scholarly journals Trends and synchrony in fluctuations of the numbers of Whinchat (Saxicola rubetra) and European Stonechat (S. rubicola) in chalk steppe of North-eastern Ukraine

2019 ◽  
Keyword(s):  
Time Series ◽  
National Parks ◽  
Standard Error ◽  
Bird Species ◽  
Nature Reserves ◽  
North Eastern ◽  
Saxicola Rubetra ◽  
Species Abundances ◽  
In Series ◽  
Grassland Habitats

The problem of coexistence of related species within the same communities poses a question of how similar are the fluctuations of their numbers. Whinchat (Saxicola rubetra) and European Stonechat (S. rubicola) is an example of such a pair of phylogenetically related bird species, which are members of a foraging guild of sit-and-wait insectivores in open habitats. In Ukraine both species are quite common in meadows, steppes, fallow lands and other grassland habitats including undisturbed areas in nature reserves. In North-eastern Ukraine Whinchat and European Stonechat are characteristic of the bird communities of hills with chalk outcrops where they represent a group of species linked to chalk steppe. The trends in numbers and synchrony in fluctuations in the numbers of both species in this habitat were studied in national nature park ‘Dvorichanskyi’, Kharkiv region, North-eastern Ukraine for 9 years’ period (2010–2018). The data were retrieved from the results of yearly monitoring bird counts in chalk grassland habitats. The total-area census method was used on 3 plots of unequal size (17.8, 33.2, and 41.0 ha). The trends were analysed in programme TRIM (TRends & Indices for Monitoring data) vers. 3.53. The extent of synchrony was estimated by means of zero-lag cross-correlation between the time series of log-transformed growth rates. Additionally, the coincidence of the direction of changes and the coincidence of peaks in series were checked. The trend in Whinchat abundance is characterised as significant steep decline (multiplicative slope 0.840, standard error 0.03; p<0.01). The trend in European Stonechat abundance is classified as non-significant uncertain (multiplicative slope 0.909, standard error 0.06). The trends in both species correspond to general trends in Europe evidenced in PanEuropean Common Bird Monitoring Scheme for 1980–2016 and 1989–2016 for Whinchat and European Stonechat accordingly. The synchrony in fluctuations of the numbers of Whinchat and European Stonechat in chalk steppe habitats proved to be weak. Time series of both species abundances run in different directions almost in all cases where the comparison was possible that indicates probable differences in the causes of the dynamics of their populations. The study prompts to launch new or extend existing monitoring schemes in nature reserves and national parks in Ukraine to get reliable estimates for the trends in numbers of both rare and common bird species.

scholarly journals Population structures among epiphytal foraminiferal communities, Nevis, West Indies

2008 ◽  
Vol 27 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Brent Wilson
Keyword(s):  
Time Series ◽  
Shallow Water ◽  
West Indies ◽  
Septic Tank ◽  
Amphistegina Gibbosa ◽  
Species Abundances ◽  
Population Structures ◽  
Logarithmic Series ◽  
One Year ◽  
Structure Investigations

Abstract. The taxocene of live epiphytal foraminifera was for one year monitored monthly on six phytal substrates in shallow water (<1 m) in two bays around Nevis, NE Caribbean Sea. Mosquito Bay was subject to a nutrient flux from a leaking septic tank. Long Haul Bay was comparatively undeveloped. SHE Community Structure Investigations (SHECSIs) revealed that the populations on five plants had logarithmic series distributions of species abundances, the slopes of lnS vs. lnE for these five time-series being within −1±0.3. In three time-series, they were within −1±0.05.Cluster analysis of twenty-five sediment samples in shallow water (<3 m) indicates that Nevis is largely surrounded by a single thanatacoenosis, for which SHECSI indicates a logarithmic series population structure. However, it is not possible to reconstruct perfectly the epiphytal population from the sediment thanatacoenosis. The thanatacoenosis included 40% allochthonous Amphistegina gibbosa, Archaias angulatus and Asterigerina carinata, washed in from offshore reefs, and few planorbulinids, although the latter dominates the biocoenosis on seagrass leaves in the backreef.

scholarly journals Preliminaries on the Accurate Estimation of the Hurst Exponent Using Time Series

2021 ◽  
Author(s):  
Ginno Millán ◽  
Román Osorio-Comparán ◽  
Gastón Lefranc
Keyword(s):  
Time Series ◽  
Hurst Exponent ◽  
High Speed ◽  
Mean Squared Error ◽  
Computer Network ◽  
Accurate Estimation ◽  
Minimum Length ◽  
Squared Error ◽  
In Series ◽  
Speed Computer

<div>This article explores the required amount of time series points from a high-speed computer network to accurately estimate the Hurst exponent. The methodology consists in designing an experiment using estimators that are applied to time series addresses resulting from the capture of high-speed network traffic, followed by addressing the minimum amount of point required to obtain in accurate estimates of the Hurst exponent. The methodology addresses the exhaustive analysis of the Hurst exponent considering bias behaviour, standard deviation, and Mean Squared Error using fractional Gaussian noise signals with stationary increases. Our results show that the Whittle estimator successfully estimates the Hurst exponent in series with few</div><div>points. Based on the results obtained, a minimum length for the time series is empirically proposed. Finally, to validate the results, the methodology is applied to real traffic captures in a high-speed computer network.</div>

FEATURES OF RESEARCH, DESIGN AND OPERATION OF HYDROMELIORATIVE SYSTEMS IN THE AREA OF INTERNATIONAL AIRPORTS

2021 ◽  
pp. 30-35
Author(s):  
A. E. KASYANOV ◽  
Keyword(s):  
Research Design ◽  
Standard Error ◽  
Land Reclamation ◽  
Survey Design ◽  
Bird Species ◽  
The State ◽  
Moscow Region ◽  
International Airport ◽  
Nesting Sites ◽  
Reclamation System

The features of the survey, design and operation of irrigation and drainage systems in the area of the international airport «Zhukovsky» located in the Moscow region, Russia. Design surveys included an ornithological survey of the reclaimed area. Bird species, nesting sites and the number of nests were identified. The number of nests before reclamation averaged 200 ± 1.5 (mean ± standard error). Hydro reclamation in the airport area eliminated local swamping areas and nesting areas disappeared. Draining was carried out by open drains. The distance between the open drains is 120 m, the length is from 700 to 1200 m. There are no capital irrigation and drainage facilities. On the polder site the project provides for open drains and drains. The state of the land reclamation system has been deteriorating since 2001. Periodic waterlogging of a part of the polder area and the formation of a nesting area for black-headed gulls are noted. Airbus A321 aircraft fl y over the chicks while feeding at an altitude of 231.5 m, the size of which in the eyes of the chicks is comparable to the size of the parent gulls.

scholarly journals A Fixed-radius Point Count Method for Nonbreeding and Breeding Season Use

The Auk ◽  
1986 ◽  
Vol 103 (3) ◽  
pp. 593-602 ◽  
Author(s):  
Richard L. Hutto ◽  
Sandra M. Pletschet ◽  
Paul Hendricks
Keyword(s):  
Bird Species ◽  
Common Species ◽  
Bird Abundance ◽  
Point Count ◽  
Bird Density ◽  
Count Method ◽  
Species Abundances ◽  
Fixed Radius ◽  
Point Count Method ◽  
A Site

Abstract We provide a detailed description of a fixed-radius point count method that carries fewer assumptions than most of the currently popular methods of estimating bird density and that can be used during both the nonbreeding and breeding seasons. The method results in three indices of bird abundance, any of which can be used to test for differences in community composition among sites, or for differences in the abundance of a given bird species among sites. These indices are (1) the mean number of detections within 25 m of the observer, (2) the frequency of detections within 25 m of the observer, and (3) the frequency of detections regardless of distance from the observer. The overall ranking of species abundances from a site is similar among the three indices, but discrepancies occur with either rare species that are highly detectable at great distances or common species that are repulsed by, or inconspicuous when near, the observer. We argue that differences in the behavior among species will preclude an accurate ranking of species by abundance through use of this or any other counting method in current use.

scholarly journals DETECTING SERIES PERIODICITY WITH HORIZONTAL VISIBILITY GRAPHS

2012 ◽  
Vol 22 (07) ◽  
pp. 1250160 ◽  
Author(s):  
ANGEL NUÑEZ ◽  
LUCAS LACASA ◽  
EUSEBIO VALERO ◽  
JOSE PATRICIO GÓMEZ ◽  
BARTOLO LUQUE
Keyword(s):  
Time Series ◽  
Graph Theory ◽  
Noise Reduction ◽  
Time Domain ◽  
Generic Properties ◽  
Horizontal Visibility ◽  
Visibility Graphs ◽  
Visibility Algorithm ◽  
In Series ◽  
Periodic Signals

The horizontal visibility algorithm was recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are in its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorrelation) methods. Finally, potentials, limitations and applications are discussed.

Albert Russell ('Bert') Main 1919 - 2009

2011 ◽  
Vol 22 (1) ◽  
pp. 104
Author(s):  
S. D. Bradshaw
Keyword(s):  
Graduate Students ◽  
National Parks ◽  
Nature Reserves ◽  
Three Generations ◽  
Form Part ◽  
Biological Insight ◽  
The Creation

Bert Main (1919?2009)was recognized both nationally and internationally as one of Australia's leading zoologists and a gifted naturalist. His research and ecological teaching on a wide variety of animals, including frogs, reptiles, birds, insects and marsupials, laid the foundations for three generations of graduate students who were inspired by his imagination and biological insight. His foresight and energy as an administrator on government bodies also led to the creation of some of Western Australia's most important National Parks and Nature Reserves that are vital for the preservation of Australia's rich biodiversity and form part of his enduring legacy.

Bird Distributions on Small Rainforest Remnants in New South Wales.

1981 ◽  
Vol 8 (3) ◽  
pp. 637 ◽  
Author(s):  
RW Howe ◽  
TD Howe ◽  
HA Ford
Keyword(s):  
New South ◽  
New South Wales ◽  
Bird Species ◽  
Home Ranges ◽  
Additional Species ◽  
South Wales ◽  
High Dispersal ◽  
North Eastern ◽  
Bird Distributions ◽  
Open Country

We studied bird distributions on 15 small patches of subtropical rainforest, ranging from 0.08 to 2.5 ha, in north-eastern New South Wales. Three-quarters of the bird species found in an extensive area of nearby rainforest were recorded in one or more of these isolated patches. Species that were not recorded, generally were rare in the extensive forest or are characterized by large home ranges. Several species more typical of open country were also found in the isolated patches. The number of resident species per patch ranged from one to 19; these were added in a rather predictable order from small to larger areas. Additional species observed in the patches either were transient or had home ranges encompassing several discontinuous areas. Although area is the best single predictor of species richness, isolation, disturbance by livestock and distance from water all tend to reduce the number of resident bird species. We propose that high dispersal abilities of rainforest birds near Dorrigo reflect the geographical and palaeogeographical distribution of Australian rainforest. The small total area and discontinuity of original tracts of rainforest, perhaps accentuated during the Pleistocene, have generally prevented persistence or colonization of highly sedentary, specialized bird species.

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