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631.
Abstract: Conservation in Europe (including the establishment of protected areas) is undertaken mainly through legislation and on densely populated private land. Consequently, conflicts of interest arise between human economic activities and biodiversity conservation. We used a systematic approach to conservation planning to explore different conservation scenarios for the Apennine populations of wolves (Canis lupus) and bears (Ursus arctos marsicanus) in Italy. The conservation measures we considered were electrified fences and guard dogs to prevent wolves and bears from preying on sheep. We used habitat suitability models of the two species as an estimate of their distributions. Across the study area, we estimated the potential intensity of conflict caused by predation on sheep and the cost of the antipredator measures. We examined scenarios for the conservation of wolves and bears that identified systems of sites where antipredator measures should be applied to either minimize the economic cost of the plan or tackle a predetermined amount of conflict. The overall cost of the conservation plans ranged between €1,486,000 and €16,876,000, depending on the scenario and on the size of the conservation target. Because potential conflict intensity (i.e., potential predation) and cost of conflict resolution were correlated, the scenarios that minimized cost also minimized the amount of conflict that was addressed. Conserving these two species by addressing their predation on sheep was up to 4.36 times more expensive than conserving them by providing suitable habitat in areas of low conflict. Yet avoiding conflicts is not always desirable because it can drastically reduce the options for conservation. Choosing a conservation plan requires consideration of the level of threat to the target species and their sensitivity to conflicts. 相似文献
632.
Cuckoo growth performance in parasitized and unused hosts: not only host size matters 总被引:4,自引:0,他引:4
Tomáš Grim 《Behavioral ecology and sociobiology》2006,60(5):716-723
The quality and quantity of food delivered to young are among the major determinants of fitness. A parental provisioning capacity is known to increase with body size. Therefore, brood parasitism provides an opportunity to test the effects of varying provisioning abilities of different-sized hosts on parasitic chick growth and fledging success. Knowledge of growth patterns of common cuckoo, Cuculus canorus, chicks in nests of common hosts is very poor. Moreover, no study to date has focused on any currently unused hosts (i.e., suitable cuckoo host species in which parasitism is currently rare or absent). Here, I compare the growth performance of cuckoo chicks in nests of a common host (the reed warbler, Acrocephalus scirpaceus) and two unparasitized hosts (the song thrush, Turdus philomelos, and the blackbird, Turdus merula). Parasitic chicks were sole occupants of the observed nests, thus eliminating the confounding effect of competition with host chicks. Experiments revealed striking differences in parasitic chick growth in the two closely related Turdus hosts. Cuckoo chicks cross-fostered to song thrush nests grew much quicker and attained much higher mass at fledging than those in nests of their common reed warbler host. Alternatively, parasitic chicks in blackbird nests grew poorly and did not survive until fledging. I discuss these observations with respect to host selection by parasitic cuckoos. 相似文献
633.
Assisting the genetic parents in the rearing of young, a widespread phenomenon in many birds and mammals, is usually regarded
as an altruistic or mutualistic behavior. Infant handling by females other than the mother is also common in many primates,
but due to high within- and between-species variation and limited knowledge about fitness consequences there is no consensus
about its evolutionary and functional significance. Analysis of female infant-handling patterns and its reproductive consequences
in three groups of semifree-ranging Barbary macaques revealed that nulliparous females significantly more often handled infants
than parous females, but infant handling experience did not affect survival of their own first live-born offspring. Females
interacted preferentially with closely related infants, but infant handling frequency improved neither infant survival nor
maternal fecundity. Reciprocation of infant handling by mothers was rare. Although “aunting to death” occurred in the population,
the hypothesis that infant handling serves to reduce the fitness of competitors was not supported. Limited evidence suggests
that females at least sometimes use infants as strategic tools in the course of alliance formation. In concert with this poor
evidence for a functional basis of the behavior, several lines of evidence support the hypothesis that infant handling evolved
as a non-adaptive by-product of a strong selection for mother-offspring bonding. (1) Rates of infant handling were highest
among females that experienced early infant loss. (2) Females caring for infants or yearlings of their own handled other infants
significantly less often than females without dependent offspring. (3) Infant handling by females was most prevalent during
the infants’ first month of life. (4) Both “aunting to death” and a successful adoption occurred irrespective of kinship relations.
Although the by-product hypothesis appears to be the only one able to explain all results of this study, the apparent rarity
of infant handling in non-female-bonded species suggest that kin selection is a possible alternative explanation for the evolution
of female infant-handling in primates.
Received: 30 December 1995/Accepted after revision: 10 May 1996 相似文献
634.
Secondary sexual characters often provide indicators of a male’s resistance to infectious diseases to rivals and potential
mates, but it is unclear why. It is often suggested that males honestly signal their health due to energetic and other physiological
trade-offs between investing into secondary sexual traits vs resistance to infectious diseases. Our aim was to determine whether
such a trade-off exists using wild-derived male house mice (Mus domesticus). We exposed male mice to female scent, a manipulation that induces elevations in testosterone concentration and the expression
of a variety of testosterone-mediated secondary sexual traits, and tested whether this sexual stimulation impaired the males’
ability to resolve or cope with an experimental infection (Salmonella enterica). We kept the males on a controlled diet to prevent them from compensating by eating more food. We found that sexually stimulated
males were able to control bacterial growth as effectively as sham-stimulated controls; however, to do so, they lost more
body mass during infection compared to the controls. In contrast, we found no evidence that sexual stimulation reduced the
body mass of uninfected male mice. These results indicate that males’ responses to female odor are not immunosuppressive per
se, yet they increase the energetic costs of controlling infection. Our findings support the idea that there is a physiological
trade-off between secondary sexual signaling vs resistance to infectious diseases and suggest that studies using only immunocompetence
assays might fail to detect such energetic trade-offs.
We dedicate this paper to the late Professor Chris Barnard who conducted pioneering research on this topic. 相似文献
635.
王连龙 《中国环境管理干部学院学报》2006,16(2):16-18
《生态保护》在我院是一门重要的课程,也是一门实践性很强的学科,但是目前该课程的实践教学环节还相当薄弱。增建实习实践基地,选择合适的实习路线,拟建相关学科实验室等措施将为该课程的实践教学提供保障。 相似文献
636.
当前面料中难降解成分对环境造成很大程度污染,在服装面料选取时,为避免难降解面料的使用,提出基于近红外光谱的面料难降解成分鉴定分析方法.通过分析服装面料中难降解成分对环境的影响,提取面料中难降解成分,得出三种成分类型,通过对不同成分造成环境污染程度进行鉴定分析,完成服装面料选取时难降解成分的鉴定.实验结果表明,该方法误差控制在-0.2~0.2范围内,能够准确鉴定出服装面料中难降解成分,为降低环境污染提供了有效帮助. 相似文献
637.
L. L. McDonald L. Gonzalez B. F. J. Manly 《Environmental and Ecological Statistics》1995,2(3):225-237
The selection function (which shows how the frequency of sampling units with the value X = x at one point in time must change in order to produce the distribution that occurs at a later point in time) is proposed for describing the changes over time in an environmentally important variable X. It is shown that the theory of selection functions as used in the study of natural selection and resource selection by animals requires some modifications in this new application and that a selection function is a useful tool in long-term monitoring studies because all changes in a distribution can be examined (rather than just changes in single parameters such as the mean), and because graphical presentations of the selection function are easy for non-statisticians to understand. Estimation of the selection function is discussed using a method appropriate for normal distributions and bootstrapping is suggested as a method for assessing the precision of estimates and for testing for significant differences between samples taken at different times. Methods are illustrated using data on water chemical variables from a study of the effects of acid precipitation in Norway. 相似文献
638.
南水北调中线工程与汉江中下游地区农业的持续发展 总被引:7,自引:4,他引:7
南水北调中线工程是指从汉江的丹江口水库引水供给华北地区,同时考虑鄂,豫两省汉江唐白河流域和淮河流域的需水要求的战略性工程,是调整水资源的空白布局,解决我国北方缺水问题的紧迫任务。汉江中下游地区是湖北省的粮仓和重要的产业基地,是汉江流域经济发展的中心。由于调水的影响,汉江丹江口以下的流量及季节性分配将发生变化,航运,水质,农业灌溉,工业生产以及城市发展等将受到不同程度的影响,直接关系到汉江中下游地区 相似文献
639.
《International Journal of Sustainable Engineering》2013,6(4):277-291
The function, cost and environmental performance are the primary decision-making factors for scheme selection in green design. For the comprehensive and accurate decision-making in selecting green product design scheme, a quantitative analysis method of multi-attribute decision-making (MADM) is presented. With analysing the multi-attribute of scheme selection, the MADM model is established, which takes environmental impact of materials, disassembly performance, recycling performance, energy efficiency, noise, pollutants to environmental and functional values. Fuzzy technique for order performance by similarity to ideal solution method is applied to solve this model for the feasible solutions. Finally, a case study is given to validate the application of this methodology as a useful design guideline for scheme selection in green design. 相似文献
640.