scholarly journals Reconstructing Great Basin Butterfly-Pollen Interaction Networks over the Past Century

2020 ◽  
Author(s):  
Behnaz Balmaki ◽  
Tara Christensen ◽  
Lee A. Dyer
Keyword(s):  
Time Series ◽  
Sierra Nevada ◽  
Great Basin ◽  
Species Interactions ◽  
Interaction Networks ◽  
Spatial And Temporal Variation ◽  
Past Century ◽  
Butterfly Species ◽  
The Past ◽  
Before And After

AbstractAimsInsects and the plants they interact with dominate terrestrial biomes and constitute over half of the earth’s macro-organismal diversity. Their abundance in museum collections can provide a wealth of natural history data if they are collected as part of careful ecological studies or conservation programs. Here, we summarize pollen-insect quantitative networks gleaned from adult lepidopteran museum specimens to characterize these interactions and to examine how richness and frequency of butterfly-pollen associations have changed over a 100-year time series in Nevada and California. Pollen collected from well-curated butterfly specimens can provide insight into spatial and temporal variation in pollen-butterfly interactions and provide a complement to other approaches to studying pollination, such as pollinator observation networks.LocationGreat Basin and Sierra Nevada: California, NevadaTime periodThe last 100 yearsMajor Taxon studiedButterfliesMethodsWe estimated butterfly-pollen network parameters based on pollen collected from butterfly specimens from the Great Basin and Sierra Nevada. Additionally, we pooled interaction networks associated with specimens captured before and after 2000 to compare pollen-pollinator interaction variation under drought periods in California and Nevada in the last two decades versus previous years in the time series.ResultsButterfly-pollen networks indicated that most pollen-butterfly species interactions are specialized and appear to be different from observational networks. Interaction networks associated with specimens captured before and after 2000 revealed that compared to previous decades, butterfly-pollen networks over the past 20 years had higher nestedness and connectance, with high pollen richness and low pollen abundance.Main conclusionsThese findings represent another unique approach to understanding more about pollination biology, and how butterfly-pollen interactions are impacted by climate variation and ecosystem alteration.

scholarly journals Contribution of the Black Sea observing system to ECOOP

2011 ◽  
Vol 8 (4) ◽  
pp. 1695-1722 ◽  
Author(s):  
G. K. Korotaev ◽  
V. L. Dorofeev ◽  
S. V. Motyzhev ◽  
V. N. Belokopytov ◽  
A. Palazov ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Black Sea ◽  
The Black Sea ◽  
Past Century ◽  
Network Integration ◽  
The Past ◽  
Time Operation ◽  
Real Time Operation ◽  
Set Up

Abstract. Regular observations in the Black Sea basin started in the past century, and quite good multidisciplinary observing system operated in the 70–80ies based on the ship observations. Modern oceanographic observing system in the basin is built according to the GOOS principles. It includes space remote sensing observations, data of free floating buoys and costal observational network. Integration of the observing system and its real-time operation were started within the framework of the FP5 ARENA project and later were improved during the FP6 ASCABOS project. The coastal observing system which includes time series from the coastal platforms and multidisciplinary surveys of the coastal areas fulfilled by the research vessels was set up during the ECOOP. Paper describes all components of the Black Sea observing system operated during the ECOOP project and its applications in the framework of the project.

A comparison of western Great Basin paleoclimate records for the last 3000 yr: Evidence for multidecadal- to millennial-scale drought

2021 ◽  
pp. 183-199
Author(s):  
Steve P. Lund ◽  
Larry V. Benson
Keyword(s):  
Sierra Nevada ◽  
Tree Ring ◽  
Great Basin ◽  
Lake Level ◽  
Lake Basin ◽  
Walker Lake ◽  
Pyramid Lake ◽  
The Past ◽  
Hydrological Variability ◽  
Hydrologic Variability

ABSTRACT This paper summarizes the hydrological variability in eastern California (central Sierra Nevada) for the past 3000 yr based on three distinct paleoclimate proxies, δ18O, total inorganic carbon (TIC), and magnetic susceptibility (chi). These proxies, which are recorded in lake sediments of Pyramid Lake and Walker Lake, Nevada, and Mono Lake and Owens Lake, California, indicate lake-level changes that are mostly due to variations in Sierra Nevada snowpack and rainfall. We evaluated lake-level changes in the four Great Basin lake systems with regard to sediment-core locations and lake-basin morphologies, to the extent that these two factors influence the paleoclimate proxy records. We documented the strengths and weaknesses of each proxy and argue that a systematic study of all three proxies together significantly enhances our ability to characterize the regional pattern, chronology, and resolution of hydrological variability. We used paleomagnetic secular variation (PSV) to develop paleomagnetic chronostratigraphies for all four lakes. We previously published PSV records for three of the lakes (Mono, Owens, Pyramid) and developed a new PSV record herein for Walker Lake. We show that our PSV chronostratigraphies are almost identical to previously established radiocarbon-based chronologies, but that there are differences of 20–200 yr in individual age records. In addition, we used eight of the PSV inclination features to provide isochrons that permit exacting correlations between lake records. We also evaluated the temporal resolution of our proxies. Most can document decadal-scale variability over the past 1000 yr, multidecadal-scale variability for the past 2000 yr, and centennial-scale variability between 2000 and 3000 yr ago. Comparisons among our proxies show a strong coherence in the pattern of lake-level variability for all four lakes. Pyramid Lake and Walker Lake have the longest and highest-resolution records. The δ18O and TIC records yield the same pattern of lake-level variability; however, TIC may allow a somewhat higher-frequency resolution. It is not clear, however, which proxy best estimates the absolute amplitude of lake-level variability. Chi is the only available proxy that records lake-level variability in all four lakes prior to 2000 yr ago, and it shows consistent evidence of a large multicentennial period of drought. TIC, chi, and δ18O are integrative proxies in that they display the cumulative record of hydrologic variability in each lake basin. Tree-ring estimations of hydrological variability, by contrast, are incremental proxies that estimate annual variability. We compared our integrated proxies with tree-ring incremental proxies and found a strong correspondence among the two groups of proxies if the tree-ring proxies are smoothed to decadal or multidecadal averages. Together, these results indicate a common pattern of wet/dry variability in California (Sierra Nevada snowpack/rainfall) extending from a few years (notable only in the tree-ring data) to perhaps 1000 yr. Notable hydrologic variability has occurred at all time scales and should continue into the future.

The Role of Fire in Natural Communities: An Example from the Southern Sierra Nevada, California

1976 ◽  
Vol 3 (2) ◽  
pp. 91-99 ◽  
Author(s):  
David J. Parsons
Keyword(s):  
Sierra Nevada ◽  
Woody Species ◽  
Past Century ◽  
The Past ◽  
Shrub Community ◽  
Healthy State ◽  
Low Diversity ◽  
Vegetational Succession ◽  
Dead Material

The exclusion of fire from the low-elevation foothills of the southern Sierra Nevada of California over the past century has resulted in large expanses of over-mature, senescent chaparral. The fuel buildup associated with this situation poses a threat, in that any fire which gets started has the potential of becoming a major holocaust.A detailed analysis is made of the vegetational succession following fire in four different-aged stands of Chamise chaparral in the southern Sierra Nevada. Progression from a diverse multi-species herb and shrub community towards a dense, structurally uniform, low-diversity stand dominated by a single woody species, Adenostoma fasciculatum (Chamise), is demonstrated. An increase in shrub cover and height along with the amount of dead material found laddered through the canopy, create optimal conditions for combustion within some 35 years following the last fire. The herbaceous vegetation shows a high diversity and cover in the first few years after burning, but rapidly decreases thereafter. Evidence is presented that frequent fires are required to maintain the chaparral community in a vigorous and healthy state. The need to institute progressive fuel-management programmes which recognize the natural role of fire in the evolution of the chaparral type wherever it is found, is discussed and advocated. Attempts are also made to relate these findings to the preservation of other fire-adapted vegetation types of the world.

scholarly journals Energy flow and functional compensation in Great Basin small mammals under natural and anthropogenic environmental change

2015 ◽  
Vol 112 (31) ◽  
pp. 9656-9661 ◽  
Author(s):  
Rebecca C. Terry ◽  
Rebecca J. Rowe
Keyword(s):  
Environmental Change ◽  
Great Basin ◽  
Small Mammal ◽  
Energy Flow ◽  
Substantial Reduction ◽  
Ecological Impacts ◽  
Past Century ◽  
The Past ◽  
Small Mammal Community ◽  
Mammal Community

Research on the ecological impacts of environmental change has primarily focused at the species level, leaving the responses of ecosystem-level properties like energy flow poorly understood. This is especially so over millennial timescales inaccessible to direct observation. Here we examine how energy flow within a Great Basin small mammal community responded to climate-driven environmental change during the past 12,800 y, and use this baseline to evaluate responses observed during the past century. Our analyses reveal marked stability in energy flow during rapid climatic warming at the terminal Pleistocene despite dramatic turnover in the distribution of mammalian body sizes and habitat-associated functional groups. Functional group turnover was strongly correlated with climate-driven changes in regional vegetation, with climate and vegetation change preceding energetic shifts in the small mammal community. In contrast, the past century has witnessed a substantial reduction in energy flow caused by an increase in energetic dominance of small-bodied species with an affinity for closed grass habitats. This suggests that modern changes in land cover caused by anthropogenic activities—particularly the spread of nonnative annual grasslands—has led to a breakdown in the compensatory dynamics of energy flow. Human activities are thus modifying the small mammal community in ways that differ from climate-driven expectations, resulting in an energetically novel ecosystem. Our study illustrates the need to integrate across ecological and temporal scales to provide robust insights for long-term conservation and management.

scholarly journals Testing climate tracking of montane rodent distributions over the past century within the Great Basin ecoregion

2020 ◽  
Vol 24 ◽  
pp. e01238
Author(s):  
Melissa I. Pardi ◽  
Rebecca C. Terry ◽  
Eric A. Rickart ◽  
Rebecca J. Rowe
Keyword(s):  
Great Basin ◽  
Past Century ◽  
The Past

Climate-related spatial and temporal variation in bill morphology over the past century in Australian parrots

2015 ◽  
Vol 42 (6) ◽  
pp. 1163-1175 ◽  
Author(s):  
Daniel J. E. Campbell-Tennant ◽  
Janet L. Gardner ◽  
Michael R. Kearney ◽  
Matthew R. E. Symonds
Keyword(s):  
Temporal Variation ◽  
Spatial And Temporal Variation ◽  
Past Century ◽  
The Past ◽  
Bill Morphology

Cycles in American National Electoral Politics, 1854–2006: Statistical Evidence and an Explanatory Model

2008 ◽  
Vol 102 (1) ◽  
pp. 1-17 ◽  
Author(s):  
SAMUEL MERRILL ◽  
BERNARD GROFMAN ◽  
THOMAS L. BRUNELL
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Feedback Loop ◽  
Interaction Model ◽  
Electoral Politics ◽  
Party Politics ◽  
Negative Feedback Loop ◽  
Past Century ◽  
The Past ◽  
Political Forces

Are there cycles in American politics? In particular, does the proportion of the Democratic/Republican vote share for president and/or seat share in Congress rise and fall over extended periods of time? If so, are the cycles regular, and what are the cycling periods? Moreover, if there are regular cycles, can we construct an integrated model—such as a negative feedback loop—that identifies political forces that could generate the observed patterns? First, we use spectral analysis to test for the presence and length of cycles, and show that regular cycles do, in fact, exist—with periods that conform to those predicted by the Schlesingers—for swings between liberalism and conservatism—but with durations much shorter than those most commonly claimed by Burnham and others in characterizing American political realignments. Second, we offer a voter–party interaction model that depends on the tensions between parties' policy and office motivations and between voters' tendency to sustain incumbents while reacting against extreme policies. We find a plausible fit between the regular cycling that this model projects and the time series of two-party politics in America over the past century and a half.

scholarly journals A New State-Level Panel of Annual Inequality Measures Over The Period 1916-2005

1970 ◽  
Vol 31 (1) ◽  
pp. 241-263
Author(s):  
Mark Frank
Keyword(s):  
Time Series ◽  
Income Inequality ◽  
State Level ◽  
Past Century ◽  
Strongly Correlated ◽  
Cross Sectional ◽  
Inequality Measures ◽  
The Past ◽  
Shaped Pattern ◽  
New Millennium

This paper introduces a new panel of annual state-level income inequalitymeasures over the ninety year period 1916-2005. Among many of the states inequalityfollowed a U-shaped pattern over the past century, peaking both before the GreatDepression and again at the time of the new millennium. The new panel revealssignificant state-level variations, both before the year 1945, and regionally. WhileNortheastern states are strongly correlated with aggregate U.S. trends, we find manyof the Western states have little overall correlation over the past century. The availabilityof this new panel may prove useful to empirical researchers interested in allaspects of income inequality, particularly given the panel’s unusually large numberof both time-series and cross-sectional observations.

Grading of Diffuse Astrocytic Gliomas: A Review of Studies Before and After the Advent of IDH Testing

2018 ◽  
Vol 38 (01) ◽  
pp. 019-023 ◽  
Author(s):  
Takahiro Ono ◽  
Mitsuaki Shirahata ◽  
David Louis ◽  
Andreas von Deimling
Keyword(s):  
Diagnostic Testing ◽  
World Health ◽  
Histological Evaluation ◽  
Molecular Diagnostic ◽  
Past Century ◽  
The Past ◽  
Before And After ◽  
Microscopic Features ◽  
Astrocytic Gliomas

AbstractEstimating the malignancy level of tumors is key to management, and has been part of oncology practice for the past ∼100 years. A central aspect of assessing malignancy level is based on histological “grading”—a process in which a pathologist evaluates microscopic features of a tumor and interprets those findings in light of large prognostic studies. For the diffuse astrocytic gliomas, there have been many such studies over the past century and these have proven useful in estimating prognosis for patients. With the advent of molecular genetics, molecular diagnostic testing has been added to histological evaluation in the armamentarium of the pathologist, and the recent World Health Organization (WHO) Classification of Tumors of the Central Nervous System encourages testing for isocitrate dehydrogenase (IDH) gene status in the classification of diffuse astrocytic gliomas. The present review catalogues a large series of diffuse astrocytic glioma grading studies over the past few decades, and compares the prognostic value of such grading schema before and after the emergence of IDH testing. The review concludes that novel approaches to diffuse astrocytic tumor grading are required in the era of IDH testing.

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