An exotic insect and pathogen disease complex reduces aboveground tree biomass in temperate forests of eastern North America

2011 ◽  
Vol 41 (2) ◽  
pp. 401-411 ◽  
Author(s):  
Posy E. Busby ◽  
Charles D. Canham
Keyword(s):  
North America ◽  
Negative Relationship ◽  
Fagus Grandifolia ◽  
Carbon Accumulation ◽  
Host Tree ◽  
Eastern North America ◽  
Tree Biomass ◽  
Growth And Survival ◽  
The Impact ◽  
Aboveground Tree Biomass

Forests store a large portion of global carbon in tree and soil biomass. However, our understanding of the factors that may reduce rates of forest carbon accumulation is incomplete. This study examines the impact of an exotic insect and fungal pathogen disease on aboveground tree biomass in forests of eastern North America. We determine how beech bark disease (BBD) — a pervasive but nonextirpating disease — influences the growth and survival of its host tree, Fagus grandifolia Ehrh., and the effects of changes in the demography of this late-successional dominant tree species on total stand-level aboveground tree biomass. Our analyses use US Forest Service Forest Inventory and Analysis data from eastern states located along a gradient in the time since introduction of BBD. In Maine, where BBD has been present for >50 years, we observed reduced growth and survival of the host tree and reduced overall stand-level aboveground tree biomass compared with states where BBD arrived more recently. Additionally, there is a negative relationship between host tree abundance and overall stand-level aboveground tree biomass. Where beech is most abundant, BBD results in substantial declines in aboveground tree biomass (e.g., 11% in Maine); where beech is less abundant, we expect more modest declines (1%–4%).

scholarly journals Scale and strength of oak–mesophyte interactions in a transitional oak–hickory forest

2018 ◽  
Vol 48 (11) ◽  
pp. 1366-1372 ◽  
Author(s):  
David Allen ◽  
Christopher W. Dick ◽  
Ethan Strayer ◽  
Ivette Perfecto ◽  
John Vandermeer
Keyword(s):  
North America ◽  
Census Data ◽  
Spatial Association ◽  
Acer Rubrum ◽  
Forest Plot ◽  
Eastern North America ◽  
Red Maple ◽  
Growth And Survival ◽  
Shade Tolerant Species ◽  
Compositional Changes

Forests in eastern North America are undergoing rapid compositional changes as they experience novel climate, disturbance, and pest conditions. One striking pattern is the replacement of canopy oaks (Quercus spp.) by mesic, fire-sensitive, shade-tolerant species like red maple (Acer rubrum L.). To gain insight into the successional patterns driving stand-level canopy oak replacement, we ask two questions: (i) What is the spatial association of oak and mesophyte recruitment compared with oak and mesophyte overstory individuals, and (ii) How do oaks and mesophytes differentially respond to canopy openings. We analyzed census data from a 23 ha forest plot surveyed in 2003, 2008, and 2014. We show that oak recruits are negatively associated with overstory red maples and black cherries (Prunus serotina Ehrh.), whereas mesophytic recruits were positively associated with overstory oaks. Second, we found that proximity to a dead overstory tree increased growth and survival for black cherries, increased growth for red maples, but had no effect on oaks. Black cherries and red maples are therefore better suited than oaks to take advantage of canopy openings and the moderate light available under adult oaks. These same fine scale competitive processes are contributing to canopy oak replacement across eastern North America.

NEW AND LITTLE-KNOWN APHIDS (HOMOPTERA: APHIDIDAE) FROM EASTERN NORTH AMERICA

1971 ◽  
Vol 103 (8) ◽  
pp. 1083-1106 ◽  
Author(s):  
F. W. Quednau
Keyword(s):  
North America ◽  
Quercus Rubra ◽  
Aphid Species ◽  
Fagus Grandifolia ◽  
Eastern North America ◽  
Quercus Prinus

AbstractSeven aphid species, Longistigma chantali from Fagus grandifolia, Diphyllaphis microtrema from Quercus rubra, Hoplochaitophorus heterotrichus from Quercus prinus, Calaphis leonardi from Betula populifolia, Calaphis neobetulella from Betula nigra, Monellia hispida from Carya glabra, and Iziphya mackaueri from Carex sp., are described as new. Neosymydobius quercihabitus Miller and Calaphis betulaecolens (Fitch) are redescribed.

Phylogeography and genetic characteristics of a putative secondary-contact zone of the loggerhead shrike in central and eastern North America

2001 ◽  
Vol 79 (12) ◽  
pp. 2221-2227 ◽  
Author(s):  
M Vallianatos ◽  
S C Lougheed ◽  
P T Boag
Keyword(s):  
North America ◽  
Contact Zone ◽  
Sequence Data ◽  
Phylogeographic Structure ◽  
Secondary Contact ◽  
Eastern North America ◽  
Management Units ◽  
Genetic Characteristics ◽  
Loggerhead Shrike ◽  
The Impact

The loggerhead shrike (Lanius ludovicianus) is found throughout North America in grassland and open scrub habitats. We previously described four loggerhead shrike management units found in central and eastern North America within the geographic ranges of three subspecies, L. l. migrans, L. l. ludovicianus, and L. l. excubitorides. A contact zone has been suggested to occur between L. l. migrans and L. l. excubitorides. The present study uses mitochondrial DNA sequence data to explore historical, ecological, and geographical factors that may have played a role in the genetic differentiation of these four management units, and examines the evidence for and characteristics of the migrans–excubitorides contact zone. Geographically discrete, monophyletic clades were not evident, but the distribution of haplotypes (especially those exceeding 10% overall frequency) indicated some phylogeographic structure that perhaps reflects an intermediate stage of differentiation between paraphyly and reciprocal monophyly. The contact zone between L. l. migrans and L. l. excubitorides is supported by the mixing of haplotypes unique to each of the hybridizing populations and intermediate frequencies of common haplotypes. We interpret these patterns as possibly reflecting the impact of both glacial refugial dynamics and anthropogenic changes to habitat in eastern North America.

The Impact of U.S. Non-price Export Promotion Program on Export Demand for U.S. Peanuts in North America

2010 ◽  
Vol 37 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Tullaya Boonsaeng ◽  
Stanley M. Fletcher
Keyword(s):  
North America ◽  
Negative Relationship ◽  
Single Equation ◽  
Real Income ◽  
Export Promotion ◽  
Export Demand ◽  
Demand Model ◽  
The Impact ◽  
Positive Effect ◽  
The U.S

Abstract The purpose of this study was to evaluate the effectiveness of the U.S. federal non-price export promotion programs on U.S. export demand in North America. A single-equation framework was specified for estimation of the peanut export demand model. Results indicate that the own-price of the importing country had a negative relationship with U.S. peanut exports, while the price of Chinese peanut exports and real income (GDP) of the importing country were positively related to U.S. peanuts exports. Export promotion programs had a positive effect on the export demand for U.S. peanut to Mexico while these programs seemed to have no effect in Canada.

Masting behaviour in beech: linking reproduction and climatic variation

2001 ◽  
Vol 79 (9) ◽  
pp. 1039-1047 ◽  
Author(s):  
Gianluca Piovesan ◽  
Jonathan M Adams
Keyword(s):  
North America ◽  
Evolutionary Ecology ◽  
Floral Induction ◽  
Strong Predictor ◽  
Early Summer ◽  
Fagus Grandifolia ◽  
Climatic Variation ◽  
Eastern North America ◽  
Flower Initiation ◽  
Drought Event

The question of what triggers masting in beech (Fagus) has been a source of uncertainty and curiosity. Analysing seed production series from Europe (Fagus sylvatica L.), eastern North America (Fagus grandifolia Ehrh.), and Japan (Fagus crenata Blume), for various periods (lasting between 6 and 34 years) over the last 150 years, we find a close relationship between masting (mast year) and preceding growing season climate events (mast year–1 and mast year–2) in eastern North America and Europe, with tentative indications of this pattern in Japan. A drought in the early summer preceding masting (mast year–1) is a very strong predictor in Europe and eastern North America, but drought events were not found for the Japan series. The predictive power is increased in all three regions if there has been an unusually moist, cool summer the year before the drought (mast year–2). We suggest that, in this initial moist summer (mast year–2), carbohydrate buildup within the trees "primes" them for floral induction the following year (year–1). In the European and eastern North American series, a drought event in the early part of the following summer (mast year–1) acts as a proximal trigger for the release of those reserves into flower initiation and then seed production.Key words: masting, Fagus spp., floral induction, drought, climatic variation, evolutionary ecology.

scholarly journals The Influence of Chronic Ozone Exposure on Global Carbon and Water Cycles

2014 ◽  
Vol 28 (1) ◽  
pp. 292-305 ◽  
Author(s):  
D. Lombardozzi ◽  
Samuel Levis ◽  
G. Bonan ◽  
P. G. Hess ◽  
J. P. Sparks
Keyword(s):  
United States ◽  
Stomatal Conductance ◽  
North America ◽  
Southeast Asia ◽  
Greenhouse Gas ◽  
Eastern North America ◽  
Plant Responses ◽  
Eastern United States ◽  
Community Land Model ◽  
The Impact

Abstract Ozone (O3) is a phytotoxic greenhouse gas that has increased more than threefold at Earth’s surface from preindustrial values. In addition to directly increasing radiative forcing as a greenhouse gas, O3 indirectly impacts climate through altering the plant processes of photosynthesis and transpiration. While global estimates of gross primary productivity (GPP) have incorporated the effects of O3, few studies have explicitly determined the independent effects of O3 on transpiration. In this study, the authors include effects of O3 on photosynthesis and stomatal conductance from a recent literature review to determine the impact on GPP and transpiration and highlight uncertainty in modeling plant responses to O3. Using the Community Land Model, the authors estimate that present-day O3 exposure reduces GPP and transpiration globally by 8%–12% and 2%–2.4%, respectively. The largest reductions were in midlatitudes, with GPP decreasing up to 20% in the eastern United States, Europe, and Southeast Asia and transpiration reductions of up to 15% in the same regions. Larger reductions in GPP compared to transpiration decreased water-use efficiency 5%–10% in the eastern United States, Southeast Asia, Europe, and central Africa; increased surface runoff more than 15% in eastern North America; and altered patterns of energy fluxes in the tropics, high latitudes, and eastern North America. Future climate predictions will be improved if plant responses to O3 are incorporated into models such that stomatal conductance is modified independently of photosynthesis and the effects on transpiration are explicitly considered in surface energy budgets. Improvements will help inform regional decisions for managing changes in hydrology and surface temperatures in response to O3 pollution.

scholarly journals Phylogenomics and biogeography of Wisteria (Fabaceae), with implication on plastome evolution of inverted repeat-lacking clade

2019 ◽  
Author(s):  
Mao-Qin Xia ◽  
Ren-Yu Liao ◽  
Jin-Ting Zhou ◽  
Han-Yang Lin ◽  
Jian-Hua Li ◽  
...  
Keyword(s):  
North America ◽  
Late Miocene ◽  
North American ◽  
Inverted Repeat ◽  
Disjunct Distribution ◽  
Eastern North America ◽  
Eastern Asia ◽  
Asian Continent ◽  
The Impact ◽  
Japanese Islands

Abstract Background: The inverted repeat-lacking clade (IRLC) of Fabaceae is characterized by loss of an IR region in plastomes. Both the loss of an IR region and the life history may have affected the evolution of the plastomes in the clade. Nevertheless, few studies have been done to test the impact explicitly. Wisteria , an important member of IRLC and has a disjunct distribution between eastern Asia and eastern North America, has confused interspecific relationships and biogeography, which need to elucidate in depth. Results: The plastome of six newly sequenced Wisteria species and a Millettia japonica ranged from 130,116 to 132,547 bp. Phylogenetic analyses recognized two major clades in IRLC: Glycyrrhiza - Millettia - Wisteria clade and a clade containing the remaining genera. North American Wisteria species and Asian species formed reciprocal clades. Within Asian clade, each of the two Japanese species was sister to a species in the Asian continent. A ~16kb inversion from ndh F to ycf 1 in all IRLC species. Wisteria and Millettia japonica have two intron of rps 12 gene but all other IRLC species just have one. Synonymous substitution rates ( d S ) of protein coding genes were higher in the IRLC species than non-IRLC species. Woody species have lower substitutions rates than herbs. Wisteria may have originated in East Asia by the boundary of Oligocene and Miocene and the eastern Asian-eastern North American disjunction formed in the Late Miocene, while two vicariance events formed the disjunct distributions between the Asian continent and the Japanese islands in the Quaternary. Conclusions: In the IRLC clade, Wisteria , Milletia japonica and Glycyrrhiza form a clade to the remaining genera, most of which are herbaceous. Both the loss of one IR region and the herbaceous habit elevated mutation rates of the plastomes. Multiple vicariance events between eastern Asia and eastern North America, and between the Asian continent and the Japanese Islands may have promoted speciation of Wisteria since the Late Miocene. Plastomes contain rich genetic diversity for studying genetic structure and migration of populations in response to climatic changes, which benefits conservation of rare and endangered species.

Dampak Kebijakan Moneter Pada Output Di Negara-Negara ASEAN Tahun 1980-2014

2017 ◽  
Vol 4 (1) ◽  
pp. 58-70
Author(s):  
Nur Widiastuti
Keyword(s):  
Monetary Policy ◽  
Interest Rate ◽  
Fixed Effects ◽  
Empirical Studies ◽  
Negative Relationship ◽  
Least Square ◽  
Fixed Effects Model ◽  
State Data ◽  
Ordinary Least Square ◽  
The Impact

The Impact of monetary Policy on Ouput is an ambiguous. The results of previous empirical studies indicate that the impact can be a positive or negative relationship. The purpose of this study is to investigate the impact of monetary policy on Output more detail. The variables to estimatate monetery poicy are used state and board interest rate andrate. This research is conducted by Ordinary Least Square or Instrumental Variabel, method for 5 countries ASEAN. The state data are estimated for the period of 1980 – 2014. Based on the results, it can be concluded that the impact of monetary policy on Output shown are varied.Keyword: Monetary Policy, Output, Panel Data, Fixed Effects Model

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