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USGS1930

The flora of the Denver and associated formations of Colorado

In the introduction to my report on the Laramie flora of the Denver Basin I stated that that was the first of what was proposed to be a series of papers dealing with the stratigraphy and paleobotany of certain Upper Cretaceous and lower Tertiary plant-bearing formtions of the Rocky Mountain region. The present paper is the second of this series and deals with the flora of the Denver formation and certain identical or closely related formations that occur mainly in or adjacent to the Denver Basin of Colorndo. The additional formational units treated are the Arapahoe formation, the Dawson arkose, and the Middle Park formation.

Colorado↗

USGS1917

The physical conditions and age indicated by the flora of the Alum Bluff formation

The present paper has for its purpose the description of a small flora collected from the Alum Bluff formation, representing a horizon hitherto unrepresented paleobotanically in southeastern North America, and the discussion of the bearing of this flora on the physical conditions of deposition and the probable age of the deposits.

Florida↗

USGS2004

The flora of the Cottonwood Lake Study Area, Stutsman County, North Dakota

The 92 ha Cottonwood Lake Study Area is located in south-central North Dakota along the eastern edge of a glacial stagnation moraine known as the Missouri Coteau. The study area has been the focus of biologic and hydrologic research since the U.S. Fish and Wildlife Service purchased the site in 1963. We studied the plant communities of the Cottonwood Lake Study Area from 1992 to 2001. During this time period, the vascular flora of the study area consisted of 220 species representing 51 families. Over half of the species were perennial forbs (117 species). Perennial grasses (26 species) and annual forbs (22 species) made up the next two largest physiognomic groupings. The flora, having a mean Coefficient of Conservatism of 4.6 and a Floristic Quality Index of 62, consisted of 187 native species. Thirty-three species were non-natives. Our annotated list should provide information useful to researchers, graduate students, and others as they design and implement future studies in wetlands and uplands both in and around the Cottonwood Lake Study Area.

Prairie Naturalist↗

USGS1996

Similarities and life cycle distributions of floras of 22 national parks in the midwestern United States

Twenty-two midwestern U.S. national parks were studied to examine the similarities of their floras and analyses of the floras in each national park were used to construct groupings of these smaller sample areas at various similarity levels in order to classify larger floristic areas. The parks were not on average very similar based on Jaccard's similarity index. The maximum average park similarity was 21% (St. Croix National Scenic Riverway), and the maximum park pair similarity was just over 55% for Isle Royale National Park and Pictured Rocks National Lakeshore. The average similarity of parks increased with park area and numbers of native species, and weakly decreased with the percentage of non-native species. Weak trends were observed with latitude and negative trends with longitude. Four park groups were partitioned by cluster analysis of species relative abundance data: 7 prairie parks, 6 northern parks, 4 intermediate parks and 5 southern parks. The average percentage of non-native species was ~33% in the prairie and southern park clusters, while percentage of evergreen perennials was 2 to 4 times greater in the northern parks (8%) compared with other clusters. Deciduous perennials approached 80% in the northern and intermediate park clusters, compared with about 70% for the prairie and southern clusters. Percentage of annuals was almost double in the prairie and southern clusters (average 24%) compared with the northern and intermediate clusters (average 13%).

Illinois, Indiana, Iowa, Kansas, Michigan, Minneso↗

USGS2001

Coefficients of conservatism for the vascular flora of the Dakotas and adjacent grasslands

Floristic quality assessment can be used to identity natural areas, to facilitate comparisons among different sites, to provide long-term monitoring of natural area quality, and to evaluate habitat management and restoration efforts. To facilitate the use of floristic quality assessment in North Dakota, South Dakota (excluding the Black Hills), and adjacent grasslands, we developed a species list and assigned coefficients of conservatism (C values; range 0 to 10) to each plant species in the region's flora. The C values we assigned represented our collective knowledge of the patterns of occurrence of each plant species in the Dakotas and our confidence that a particular taxon is natural-area dependent. Because state boundaries usually do not follow ecological boundaries, the C values we assigned should be equally valid in nearby areas with the same vegetation types. Of the 1,584 taxa we recognized in this effort, 275 (17%) were determined to be nonnative to the region. We assigned C values of 4 or higher to 77% of our taxa, and the entire native flora had a mean C value (C) of 6.l. A floristic quality index (FQI) can be calculated to rank sites in order of their floristic quality. By applying the coefficients of conservatism supplied here and calculating C and FQI, an effective means of evaluating the quality of plant communities can be obtained. Additionally, by repeating plant surveys and calculations of C and FQI over time, temporal changes in floristic quality can be identified.

North Dakota, South Dakota↗

USGS1998

Uredo maua , sp. nov., and Uromyces tairae : Additions to the rust flora of Hawai’i

Uredo maua , on Xylosma hawaiiense (Flacourtiaceae), an endemic tree of Hawaiian forests, is newly described as an addition to Hawai’i's native rust flora. Uredo wakensis , originally described from Wake Island and reported from other Pacific islands on Tournefortia argentea (Boraginaceae), represents the uredinial state of Uromyces tairae , described from Okinawa. This rust is newly reported from Hawai’i.

Hawai'i↗

USGS1971

A Pliocene flora and insect fauna from the Bering Strait region

A flood-plain forest has been preserved beneath a lava flow that invaded the Inmachuk River Valley in the northern part of the Seward Peninsula, Alaska, during the Pliocene Epoch. The fossil flora is of great biogeographic interest because of its position (Fig. 1) in a tundra region about 250 km east of Bering Strait, 75 km south of the Arctic Circle, and 65 km west of the northwestern limit of spruce-birch forest. It provides insight into the history of the development of the circumpolar boreal forest (taiga). A rich arthropod fauna casts light on the phylogeny of several modern insect genera and on the origin of modern tundra faunas. A potassium-argon analysis of the overlying basaltic lava provides our first radiometric age estimate (5.7±0.2 million years) for the Clamgulchian Stage, a Late Tertiary time-stratigraphic unit based on fossil plants and widely recognized in Alaska ( Wolfe and Hopkins 1967) and northeastern Siberia.

Palaeogeography, Palaeoclimatology, Palaeoecology↗

USGS1990

Effects of benthic flora on arsenic transport

Chemical and biological interactions involving arsenic (As) and phosphorus (P) appear to affect significantly As transport and distribution in Whitewood Creek, South Dakota. Data (first‐order uptake rate constants, standing crop, and accumulation factors) that can be used to predict As transport have been determined using algae collected in the creek along a transect from upstream of mine discharge down gradient through a 57‐km impacted reach. Cultures of Achnanthes minutissima (Bacillariophyceae) were isolated from four sites along a longitudinal gradient of dissolved As within the study reach and were maintained at ambient dissolved‐As concentrations. Arsenic sorption‐rate constants for cell surfaces of these isolates were estimated as a function of dissolved arsenate and orthophosphate. All isolates sorbed orthophosphate preferentially over arsenate. Initial sorption of both arsenate and orthophosphate appeared to follow a first‐order equation within media formulations but did not adequately describe other observed effects among formulations or between isolates. Although estimated sorption‐rate constants increased slightly with increased dissolved arsenate concentration, algae isolated from a site with elevated dissolved As had a significantly slower rate of As uptake compared with the same species isolated from an uncontaminated site upstream. Field and laboratory results indicate that the benthic flora represent a significant As pool, which may episodically affect water‐column concentrations.

Journal of Environmental Engineering↗

USGS1993

Late Quaternary paleoceanography of the Pervenets Canyon area of the Bering Sea: Evidence from the diatom flora

Sediments from three gravity cores from an east-west shelf-to-slope transect along the axis of Pervenets Canyon in the northern Navarin basin, Bering Sea were analyzed for diatoms. The diatom floras present in the cores were divided into four assemblages following Sancetta (1981). The Bering Basin (deep water open ocean) and Sea Ice (ice cover at least six months per year) Assemblages were dominant in each core. The taxa that comprise the Bering Shelf Assemblage (continental shelf) indicate that downslope transport plays only a minor part in the development of the thanatocenoses. The presence (up to 10% of the total valve count) of the Productivity Assemblage, which consists mainly of poorly silicified, easily dissolved taxa, indicates that nutrient flux is relatively high in the region. Several taxa can be used as proxy indicators for specific water masses. Neodenticula seminae (Simonsen & Kanaya) Akiba & Yanagisawa is indicative of Holocene open marine (deep water) conditions. Nitzschia cylindra (Grunow) Hasle and N. grunowii Hasle are both associated with sea ice and are thought to indicate late Pleistocene conditions. The relative downcore abundance of these taxa was used to approximate the Pleistocene- Holocene boundary (recognized in Core 80–65 at a depth of about 75 cm).

Diatom Research↗

USGS2025

A comparison of ground flora sampling methods to assess recovery of bottomland forest restorations

We compared ground flora sampling methods for assessing the state of multiple bottomland forest restorations 6–21 years after restoration implementation in northeast Indiana, United States. Data from standard fixed-area plots of appropriate size and complexity for forest assessments were compared with data from smaller fixed-area plots of different shapes and plotless sampling methods. The methods were compared for their ability to (1) assess species richness and abundance, (2) detect and monitor invasive and dominant species, and (3) understand community composition. We assessed the biases of the compared methods, identified the training and skills needed to conduct sampling, and examined sampling costs in relation to total monitoring costs. Results show that smaller plots are able to detect more species per unit area sampled without significant differences in floristic quality measures. Data from smaller plots were sufficient for comprehensively describing site conditions even when less of the total site area was sampled. Although multivariate analyses of data from smaller plots yielded greater within-group dissimilarity than data from larger plots, multiple response permutation procedure analyses indicated no significant differences between nonmetric multidimensional scaling solutions based on data from the different sampling methods. Regardless of the sampling methods used to collect data, use of multivariate analyses identified a gradient of time since restoration was implemented as the dominant factor relating to differences between community composition. Sampling costs spanned a range of one order of magnitude but generally represented less than 6% of total assessment costs. Results suggest that when selecting sampling methods, matching monitoring effort to specific measurable management endpoints is more important than sampling cost.

Indiana↗

USGS2025

A quantitative classification of the geography of non-native flora in the United States

Aim Non-native plants have the potential to harm ecosystems. Harm is classically related to their distribution and abundance, but this geographical information is often unknown. Here, we assess geographical commonness as a potential indicator of invasive status for non-native flora in the United States. Geographical commonness could inform invasion risk assessments across species and ecoregions. Location Conterminous United States. Time Period Through 2022. Major Taxa Studied Plants. Methods We compiled and standardised occurrence and abundance data from 14 spatial datasets and used this information to categorise non-native species as uncommon or common based on three dimensions of commonness: area of occupancy, habitat breadth and local abundance. To assess consistency in existing categorizations, we compared commonness to invasive status in the United States. We identified species with higher-than-expected abundance relative to their occupancy, habitat breadth or residence time. We calculated non-native plant richness within United States ecoregions and estimated unreported species based on rarefaction/extrapolation curves. Results This comprehensive database identified 1874 non-native plant species recorded in 4,844,963 locations. Of these, 1221 species were locally abundant (> 10% cover) in 797,759 unique locations. One thousand one hundred one non-native species (59%) achieved at least one dimension of commonness, including 565 species that achieved all three. Species with longer residence times tended to meet more dimensions of commonness. We identified 132 species with higher-than-expected abundance. Ecoregions in the central United States have the largest estimated numbers of unreported, abundant non-native plants. Main Conclusions A high proportion of non-native species have become common in the United States. However, existing categorizations of invasive species are not always consistent with species' abundance and distribution, even after considering residence time. Considering geographical commonness and higher-than-expected abundance revealed in this new dataset could support more consistent and proactive identification of invasive plants and lead to more efficient management practices.

Conterminous United States↗

USGS2017

Temporospatial dynamics and public health significance of bacterial flora identified on a major leatherback turtle (Dermochelys coriacea) nesting beach in the Southern Caribbean

Grande Riviere beach, on the island of Trinidad, supports the largest nesting population of leatherback turtles in the Caribbean region. Throughout the nesting season, nests are naturally disturbed by newly nesting females, resulting in egg breakage and loss of some nest viability. This environment is ideal for the growth and proliferation of microorganisms. The range of bacterial flora present in beach sand and egg shells was examined, with emphasis on bacteria that may pose a threat to public and animal health. The extent to which the bacterial load and genera on the beach changed throughout the season was also assessed. Twenty-five genera were identified, with Pseudomonas spp. found to be the most predominant environmental bacteria. Four genera identified possess zoonotic potential, while five additional genera are known to be of public and animal health significance. Distinct shifts in the density and distribution of bacteria were observed along the beach from early to peak nesting season. Shifts were seen across heavily traversed zones, thus highlighting the potential exposure threats posed to beach visitors and animals alike. Further studies aimed at speciating this population of bacteria, as well as isolating potential fungal pathogens may mitigate this threat. Identification of bacterial agents that are specifically pathogenic to leatherback turtles, turtle eggs, hatchlings and those who may interact with these animals will serve to enhance and guide efforts to better conserve this species and protect the health of all who visit this ecologically significant site.

Grande Riviere beach↗

USGS2018

Diatom floras in lakes in the Ruby Mountains and East Humboldt Range, Nevada, USA: A tool for assessing high-elevation climatic variability

Local conditions, including lake size, depth, bathymetric profile, watershed characteristics, and timing and extent of ice cover determine the characteristics of diatom floras, and how those assemblages respond to short and long-term changes in climate. The diatom assemblages from fourteen sediment samples collected from marginal and profundal zones of seven lakes in the Ruby Mountains and East Humboldt Range of northeastern Nevada are characterized in order to identify the factors affecting controlling species diversity, equitability, and assemblage structure. Principle component analysis delineates three depth-controlled diatom assemblages: shallow (~1), medium (~11 m), and deep (>12 m). The shallowest samples are characterized by a diverse benthic assemblage, the medium depth sample is dominated by small fragilarioid taxa, and, the deepest samples, while not dominated by planktonic species, show an increase in their abundance. In general, diatom assemblages in shallower samples exhibit higher diversity and greater equitability.

Nevada↗

USGS2006

Invasion in a diversity hotspot: Exotic cover and native richness in the Californian serpentine flora

Exotic species have been observed to be more prevalent in sites where the richness of native species is highest, possibly reflecting variation among sites in resources, propagule supply, heterogeneity, or disturbance. However, such a pattern leaves unclear whether natives at species-rich sites are subject to especially severe impacts from exotics as a result. We considered this question using path models in which relationships between exotic cover and native richness were evaluated in the presence of correlated environmental factors. At 109 sites on serpentine soils across California, USA, exotic cover was positively correlated with total native herbaceous richness and was negatively correlated with the richness of both serpentine-endemic and rare native herbs. However, in path models that accounted for the influences of soil chemistry, disturbance, overstory cover, and regional rainfall and elevation, we found no indication that exotic cover reduced any component of native herb richness. Rather, our results indicated similarities and differences in the conditions favoring exotic, native, endemic, and rare species. Our results suggest that, in spite of some localized impacts, exotic species are not exerting a detectable overall effect on the community richness of the unique native flora of Californian serpentine. ?? 2006 by the Ecological Society of America.

California↗

USGS1902

Fossil flora of the John Day basin, Oregon

For a number of years I have been gradually accumulating material for a thorough revision of the Tertiary floras of the Pacific slope. Fossil plants are known to occur at numerous points within this area, and their study and identification has already furnished valuable data bearing on the geological history of the region, and when still further exploited it is confidently expected that they will afford more exact data for the use of geologists. This investigation is progressing satisfactorily, and at no distant day it is hoped to have it in form for final publication. From time to time various members of the United States Geological Survey, as well as others not connected with this organization, have sent in small collections of fossil plants for determination. These have been studied and reported upon as fully as the condition of the problem permitted, so that the determinations could be immediately available to geologists, but with the reservation that none of the questions could be fully settled until all known material had been studied and properly correlated. The rich fossil plant deposits in the John Day Basin, as set forth more fully in the historical account which follows, have been known for a period of nearly fifty years, but their study has been carried on in a more or less desultory manner. There has also been considerable confusion as to the horizons whence these plants came. As various species of plants described originally from the John Day region were detected in various other localities in Oregon, and in surrounding areas, as central Washington, western Idaho, and northern California, it became more than ever apparent that a thorough study of all material obtainable from this type area would be necessary before any definite or satisfactory conclusions could be reached. The immediate incentive for this revision was furnished by the receipt of a considerable collection of plants, made by Dr. John C. Merriam in 1900 while he was in charge of an expedition into this region made under the auspices of the University of California. When these plants were submitted to me for study, it was thought possible to present their description, together with a revision of our knowledge of the previously known forms, within a space sufficiently small to permit the publication of the matter as an appendix to a paper on the general geology of the area, then in preparation by Dr. Merriam. But it soon became apparent that this could not be adequately done within the space available, and a short preliminary report was prepared for and published by Dr. Merriam. The results of a complete restudy of all available fossil plant material from the John Day Basin are now presented. I wish to record my great indebtedness to Dr. Merriam, who not only accompanied me at a considerable personal sacrifice on a trip through the region in 1901, but placed unreservedly at my disposal all material bearing in any way on the problem then in the paleontological museum of the University of California. To Dr. Arthur Hollick I am indebted for the loan of all material from the John Day region belonging to Columbia University, and now deposited in the New York Botanical Garden at Bronx Park. This material, together with the rich collections belonging to the United States National Museum, represents practically all now known to have come from the John Day Basin.

Oregon↗

USGS1887

Types of the Laramie flora

I have in preparation a work on the flora of the Laramie group, in which will be described and figured a very large number of fossil plants, most of which were collected by myself in the seasons of 1881 and 1883 and the elaboration of which has occupied most of my time since the latter date.

Bulletin↗

USGS1920

An Eocene flora from trans-Pecos Texas

During the fall of 1916 I received a small collection of fossil plants which had been obtained during a geologic reconnaissance of the trans-Pecos region of Texas, by Charles Lawrence Baker. A preliminary report was sent to Mr. Baker in November of that year and was quoted in his discussion of the geology of that region. I have since made a careful study of the collection, and although it contains only a few species the occurrence of fossil plans in this region is worthy of more definite and detailed record, especially as these plants enabled me to assign a definite age to the beginning of the igneous activity of the region and to establish correlations between the floras of the Mississippi embayment and the Rocky Mountain Region.

Professional Paper↗

USGS1923

Additions to the flora of the Wilcox group

A rather full account of the extensive flora contained in the lower Eocene strata of the Mississippi embayment which are referred to the Wilcox group was published in 1916. At that time it was not possible to obtain sections of the numerous specimens of petrified wood that had been collected from these beds. These woods have since been sectioned and studied, and it seems eminently desirable to place the results of this study on record, for although much of the material had suffered greatly from decay before silicification, some of it is fairly well preserved and shows, among other results, that conifers were individually much more plentiful during Wilcox time than would be inferred from the almost total absence of their foliage in the very large collections of remains of this class that have been studied.

Texas↗