scholarly journals Environmental and Management Effects on Demographic Processes in the U.S. Threatened Platanthera leucophaea (Nutt.) Lindl. (Orchidaceae)

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1308
Author(s):  
Timothy J. Bell ◽  
Marlin L. Bowles ◽  
Lawrence W. Zettler ◽  
Catherine A. Pollack ◽  
James E. Ibberson
Keyword(s):  
Moisture Stress ◽  
Fire Frequency ◽  
Climatic Variation ◽  
Interactive Effects ◽  
Population Demography ◽  
Mortality Trends ◽  
Demographic Modeling ◽  
The U.S ◽  
Management Effects ◽  
Platanthera Leucophaea

Populations of the U.S. threatened orchid, Platanthera leucophaea, are restricted to fragmented grassland and wetland habitats. We address the long-term (1998–2020) interactive effects of habitat (upland prairie vs. wetland), fire management (burned vs. unburned) and climatic variation, as well as pollination crossing effects, on population demography in 42 populations. Our analysis revealed the consistent interactive effects of habitat, dormant season burning, and climatic variation on flowering, reproduction, and survival. Burning increased flowering and population size under normal or greater than normal precipitation but may have a negative effect during drought years apparently if soil moisture stress reduces flowering and increases mortality. Trends in the number of flowering plants in populations also correspond to precipitation cycles. As with flowering and fecundity, survival is significantly affected by the interactive effects of habitat, fire, and climate. This study supports previous studies finding that P. leucophaea relies on a facultative outcrossing breeding system. Demographic modeling indicated that fire, normal precipitation, and outcrossing yielded greater population growth, and that greater fire frequency increased population persistence. It also revealed an ecologically driven demographic switch, with wetlands more dependent upon survivorship than fecundity, and uplands more dependent on fecundity than survivorship. Our results facilitate an understanding of environmental and management effects on the population demography of P. leucophaea in the prairie region of its distribution. Parallel studies are needed in the other habitats such as wetlands, especially in the eastern part of the range of the species, to provide a more complete picture.

Human drivers, biophysical changes, and climatic variation affecting contemporary cropping proportions in the northern prairie of the U.S

2017 ◽  
Vol 13 (1-2) ◽  
pp. 32-58 ◽  
Author(s):  
Roger F. Auch ◽  
George Xian ◽  
Christopher R. Laingen ◽  
Kristi L. Sayler ◽  
Ryan R. Reker
Keyword(s):  
Climatic Variation ◽  
Biophysical Changes ◽  
The U.S

scholarly journals Interactive effects of ambient ozone and climate measured on growth of mature loblolly pine trees

1996 ◽  
Vol 26 (4) ◽  
pp. 670-681 ◽  
Author(s):  
S.B. McLaughlin ◽  
D.J. Downing
Keyword(s):  
Soil Moisture ◽  
Loblolly Pine ◽  
Moisture Stress ◽  
Growth Patterns ◽  
Forest Growth ◽  
Interactive Effects ◽  
Forest Trees ◽  
Short Term ◽  
Data Set ◽  
Ambient Ozone

Seasonal growth patterns of mature loblolly pine (Pinustaeda L.) trees over the interval 1988–1993 have been analyzed to evaluate the effects of ambient ozone on growth of large forest trees. Patterns of stem expansion and contraction of 34 trees were examined using serial measurements with sensitive dendrometer band systems. Study sites, located in eastern Tennessee, varied significantly in soil moisture, soil fertility, and stand density. Levels of ozone, rainfall, and temperature varied widely over the 6-year study interval. Regression analysis identified statistically significant influences of ozone on stem growth patterns, with responses differing widely among trees and across years. Ozone interacted with both soil moisture stress and high temperatures, explaining 63% of the high frequency, climatic variance in stem expansion identified by stepwise regression of the 5-year data set. Observed responses to ozone were rapid, typically occurring within 1–3 days of exposure to ozone at ≥40 ppb and were significantly amplified by low soil moisture and high air temperatures. Both short-term responses, apparently tied to ozone-induced increases in whole-tree water stress, and longer term cumulative responses were identified. These data indicate that relatively low levels of ambient ozone can significantly reduce growth of mature forest trees and that interactions between ambient ozone and climate are likely to be important modifiers of future forest growth and function. Additional studies of mechanisms of short-term response and interspecies comparisons are clearly needed.

Interactive effects of air pollutants and atmospheric moisture stress on aspen growth and photosynthesis along an urban-rural gradient

2020 ◽  
Vol 260 ◽  
pp. 114076 ◽  
Author(s):  
Zhenhua Wang ◽  
Chengzhang Wang ◽  
Bin Wang ◽  
Xin Wang ◽  
Jing Li ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Moisture Stress ◽  
Interactive Effects ◽  
Atmospheric Moisture ◽  
Urban Rural

Stubble management effects on canola performance across different climatic regions of western Canada

2015 ◽  
Vol 95 (1) ◽  
pp. 149-159 ◽  
Author(s):  
Michael J. Cardillo ◽  
Paul Bullock ◽  
Rob Gulden ◽  
Aaron Glenn ◽  
Herb Cutforth
Keyword(s):  
Snow Water Equivalent ◽  
Growing Season ◽  
Moisture Stress ◽  
Climatic Conditions ◽  
Western Canada ◽  
Spring Precipitation ◽  
Canadian Prairies ◽  
Climatic Regions ◽  
Snow Water ◽  
Management Effects

Cardillo, M. J., Bullock, P., Gulden, R., Glenn, A. and Cutforth, H. 2015. Stubble management effects on canola performance across different climatic regions of western Canada. Can. J. Plant Sci. 95: 149–159. Previous research in the most arid region of the Canadian prairies has shown that wheat stubble cut tall the previous year can improve performance of the following canola crop. This study aimed to determine if tall stubble could benefit canola across the climatic conditions typically experienced in western Canada. Tall stubble impacts on canola were monitored over 11 site-years located throughout the prairies. At each site, tall stubble (50 cm) was compared with short stubble (20 cm). At some sites the stubble lodged allowing an unintended comparison between stubble that remained intact and stubble that was flattened. The comparison of snow water equivalent showed tall stubble caught more snow than short stubble but the benefit of additional spring soil moisture was masked by heavy spring precipitation in both 2011 and 2012. Canola biomass and yield were significantly lower in damaged versus intact stubble, either short or tall. In both years, wet spring conditions were followed by hotter and drier weather in the mid to late growing season. Soil under the damaged stubble (short or tall) likely warmed and dried more slowly in the spring, limiting early-season growth, biomass and yield. At sites where both tall and short stubble remained intact, there was a significant yield advantage with tall stubble. The intact tall stubble may have slowed evaporation and soil drying compared with intact short stubble, which reduced moisture stress later in the growing season, imparting a yield advantage.

Effects of earthworms and warming on tree seedling growth: a small-scale microcosm experiment

2020 ◽  
Vol 50 (11) ◽  
pp. 1253-1257
Author(s):  
Justin M. Gaudon ◽  
Michael J. McTavish ◽  
Sivajanani Sivarajah ◽  
Emmett H.U. Snyder ◽  
Samara M.M. Andrade ◽  
...  
Keyword(s):  
Plant Growth ◽  
Sugar Maple ◽  
Moisture Stress ◽  
Interactive Effects ◽  
Soil Conditions ◽  
Small Scale ◽  
Width Ratio ◽  
Long Term Effects ◽  
Tree Seedling ◽  
Microcosm Experiment

Warming global temperatures are expected to strongly influence plant communities, yet there is limited knowledge of how these changes will interact with stressors such as the invasion of exotic earthworms. We conducted a small-scale microcosm experiment to assess the individual and interactive effects of warming and exotic anecic earthworms (Lumbricus terrestris L.) on the growth of sugar maple (Acer saccharum Marsh.) seedlings. After 50 days, the elevated-temperature chamber created warmer and drier soil conditions and increased several measures of plant growth, including stem width, ratio of stem width to stem height, stem biomass, and fine-root biomass. Earthworms did not have any clear impacts on plant growth on their own nor in interactions with the temperature chambers. However, earthworms both reduced surface leaf litter cover and exposed soils, which could exacerbate evaporative losses and moisture stress in field soils resulting from a warming climate under different growing conditions. Future studies should consider the long-term effects of earthworm–temperature interactions on sugar maple growth, as well as diurnal and seasonal changes in temperature.

scholarly journals Contribution of Marijuana Legalization to the U.S. Opioid Mortality Epidemic: Individual and Combined Experience of 27 States and District of Columbia

2019 ◽  
Author(s):  
Archie Bleyer ◽  
Brian Barnes
Keyword(s):  
Death Rate ◽  
District Of Columbia ◽  
Mortality Data ◽  
Joinpoint Regression ◽  
Mortality Trends ◽  
Significant Acceleration ◽  
Before And After ◽  
Control And Prevention ◽  
The U.S ◽  
Significant Mortality

AbstractBackgroundPrior studies of U.S. states as of 2013 and one state as of 2015 suggested that marijuana availability reduces opioid mortality (marijuana protection hypothesis). This investigation tested the hypothesis with opioid mortality trends updated to 2017 and by evaluating all states and the District of Columbia (D.C.).MethodsOpioid mortality data obtained from the U.S. Centers for Disease Control and Prevention were used to compare opioid death rate trends in each marijuana-legalizing state and D.C. before and after medicinal and recreational legalization implementation and their individual and cumulative aggregate trends with concomitant trends in non-legalizing states. The Joinpoint Regression Program identified statistically-significant mortality trends and when they occurred.ResultsOf 23 individually evaluable legalizing jurisdictions, 78% had evidence for a statistically-significant acceleration of opioid death rates after medicinal or recreational legalization implementation at greater rates than their pre-legalization rate or the concurrent composite rate in non-legalizing states. All four jurisdictions evaluable for recreational legalization had evidence (p <0.05) for subsequent opioid death rate increases, one had a distinct acceleration, and one a reversal of prior decline. Since 2009-2012, when the cumulative-aggregate opioid death rate in the legalizing jurisdictions was the same as in the non-legalizing group, the legalizing group’s rate accelerated increasingly faster (p=0.009). By 2017 it was 67% greater than in the non-legalizing group (p <<0.05).ConclusionsThe marijuana protection hypothesis is not supported by recent U.S. data on opioid mortality trends. Instead, legalizing marijuana appears to have contributed to the nation’s opioid mortality epidemic.

scholarly journals Study on Climatic Variation and Its Effect on Vegetable Type Soybean Genotypes at Khumaltar, Lalitpur in the Last Ten Years

2015 ◽  
Vol 3 (6) ◽  
pp. 484
Author(s):  
Santosh Raj Tripathi ◽  
Jiban Shrestha ◽  
Jagat Devi Ranjit ◽  
Reshma Neupane
Keyword(s):  
Seed Yield ◽  
Disease Incidence ◽  
Moisture Stress ◽  
Climatic Variation ◽  
Vegetative Stage ◽  
High Moisture ◽  
Growing Period ◽  
Soybean Genotypes ◽  
Glycine Max L ◽  
Increase Soil Moisture

Soybean (Glycine max L. Merril) is widely grown in the mid hills as intercrop with maize or in paddy bunds, while it is gaining popularity as sole crop in terai and inner terai. Mean temperature at Khumaltar during soybean growing period was mostly fluctuating; but we observed an increasing trend in temperature. Amount of rainfall was not changed dramatically but number of rainy days was decreased during study period. Rainfall during germination time increase soil moisture which also increase germination and found higher early stand. Days from sowing to 50% flowering and 90% maturity were short in the case of higher minimum temperature and low rainfall. Among the genotypes, AGS-377, AGS-378, AGS-379 and Tarkari Bhattmas-1 were more sensitive. However, seed yield decreased in the case of higher temperatures and low rainfall. Cool night temperatures and high moisture increased disease incidence in soybean which, eventually reduced yield. In last three years, plant suffered from moisture stress during early vegetative stage and high moisture during late vegetative stage which reduced seed yield and seed weight. In conclusion, we found that genotypes like AGS- 360, Sathiya and Tarkari Bhatmas-1 are very sensitive to climatic variation.

Linking Environmental Change to Strategic Response: Some Empirical Evidence from the U.S. Oil Industry

1995 ◽  
Vol 77 (3_suppl) ◽  
pp. 1123-1135 ◽  
Author(s):  
John L. Little ◽  
Mingfang Li ◽  
Roy Simerly
Keyword(s):  
Environmental Change ◽  
Environmental Variables ◽  
Resource Dependence ◽  
Longitudinal Design ◽  
External Environment ◽  
Oil Industry ◽  
Strategic Orientation ◽  
Interactive Effects ◽  
Strategic Response ◽  
The U.S

A longitudinal design was used to examine the effects of changes in both environmental uncertainty and resource dependence in the external environment on the change in strategic orientation of organizations in the oil industry, using revenue flows during three distinguishable phases of growth. The authors argue that the interactive effects of these two environmental variables yield more meaningful results than either variable observed separately. Implications of the study are discussed, along with recommendations for research.

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