Taxonomy of the Carex straminea complex (Cyperaceae)

1997 ◽  
Vol 75 (12) ◽  
pp. 2177-2195 ◽  
Author(s):  
P. E. Rothrock ◽  
A. A. Reznicek ◽  
L. R. Ganion
Keyword(s):  
Numerical Analysis ◽  
North America ◽  
Key Words ◽  
Endemic Species ◽  
Atlantic Coast ◽  
Interspecific Variation ◽  
Eastern North America ◽  
Upper Midwest ◽  
The Relationship ◽  
Sem Investigation

The Carex straminea complex (section Ovales) consists of five species limited to hydric communities of eastern North America. Based upon gross morphology and perigynium structure, these species are closely aligned with the Carex albolutescens complex but not the western species Carex feta. An SEM investigation of the micromorphology of achene and style epidermis from 15 species of Carex section Ovales demonstrated much interspecific variation. As a result, these data could not confirm the relationship between the C. straminea complex and the C. albolutescens complex but did support the delimitation of section Ovales. Numerical analysis showed that characters of the inflorescence and perigynium are satisfactory for separating C. straminea from Carex hormathodes, a species limited to the Atlantic coast. Likewise, characters of inflorescence, pistillate scale, and perigynium could clearly separate the geographically widespread Carex alata from the Florida endemic species Carex vexans. A fifth and relatively distinctive species, Carex suberecta, was found to have a narrow ecological preference for fens and a distribution limited to the upper Midwest, with outlying populations in western Virginia. Putative natural hybrids are documented between Carex scoparia and Carex longii and some species in the C. straminea complex. Key words: Carex, Cyperaceae, section Ovales, taxonomy, SEM, biogeography, hybrid.

scholarly journals Effects of aerosols on precipitation in north-eastern North America

2014 ◽  
Vol 14 (10) ◽  
pp. 5111-5125 ◽  
Author(s):  
R. Mashayekhi ◽  
J. J. Sloan
Keyword(s):  
North America ◽  
Atlantic Coast ◽  
Inverse Correlation ◽  
Cloud Droplet ◽  
Cloud Microphysics ◽  
Convective Precipitation ◽  
Eastern North America ◽  
Anthropogenic Aerosols ◽  
Convective Rain ◽  
North Eastern

Abstract. The changes in precipitation in north-eastern North America caused by chemistry – and particularly anthropogenic aerosols – are investigated using the Weather Research Forecasting with Chemistry (WRF/Chem v3.2) model. The simulations were carried out for a five-month period from April to August 2009. The model results show that non-negligible changes in both convective and cloud-resolved (non-convective) precipitation are caused by chemistry and/or aerosols over most parts of the domain. The changes can be attributed to both radiative and microphysical interactions with the meteorology. A chemistry-induced change of approximately −15% is found in the five-month mean daily convective precipitation over areas with high convective rain; most of this can be traced to radiative effects. Total convective rain is greater than total non-convective rain in the domain, but a chemistry-induced increase of about 30% is evident in the five-month mean daily non-convective precipitation over the heavily urbanized parts of the Atlantic coast. The effects of aerosols on cloud microphysics and precipitation were examined for two particle size ranges, 0.039–0.1 μm and 1–2.5 μm, representing the nucleation and accumulation modes respectively. Strongly positive spatial correlation between cloud droplet number and non-convective rain are found for activated (cloud-borne) aerosols in both size ranges. Non-activated (interstitial) aerosols have a positive correlation with cloud droplet number and non-convective rain when they are small and an inverse correlation for larger sizes.

Detection of Adelges tsugae (Hemiptera: Adelgidae) wool using Velcro-covered balls

2021 ◽  
pp. 1-11
Author(s):  
Jeffrey G. Fidgen ◽  
Mark C. Whitmore ◽  
Chris J.K. MacQuarrie ◽  
Jean J. Turgeon
Keyword(s):  
Life Cycle ◽  
North America ◽  
Insect Pest ◽  
Adelges Tsugae ◽  
Eastern North America ◽  
Sample Sizes ◽  
Field Sampling ◽  
Individual Tree ◽  
Precision Level ◽  
The Relationship

Abstract Adelges tsugae Annand (Hemiptera: Adelgidae), a nonindigenous insect pest of hemlock (Tsuga spp.) (Pinaceae) in eastern North America, spends most of its life cycle within an ovisac, which resembles a woolly white mass on twigs. We evaluated the probability of detecting adelgid wool with Velcro®-covered balls when taking an increasing number of samples per tree (field sampling) and number of trees per simulated stand. We examined the relationship between the detection of adelgid wool using this technique and the incidence of A. tsugae-infested twigs by sampling lower-crown branch tips of the same trees. We found that the probability of detecting wool with ball sampling increased with number of ball samples per tree, with number of trees per simulated stand, and with increasing incidence of ovisacs in the lower crown. When sampling an individual tree, we found that 20 ball samples per tree achieved a targeted precision level of 0.75, but when sampling a stand, we found that 10 ball samples per tree took the least time for the range of simulated A. tsugae infestations we tested. These sample sizes are recommended for detection of A. tsugae infestations on an individual tree and in a hemlock stand.

scholarly journals Rain, Riches, and Empire: The Relationship between Nations Ruling Distant Lands, Nations of Great Wealth, and Regions of Regular Moderate Atmospheric Precipitation

2017 ◽  
Vol 9 (3) ◽  
pp. 455-469 ◽  
Author(s):  
L. Bruce Railsback
Keyword(s):  
North America ◽  
Small Proportion ◽  
Average Rate ◽  
Atmospheric Precipitation ◽  
Eastern North America ◽  
Human History ◽  
Per Capita Gdp ◽  
Per Capita ◽  
Human Construction ◽  
The Relationship

Abstract Two of the great questions of human history and economics are why some nations held far-flung empires and why some presently enjoy great wealth. One factor that should be included in the inevitably multifactorial answer to these questions is regular moderate precipitation (precipitation with an average rate between 30 and 120 mm for each month). Only a small proportion of Earth’s surface has regular moderate precipitation, and most of that area is in Europe and eastern North America. Strikingly, of the 13 nations that held geographically discontinuous multicontinental transoceanic empires, 12 overlap with regions of regular moderate precipitation. Similarly, of the 20 nations with the greatest per capita GDP in 2015, 16 coincide with regions of regular moderate precipitation. These relationships are presumably rooted in the greater success, or lesser inhibition, of human construction of infrastructure, husbandry of livestock, and cultivation of crops, some combination of which likely allowed industrialization, projection of geopolitical power, and accumulation of wealth. One instructive example is that of China, which has a climate superficially like that of Europe and eastern North America but no regions of regular moderate rainfall, and which neither developed an overseas empire nor is among the world’s nations with greatest per capita GDP. Furthermore, concentration of nations holding empires and wealth in the Northern Hemisphere and their absence from the south can be linked to the coincidence that the Southern Hemisphere’s latitudinal zone of regular moderate rainfall is over the Southern Ocean, where there is little land on which human societies could have enjoyed the benefits of that supportive climate.

Regional variation in the terminal Pleistocene and early Holocene radiocarbon record of eastern North America

2013 ◽  
Vol 79 (2) ◽  
pp. 175-188 ◽  
Author(s):  
D. Shane Miller ◽  
Joseph A.M. Gingerich
Keyword(s):  
North America ◽  
Regional Variation ◽  
Probability Distributions ◽  
Younger Dryas ◽  
Eastern North America ◽  
Northeastern United States ◽  
Radiocarbon Dates ◽  
Terminal Pleistocene ◽  
The Relationship ◽  
Data Result

AbstractIn this paper we use radiocarbon dates to evaluate the signature of the Younger Dryas Chronozone (YDC) in eastern North America. Using an approach that examines radiocarbon dates by region, we argue that the northeastern United States shows a better overall representation of radiocarbon dates when compared to the Mid-Atlantic and Southeast. These data result in a peak in summed probability distributions during the YDC, which is often interpreted as evidence of population growth. Further examination of these distributions, however, illustrates that differential standard deviations, varying sample size, and the effect of taphonomic and research biases likely overwhelm any demographic signatures in our study sample. Consequently, the frequency of radiocarbon dates by itself is insufficient for understanding the relationship between climate, culture and demography in eastern North America.

Biogeographic relationships between the macrofungi of temperate eastern Asia and eastern North America

1997 ◽  
Vol 75 (12) ◽  
pp. 2108-2116 ◽  
Author(s):  
Qiuxin Wu ◽  
Gregory M. Mueller
Keyword(s):  
North America ◽  
Key Words ◽  
North American ◽  
Field Work ◽  
Disjunct Distribution ◽  
Eastern North America ◽  
Western North America ◽  
Eastern Asia ◽  
Key Words Biogeography

Eastern North America and temperate eastern Asia reportedly share a relatively high number of taxa of macrofungi (mushrooms and relatives), including a number of taxa that have putative eastern North America – temperate eastern Asia disjunct distributions. These reports have been used to imply an affinity between the mycota (fungal equivalent of flora and fauna) of the two regions. To date, however, this affinity has not been examined in detail. A comparison of north temperate macrofungal mycotas was undertaken to examine the similarity between these regions. We used two methods in this study: (i) direct comparison of taxon lists and (ii) calculation of the Simpson Coefficient of similarity from lists of selected taxa. These analyses were based on field work, herbarium records, and published taxonomic treatments for Amanita, Lactarius, Ramaria, and Boletaceae. Results of these analyses document that taxonomic similarity between eastern North America and temperate eastern Asia mycotas can be quite high. In all cases, the calculated similarity values for eastern North America – temperate eastern Asia comparisons are higher than those between either region of North America and Europe or between western North America and eastern Asia. Furthermore, the eastern North American and temperate eastern Asian disjunct distributions of macrofungi are usually limited to the level of species or lower. Key words: biogeography, China, disjunct distribution, macrofungi, North America, Simpson Coefficient.

scholarly journals Ten Years on from the Quake That Shook the Nation’s Capital

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Thomas Pratt ◽  
Martin Chapman ◽  
Anjana Shah ◽  
J. Horton Jr. ◽  
Oliver Boyd
Keyword(s):  
North America ◽  
Atlantic Coast ◽  
Eastern North America ◽  
Virginia Earthquake ◽  
Shed Light

A decade of study into the Virginia earthquake that damaged D.C. and reverberated up and down the Atlantic coast in 2011 has shed light on rare, but risk-laden, seismicity in eastern North America.

MULTIPLE INTRODUCTIONS OF THE FORFICULA AURICULARIA SPECIES COMPLEX (DERMAPTERA: FORFICULIDAE) IN EASTERN NORTH AMERICA

2000 ◽  
Vol 132 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Stéphanie Guillet ◽  
Nathalie Josselin ◽  
Michel Vancassel
Keyword(s):  
North America ◽  
Species Complex ◽  
Atlantic Coast ◽  
Eastern North America ◽  
Forficula Auricularia ◽  
Multiple Introductions ◽  
As Species ◽  
Mitochondrial Data ◽  
Restriction Polymorphism ◽  
Selection Of

AbstractA survey of nine populations of the European earwig, Forficula auricularia L., species complex from eastern North America revealed the presence of the two sibling species recently identified as species A and B. A mitochondrial analysis, based on restriction polymorphism observed on the 16S rRNA and the cytochrome oxydase regions, proved to be a rapid method to identify and distinguish these two species. Furthermore, consistency between these mitochondrial data and a biological diagnosis, based on the dates and number of oviposition periods in each population, revealed that species A and B occupy different habitats. These observations are consistent with the hypothesis of multiple introductions of the two species on the Atlantic coast of North America, followed by a selection of the most adapted species to each habitat.

scholarly journals Limited Range-Filling Among Endemic Forest Herbs of Eastern North America and Its Implications for Conservation With Climate Change

2021 ◽  
Vol 9 ◽  
Author(s):  
Stephanie K. Erlandson ◽  
Jesse Bellemare ◽  
David A. Moeller
Keyword(s):  
Climate Change ◽  
North America ◽  
Endemic Species ◽  
Species Distribution Models ◽  
Future Climate Change ◽  
Eastern North America ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Herb Species ◽  
Forest Herb

Biodiversity hotspots host a high diversity of narrowly distributed endemic species, which are increasingly threatened by climate change. In eastern North America, the highest concentration of plant diversity and endemism occurs in the Southern Appalachian Mountains (SAM). It has been hypothesized that this region served as a refugium during Pleistocene glacial cycles and that postglacial migration northward was dispersal limited. We tested this hypothesis using species distribution models for eight forest herb species. We also quantified the extent to which the geography of suitable habitat shifted away from the current range with climate change. We developed species distribution models for four forest herb species endemic to the SAM and four that co-occur in the same SAM habitats but have broader ranges. For widespread species, we built models using (1) all occurrences and (2) only those that overlap the SAM hotspot in order to evaluate the extent of Hutchinsonian shortfalls and the potential for models to predict suitable habitat beyond the SAM. We evaluated the extent to which predicted climatically suitable areas are projected to shift away from their current ranges under future climate change. We detected unoccupied but suitable habitat in regions up to 1,100 km north of the endemic species’ ranges. Endemic ranges are disjunct from suitable northern areas due to a ∼100–150 km gap of unsuitable habitat. Under future climate change, models predicted severe reductions in suitable habitat within current endemic ranges. For non-endemic species, we found similar overall patterns and gap of unsuitability in the same geographic location. Our results suggest a history of dispersal limitation following the last glacial maximum along with an environmental barrier to northward migration. Conservation of endemic species would likely require intervention and assisted migration to suitable habitat in northern New England and Canada.

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