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941.
The remote effect of the nuclear polyhedrosis virus on the gypsy moth was studied for the first time under natural conditions.
In the generation that developed from infected eggs, the weight of pupae was reduced, sex ratio was altered, and female fecundity
and egg fertility were lower than in control individuals. The F1 progeny of these moths were characterized by an increased rate of latent virus carriage and high mortality caused by the
combined effect of polyhedrosis and insect parasites. 相似文献
942.
943.
944.
V. V. Tuzhilkina 《Russian Journal of Ecology》2009,40(4):227-232
To estimate the response of conifers to long-term industrial air pollution at the pigment system level, the dynamics of photosynthetic pigments have been studied in needles of Scots pine (Pinus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) growing at different distances from the emission source (a pulp and paper mill). It has been shown that the pigment apparatus of spruce. The results show that in spruce, unlike in pine, the pigment apparatus remains unchanged under the effect of weak pollution. Long-term exposure at high levels of industrial emission results in suppression of chlorophyll and carotenoid syntheses in pine but stimulates pigment production in spruce. An increase in the contents of pigments in the needles of conifers growing in the impact zone of the pulp and paper mill reflects a compensatory mechanism of adaptation of their pigment system to long-term stress exposure. 相似文献
945.
V. E. Zverev 《Russian Journal of Ecology》2009,40(4):254-260
Long-term monitoring of mountain birch populations (1992–2006) was performed in 14 test plots located at distances of 1 to 63 km from the copper-nickel smelter in Monchegorsk (Murmansk oblast) and differing in the degree of disturbance. In the period from 1999 to 2006, atmospheric emissions of sulfur dioxide and heavy metals amounted to only one-third of those between 1992 and 1998, but birch mortality in heavily polluted areas (with nickel concentrations in leaves exceeding 160 mg/kg) remained at the same level, being absent (as previously) in less polluted areas. Throughout the observation period, birch recruitment was observed only in areas where nickel concentrations in the leaves were below 160 mg/kg; i.e., this concentration proved to be the threshold with respect to both mortality and recruitment of mountain birch. The course of demographic processes in its populations has remained unchanged after the reduction of emissions, confirming the hypothesis of the “inertial“ effect of industrial emissions on ecosystems. In some areas of industrial barrens, mountain birch may perish completely within the next decade. 相似文献
946.
S. M. Shafigullina 《Russian Journal of Ecology》2009,40(3):218-226
Interannual changes in geobiont and chortobiont abundance on the islands of Kuibyshev Reservoir are largely determined by flood conditions, because the seasonal average abundance of many taxa is negatively correlated to the water level in May and June. Floods influence the abundance of these animals both directly and indirectly, through biocenotic connections and some aspects of behavior. Long-term positive trends are observed in the abundance of many species. The hypothesis is proposed that this increase in the abundance of geobionts and chortobionts is a consequence of adaptation processes in these communities, which are stimulated by the flood regime of the reservoir. 相似文献
947.
948.
Landscape-geochemical features providing for manifestation of gigantism in herbaceous plants have been revealed in natural habitats in the south of Sakhalin and Kunashir islands. Tall herb assemblages have proved to be associated with geochemical landscapes characterized by reducing (gley or hydrogen sulfide) conditions and increased contents of petroleum hydrocarbons and some trace elements (total and movable forms). A hypothesis is put forward that gigantism in herbaceous plants is manifested in zones of active faults, which serve as a kind of conduits supplying endogenous heat, matter, and water to the root systems. 相似文献
949.
The composition of pied flycatcher (Ficedula hypoleuca Pall.) nestling diet was studied in the zone of strong pollution with emissions from the Middle Ural Copper Smelter (Revda,
Sverdlovsk oblast) and in the background area from 2005 to 2007. The results show that diversity of the diet decreases and
prevalence in it of one insect taxon (Lepidoptera) increases near the source of emissions. The proportion of uncharacteristic
food objects (orthopterans, herpetobiont invertebrates) and variation in the size of invertebrates brought by parents to their
nestlings increase, which is explained by degradation of forest habitats in the polluted area. Pied flycatchers provide nestlings
with sufficient quantities of food, but its quality in the polluted zone is lower than in the background area. 相似文献
950.
Use and knowledge of fuelwood in three rural caatinga (dryland) communities in NE Brazil 总被引:1,自引:0,他引:1
I. M. M. Sá e Silva L. C. Marangon N. Hanazaki U. P. Albuquerque 《Environment, Development and Sustainability》2009,11(4):833-851
The woody species known, used, and preferred as fuelwood were examined in three rural communities within the county of Soledade,
Paraíba State, NE Brazil. Ethnobotanical information was collected using semi-structured interviews with more than 90% of
the local households (55 adult residents; 31 women, and 24 males). The interviewees cited 36 plant species as fuelwoods, distributed
among 30 genera and 15 families, in addition to two unidentified plants. The plant families represented by the largest numbers
of species were Euphorbiaceae, Anacardiaceae, Mimosaceae, Caesalpiniaceae, Sapotaceae, and Fabaceae. The species Caesalpinia pyramidalis Tul. (“catingueira”) was cited with the greatest frequency in all three communities. Within the communities we found significant
differences on the number of plants cited and actually used (p < 0.05), indicating that the residents knew more fuelwood species than they effectively harvest. The different distances
from the communities to the urban centers were not related to differences on the use or the size of the stocks of fuelwood.
Additionally, the study revealed that the communities examined still maintain a significant knowledge of the use of energy-providing
plants in spite of the widespread use of liquefied petroleum gas (LPG).
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献