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441.
为应对气候变化,我国开发性金融部门探索绿色投资倒逼其低碳转型之路,相应的气候变化对其绿色投资的影响和风险值得深入研究。运用气候压力测试模型、WITCH模型和气候VaR对我国开发性金融机构绿色投资的气候冲击影响、气候风险进行实证研究。研究发现,极端气候冲击会对我国的开发性金融机构的投资价值及其投资表现产生负面影响;我国开发性金融机构绿色债券的票面利率受气候变化影响程度各异,国家开发银行随着气温的上升而增加,中国农业发展银行随着气温的下降而减少;我国开发性金融机构绿色投资气候风险各异,中国农业发展银行绿色投资的气候风险相对较大。研究成果为我国开发性金融部门应对气候变化的低碳转型和绿色投资的风险管理提供决策参考。 相似文献
442.
Cristina Lazaro-Perea Charles T. Snowdon Maria de Fátima Arruda 《Behavioral ecology and sociobiology》1999,46(5):313-324
Scent-marking in mammals has been frequently related to within-group social and reproductive dominance and to defense of
territory and resources. We studied the scent-marking behavior of five wild groups of common marmosets, Callithrix jacchus, during 5 months of the fruiting season in northeastern Brazil. Circumgenital marking was the most common type of marking.
Marks were distributed throughout the home range and were deposited mainly during travel and intergroup encounters. Although
marks were commonly deposited at gum trees, there was no evidence that the animals used scent marks to label fruiting trees
or sleeping sites. Contrary to expectations, reproductively dominant females did not mark more than reproductively subordinate
females. Moreover, during intergroup encounters, reproductively subordinate females displayed higher frequencies of scent-marking
than the reproductively dominant females of their group. Our results suggest that scent-marking is not strictly tied to reproductive
dominance or territorial (or resource) defense in common marmosets. Because marks provide information about individual identity
and reproductive condition, scent marks could serve different functions when used by different individuals. The high frequency
of marking by reproductively subordinate females during intergroup encounters suggests that scent-marking might be used to
signal to individuals of neighboring groups. Our data highlight the importance of social and ecological variables in scent-marking
behavior.
Received: 26 October 1998 / Received in revised form: 20 May 1999 / Accepted: 30 May 1999 相似文献
443.
秦天宝 《城市环境与城市生态》1999,12(5):61-62,F003
为调整外商中的投资环境保护问题,我佃环境法已经形成了一个包括宪法性规范,专项单行立法,地方性法规及国际公约等多层次的法律框架。我国将外商投资项目分为鼓励允许、限制禁止四类,并规定了外商投资应遵循的若干环境管理措施。但总体上看我国环境法还存在立法和执法缺陷,亟待完善。 相似文献
444.
The primates of Madagascar (Lemuriformes) are unusual among mammals in that polygynous species lack sexual dimorphism, and
females dominate males socially in most species. Moreover, lemur groups are relatively small and characterized by even adult
sex ratios despite the fact that one male should be able to exclude other males from the group. One hypothesis to explain
this combination of behavioral, morphological, and demographic traits (the “lemur syndrome”) postulates that male–male competition
is relaxed and, hence, variance in male reproductive success is low. Reproductive skew theory provides a framework for testing
this and several related predictions about lemur social evolution. Specifically, low reproductive skew is also predicted if
dominant males or adult females make reproductive concessions to subordinates or if the latter group successfully pursues
alternative reproductive tactics. However, suitable data on paternity, demography, and behavior for a conclusive test of these
predictions have not been available in the past. In this paper, we show that male reproductive success in ten groups of Verreaux’s
sifakas (Propithecus verreauxi) was extremely skewed in favor of the dominant male over 9 years. Our genetic analyses also revealed that more than a third
of all groups are effectively harem groups because only one male was unrelated to the resident female(s). In groups with two
or more non-natal males, the dominant sired 91% of 33 infants. Together, males pursuing one of several alternative reproductive
tactics, such as roaming among several groups or immigrating peacefully, sired only 11% of infants. Thus, female sifakas do
not control group composition by offering reproductive opportunities to subordinate males as staying incentives, intrasexual
selection is not relaxed, and dominant males prevail in a tug-of-war over subordinate males. Because male reproductive skew
in sifakas is even more pronounced than in harem-living anthropoids studied to date, intrasexual selection is clearly not
relaxed, and the lemur syndrome is more puzzling than ever. 相似文献
445.
Dominance status influences the fitness of many mammals. Using African striped mice Rhabdomys pumilio, we tested whether (1) dominant females have greater reproductive success than subordinate females, (2) dominant females
influence the reproductive output of subordinate females when they are housed in close proximity, (3) reproductive output
of a female changes in response to the dominance status of her neighbours, and (4) whether prolonged association between individuals
influences the variance in reproductive success between dominants and subordinates (i.e. the ‘dear enemy’ phenomenon). The
size and mass of litters of dominants increased significantly when housed adjacent to subordinates than when housed apart.
The litter size and mass of subordinates remained unchanged, although subordinates spent significantly more time with their
pups when housed close to dominants than when housed apart; time spent with pups by dominants remained unchanged. Moreover,
females modified their reproductive output and behaviour in relation to the dominance status of their neighbours. Following
prolonged association, dominants still had greater reproductive success, but now, the time spent with pups decreased in subordinates.
We suggest that dominants adopt a strategy to increase the reproductive value of their litter, whereas subordinates adopt
a pup defence strategy. These strategies are flexible and are influenced by the dominance status and period of association
between neighbours, so that females could maximize their fitness in response to varying social conditions. 相似文献
446.
Masashi Kiyota Stephen J. Insley Stacey L. Lance 《Behavioral ecology and sociobiology》2008,62(5):739-746
We conducted a 6-year longitudinal behavioral and genetic investigation of a highly polygynous pinniped, the northern fur
seal (Callorhinus ursinus), to determine the contribution of terrestrial polygyny to male fertilization success and to assess the occurrence of alternative
mating strategies. Genetic samples from 37 adult males, 50 adult females, and 85 pups were collected and genotyped using five
polymorphic microsatellite loci. Pup paternity was assigned using Cervus 2.0 at 99% confidence level. Paternity of 83 pups
(98%) was assigned to terrestrial males who held territories or stayed temporarily in the study area during the breeding season
when fertilization occurred. For 56 pups of which attendance records of their mothers were available, paternity of 45 pups
(80%) was assigned to the associate males in whose territory their mothers stayed during the perioestrus period. In addition
to defending breeding territories, territorial males have often been observed attempting to forcibly abduct adult females
from adjacent territories (female stealing): We observed a total of 95 such cases, in which the stealers had significantly
fewer females than the territorial males from whose territories they stole females. Our results indicate that terrestrial
resource-defense polygyny is the major mating system in this species and that nonassociated paternity occurs mostly as a result
of alternative mating strategies of less successful males. Male northern fur seals thus appear to adopt conditional alternative
strategies that depend on their current social status to maximize their life-time reproductive success. 相似文献
447.
We investigated the effects of population fluctuation on the offspring’s sex allocation by a weakly polygynous mouse, Apodemus argenteus, for 3 years. In acorn-poor seasons, heavier mothers invested more in sons, and lighter mothers invested more in daughters.
In acorn-rich seasons, heavier mothers invested more in daughters, and lighter mothers invested more in sons. Maternal body
condition and litter size affected the sex allocation. Furthermore, there was a maternal investment trade-off between a son’s
birth mass and the number of daughters. Based upon the effect of population fluctuation on the lifetime reproductive success
of each sex, we proposed the new “safe bet hypothesis”. This hypothesis predicts that frequent and unpredictable change in
female distribution, which is often caused by abrupt fall in food condition, favors female-biased maternal investment to offspring
by polygynous mammals and is applicable to many small mammals inhabiting in unstable environments. 相似文献
448.
Michael J. L. Magrath Peter Santema Karen M. Bouwman Dušan M. Brinkhuizen Simon C. Griffith Naomi E. Langmore 《Behavioral ecology and sociobiology》2009,63(5):661-672
Reproductive success within populations often varies with the timing of breeding, typically declining over the season. This
variation is usually attributed to seasonal changes in resource availability and/or differences in the quality or experience
of breeders. In colonial species, the timing of breeding may be of particular importance because the costs and benefits of
colonial breeding are likely to vary over the season and also with colony size. In this study, we examine the relationship
between timing of breeding and reproductive performance (clutch size and nest success) both within and between variable sized
colonies (n = 18) of fairy martins, Petrochelidon ariel. In four of these colonies, we also experimentally delayed laying in selected nests to disentangle the effects of laying
date and individual quality/experience on reproductive success. Within colonies, later laying birds produced smaller clutches,
but only in larger colonies. The general seasonal decline in nest success was also more pronounced in larger colonies. Late
laying birds were generally smaller than earlier laying birds, but morphological differences were also related to colony size,
suggesting optimal colony size also varies with phenotype. Experimentally delayed clutches were larger than concurrently produced
non-delayed clutches, but only in larger colonies. Similarly, delayed clutches were more likely to produce fledglings, particularly
later in the season and in larger colonies. We suggest that the reduced performance of late breeding pairs in larger colonies
resulted primarily from inexperienced/low quality birds preferring to settle in larger colonies, possibly exacerbated by an
increase in the costs of coloniality (e.g., resource depletion and ectoparasite infestations) with date and colony size. These
findings highlight the importance of phenotype-related differences in settlement decisions and reproductive performance to
an improved understanding of colonial breeding and variation in colony size. 相似文献
449.
450.
Testing genuine savings as a forward-looking indicator of future well-being over the (very) long-run
David Greasley Nick Hanley Jan Kunnas Eoin McLaughlin Les Oxley Paul Warde 《Journal of Environmental Economics and Management》2014
Genuine Savings (GS) have been much used in recent years as an indicator of a country's sustainability. According to some theorists (e.g. Arrow et al., 2012), under certain conditions a country with a positive level of GS should experience non-declining future utility, given the assumption of unlimited substitutability among all forms of capital (sometimes called “weak” sustainability). This paper reports the first very long-run tests of GS (also called comprehensive investment or adjusted net savings) as a forward-looking indicator of future well-being. We assemble data for British capital back to 1765, and construct several net investment measures which are used as indicators of two alternative measures of future well-being: consumption per capita and real wages. An allowance for a “value of time” due to exogenous technological progress is included in some GS measures, and we demonstrate the importance of this measure and the choice of discount rate over the very long-run. On the whole, our results do not reject the postulated relationship between GS and future well-being, and show GS can be a forward looking indicator of future well-being for periods of up to 100 years. 相似文献