scholarly journals Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season

Ring ◽  
2006 ◽  
Vol 28 (2) ◽  
pp. 119-125
Author(s):  
Michał Ciach ◽  
Dominik Wikar ◽  
Małgorzata Bylicka
Keyword(s):  
Breeding Season ◽  
Early Spring ◽  
Food Resources ◽  
High Density ◽  
Line Transect ◽  
Flock Size ◽  
Early Winter ◽  
Corvus Corax ◽  
Line Transect Method ◽  
Breeding Seasons

Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season During the 2002/2003-2004/2005 non-breeding seasons the density of the Raven in the open habitats of the Orawa - Nowy Targ Basin was studied by line transect method. The results were analysed in four periods (autumn, early winter, winter and early spring). The median density of Ravens did not differ significantly between individual periods and was respectively: 3.5, 3.8, 4.8 and 3.8 indiv. / 10 km. Number of birds during particular controls varied from 1.0 to 24.8 indiv. / 10 km. However, while excluding flocks, the median density of single individuals and pairs of the Raven was considerably lower and in subsequent periods reached respectively: 2.2, 2.4, 2.2 and 1.7 indiv. / 10 km. Flock size did not differ significantly between individual periods. Single individuals and, less often, groups of two birds were recorded mostly. Small (3-5 indiv.) and medium (6-15 indiv.) flocks were recorded rarely and large flocks (16 indiv. and above) - only exceptionally. The high density and strong fluctuations of abundance of Ravens were determined by flocks presence, which was probably linked to irregular occurrence of food resources.

scholarly journals Nestedness of snake assemblages on islands of an inundated lake

2012 ◽  
Vol 58 (6) ◽  
pp. 828-836 ◽  
Author(s):  
Yanping Wang ◽  
Xi Wang ◽  
Ping Ding
Keyword(s):  
Passive Sampling ◽  
Life History Traits ◽  
Habitat Diversity ◽  
Line Transect ◽  
Spearman Rank ◽  
Faunal Assemblages ◽  
Wide Range ◽  
Line Transect Method ◽  
Breeding Seasons ◽  
Habitat Variables

Abstract Nestedness is a pattern frequently reported for faunal assemblages in fragmented systems. Although nestedness has been documented for a wide range of taxa, it is rarely tested in snake assemblages. To arrive at robust generalizations about processes and mechanisms structuring island biotas, it is important to examine under-represented taxa such as snakes for the insights they may offer. We tested for the existence of nestedness and underlying causal mechanisms using snake data collected on islands in the Thousand Island Lake, China. We used the line-transect method to survey snake occupancy and abundance on 20 islands during two breeding seasons in 2009 and 2010. We used the recently developed metric WNODF to estimate nestedness. We used Spearman rank correlations to examine the associations of nestedness and habitat variables (area, isolation, and habitat diversity) as well as life-history traits (body size, clutch size, geographical range size and area requirement) related to species extinction and immigration tendencies. Snake assemblages were significantly nested and were shaped by extinction processes mediated through area effects and habitat nestedness. The nestedness of snake assemblages was not due to passive sampling or selective colonization. From a conservation viewpoint, our results indicate that we should protect both the largest island with the most species-rich community and habitat-rich islands to maximize the number of species preserved.

scholarly journals Evidence for use of both capital and income breeding strategies in the mangrove tree crab, Aratus pisonii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jade Carver ◽  
Morgan Meidell ◽  
Zachary J. Cannizzo ◽  
Blaine D. Griffen
Keyword(s):  
Breeding Season ◽  
Breeding Strategy ◽  
Reproductive Period ◽  
Breeding Strategies ◽  
Mangrove Tree ◽  
Income Breeding ◽  
Aratus Pisonii ◽  
Breeding Seasons ◽  
And Storage ◽  
Capital And Income Breeding

AbstractTwo common strategies organisms use to finance reproduction are capital breeding (using energy stored prior to reproduction) and income breeding (using energy gathered during the reproductive period). Understanding which of these two strategies a species uses can help in predicting its population dynamics and how it will respond to environmental change. Brachyuran crabs have historically been considered capital breeders as a group, but recent evidence has challenged this assumption. Here, we focus on the mangrove tree crab, Aratus pisonii, and examine its breeding strategy on the Atlantic Florida coast. We collected crabs during and after their breeding season (March–October) and dissected them to discern how energy was stored and utilized for reproduction. We found patterns of reproduction and energy storage that are consistent with both the use of stored energy (capital) and energy acquired (income) during the breeding season. We also found that energy acquisition and storage patterns that supported reproduction were influenced by unequal tidal patterns associated with the syzygy tide inequality cycle. Contrary to previous assumptions for crabs, we suggest that species of crab that produce multiple clutches of eggs during long breeding seasons (many tropical and subtropical species) may commonly use income breeding strategies.

Abundance Estimation of Diving Animals by the Double-Platform Line Transect Method

Biometrics ◽  
2003 ◽  
Vol 59 (3) ◽  
pp. 512-520 ◽  
Author(s):  
Hiroshi Okamura ◽  
Toshihide Kitakado ◽  
Kazuhiko Hiramatsu ◽  
Mitsuyo Mori
Keyword(s):  
Abundance Estimation ◽  
Line Transect ◽  
Line Transect Method

scholarly journals A fencing experiment on a high-density population of Microtus townsendii

1977 ◽  
Vol 55 (7) ◽  
pp. 1166-1175 ◽  
Author(s):  
Rudy Boonstra ◽  
Charles J. Krebs
Keyword(s):  
Survival Rate ◽  
Breeding Season ◽  
Population Regulation ◽  
Control Area ◽  
High Density ◽  
Low Density ◽  
Vole Population ◽  
Sharp Decline ◽  
Density Population ◽  
Microtus Townsendii

If dispersal is prevented, a low-density vole population will increase to unusually high densities. A mouse-proof fence was constructed around a vole population that had already reached high density and both this population and one on a control area were live-trapped from January 1975 to November 1975. The population on the control remained at peak densities. The enclosed population increased to even higher density once the breeding season had started and had a higher survival rate than the control population. By midsummer the enclosed population had severely overgrazed the vegetation and went into a sharp decline. Dispersal losses from the control were estimated at 32% for males and 31% for females in these high-density populations. Microtus townsendii populations thus responded to a fence in a manner similar to that of other species that have been studied. This experiment indicates the importance of dispersal to population regulation in voles even at peak densities.

scholarly journals STUDI EKOLOGI SUMBERDAYA TERIPANG DI NEGERI PORTO PULAU SAPARUA MALUKU TENGAH

2014 ◽  
Vol 1 (1) ◽  
pp. 32-42
Author(s):  
Yona Aksa Lewerissa
Keyword(s):  
Sea Cucumber ◽  
Water Environment ◽  
Turbidity Current ◽  
Line Transect ◽  
Community Structures ◽  
Sea Cucumbers ◽  
Environment Factors ◽  
Line Transect Method ◽  
Environment Measurement

Background: Decreasing of sea cucumber resources on numbers and size of fishing capture in Negeri Porto waters influenced its community structures. Further, water environment steadiness will questionable. For this reason, study was done to analyzed community structures of sea cucumbers include of numbers species found, density, potency, species presence frequency, distribute pattern, ecology index and environment measurement. Method: Research done on February to May, 2008 at Negeri Porto used Line Transect Method. Result: showed there were eight species of sea cucumbers found (potency as much as 12.286 individuals). Bohadschia marmorata got highest in numbers species found, density, potency and species presence frequency. There were three distribute pattern of sea cucumbers found wich are uniform, random and group. Conclusion: Sea cucumbers diversity was in lower, species are closed to compatible. B. marmorata and Holothuria edulis are tends to dominate this water. Environment factors such temperature, pH, salinity, DO, turbidity, current and sediment distribute showed that Porto waters was suitable to sea cucumbers growth.

scholarly journals Pengaruh Kerapatan Vegetasi Terhadap Produktivitas Serasah Hutan Taman Nasional Gunung Leuser

Elkawnie ◽  
2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Sri Jayanthi ◽  
Zulfan Arico
Keyword(s):  
High Density ◽  
Biological Factor ◽  
Systematic Sampling ◽  
Line Transect ◽  
Vegetation Density ◽  
Location Determination ◽  
Aceh Province ◽  
Chemical Content ◽  
Chemical Factors ◽  
Physical And Chemical

The research was conducted in January-September 2017 and will continue until December 2017 at Gunung Leuser National Park Resort Tenggulun, Aceh Tamiang District, Aceh Province. The method used to determine the vegetation density is purposive sampling by using a combination of line method and the method of with 20 m x 20 m. For determination of litter productivity by using Litter Trap method, and to analyze physical and chemical content of soil by laboratory test and calculate soil fauna density (biological factor) location determination by using line transect along 100 m, then on every line taken 10 point by method Systematic Sampling is systematically on the 3 (three) research sites that have been determined. Based on the research results for the highest density of tree vegetation found in plot 4 with the absolute density of 175 Ind/ ha this is in line with the highest litter productivity value also found at high density (plot 4) which is 14,5 gr/m2/week. Physical chemical factors are found in high density of air temperature 26 0C, humidity 80 %, soil temperature 25 0C, light intensity 118 Candella, soil pH 5.6, C-Organic 4.80 %, N-Total 0.55%, C/N of 4,24 %, P-Bray 23,03 ppm and K-tukar 0,41 Me/100.

scholarly journals Estimation of Orangutan Population in Sibongkaras Pakpak Bharat Village Forest Area

Elkawnie ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 133
Author(s):  
Juhardi Sembiring ◽  
Taufiq Siddiq Azvi
Keyword(s):  
Sampling Method ◽  
Data Retrieval ◽  
Forest Area ◽  
Line Transect ◽  
Habitat Conditions ◽  
Dominant Position ◽  
Purposive Sampling ◽  
Management Measures ◽  
Nahdlatul Ulama ◽  
Line Transect Method

Abstract : Orangutan is classified as an endangered species. Forest clearance for a variety of purposes and functions over the region led to the limited habitat for orangutans. Orangutans habitat is fragmented into several regions led to the survival of a population of a species depends on habitat conditions. Performing a nest survey is important to give a deeper understanding of the ecology and help determine the best protective management measures. We provide basic data of orangutan density and orangutan nesting characteristics in protected forest area Sibongkaras village. This study was conducted in April 2019 until June 2019 in protected forest area Sibongkaras village, Pakpak Bharat. Tracking begins with observed the presence of a nest based on a purposive sampling method. And data retrieval was done by line transect method. Data analyzed at Universitas Nahdlatul Ulama Sumatera Utara. Our result showed that the orangutan population density was 0.0072 individuals/km2 or 0.72 individuals/ha. The dominant position of the nest is in a position which is a position I nest close to the main stem of the tree with the nest number 13 (43.3%). Generally, the nest is found at an altitude of  >15 meters with a sum of 27 nests (90%).Abstrak : Orangutan diklasifikasikan sebagai spesies yang terancam punah. Penebangan hutan untuk berbagai tujuan dan fungsi di kawasan tersebut menyebabkan terbatasnya habitat orangutan. Habitat orangutan yang terfragmentasi menjadi beberapa wilayah menyebabkan kelangsungan hidup suatu populasi suatu spesies tergantung pada kondisi habitat. Melakukan survei sarang penting untuk memberikan pemahaman yang lebih dalam tentang ekologi dan membantu menentukan langkah-langkah manajemen perlindungan terbaik. Kami menyediakan data dasar kepadatan orangutan dan karakteristik sarang orangutan di kawasan hutan lindung Desa Sibongkaras. Penelitian ini dilakukan pada bulan April 2019 hingga Juni 2019 di kawasan hutan lindung Desa Sibongkaras, Pakpak Bharat. Pengamatan dimulai dengan mengamati keberadaan sarang berdasarkan metode purposive sampling. Dan pengambilan data dilakukan dengan metode transek garis. Data yang diperoleh di analisis di Universitas Nahdlatul Ulama Sumatera Utara. Hasil Penelitian kami menunjukkan kepadatan populasi orangutan di 0,0072 individuals/km2 atau 0,72 individu / ha. Posisi sarang yang dominan adalah pada posisi sarang yang berada di posisi paling dekat dengan batang utama, dengan jumlah sarang 13 (43,3%). Umumnya sarang ditemukan di ketinggian > 15 meter dengan jumlah 27 sarang (90%).

Phenotypic plasticity of the montane vole (Microtus montanus) in unpredictable environments

1992 ◽  
Vol 70 (11) ◽  
pp. 2121-2124 ◽  
Author(s):  
Norman C. Negus ◽  
Patricia J. Berger ◽  
Aelita J. Pinter
Keyword(s):  
Phenotypic Plasticity ◽  
Breeding Season ◽  
Growth Rates ◽  
Adaptive Strategy ◽  
Severe Drought ◽  
Microtus Montanus ◽  
Age Cohort ◽  
Montane Meadow ◽  
Study Sites ◽  
Breeding Seasons

From 1987 to 1989, the cohort dynamics of Microtus montanus populations were studied at two montane meadow sites approximately 160 km apart, in northwestern Wyoming. The 1987 and 1988 breeding seasons differed markedly from each other. In 1987, melt off occurred in April, and the first cohort was born in May (cohort 1). The entire breeding season was favorable owing to frequent rainfall throughout the summer. Cohort 1 animals grew rapidly and females began breeding at 4–5 weeks of age. Likewise, cohort 2 (June) animals exhibited rapid growth and females were breeding at 7–8 weeks of age. Cohort 3 (July and August) animals grew more slowly and most entered the winter as prepubertal animals of subadult size. At the end of the summer, cohort 3 animals represented >70% of the voles recruited during the breeding season. In 1988, following melt off in late April, precipitation was below normal and the situation intensified to severe drought through the summer. The growth rates of cohort 1 and 2 animals were significantly lower than 1987 growth rates, and very few females attained sexual maturity. At the end of the summer, cohort 3 animals represented <25% of the total recruitment at both study sites. Such apparent phenotypic plasticity of growth and maturation appears to be an evolved adaptive strategy that is responsive to several environmental cues. Both study sites, although widely separated, exhibited virtually identical patterns throughout the study.

Flexibility of nuptial colouration in a unique ecotype of Threespine Stickleback (Gasterosteus aculeatus)

2021 ◽  
Author(s):  
Rachel Corney ◽  
Anne Haley ◽  
Laura Weir
Keyword(s):  
Breeding Season ◽  
Gasterosteus Aculeatus ◽  
Colour Change ◽  
Threespine Stickleback ◽  
Relative Role ◽  
Mate Quality ◽  
Breeding Seasons ◽  
Potential Signal ◽  
Intersexual Competition

Nuptial colouration in animals may serve as a signal of competitor and/or mate quality during breeding. In many temperate fishes, nuptial colouration develops during discrete breeding seasons and is a target of sexual selection. We examine nuptial colouration and behaviour of a unique ecotype of Threespine Stickleback (Gasterosteus aculeatus Linnaeus, 1758), wherein males turn from dull brown-grey to pearlescent white during the breeding season. The main goal of this work was to determine the relative role of white colouration in intersexual competition and mate choice. In a combination of a field and laboratory work, we found that males are brightest white when engaging in courtship activities in the presence of a female; this indicates that white colouration may be primarily related to enhancing signalling during mate attraction. White colouration intensity increased as the breeding season progressed and may be related to an influx of conspecifics. Colour change from cryptic grey to bright white occurred rapidly (< 90 seconds) and may be deployed to enhance behavioural signals. We conclude that bright white colouration in the white ecotype is a potential signal of mate quality and may have evolved from a previously existing capacity for colour plasticity in common Threespine Stickleback.

“Data for the Problem of Evolution in Man. V. On the Correlation between Duration of Life and the Number of Offspring”

1901 ◽  
Vol 35 (6) ◽  
pp. 458-479
Author(s):  
M. Beeton ◽  
G. U. Yule ◽  
Karl Pearson
Keyword(s):  
Natural Selection ◽  
Breeding Season ◽  
The Other ◽  
Similar Statement ◽  
Men And Women ◽  
Darwinian Theory ◽  
Theory Of Evolution ◽  
Biennial Plants ◽  
Long Life ◽  
Breeding Seasons

According to the Darwinian theory of evolution the members of a community less fitted to their environment are removed by death. But this process of natural selection would not permanently modify a race, if the members thus removed were able before death to propagate their species in average numbers. It then becomes an important question to ascertain how far duration of life is related to fertility. In the case of many insects death can interfere only with their single chance of offspring; they live or not for their one breeding season only. A similar statement holds good with regard to annual and biennial plants. In such cases there might still be a correlation between duration of life and fertility, but it would be of the indirect character, which we actually find in the case of men and women living beyond sixty years of age—a long life means better physique and better physique increased fertility. On the other hand, there is a direct correlation of fertility and duration of life in the case of those animals which generally survive a number of breeding seasons, and it is this correlation which we had at first in view when investigating the influence of duration of life on fertility in man. The discovery of the indirect factor in the correlation referred to above was therefore a point of much interest. For it seems to show that the physique fittest to survive is really the physique which is in itself (and independently of the duration of life) most fecund.

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