scholarly journals Long-term trends in the occupancy of ants revealed through use of multi-sourced datasets

2021 ◽  
Vol 17 (10) ◽  
Author(s):  
Julie K. Sheard ◽  
Carsten Rahbek ◽  
Robert R. Dunn ◽  
Nathan J. Sanders ◽  
Nick J. B. Isaac
Keyword(s):  
Life History ◽  
Science Data ◽  
Occupancy Modelling ◽  
Habitat Changes ◽  
Participatory Science ◽  
Long Term Changes ◽  
Biodiversity Change ◽  
Long Term Trends ◽  
Insect Decline

We combined participatory science data and museum records to understand long-term changes in occupancy for 29 ant species in Denmark over 119 years. Bayesian occupancy modelling indicated change in occupancy for 15 species: five increased, four declined and six showed fluctuating trends. We consider how trends may have been influenced by life-history and habitat changes. Our results build on an emerging picture that biodiversity change in insects is more complex than implied by the simple insect decline narrative.

scholarly journals Long-term trends in the relation between daytime and nighttime values of <I>fo</I>F2

2008 ◽  
Vol 26 (5) ◽  
pp. 1199-1206 ◽  
Author(s):  
A. D. Danilov
Keyword(s):  
Solar Activity ◽  
Term Trend ◽  
The World ◽  
Long Term Changes ◽  
Long Term Trends ◽  
Thermospheric Winds ◽  
Long Term Trend ◽  
Ionospheric Sounding ◽  
Limiting Value

Abstract. The data from the vertical ionospheric sounding for 12 stations over the world were analyzed to find the relation between the values of foF2 for 02:00 LT and 14:00 LT of the same day. It is found that, in general, there exists a negative correlation between foF2(02) and foF2(14). The value of the correlation coefficient R(foF2) can be in some cases high enough and reach minus 0.7–0.8. The value of R(foF2) demonstrates a well pronounced seasonal variations, the highest negative values being observed at the equinox periods of the year. It is also found that R(foF2) depends on geomagnetic activity: the magnitude of R(foF2) is the highest for the choice of only magnetically quiet days (Ap<6), decreasing with the increase of the limiting value of Ap. For a fixed limitation on Ap, the value of R(foF2) depends also on solar activity. Apparently, the effects found are related to thermospheric winds. Analysis of long series of the vertical sounding data shows that there is a long-term trend in R(foF2) with a statistically significant increase in the R(foF2) magnitude after about 1980. Similar analysis is performed for the foF2(02)/foF2(14) ratio itself. The ratio also demonstrates a systematic trend after 1980. Both trends are interpreted in terms of long-term changes in thermospheric circulation.

Quantifying and attributing changes in tropospheric ozone from a combination of satellite measurements and models

2020 ◽  
Author(s):  
Jessica Neu ◽  
Kazuyuki Miyazaki ◽  
Kevin Bowman ◽  
Gregory Osterman
Keyword(s):  
Time Series ◽  
Tropospheric Ozone ◽  
Earth Science ◽  
Satellite Measurements ◽  
Science Data ◽  
The Past ◽  
Long Term Changes ◽  
Earth Science Data

&lt;p&gt;Given the importance of tropospheric ozone as a greenhouse gas and a hazardous pollutant that impacts human health and ecosystems, it is critical to quantify and understand long-term changes in its abundance.&amp;#160; Satellite records are beginning to approach the length needed to assess variability and trends in tropospheric ozone, yet an intercomparison of time series from different instruments shows substantial differences in the net change in ozone over the past decade.&amp;#160; We discuss our efforts to produce Earth Science Data Records of tropospheric ozone and quantify uncertainties and biases in these records.&amp;#160; We also discuss the role of changes in the magnitude and distribution of precursor emissions and in downward transport of ozone from the stratosphere in determining tropospheric ozone abundances over the past 15 years.&lt;/p&gt;

scholarly journals Infrared Light Curves of Carbon-Rich Variables

2000 ◽  
Vol 177 ◽  
pp. 179-190 ◽  
Author(s):  
Patricia Whitelock
Keyword(s):  
Large Amplitude ◽  
Light Curves ◽  
Infrared Light ◽  
Dust Shells ◽  
Long Term Changes ◽  
Long Term Trends

Long-term trends in the infrared (JHKL) light curves of various carbon variables are described. Some stars, e.g. the semi-regular variables R Scl and GM CMa, show multiple periodicities; others, particularly the Miras with moderately thick dust-shells, show more erratic long-term changes. The light curves for R For, which have been intensively monitored over 20 years, show a pattern which is reminiscent of that seen for R CrB stars. This pattern is superimposed on regular large-amplitude Mira pulsations. The multi-periodic and erratic behaviour of these stars is compared with the predictions from various models.

scholarly journals Long-term trends in carabids over 25 years – community and population level analyses

2019 ◽  
Vol 2 ◽  
Author(s):  
Claudia Drees ◽  
Estève Boutaud ◽  
Katharina Homburg ◽  
Dorothea Nolte ◽  
Wiebke Schuett ◽  
...  
Keyword(s):  
Ground Beetle ◽  
Population Level ◽  
Abundant Species ◽  
Temporal Changes ◽  
Northern Germany ◽  
Long Term Trends ◽  
Using Data ◽  
Insect Decline ◽  
Term Data

In times of insect decline, long-term data become more and more important. Such data allow insights into long-term trends and an analysis of possible drivers underlying temporal changes of community and population structure. Using data from 25 years of continuous ground beetle trapping in an ancient woodland located in a large nature reserve in Northern Germany, we analysed temporal changes at both community and population level and identified potential underlying drivers. Ground beetle species significantly declined over time but biomass and number of trapped individuals remained constant. As the habitat was kept stable und unchanged in the last 25 years we also study the influence of external drivers such as climatic variables on phenology and population trends of the most-abundant species. We discuss our results in light of the ongoing insect decline and climate change.

scholarly journals The method of determination of the long-term trends in the F2 region independent of geomagnetic activity

2002 ◽  
Vol 20 (4) ◽  
pp. 511-521 ◽  
Author(s):  
A. D. Danilov
Keyword(s):  
Geomagnetic Activity ◽  
Regression Line ◽  
Close Relation ◽  
Layer Parameter ◽  
Modeling And Forecasting ◽  
Long Term Changes ◽  
Long Term Trends ◽  
Ap Index

Abstract. A detailed analysis of the f oF2 data at the Sverdlovsk station is performed to answer the question: whether the long-term trends of the F2-layer parameter detected recently are mainly due to the long-term changes in geomagnetic activity during the recent decades. Two methods to derive trends independent of geomagnetic activity are developed. It is found that both methods agree well and give a relative nongeomagnetic trend of about - 0.0015 per year (or an absolute nongeomagnetic trend of about - 0.015 MHz per year). The close relation of foF2 to Ap found by several authors is mainly due to a high correlation between the foF2 deviations from the regression line and year-to-year changes in the Ap index rather than to systematic long-term changes of Ap as has been suggested earlier.Key words. Ionosphere (ionospheric distances; modeling and forecasting)

scholarly journals The pace of plant community change is accelerating in remnant prairies

2016 ◽  
Vol 2 (2) ◽  
pp. e1500975 ◽  
Author(s):  
Amy O. Alstad ◽  
Ellen I. Damschen ◽  
Thomas J. Givnish ◽  
John A. Harrington ◽  
Mark K. Leach ◽  
...  
Keyword(s):  
Fire History ◽  
Community Change ◽  
Ecological Change ◽  
Single Pair ◽  
Biodiversity Change ◽  
Long Term Trends ◽  
Using Data ◽  
The Impact ◽  
Historical Samples

Patterns of biodiversity are changing rapidly. “Legacy studies” use historical data to document changes between past and present communities, revealing long-term trends that can often be linked to particular drivers of ecological change. However, a single pair of historical samples cannot ascertain whether rates of change are consistent or whether the impact and identity of drivers have shifted. Using data from a second resurvey of 47 Wisconsin prairie remnants, we show that the pace of community change has increased with shifts in the strength of particular drivers. Annual rates of local colonization and extinction accelerated by 129 and 214%, respectively, between 1950 and 1987 and between 1987 and 2012. Two anthropogenic drivers—patch area and fire history—increased in importance between these periods. As the strength and number of anthropogenic forces increase, rates of biodiversity change are likely to accelerate in other ecosystems as well.

scholarly journals Spectral UV measurements in Austria from 1994 to 2006: investigations of short- and long-term changes

2008 ◽  
Vol 8 (1) ◽  
pp. 2403-2428
Author(s):  
S. Simic ◽  
P. Weihs ◽  
A. Vacek ◽  
H. Kromp-Kolb ◽  
M. Fitzka
Keyword(s):  
Trend Test ◽  
Atmospheric Variability ◽  
Short Term ◽  
Time Period ◽  
Uv Irradiance ◽  
Long Term Changes ◽  
Long Term Trends ◽  
Short And Long Term ◽  
Double Monochromator

Abstract. Influences of atmospheric variability on short- and long-term changes of spectral UV irradiance measured at the Sonnblick observatory (47.03 N, 12.57 E, 3106 m) during the period from 1994 to 2006 is studied. Measurements are performed with a Brewer ozone single spectrophotometer and with a Bentham DM150 spectroradiometer (double monochromator). The influence of ozone, albedo and clouds on UV variability is evaluated separately using 10-year climatology. It is found that the effect of total ozone on short-term variability of UV irradiance at 305 nm can be more than 200% and on average more than 50%. Clouds can cause variability of 150% or more and on average 35%. Variability caused by albedo is maximum 32%. Long-term trends are investigated for the time period from 1994 to 2006 using the non-parametric Mann-Kendall trend test. Significant downwards trends (99% confidence level) were found for solar zenith angle 55° at wavelengths from 305 nm to 324 nm and CIE.

scholarly journals Long-term trends of <i>fo</i>F2 independent of geomagnetic activity

2003 ◽  
Vol 21 (5) ◽  
pp. 1167-1176 ◽  
Author(s):  
A. D. Danilov
Keyword(s):  
Detailed Analysis ◽  
Local Time ◽  
Geomagnetic Activity ◽  
Geomagnetic Latitude ◽  
Ionospheric Disturbances ◽  
Strong Argument ◽  
Long Term Changes ◽  
Long Term Trends ◽  
The Difference

Abstract. A detailed analysis of the foF2 data at a series of ionospheric stations is performed to reveal long-term trends independent of the long-term changes in geomagnetic activity during the recent decades (nongeomagnetic trends). The method developed by the author and published earlier is used. It is found that the results for 21 out of 23 stations considered agree well and give a relative nongeomagnetic trend of -0.0012 per year (or an absolute nongeomagnetic trend of about -0.012 MHz per year) for the period between 1958 and the mid-nineties. The trends derived show no dependence on geomagnetic latitude or local time, a fact confirming their independence of geomagnetic activity. The consideration of the earlier period (1948–1985) for a few stations for which the corresponding data are available provides significantly lower foF2 trends, the difference between the later and earlier periods being a factor of 1.6. This is a strong argument in favor of an anthropogenic nature of the trends derived.Key words. Ionosphere (ionosphere-atmosphere interactions; ionospheric disturbances; mid-latitude ionosphere)

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