Canopy disturbance history of old-growth Quercus alba sites in the eastern United States: Examination of long-term trends and broad-scale patterns

2012 ◽  
Vol 267 ◽  
pp. 28-39 ◽  
Author(s):  
Megan L. Buchanan ◽  
Justin L. Hart
Keyword(s):  
United States ◽  
Quercus Alba ◽  
Eastern United States ◽  
Disturbance History ◽  
Old Growth ◽  
Canopy Disturbance ◽  
History Of ◽  
Long Term Trends ◽  
Broad Scale

scholarly journals Long-term trends and drought: spatiotemporal variation in juvenile sex ratios of North American ducks

2021 ◽  
Author(s):  
Sage Ellis ◽  
Madeleine Lohman ◽  
James Sedinger ◽  
Perry Williams ◽  
Thomas Riecke
Keyword(s):  
United States ◽  
North American ◽  
Sex Ratios ◽  
Survival Rates ◽  
The United States ◽  
Avian Communities ◽  
Eastern United States ◽  
Bird Populations ◽  
Long Term Trends

Sex ratios affect population dynamics and individual fitness, and changing sex ratios can be indicative of shifts in sex-specific survival at different life stages. While climate- and landscape-change alter sex ratios of wild bird populations, long-term, landscape scale assessments of sex ratios are rare. Further, little work has been done to understand changes in sex ratios in avian communities. In this manuscript, we analyse long-term (1961-2015) data on five species of ducks across five broad climatic regions of the United States to estimate the effects of drought and long-term trends on the proportion of juvenile females captured at banding. As waterfowl have a 1:1 sex ratio at hatch, we interpret changes in sex ratios of captured juveniles as changes in sex-specific survival rates during early life. Seven of twelve species-region pairs exhibited evidence for long-term trends in the proportion of juvenile females at banding. The proportion of juvenile females at banding increased for duck populations in the western United States and typically declined for duck populations in the eastern United States. We only observed evidence for an effect of drought in two of the twelve species-region pairs, where the proportion of females declined during drought. As changes to North American landscapes and climate continue and intensify, we expect continued changes in sex-specific juvenile survival rates. More broadly, we encourage further research examining the mechanisms underlying long-term trends in juvenile sex ratios in avian communities.

scholarly journals American Engineering Doctoral Enrollments

2015 ◽  
pp. 23-24
Author(s):  
Richard Skinner
Keyword(s):  
Higher Education ◽  
United States ◽  
International Education ◽  
Doctoral Programs ◽  
The United States ◽  
American Higher Education ◽  
Long Term Trends

International education has deep historical roots and has spurred relationships that persist for decades. In the case of the United States and the field of engineering, American dependence since the mid-1960s on other countries' students – especially Indian ones – for enrollments and graduates of engineering doctoral programs has been, is and will likely continue to be significant. But long-term trends portend a time when the appeal of American higher education may be less than has been the case.

scholarly journals The 2009 Late Blight Pandemic in the Eastern United States – Causes and Results

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 296-306 ◽  
Author(s):  
W. E. Fry ◽  
M. T. McGrath ◽  
A. Seaman ◽  
T. A. Zitter ◽  
A. McLeod ◽  
...  
Keyword(s):  
United States ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Current Situation ◽  
Causal Agent ◽  
Community Supported Agriculture ◽  
Eastern United States ◽  
Tomato Crop ◽  
History Of ◽  
Mainstream Press

The tomato late blight pandemic of 2009 made late blight into a household term in much of the eastern United States. Many home gardeners and many organic producers lost most if not all of their tomato crop, and their experiences were reported in the mainstream press. Some CSAs (Community Supported Agriculture) could not provide tomatoes to their members. In response, many questions emerged: How did it happen? What was unusual about this event compared to previous late blight epidemics? What is the current situation in 2012 and what can be done? It's easiest to answer these questions, and to understand the recent epidemics of late blight, if one knows a bit of the history of the disease and the biology of the causal agent, Phytophthora infestans.

“Theoretically all Children are Equal. Practically this can Never be So”: The History of the District Property Tax in California and the Choice of Inequality

2020 ◽  
Vol 122 (2) ◽  
pp. 1-32
Author(s):  
Matthew Gardner Kelly
Keyword(s):  
School Finance ◽  
Research Question ◽  
Property Tax ◽  
School Funding ◽  
State Governments ◽  
Property Taxation ◽  
History Of ◽  
Long Term Trends ◽  
Funding Disparities

Background/Context Dealing mostly in aggregate statistics that mask important regional variations, scholars often assume that district property taxation and the resource disparities this approach to school funding creates are deeply rooted in the history of American education. Purpose/Objective/Research Question/Focus of Study This article explores the history of district property taxation and school funding disparities in California during the 19th and 20th centuries. First, the article documents the limited use of district property taxation for school funding in California and several other Western states during the 19th century, showing that the development of school finance was more complicated than standard accounts suggest. Then, the article examines how a coalition of experts, activists, and politicians worked together during the early 20th century to promote district property taxation and institutionalize the idea that the wealth of local communities, rather than the wealth of the entire state, should determine the resources available for public schooling. Research Design This article draws on primary source documents from state and regional archives, including district-level funding data from nine Northern California counties, to complete a historical analysis. Conclusions/Recommendations The history of California's district property tax suggests the need for continued research on long-term trends in school finance and educational inequality. Popular accounts minimizing the historical role of state governments in school funding obscure how public policies, not just market forces shaping property values, create funding inequalities. In turn, these accounts communicate powerful messages about the supposed inevitability of funding disparities and the responsibility of state governments to correct them. Through increased attention to long-term trends in school funding, scholars can help popular commentators and policymakers avoid assumptions that naturalize inequality and narrow the possibilities for future funding reforms.

scholarly journals Examining the Climatology of Shortwave Radiation in the Northeastern United States

2017 ◽  
Vol 56 (10) ◽  
pp. 2869-2881
Author(s):  
Janel Hanrahan ◽  
Alexandria Maynard ◽  
Sarah Y. Murphy ◽  
Colton Zercher ◽  
Allison Fitzpatrick
Keyword(s):  
Climate Change ◽  
United States ◽  
Renewable Energy ◽  
Renewable Energy Sources ◽  
Predictor Variable ◽  
Shortwave Radiation ◽  
Northeastern United States ◽  
Weather Patterns ◽  
Long Term Trends

AbstractAs demand for renewable energy grows, so does the need for an improved understanding of renewable energy sources. Paradoxically, the climate change mitigation strategy of fossil fuel divestment is in itself subject to shifts in weather patterns resulting from climate change. This is particularly true with solar power, which depends on local cloud cover. However, because observed shortwave radiation data usually span a decade or less, persistent long-term trends may not be identified. A simple linear regression model is created here using diurnal temperature range (DTR) during 2002–15 as a predictor variable to estimate long-term shortwave radiation (SR) values in the northeastern United States. Using an extended DTR dataset, SR values are computed for 1956–2015. Statistically significant decreases in shortwave radiation are identified that are dominated by changes during the summer months. Because this coincides with the season of greatest insolation and the highest potential for energy production, financial implications may be large for the solar energy industry if such trends persist into the future.

Warming is Driving Decreases in Snow Fractions While Runoff Efficiency Remains Mostly Unchanged in Snow-Covered Areas of the Western United States

2018 ◽  
Vol 19 (5) ◽  
pp. 803-814 ◽  
Author(s):  
Gregory J. McCabe ◽  
David M. Wolock ◽  
Melissa Valentin
Keyword(s):  
United States ◽  
Time Series ◽  
Winter Precipitation ◽  
Western United States ◽  
Balance Model ◽  
Winter Temperatures ◽  
Long Term Trends ◽  
Monthly Water Balance ◽  
Surface Water Supply

Abstract Winter snowfall and accumulation is an important component of the surface water supply in the western United States. In these areas, increasing winter temperatures T associated with global warming can influence the amount of winter precipitation P that falls as snow S. In this study we examine long-term trends in the fraction of winter P that falls as S (Sfrac) for 175 hydrologic units (HUs) in snow-covered areas of the western United States for the period 1951–2014. Because S is a substantial contributor to runoff R across most of the western United States, we also examine long-term trends in water-year runoff efficiency [computed as water-year R/water-year P (Reff)] for the same 175 HUs. In that most S records are short in length, we use model-simulated S and R from a monthly water balance model. Results for Sfrac indicate long-term negative trends for most of the 175 HUs, with negative trends for 139 (~79%) of the HUs being statistically significant at a 95% confidence level (p = 0.05). Additionally, results indicate that the long-term negative trends in Sfrac have been largely driven by increases in T. In contrast, time series of Reff for the 175 HUs indicate a mix of positive and negative long-term trends, with few trends being statistically significant (at p = 0.05). Although there has been a notable shift in the timing of R to earlier in the year for most HUs, there have not been substantial decreases in water-year R for the 175 HUs.

Sign in / Sign up

Export Citation Format

Share Document