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301.
城市绿地降低空气中含菌量的生态效应研究 总被引:24,自引:0,他引:24
按照大气生物监测的方法和要求,选择了上海市区的交通干通。公园和居住区的主要类型的绿地,对绿地降低气挟菌数量的生态效应进行了初步研究,结果表明,绿地结构,植物种类配置和粉尘污染是影响绿地降低气挟菌数量效应的主要因素。 相似文献
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Markus??stEmail author Ron?Ydenberg Kai?Lindstr?m Mikael?Kilpi 《Behavioral ecology and sociobiology》2003,54(5):451-457
Both theoretical and empirical work has shown that group size increases with increasing ecological constraints on solitary breeding. Ecological constraints refer to extrinsic factors such as availability of breeding sites, food or mates. Common eider (Somateria mollissima) females pool their broods and share brood-rearing duties, or rear broods alone. Females are often in poor condition at hatching, as incubation is accomplished without feeding, and variation in body condition is largely environmentally induced and thus unpredictable. We found that the intensity of and duration of parental care that females provide is positively correlated with their body condition at hatching. This suggests that body condition is an ecological constraint on successful solitary breeding. We further observed that group productivity in common eider broods is a decelerating function of the number of tending females. As predicted, females in poorer condition (i.e., facing stronger ecological constraints) were found in larger groups. This result is straightforward if solitary tenders can enter any group at no cost. However, if entry is group-controlled, stable groups of non-relatives are predicted not to occur when per capita reproduction declines with group size. The N-person staying incentive model permits groups to form under these conditions, because reproduction is unevenly divided between dominants and subordinates in the group. We discuss the plausibility of these alternative models of group size for understanding the grouping behavior of brood-caring female common eiders.Communicated by M. Webster 相似文献
305.
Modelling the responses of the Lagoon of Venice ecosystem to variations in physical forcings 总被引:1,自引:0,他引:1
A Finite Element Ecological Model for the Lagoon of Venice (VELFEEM) has been used to test the responses of the Lagoon of Venice ecosystem to variations in physical conditions.The model is obtained by coupling a finite element hydrodynamic model, that computes the velocity fields of water, an energetic model to compute the water temperature fields, and an ecological model that simulates the dynamic of phytoplankton, zooplankton, nutrients (ammonia, nitrate and phosphate) organic detritus (organic nitrogen, organic phosphorous and CBOD) and dissolved oxygen.The transport model is a two-dimensional barotropic finite element model which allows for a better resolution of the lagoon morphology.The ecological model has been developed by starting from the ecological module EUTRO of WASP (Water Analysis Simulation System released by US EPA), and by adapting it to the peculiarity of the Lagoon of Venice.A reference condition has been identified by running a 1-year simulation under climatologic condition. Then, the sensitivity to physical forcing (tide and wind) and to the input of macronutrients has been investigated, by comparing model predictions of spatial and temporal evolution of major state variables and of an aggregate index of Water Quality Trophic Index (TRIX). 相似文献
306.
Brooke L. Sargeant Aaron J. Wirsing Michael R. Heithaus Janet Mann 《Behavioral ecology and sociobiology》2007,61(5):679-688
Because behavioral variation within and among populations may result from ecological, social, genetic and phenotypic differences,
identifying the mechanism(s) responsible is challenging. Observational studies typically examine social learning by excluding
ecological and genetic factors, but this approach is insufficient for many complex behaviors associated with substantial environmental
variation. Indian Ocean bottlenose dolphins (Tursiops sp.) in Shark Bay, Western Australia show individual differences in foraging tactics, including possible tool use with marine
sponges and social learning may be responsible for this diversity. However, the contributions of ecological factors to the
development of these foraging tactics were not previously investigated. Here, we determined the relationship between ecological
variables and foraging tactics and assessed whether differences in habitat use could explain individual differences in foraging
tactics. We monitored 14 survey zones to identify how foraging tactics were spatially distributed and matched behavioral data
to the ecological variables within each zone. Three of four foraging tactics were significantly correlated with ecological
characteristics such as seagrass biomass, water depth, presence of marine sponges and season. Further, individual differences
in habitat use were associated with some tactics. However, several tactics overlapped spatially and previous findings suggest
demographic and social factors also contribute to the individual variation in this population. This study illustrates the
importance of environmental heterogeneity in shaping foraging diversity and shows that investigating social learning by ruling
out alternative mechanisms may often be too simplistic, highlighting the need for methods incorporating the relative contributions
of multiple factors. 相似文献
307.
Diego Rubolini Maria Romano Roberta Martinelli Barbara Leoni Nicola Saino 《Behavioral ecology and sociobiology》2006,59(4):549-560
Mothers may profoundly affect offspring phenotype and performance by adjusting egg components, including steroid hormones.
We studied the effects of elevated prenatal testosterone (T) exposure in the ring-necked pheasant on the expression of a suite
of male and female traits, including perinatal response to stress, immune response, growth, and secondary sexual traits. Prenatal
T levels were increased by injecting the yolk of unincubated eggs with physiological doses of the hormone. Yolk T injection
resulted in a reduced length of male tarsal spurs, a trait which positively predicts male success in intra- and intersexual
selection and viability, whereas no direct effect on male wattle characteristics or plumage traits of either sex was observed.
Female spur length was also negatively affected by T, but to a lesser extent than in males. In addition, the covariation between
male secondary sexual traits, which are reliable quality indicators, differed between T and control males, suggesting that
the manipulation may have altered the assessment of overall male quality by other males and females. In conclusion, the negative
effects of elevated yolk T on spur length, a trait which positively predicts male fitness, coupled with the lack of effects
on growth or other traits in both sexes, provided limited evidence for mothers being subjected to a trade-off between positive
and negative consequences of yolk T deposition on offspring traits and suggest that directional selection for reduced yolk
T levels may occur in the ring-necked pheasant. 相似文献
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309.
乡镇铝厂大气氟污染对区域冬小麦生长影响的研究 总被引:2,自引:0,他引:2
通过对郑州市某乡镇电解铝厂附近的参气,土壤及冬小麦等生态因素含氟量的分析与研究,表明:(1)铝厂所排放的化物是造成冬小麦减产的主要原因:(2)冬小麦各部位器官含量与距污染源的距离呈负相关;(3)对电解铝生产过程排放的气态氟化物应采取相应的治理和防护措施。 相似文献
310.
抓住呼伦贝尔市建设生态市的历史机遇,促进辉河国家级自然保护区的全面发展 总被引:1,自引:0,他引:1
当前呼伦贝尔市正在进行生态市建设,本文就辉河自然保护区在生态环境建设中发挥的作用及其需要采取的措施作了简要分析。 相似文献