, respectively. Corylus johnsonii resembles three extant Asian species: Corylus wangii, Corylus ferox, and Corylus heterophylla. Involucres of this fossil species vary from being highly dissected and spiny like C. wangii and C. ferox to more laminar like C. heterophylla. This similarity is interesting because C. ferox and perhaps also C. wangii are members of section Acanthochlamys, thought to be basal within the genus. Carpinus perryae has asymmetric leaflike bracts that partly enclose an ovate nutlet and, thus, fits within the extant Carpinus subgenus Carpinus, a group with Asian, European, and North American affinities today. Palaeocarpinus, thought to be basal within the Coryloideae, is reported from several Eocene localities in the Okanogan Highlands. These occurrences demonstrate that this primarily Paleocene, extinct genus extended into the Eocene in western North America as it did in Asia. Associated staminate catkins containing coryloid pollen and Corylus‐like leaves also occur at Republic along with P. barksdaleae. The presence in the Okanogan Highlands floras of a suite of coryloid plants including both extinct and extant genera demonstrates that, like the birch subfamily Betuloideae, the subfamily Coryloideae was also a significant and diverse group in western North America during the middle Eocene.

Climatic and biophysical controls on conifer species distributions in mountain forests of Washington State, USA

Abstract Aim The purpose of this study was to quantify relationships between conifer species distributions and climatic and biophysical variables, in order to provide better insight into the potential for redistribution of species on the landscape in response to climatic change.Location Data are from 10,653 georeferenced sites in Washington State, USA, along a longitudinal gradient from west of the crest of the Cascade Range to the beginnings of the western slope of the Rocky Mountains, and across two physiographic provinces, the Northern Cascades, characterized by steep, rugged topography, and the Okanogan Highlands, presenting moderate slopes and broad rounded summits.Methods Tree data were drawn from the USDA Forest Service Area Ecology Program database, collected in mature, undisturbed stands. We compared simple climatic variables (annual temperature, growing‐degree days, annual and seasonal precipitation) to biophysical variables (soil, hydrologic, and solar radiation) derived from climatic variables. Climatic and biophysical variables were taken from the output of climatological and hydrological simulation models and estimated for each plot in the tree database. Generalized linear models were used, for each of fourteen tree species, at multiple spatial extents, to estimate the probability of occurrence of that species as a function of climatic and biophysical predictors. Models were validated by a combination of bootstrapping and estimating receiver operating characteristic (ROC) curves.Results For the majority of species, we were able to fit variables representing both moisture and temperature gradients, and in all but a few cases these models identified a unimodal response of species occurrence to these gradients. In some cases the ecological/environmental niche of a species had been clearly captured by the model, whereas in others a longer gradient in the predictor variable(s) would be needed. Responses of most species were consistent across three spatial scales.Main conclusions By identifying the ecological niches of multiple species, we can forecast their redistribution on the landscape in response to climatic change, evaluate the predictions of simulation models, and alert managers to particularly sensitive or vulnerable ecosystems and landscapes.

Patterns of Rarity in Mosses of the Okanogan Highlands of Washington State: An Emerging Coarse Filter Approach to Rare Moss Conservation

Increasing awareness of the importance of bryophytes in ecosystems has heightened efforts to conserve rare bryophyte species. Understanding the factors that influence rarity in bryophytes thus becomes valuable in developing conservation strategies. In order to decipher these patterns of rarity in mosses, 141 sites were sampled from a variable landscape in the Okanogan Highlands of Washington State. We split the 209 moss species found into three frequency groups (rare, frequent, and common) based on occurrence information and compared these groups based on different attributes. Comparison of these species to known lists of the area shows that the dry interior of Washington is grossly understudied. Moss distribution patterns on a local scale reflect world distribution patterns and may be dictated by habitat availability. Rare species occur on fewer habitats and occur in habitats that are unique or restricted on the landscape. Further, they occur more often in restricted mesohabitats (e.g., streams, cliffs, fens) than they do in unrestricted mesohabitats (forested or non-forested uplands). Mesohabitats, thus, emerge as an appropriate level for a coarse filter approach to prioritizing conservation efforts for rare mosses by land managers.

Middle Eocene dike swarms and their relation to contemporaneous plutonism, volcanism, core-complex mylonitization, and graben subsidence, Okanogan Highlands, Washington

Research Article| November 01, 1990 Middle Eocene dike swarms and their relation to contemporaneous plutonism, volcanism, core-complex mylonitization, and graben subsidence, Okanogan Highlands, Washington Grace A. McCarley Holder; Grace A. McCarley Holder 1Department of Geology, Washington State University, Pullman, Washington 99165 Search for other works by this author on: GSW Google Scholar R. Wade Holder; R. Wade Holder 2Department of Geology and Geography, Georgia Southern College, Statesboro, Georgia 30460 Search for other works by this author on: GSW Google Scholar Diane H. Carlson Diane H. Carlson 3Department of Geology, California State University, Sacramento, California 95819 Search for other works by this author on: GSW Google Scholar Author and Article Information Grace A. McCarley Holder 1Department of Geology, Washington State University, Pullman, Washington 99165 R. Wade Holder 2Department of Geology and Geography, Georgia Southern College, Statesboro, Georgia 30460 Diane H. Carlson 3Department of Geology, California State University, Sacramento, California 95819 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1990) 18 (11): 1082–1085. https://doi.org/10.1130/0091-7613(1990)018<1082:MEDSAT>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Grace A. McCarley Holder, R. Wade Holder, Diane H. Carlson; Middle Eocene dike swarms and their relation to contemporaneous plutonism, volcanism, core-complex mylonitization, and graben subsidence, Okanogan Highlands, Washington. Geology 1990;; 18 (11): 1082–1085. doi: https://doi.org/10.1130/0091-7613(1990)018<1082:MEDSAT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Sheeted porphyry dike swarms are concentrated along and parallel to the margins of the Republic and Keller grabens in northeast Washington. They were emplaced during graben subsidence and, in part, during mylonitization of the Kettle and Okanogan domes (core complexes) above the transition into the brittle deformation zone during Eocene regional extension. The swarms consist of older high-K biotite rhyolite and younger high-K hornblende dacite and andesite dikes. The biotite rhyoGte is correlative with the basal O'Brien Creek Formation now exposed in the grabens but has no documented plutonic equivalent in the adjacent Colville batholith. The hornblende dacite and andesite dikes (Scatter Creek Formation) are divided into (1) a low-Zr, low-K2O type that fed the lower part of the Sanpoil Volcanics and (2) a high-Zr, high-K2O type that fed the upper part of the Sanpoil Volcanics, respectively. The Scatter Creek Formation dikes are the hypabyssal equivalents of both the Devils Elbow intrusive suite and the earlier phases of the Herron Creek intrusive suite in the Colville batholith. The occurrence of the dike swarms both within and adjacent to grabens filled with comagmatic volcanic rocks demonstrates that the graben fill was deposited in situ during regional extension and is not an allochthonous fault block transported to its present location during regional compression. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.