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29922. Population dynamical behavior of a single-species nonlinear diffusion system with random perturbation
- Creator:
- Zu, Li, Jiang, Daqing, and Donal O'Regan
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- matematika, mathematics, stochastic permanence, persistent in mean, extinction, stationary distribution, 13, and 51
- Language:
- English
- Description:
- We consider a single-species stochastic logistic model with the population's nonlinear diffusion between two patches. We prove the system is stochastically permanent and persistent in mean, and then we obtain sufficient conditions for stationary distribution and extinction. Finally, we illustrate our conclusions through numerical simulation., Li Zu, Daqing Jiang, Donal O'Regan., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
29923. Population dynamics and structure of roe deer (Capreolus capreolus) inhabiting small-size forests in north-western Poland
- Creator:
- Orłowska, Lidia and Rembacz, Wojciech
- Type:
- article, model:article, and TEXT
- Subject:
- line transects, snow tracking, population density, sex ratio, age structure, and driving census
- Language:
- English
- Description:
- According to hunting statistics in the last two decades, both the population numbers and harvesting of roe deer in Poland have been on the increase from 597000 to 876000 animals and from 158000 to 172000 harvested individuals, respectively. The number of roe deer reported by hunters are mainly based on guesswork, therefore the objective of the study was to verify the inventory of roe deer conducted by hunting clubs in the Myślibórz Forest District (north-western Poland) and to determine the sex ratio and age structure this species. The study area is including 86 small size forest complexes and covers 12990 ha. Roe deer number were determined over four years from 2002 to 2006. In sampling plots (February 2002) data from snow tracking and driving census showed significant correlation (r = 0.663, p = 0.003) between the relative population density (N/km) – independent variable and population density (N/1000 ha) – dependent variable. Roe deer snow tracks were counted during five days each year on 16 line transects (length 66.4 km) and the relative population densities (animal per km*day–1) for the whole study area were calculated. These indices were inserted into the regression formula that was obtained from sampling plots. It allowed to calculate the population density (N/1000 ha) and then roe deer numbers inhabiting the study area. Population density ranged from 300.1-319.0 individuals/1000 hectares of forest, and the differences between the four years of study were statistically insignificant. In summer, the sex ratio of the population was 1:1.4 in favour of females, and the autumn increment of young animals amounted to 70.2 fawns/100 does. The average population number of roe deer assessed for these four years was 3568 individuals and was more than two times higher than the average population size (n = 1670) given by hunters.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29924. Population dynamics of blue sheep Pseudois nayaur in Ningxia Helan Mountain National Nature Reserve, China
- Creator:
- Zhang, Mingchun, Wang, Xiaoming, Ding, Yiuzhong, Zhang, Zejun, Wang, Zhenghuan, Li, Zhigang, Hu, Tianhua, and Ma, Bo
- Type:
- article, model:article, and TEXT
- Subject:
- line transect, encounter rates, density area, and rainy days
- Language:
- English
- Description:
- Long-term studies of population dynamics are important for conservation biology and wildlife management. We conducted 2790 line transects and observed 12516 blue sheep Pseudois nayaur from 2004 to 2009 in the Ningxia Helan Mountain National Nature Reserve of China, and found that the blue sheep population size fluctuated from 12375 in 2004 to 8188 in 2006 then 13344 in 2009, but did not ascend or decline continuously. Population size was positively correlated with the number of rainy days during the previous year. We divided the reserve into high, middle and low density areas according to average sheep encounter rates, and found that in different density areas blue sheep had different population dynamics, sex ratios and group sizes. Ratios between females and males, females and juveniles, and adults and juveniles were not different across six years in all three density areas. Group sizes increased with population size. We deduce that the blue sheep population will not increase or decrease constantly in the reserve, and that managers should manage varying density areas differently to maximize the conservation of blue sheep.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29925. Population dynamics of Coccinella septempunctata (Coleoptera: Coccinellidae) in the region of Edremit Gulf in West Anatolia (Mount Ida)
- Creator:
- Özpinar, Ali, Kürşat Şahin, Ali, and Polat, Burak
- Format:
- print, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- brouci, slunéčkovití, populační dynamika, beetles, Coccinellidae, population dynamics, Coleoptera, Coccinella septempunctata, aestivation, overwintering, aestivo-hibernation sites, reproduction period, 2, and 59
- Language:
- English
- Description:
- This study reports seasonal presence of Coccinella septempunctata L. (Coleoptera: Coccinellidae) in Southeast Turkey, in 2008, 2009 and 2010. Samples were collected from crops in agricultural areas at altitudes of 10 m, 800 m and 1400 m from stands of wild herbaceous plants , and at 1750 m from stone debris fields. First C. septempunctata adults were collected at the beginning of June at Tentcamp (800 m) and Tozlu (1400 m), early in July at Sarikiz (1700 m) when the mean air temperature reached 30°C. Adults became active in spring, after aestivating around Sarikiz and overwintering there under snow. First adults emerged on 2nd April in 2009 around Edremit Gulf when mean air temperature reached 14.8°C. Adult and immature stages of C. septempunctata were recorded attacking aphid populations till the end of June. C. septempunctata was present there for only one period each year during which they completed one generation. Adult individuals of this generation returned to Mount Ida to aestivate. Maximum numbers of adults present on Mount Ida in the first week of August in 2009 and 2010 were recorded. C. septempunctata adults aestivate and overwinter at Sarikiz on Mount Ida after completing their development on aphids in April, May and June around Edremit Gulf., Ali Özpinar, Ali Kürşat Şahin, Burak Polat., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
29926. Population dynamics, seasonality and aphid prey of Cheilomenes sexmaculata (Coleoptera: Coccinellidae) in an urban park in central Japan
- Creator:
- Kawakami, Yasuko, Yamazaki, Kazuo, and Ohashi, Kazunori
- Format:
- print, počítač, and online zdroj
- Type:
- article, články, journal articles, model:article, and TEXT
- Subject:
- Zoologie, brouci, slunéčkovití, mšice, beetles, Coccinellidae, aphids, Coleoptera, Cheilomenes sexmaculata, climate conditions, ladybird beetle, life cycle, urban vegetation, 2, and 59
- Language:
- English
- Description:
- The ladybird beetle, Cheilomenes sexmaculata (Fabricius), has been extending its distribution in and around urban areas at higher latitudes in Japan over the past 100 years. Between 2003 and 2011, we investigated the seasonal occurrence, aphid prey and population dynamics of this species in an urban park in Osaka City, central Japan. We found that C. sexmaculata completes three generations a year in Osaka. Overwintered adults emerge in March or April and produce two (or rarely one) generations by summer. Second-generation adults aestivate and subsequently produce another generation in autumn. This species feeds on five species of aphids that infest planted shrubs and alien weeds throughout the vegetative season. We analyzed the association between accumulated temperature and when overwintered adults first emerged. In addition, we determined the association between their time of emergence, peak abundance and last occurrence, and meteorological conditions. There was no association between the sum of effective temperatures and termination of adult overwintering. There was, however, an association between first occurrence and peak abundance, and climatic conditions, such as warm temperatures or low humidity. This species maintained a stable population in an urban park by becoming quiescent when climatic conditions were unfavourable or prey was scarce. We discussed these findings in relation to urban environmental factors, such as climate, food conditions and vegetation., Yasuko Kawakami, Kazuo Yamazaki, Kazunori Ohashi., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29927. Population ecology and clone dynamics of the galling aphid Geoica wertheimae (Sternorrhyncha: Pemphigidae: Fordinae)
- Creator:
- Wool, David and Ben-Zvi, Ofra
- Type:
- article, model:article, and TEXT
- Subject:
- Galls, aphids, Fordinae, Pistacia, and population ecology
- Language:
- English
- Description:
- Geoica wertheimae induces spherical galls on its primary host, Pistacia palaestina (Anacardiaceae). We studied the temporal changes in gall size and aphid clone size, as well as gall distribution and abundance on marked trees during two consecutive years. The density of galls (per shoot and per leaf) was low during the study period, and gall distribution was clumped. Gall abundance varied greatly among trees, but gall abundance and tree budburst phenology were uncorrelated. Galls increased eight-fold in volume during the season, in parallel with the increase in aphid clone size, from one individual to several hundred aphids per gall. The trigger for the induction of the alate morph in the galls in late summer seems to be an abrupt change in aphid density within the galls, which occurs when aphid reproductive rate exceeds the rate of change in gall internal surface area. Two species of Lepidopterous larvae were present in about one-third of the galls. They occasionally destroyed the aphid clone, but many aphids often remained alive. However, the volume of parasitized galls was significantly smaller than that of unparasitized galls, illustrating the dependence of gall size on aphid clone size.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
29928. Population genetic structure of the tropical eel Anguilla bicolor in Indonesian waters based on microsatellite markers
- Creator:
- Fahmi, Melta Rini, Solihin, Dedy Duryadi, Shao, Zaojun, Pouyaud, Laurent, and Berrebi, Patrick
- Type:
- article, model:article, and TEXT
- Subject:
- microsatllite, cytochrome b, Anguilla bicolor bicolor, A. bicolor pacifica, and population structure
- Language:
- English
- Description:
- The short-finned eel Anguilla bicolor is known to be subdivided in two distinct subspecies (i.e. A. bicolor bicolor and A. bicolor pacifica), each subspecies being geographically distributed in allopatry. The present survey intends to describe genetic differentiation, population structure, molecular variance and phylogeny of both subspecies of A. bicolor in Indonesian waters. The genotypes of seven microsatellite locus and sequences of the entire cytochrome b were analyzed on 180 specimens collected in 10 representative locations, where one of the two subspecies spend their freshwater life. The results showed high heterozygosity (0.767 < He < 0.891). Significant deviation from Hardy-Weinberg equilibrium were essentially detected on AjTR04 and Aro63 loci. No diagnostic microsatellite loci was observed between the subspecies which shared most of their alleles. Genetic Reynolds distances computed for each population ranged between 0.029 and 0.073 among A. bicolor pacifica populations, between 0.045 and 0.149 among A. bicolor bicolor populations and between 0.042 and 0.114 among populations of different subspecies. Both the mitochondrial and the microsatellite markers confirm the subdivision into two subspecies while microsatellite loci suggest a moderate differentiation between subspecies.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
29929. Population in History :
- Type:
- text and monografie kolektivní
- Subject:
- Demografie. Populace, sborníky, demografie historická, dějiny společnosti, společenská struktura, přehledná zpracování světových dějin (chronologicky), zahraniční periodika a sborníky, and zahraniční historická demografie a statistika
- Language:
- English
- Rights:
- unknown
29930. Population Migration in the Territory of Former Yugoslavia in the 20th Century /
- Creator:
- Škerlová, Jana,
- Type:
- text and studie
- Subject:
- Dějiny států a území na Balkánském poloostrově, migrace obyvatelstva, otázka národní, Jugoslávie, světové dějiny od r. 1918 do současnosti, migrace, vystěhovalectví, kolonizace, and národnosti, vztahy mezi národnostmi a národní hnutí
- Language:
- English
- Rights:
- unknown