昔日丹麦的家畜管理方式对景观中植物种子散布的影响

目前,北欧自然(半自然)生境中物种丰富度的降低很大程度上归咎于生境破坏以及由此而导致的植物种子在破碎化生境之间扩散的局限性.尽管一些生境可能早已从以往的景观中分割出去,但是那些分割部分的隔离程度可能不及目前的状态.本文试图从三个空间尺度上寻求家畜在昔日农业景观中充当植物繁殖体载体的证据.家畜充当植物种子散布者主要在以下三个尺度具有重要意义:在景观中自由活动(1～10 km);驱使动物摄食坚果以及将动物赶到庄园(10～50km):将活的牲畜输送出去(数百公里).对于大多数植物物种来说,在现代景观中扩散的机会大为减少了,其结果可能导致诸如草原、草地和荒野等自然(半自然)植物群落物种丰富度的减少.     

Boating and navigation activities influence the recruitment of fish in a Baltic Sea archipelago area

We studied the effects of boating and navigation activities on the recruitment of coastal fish in the Stockholm archipelago in the NW Baltic proper. The impacts were quantified by sampling metamorphosed young-of-the-year (Y-O-Y) fish in inlets adjacent to i) routes for medium-sized passenger ferries; ii) berths (small marinas) with small boats; and iii) references. Species with high preference for vegetation were negatively influenced by boating and navigation activities and species with low preference positively influenced. Pike (Esox lucius) Y-O-Y were significantly more abundant in reference areas, while bleak (Alburnus alburnus) were more abundant in dredged marinas. No statistically significant patterns were identified for perch (Perca fluviatilis) although there was a trend of low abundance along ferry routes. Many species of nearshore fishes are dependent on submerged vegetation as spawning and larval substrate, structural refuge and feeding habitat. Our results suggest that the negative effects from boating and navigation activities on the coverage and height of vegetation, especially on species of Chara and Potamogeton spp., may contribute to changes in the Y-O-Y fish community.     

Speciation and leachability of copper in mine tailings from porphyry copper mining: influence of particle size

Mine tailing from the El Teniente-Codelco copper mine situated in VI Region of Chile was analysed in order to evaluate the mobility and speciation of copper in the solid material. Mine tailing was sampled after the rougher flotation circuits, and the copper content was measured to 1150 mg kg (-1) dry matter. This tailing was segmented into fractions of different size intervals: 0-38, 38-45, 45-53, 53-75, 75-106, 106-150, 150-212, and >212 microm, respectively. Copper content determination, sequential chemical extraction, and desorption experiments were carried out for each size interval in order to evaluate the speciation of copper. It was found that the particles of smallest size contained 50-60% weak acid leachable copper, whereas only 32% of the copper found in largest particles could be leached in weak acid. Copper oxides and carbonates were the dominating species in the smaller particles, and the larger particles contained considerable amounts of sulphides.     

Aerobic biodegradation of vinyl chloride and cis-1,2-dichloroethylene in aquifer sediments

Laboratory batch experiments have been performed with sediment and groundwater obtained from two sites in Denmark to study the aerobic biodegradation of vinyl chloride (VC) and cis-1,2-dichloroethylene (c-1,2-DCE) to assess the natural aerobic biodegradation potential at two sites. The experiments revealed that VC was degraded to below the detection limit within 204 and 57 days at the two sites. c-1,2-DCE was also degraded in the experiments but not completely. At the two sites 50% and 35% was removed by the end of the experimental period of 204 and 274 days. The removal of c-1,2-DCE seems to occur concomitantly with VC indicating that the biodegradation of c-1,2-DCE may depend on the biodegradation of VC. However, in both cases natural groundwater was mixed with sediment and consequently there may be other compounds (e.g. ammonium, natural organic compound etc.) that serves as primary substrates for the co-metabolic biodegradation of c-1,2-DCE. At one of the sites methane was supplied to try to enhance the biodegradation of VC and c-1,2-DCE. That was successful since the time for complete biodegradation of VC decreased from 204 days in the absence of methane to 84 days in the presence of methane. For c-1,2-DCE the amount that was biodegraded after 204 days increased from 50% to 90% as a result of the addition of methane. It seems like a potential for natural biodegradation exists at least for VC at these two sites and also to some degree for c-1,2-DCE.     

The first haramiyoid mammal from Asia

A lower molar of a haramiyoid mammal is described from the Toutunhe Formation of Liuhuanggou near Urumqi in the southern Junggar Basin, Xinjiang, China. It is referred to Eleutherodon sp., otherwise exclusively known from the Upper Bathonian of England. It is the first record of the order Haramiyida from Asia and the first Mesozoic mammal described from the southern Junggar Basin. Apart from the English specimens of Eleutherodon and Staffia from the Upper Jurassic of East Africa, it is the geologically youngest haramiyoid known. It is the first vertebrate taxon from the Toutunhe Formation that is probably not endemic and lends some support to the dating of the Formation as late Middle Jurassic, probably Bathonian.

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Environmental accounts for households: A method for improving public awareness and participation

Recently the European Council agreed on a CO₂ reduction target of 10% by the year 2010. In accordance with this, Denmark decided to reduce its CO₂ emissions by 25% over the same time period. One important element of both the European and Danish agreements is energy saving in industries and in private households. Typically industries and private households are also expected to participate in other kinds of environmental improvements, e.g. waste treatment. Such improvements in environmental performances are normally accounted for. In industry, for example, green accounting or environmental auditing are techniques used to measure progress in environmental performance. But when it comes to the environmental performance of people or households very few book-keeping principles have been developed. This paper describes a Danish share-housing project's efforts to formulate an environmental policy and outline an environmental accounting system which can keep track of a household environmental record. It describes the environmental accounting methods, the results and experiences from its first five years.     

MHC, health, color, and reproductive success in sand lizards

Good genes are genetic elements that contribute to lifetime reproductive success, regardless of an individuals additional genotype. Their existence is debated, and most work has targeted their viability benefits to the offspring of choosy females. In the present study, we analyze a case of potential good genes effects in adult male sand lizards (Lacerta agilis). We show that males with a particular RFLP (Restriction Fragment Length Polymorphism) MHC genotype (O-males), as opposed to those that lack this genetic element (NO-males), have less ectoparasites under increasing physiological stress (indexed by baseline corticosterone level), and are not constrained by parasites at production of status coloration. Furthermore, O-males are more successful at mate acquisition and guard their partners longer. Ultimately, they have a higher genetic reproductive success as assigned by microsatellites.Communicated by W. Cooper     

Paternal care in the European starling,Sturnus vulgaris: nestling provisioning

The extent to which male birds in polygynous species with biparental care assist in nestling feeding often varies considerably between nests of different mating status. Both how much polygynous males assist and how they divide their effort between nests may have a profound effect on the evolution of mating systems. In this study we investigated how males in the facultatively polygynous European starling Sturnus vulgaris invested in their different nests. The amount of male assistance affected the quality of the offspring. Polygynous males invested as much as monogamous males, but divided their effort asymmetrically between nests, predominantly feeding nestlings of first-mated (primary) females. Although females partly compensated for loss of male assistance, total feeding frequency was lower at primary females’ nests than at monogamous females nests. Secondary females received even less assistance with nestling rearing, and the extent to which males assisted decreased with the length of the interval between the hatching of the primary and secondary clutches. These results are contrasted with those from a Belgian populations of starlings with a much more protracted breeding season and thus greater opportunities for males to attract additional mates during the nestling rearing period. The results show that both the “defence of male parental investment model” and the “asynchronous settlement model” have explanatory power, but that their validity depends on the potential length of the breeding season. Received: 21 July 1995/Accepted after revision: 13 July 1996     

Begging affects parental effort in the pied flycatcher, Ficedula hypoleuca

It has been suggested that nestlings use begging to increase their share of parental resources at the expense of current or future siblings. There is ample evidence that siblings compete over food with nestmates by begging, but only short-term effects of begging on parental provisioning rates have been shown. In this study, we use a new experimental design to demonstrate that pied flycatcher (Ficedula hypoleuca) nestlings that beg more are able to increase parental provisioning rates over the major part of the nestling period, thus potentially competing with future siblings. Parents were marked with microchips so that additional begging sounds could be played back when one of the parents visited the nest. By playing back begging sounds consistently at either male or female visits, a sex difference in provisioning rate that lasted for the major part of the nestling period was induced. If each parent independently adjusts its effort to the begging intensity of nestlings, begging may also be the proximate control mechanism for the sexual division of labour. Received: 24 January 1997 / Accepted after revision: 30 August 1997