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1.
Studies of nest-site selection and reproduction are essential for bird species assessment and conservation. We compared breeding habitats and random sites within a secondary cavity-nesting bird, Yellowrumped Flycatcher (Ficedula zanthopygia), in a 5-year studying period in northeast China. We also modeled the effects of factors on daily nest survival rates. The flycatcher nest cavities were mostly located in tree trunks, with only 15% found in limbs. They often located their nests in east and south direction (45°–180°) with dense canopy cover surrounding the nest trees. Yellow-rumped Flycatcher nest-site selection appears to be nonrandom, such that they select nest sites with higher tree density and higher canopy closure. Yellowrumped Flycatcher daily nest survival rate was 0.9731 ± 0.007. Daily nest survival increased with increasing percent cover of canopy closure and decreased with the distance closing to the edges. The causes for nest failure were mainly nest usurpation by other secondary cavity-nesters. Predation rate and the competition for cavities with other secondary cavity-nesters may constrain the ability of Yellow-rumped Flycatchers to optimize nest nest-site selection.  相似文献   

2.
The time course of changes in characteristics of herbaceous vegetation around Formica aquilonia Yarr. ant nests formed from artificially relocated fragments of original families was studied over 6 years. At the initial stage of nest formation, species richness and diversity of the herbaceous layer decreased, and its taxonomic, spatial, phytocenotic, and ecological structure changed. Trivialization of vegetation around anthills was observed. The proportion of zoochorous and anemophilous plants with narrow or strongly dissected leaves increased in the developing myrmecotopic assemblages.  相似文献   

3.
The gyrfalcon in the Yamal Peninsula nests mostly on trees. The average brood size in this species decreased from 3.1 nestlings per active nest (n = 28) between 1973 and 1989 to 2.2 (n = 22) between 1998 and 2008. This decrease is probably explained by switching to the habit of using mostly smaller nests (built by the rough-legged buzzard, raven, or hooded crow) instead of large nests built by the white-tailed eagle. The survival rate of gyrfalcon nestlings in smaller nests is considerably lower: the average brood size is only 1.6 (n = 12), compared to 2.5 (n = 20) in medium-sized and 3.0 (n = 34) in large nests. The possible role of increase in snow cover density caused by climate warming in making large nests less accessible to the gyrfalcon is discussed.  相似文献   

4.
The level of fidelity to potential nest site in representatives of different bird of prey species (Falconiformes) has been studied as dependent on population density and land-use status of the nesting area (a specially protected natural area or unprotected forest area). Species with high and low parameters of nest site fidelity and occupancy have been distinguished. The former group includes the Common Buzzard (Buteo buteo), Booted Eagle (Hieraaetus pennatus), and White-tailed Sea Eagle (Haliaeetus albicilla): no less than 60% of observed pairs have not changed their nest sites and nests during 5 years. The latter group includes the Common Kestrel (Falco tinnunculus), European Honey Buzzard (Pernis apivorus), and, at the nest level, Northern Goshawk (Accipiter gentiles).  相似文献   

5.
The results of long-term observations (1983–2013) on the dates of arrival of migratory birds to the Ilmen State Reserve are presented. Based on their analysis, it is conclude that (1) there is no significant positive trend of spring temperatures in the territory of the reserve, and (2) an earlier arrival of the majority of bird species is not observed, unlike in Europe. The arrival has shifted to earlier dates in the Common Chaffinch (Fringilla coelebs), White Wagtail (Motacilla alba), and Black Kite (Milvus migrans). On the other hand, the arrival of the Tree Pipit (Anthus trivialis) is observed later than usual. Multiple regression analysis has shown that the arrival dates of most species that nest in the reserve are determined by the temperature regime of spring months in their nesting area.  相似文献   

6.
Variations in breeding success of the Whiskered Terns (Chlidonias hybrida) were studied in two wetlands; Anzali (2005 and 2008) and Zarivar (2007–2008) in north and west Iran. Nesting success was modeled and compared using information-theoretic approach implemented in program Mark in order to assess effects of colony locations, years and nest initiation dates on the probability of daily nest survival. Clutch size did not vary between colonies and years. Breeding success varied between colonies (Zarivar > Anzali), and years only in Anzali (2005 > 2008). Overall daily nest survival was 0.977. (95% LCI 0.973, UCI 0.981), equivalent to a Mayfield nest survival of 0.317. (95% LCI 0.255, UCI 0.387). Egg-laying periods and colony site were important covariates affecting the daily survival rates (Σω i = 0.86 and Σω i = 0.83, respectively), while, the support for the effect of year was less (Σω i = 0.41). We concluded that Lake Zarivar provides a more favorable nesting location for Whiskered Terns probably because of little changes in rainfall and water depth during the breeding seasons which influence breeding performance.  相似文献   

7.
Topical connections between F. aquilonia ants and herbaceous plants in a fragmented forest area have been analyzed. The species composition of the group of herbaceous plants changing their occurrence frequency in response to the presence of F. aquilonia nests has been determined. Ecological and phytocenotic parameters of herbaceous plants contributing to the development of the myrmecotopic assemblage are described. Signs of meadowfication and synanthropization of the herbaceous layer around ant nests have been observed.  相似文献   

8.
A mortality event of Cladocora caespitosa corals and the extent of bleaching, necrosis and pigmented areas in the colonies were studied at the southeastern coast of Cyprus during a prolonged period of higher than average sea temperature anomalies (summer/autumn 2012). With the use of scuba diving and image analysis software, we monitored the extent of mortality of 29 colonies of C. caespitosa by measuring and comparing the area percentage of healthy tissue, affected tissue (bleached, necrotic) and older mortality events (encrusted skeleton). In September 2012, on average, 24 % of the colonies surface area was affected (bleaching and/or necrosis). In October 2012, C. caespitosa showed on average 26.3 % of the colony surface area affected, evidence of continuing deterioration. At the same time, 10 % (3 of 29) of the colonies showed an increase in the pigmentation of previously bleached polyps in small and marginal areas (6–8 %). Irrespective of the amount, the regaining of pigments recorded is considered an important find. Corals and marine organisms in general in the Levantine Sea are affected greatly by warming events, to the extent where a very small percentage of polyps/colonies show resilience under thermal stress. Natural bleaching of C. caespitosa, even though limited to a few colonies and very small portions of tissue/polyps, was documented for the first time in the Levantine Sea. We conclude that temperature anomalies are associated with the mortality event. Whether prolonged higher temperature is the direct cause, or whether it acts synergistically with other factors should be the subject of further investigations.  相似文献   

9.
The structure of genotypic diversity in eight populations of the clonal triploid (2n = 3x = 36) tulip Tulipa riparia inhabiting floodplain communities in the Southern Urals was studied. Analysis of nine polymorphic enzyme systems (ADH, IDH, SkDH, PGI, PGM, FDH, NADHdh, C-EST, GOT) was performed to identify clones. Both monoclonal (D = 0) and polyclonal populations with multiple genotypes from 3 to 12 (D from 0.73 to 0.91) were identified. The polyclonal populations had a high level of heterozygosity. Dispersal of propagules (bulbs) along rivers and even from one bank of a river to the opposite was detected. Some clones disperse along riverbanks to the distance of hundreds meters (up to four kilometres). At the same time, there is an effect of “isolated” or “closed” populations. Almost each sequentially arranged population in one river system have its own set of genotypes. Assessment of the state of the reproductive system components indicates presence of a rare sexual reproduction supporting genetic diversity of T. riparia.  相似文献   

10.
Experimental studies of interactions between two amphipod species (Gmelinoides fasciatus and Gammarus lacustris) showed that predation is the basic mechanism accounting for their mutual exclusion in nature. Mortality from predation among similar-sized specimens of both species at an equal abundance ratio was similar (24–25% in G. lacustris and 27–30% in G. fasciatus). The displacement of G. lacustris by G. fasciatus was observed when the latter was dominant. Adult G. fasciatus and G. lacustris successfully preyed on juveniles of their competitors and did not differ significantly in daily food consumption as a percentage of body weight: 6–24% at a fresh body weight of 18–24 mg in both species. The potential for rapid population growth under new conditions contributed to the success of the invasive Baikal species G. fasciatus in displacing G. lacustris from many water bodies of Russia.  相似文献   

11.
Diet, food preferences and main ecophysiological characteristics such like energy requirements and thermoregulation characteristics of Mus spicilegus spicilegus (Petenyi, 1882) were studied. The most preferred foods for the mice were seeds of weed species that composed more than 85% of their diet. The results of food selection experiments shows that the total daily consumption by mice is 2.77 ± 0.76 g/animal/day or 5.5 kJ/g/day or 84.9 kJ/animal/day. From the total daily energy consumption 16.4% go back to nature in the form of feces and urine and the rest 83.6% animals utilized for assimilation. The results of the temperature preferences for Mus s. spicilegus shows preferred temperature zone from around 26 to 36°C where mice spent about 72% of the experimental time. The lowest value of oxygen consumption for resting metabolism rate (RMR) was registered at 30°C–3.20 ± 0.71 cm3 O2/g/h. It is possible to consider that the thermoneutral zone is around these temperature values. The obtained results give reason to conclude that from an ecophysiologycal point of view the climate in the south boundary of distribution provides optimal conditions for species development. The main cause for population decreasing probably is the loss of open habitats including natural steppe grasslands.  相似文献   

12.
Determined the contribution of root derived CO2 efflux to total CO2 efflux (including root and non-root derived CO2 efflux) is import to grope the mechanism of CO2 efflux, however, becaused of ‘rhizoshere priming effect’ (RPE), it is difficult to achieve in practice. In this study, we attempted to estimate the RPE via comparing basal soil respiration (Rb) achieved by two different methods namely, y-intercept regression and direct bare plot approach in an arid cotton field, central Asia. On the basis of the y-intercept of linear regressions between below-ground respiration (BGR) and root biomass, Rb was indirectly calculated. Comparing with the first approach, the second approach involved direct measurements of soil respiration from bare plots. Rb estimated by y-intercept method contained the component of RPE whereas direct bare plot did not. We found that RPE showed a phenological trend with highest value in flowering stage at 0.145 g CO2 m–2 h–1 and lowest at budding stage (0.007 g CO2 m–2 s–1), even after the data had been corrected for the influence of soil temperature. We concluded that RPE needed to be considered when Rb was estimated by y-intercept approach.  相似文献   

13.
It was studied the tolerance of five spring pea cultivars to Bruchus pisorum based on the weevil damage and chemical composition of seeds related to pea weevil tolerance. From visibly damaged pea seeds by pea weevil was isolated the parasitoid Triaspis thoracica Curtis (Hymenoptera, Braconidae). Cultivars with a lower protein and phosphorus content had a lower level of damage. The crude protein, crude fiber and phosphorus content in damaged seeds significantly or no significantly was increased. Modus, followed Glyans had emerged as tolerant cultivars against the pea weevil. They had the lowest total damaged seed degree, loss in weight of damaged seeds, values of harmfulness coefficient and lower protein and phosphorus content.  相似文献   

14.
Study of the seasonal variation of the sex ratio in the honeybee mite Varroa jacobsoni demonstrated that sex determination was affected by temperature, order of reproductive cycles, and population densities in the host’s brood cell and the honeybee nest. The mechanism of reproduction ensuring adaptation of the mite to parasitism and reproduction on honeybees are discussed.  相似文献   

15.
Accelerated aging of Drosophila strains with impaired detoxification of free radicals (Sod) and DNA repair (mus-210) under illumination as compared to the wild type has been demonstrated. In contrast, in a strain carrying a defective homolog of mammalian gene PCNA, the life span increases under conditions of round-the-clock illumination compared to constant darkness. The first review of the possible mechanisms underlying the effect of the illumination regime on the life span is presented, with special emphasis on the roles of the disturbance of normal circadian rhythms, increase in fecundity and physical activity (metabolic rate), and the neuroendocrine control of the insulin/IGF-1 pathway.  相似文献   

16.
The topic of carbon sequestration in plants has received much attention recently due to concerns about global climate change, which is being exacerbated by deforestation. In the early days of the global bioenergy boom, the private sector and non-government organizations enthusiastically promoted the planting of Jatropha curcas L. as a key candidate shrub species for the production of bioenergy in West Africa. This study investigates the aboveground biomass production and carbon sequestration potential of J. curcas, which is already widely cultivated for the production of oil seeds, biodiesel and biokerosene. The specific objective is to use a destructive method to develop allometric prediction equations of the aboveground biomass production of J. curcas plantations. 38 J. curcas shrubs were harvested and weighed in order to estimate biomass production. These data were used to develop allometric equations for the estimation of wood, leaf and total aboveground biomass production. The best-fit models found for estimating shrub component biomass and total aboveground biomass production were of the power form. All of the regression equations relating the prediction of leaf biomass, wood biomass and total aboveground biomass with J. curcas diameter at 20 cm above the ground (D) were statistically significant (p < 0.001) and also presented the highest goodness of fit (high R 2). The aboveground biomass carbon content was estimated using the ash method. Carbon content in leaves and wood was, respectively, 48 and 54 %. The current established allometric equations can be helpful to provide a rapid estimation of the aboveground biomass and C stock for J. curcas biofuel projects in semi-arid conditions.  相似文献   

17.
Data published in the Handbook on the Climate of the Soviet Union have been used as a basis for estimating the temperature of the soil surrounding the nest chamber during the period of bobak marmot hibernation. Interspecific differences in the temperature conditions of hibernation have been revealed. The hypothesis is substantiated that the dates of hibernation onset in marmots depend on air temperature outside the burrow.  相似文献   

18.
The linear increment of Sphagnum fuscum and S. magellanicum in ombrotrophic mires of Western Siberia has been measured during two years over a transect about 2500 km long extending from forest–steppe to forest–tundra. Along the latitudinal gradient, the increment of both species has proved to be correlated with annual average air temperature and, in S. magellanicum, also with annual precipitation. The determinants of their growth differ between the southern, central, and northern parts of the study region. At the regional level, the annual and summer precipitation plays a more important role than the average air temperature. The increment of S. fuscum in the southern part is positively correlated with the amount of precipitation and negatively correlated with summer temperature, whereas the situation in the central part is inverse. In S. magellanicum, the linear increment is directly dependent on the annual average temperature and annual and summer precipitation in the south and on the annual and summer precipitation in the north of Western Siberia. The dynamics of linear growth of both species in bog pine forests during the growing season are similar: its rate is the highest in June, when the linear increment of S. fuscum and S. magellanicum amounts to 60 and 85% of the annual total, respectively.  相似文献   

19.
Current trends in organic agriculture have led to the need of seeking alternative methods of pest control. For that reason the influence of weather conditions, some morphological and chemical traits of common vetch (Vicia sativa) cultivars–“Liya”, “Loryna”, “Villena”, “Moldavskaya 82” (Moldovan cultivars) and “Obrazets 666” (Bulgarian cultivar), and hairy vetch (V. villosa)–“Violeta” and “Viola” [Moldovan cultivars]) on the dynamic and preference of Acyrthosiphon pisum were determined. Moldovan cultivars belonging to V. sativa were distinguished by lower aphid numbers as they had shorter duration of the flowering period unlike the V. villosa cultivars, where that duration was significantly longer. The plant morphological traits as height, branch, flower and leaflet numbers influenced on the aphid density. The aphid density was affected by branch and leaflet numbers more than by height and flower plant. “Villena” had a shorter vegetative period, lowest flower and leaflet numbers as well as low nitrogen and phosphorus content, which resulted in the lowest A. pisum population. The use of vetch cultivars with some characteristics of tolerance would result in a reduction of losses due to pea aphids. That will provide an environmentally safer option for aphid control.  相似文献   

20.
Molecular genetic methods (AFLP and ITS1–5.8S–ITS2 rDNA analysis) have been used to study the level and structure of genetic diversity in relict populations of the Ural endemic Gypsophila uralensis Less. in the northeast of European Russia. Intraspecific genetic differentiation is most clearly manifested between G. uralensis Less. subsp. pinegensis (Perf.) Kamelin locally endemic to the north of Europe (Arkhangelsk oblast, locus classicus) the population of G. uralensis Less. subsp. uralensis on limestone outcrops along the Shchugor River, the Subpolar Urals. The cluster of Timan populations (on limestone outcrops along the Svetlaya, Pizhma, and Myla rivers) is autonomous and genetically heterogeneous. Genetic distances between model G. uralensis s.l. populations are correlated with geographic distances. The size and abundance of relict populations show a descending gradient in the forest zone, and parameters of their genetic diversity [1] and unbiased expected heterozygosity have been found to decrease along this gradient.  相似文献   

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