Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

 CO₂ and N₂ anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO₂ spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated. Received: 26 August 1999 / Accepted in revised form: 22 December 1999     

Goose management schemes to resolve conflicts with agriculture: Theory,practice and effects

In 2012, the four countries hosting the Svalbard population of pink-footed goose Anser brachyrhynchus along its flyway launched an International Species Management Plan for the population. One of the aims was to reduce conflicts between geese and agriculture to an acceptable level. Since 2006, Norway has offered subsidies to farmers that provide refuge areas for geese on their land. We evaluate the mid-Norwegian goose management subsidy scheme, with a view to its adjustment to prevailing ecological and socio-economic parameters. The analysis indicates that the legitimacy of the scheme is highly dependent on transparency of knowledge management and accountability of management scheme to the farming community. Among farmers, as well as front-line officials, outcomes of prioritisation processes within the scheme are judged unfair when there is an evident mismatch between payments and genuine damage. We suggest how the scheme can be made more fair and responsive to ecological changes, within a framework of adaptive management.     

Scaring as a tool to alleviate crop damage by geese: Revealing differences between farmers’ perceptions and the scale of the problem

Expanding populations of farmland foraging geese are causing escalating conflict with agriculture. We used questionnaires to investigate farmers´ perceptions in mid-Norway of spring staging geese and the extent to which they attempt to reduce pasture damage by goose scaring. We predicted farmers’ scaring effort (a measure of dissatisfaction) to increase on fields closer to goose roosting sites where goose grazing intensity was highest (measured by dropping counts). Results showed no such relationship, suggesting that farmers’ perception of goose use was not linked to actual goose use, but influenced by sociological factors and individual opinion. These results confirm the need to distribute subsidies/compensation to affected farmers based upon quantifiable measures of goose use rather than complaint levels. To avoid further conflict escalation, it is equally important that managers are aware of farmers´ perceptions and their causes, to effectively target communication about policies and measures to mitigate goose–agriculture problems.     

Aerobic and anaerobic transformations of sulfide in a sewer system--field study and model simulations.

The formation and fate of sulfide in a force main and a downstream-located gravity sewer were investigated in an extensive field study. Sulfide formation in the force main was significant. However, during 14 minutes of transport in the gravity sewer, the sulfide concentration decreased 30%, on average. An application of a conceptual sewer process model for simulating the formation and fate of sulfide was demonstrated. Overall, the model predicted that approximately 90% of the decrease of the sulfide concentration in the gravity sewer was the result of sulfide oxidation and that only a small fraction entered the sewer atmosphere, causing odor and corrosion. Even so, the model predicted concrete corrosion rates of up to 1.2 mm/y in the gravity sewer section.     

Annual population development and production by small copepods in Disko Bay,western Greenland

The population of small copepod species (approximately <1 mm) were investigated during an annual cycle in Disko Bay, western Greenland. The small species considered were Acartia longiremis, Pseudocalanus spp., Oithona spp., Oncaea spp., Microsetella spp., and Microcalanus spp. Most of the small species were present in the surface waters year round and numerically dominated the community, and in biomass from late summer and throughout winter. Oithona spp. was numerically the main contributor, while Pseudocalanus spp. dominated in terms of biomass. In the uppermost 50 m, maximum abundance, biomass and secondary production were observed in late September after the phytoplankton production practically had terminated and the winter initiated. The free spawning Acartia longiremis showed a strong seasonal fluctuation in biomass and egg production, in contrast to the egg carrying species Pseudocalanus spp. and Oithona spp. These had a long spawning season and maintained a more stable biomass year round. Secondary production was estimated by three different ways: (1) based on the obtained specific egg production rates, (2) a temperature dependent equation, and (3) a multilinear regression taking temperature, body weight and chlorophyll into consideration. The contribution of the small species was insignificant when compared to the large Calanus species during the spring- and post-bloom. However, during late summer and winter, where Calanus had left the upper water strata for hibernation, the small species played a crucial role in the pelagic carbon cycling.     

Male sperm whale (Physeter macrocephalus) acoustics in a high-latitude habitat: implications for echolocation and communication

Sperm whales (Physeter macrocephalus) are deep-diving predators foraging in meso- and bathypelagic ecosystems off the continental shelves. To investigate the ecophysiological and communicative function of various click types from male sperm whales in a high-latitude habitat, we deployed a large-aperture array of calibrated hydrophones off northern Norway (N69, E15). Data show that sperm whales in this habitat produce three click types: usual clicks, creak clicks and, occasionally, slow clicks. Usual clicks and creak clicks exhibit short duration, profound directionality and a frequency content suited for echolocation on meso- and bathypelagic fish and squids. The acoustic properties and low repetition rate of usual clicks are suited for long-range echolocation, whereas creak clicks have properties equivalent to signals in buzzes, the terminating pulse trains known from echolocating bats during prey capture. From these source parameters and the high acoustic activity during foraging dives, it is concluded that echolocation is an important sensory cue in prey location. Sound pressure levels of creak clicks and usual clicks measured off the acoustic axis suggest that sperm whales may be subjected to eavesdropping by conspecifics, thereby conveying information about food aggregations at estimated ranges of 6 km for creak clicks and 16 km for usual clicks. Slow clicks exhibit low directionality, low-frequency emphasis and a reduced repetition rate, suggesting that this click type is more suited for communication than for echolocation. Slow clicks can be detected by submerged conspecifics at ranges up to 60 km. Thus, sperm whales producing slow clicks may represent an odontocete species that utilizes long-range sound communication.     

Female choice on male quantitative traits in lizards — why is it so rare?

Female choice on the basis of male traits has been described in an array of taxa but has rarely been demonstrated in reptiles. In the sand lizard (Lacerta agilis), and possibly in other non-territorial reptiles, a male's contribution to a female's fitness is restricted to his genes. In order to choose males of high genetic quality, females have to trade the fitness gain against the costs of active choice. In a Swedish population of sand lizards, long-lived males sired offspring with higher embryonic survival compared to offspring sired by short-lived males. In spite of this female sand lizards did not mate selectively with older and/or larger males. There appeared to be mo reliable cues to male longevity; age-specific male body size was highly variable. Furthermore, estimates of male nuptial coloration did not covary with ectoparasite load and, hence, females cannot use male coloration as a cue to heritable resistance to pathogenic parasite effects. When cues to male genetic quality are poor, or inaccurate, and males make no parental investment, we predict that female choice will be rare. Sand lizard females mating with many partners lay clutches with higher hatching success. Thus, females may obtain good genes for their young by multiple mating, thereby avoiding costs associated with mate choice.     

产业与环境：丹麦展望

近20-30年来,很多国家引进了综合性环境保护法律.然而,人们逐渐认识到,在进行具体技术调控的同时,也需要意识上和管理原则上的改变.为帮助各公司在公司层次上减少、评估、监测和控制环境影响,已经开发了各种环境管理技术.本文根据对丹麦公司的一次调查,论述了下列问题:这些技术是如何在工业中采用的?以及发生态度上的变化了吗?     

Key actions towards the sustainable management of European geese

Increasing abundance of geese in North America and Europe constitutes a major conservation success, but has caused increasing conflicts with economic, health and safety interests, as well as ecosystem impacts. Potential conflict resolution through a single, ‘one size fits all’ policy is hindered by differences in species’ ecology, behaviour, abundance and population status, and in contrasting political and socio-economic environments across the flyways. Effective goose management requires coordinated application of a suite of tools from the local level to strategic flyway management actions. The European Goose Management Platform, established under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds, aims to harmonise and prioritise management, monitoring and conservation efforts, sharing best practice internationally by facilitating agreed policies, coordinating flyway efforts, and sharing and exchanging experiences and information. This depends crucially upon adequate government financing, the collection of necessary monitoring data (e.g., on distribution, abundance, hunting bags, demography, ecosystem and agricultural damage), the collation and effective use of such data and information, as well as the evaluation of outcomes of existing management measures.