A field study of the toxicity of two oils and a dispersant to the mangrove Avicennia marina

The relative toxicities of Arabian Light crude oil, Tirrawarra crude oil, Dispersant BP-AB, and mixtures of oils and dispersant were assessed on 30 mangroves, Avicennia marina (Forsk.) Vierh. var. resinifera (Forst.) Bakh., in a coastal fringe on the eastern shore of Gulf St. Vincent, South Australia. Five treatments were applied: 100% Arabian Light crude oil, 100% Tirrawarra crude oil, Arabian Light crude oil plus dispersant (1:1), Tirrawarra crude oil plus dispersant (1:1) and 100% dispersant. Five mangroves were used for each of the treatments and five as controls. Defoliation, leaf damage, pneumatophore damage, flowering and fruiting were monitored for three years (September 1982–September 1985). Initially, the toxicity of both oils was increased by the addition of dispersant; Tirrawarra crude oil plus dispersant caused significant defoliation. 100% Tirrawarra crude oil was more toxic than 100% Arabian Light crude oil; the former caused significant leaf damage from Week 4 to Week 12 after treatment. After Week 49 production of new leaves was significantly greater in the Arabian Light crude oil plus dispersant treatment than with the Arabian Light crude oil. No such difference was found between the Tirrawarra treatments. Twelve to 26 weeks after treatment, partial pneumatophore damage was observed in all treatments. No atypical flower or fruit production was observed.     

未来决策的工具:货币与生物物理学指标相结合

考虑货币指标信息的利害,关系到一个国家的财富,它对于保护国家财富、维护国家经济命脉是不可或缺的 .生物物理学指标的考虑,则关系到国内和全球天然资产的使用 .经济命脉的维护有赖于基本的生态贡献,诸如可更新和不可更新资源、废物的消纳与稳定的气候条件等 .这两项计量指标共同为决策者们提供了经济与生态生存能力的详尽资料 .这样一种方法也可以用来解释国家与全球之间的可持续性关系,以及参与政策的制定 .     

Biology and population dynamics of the intertidal isopod Cirolana harfordi

The distribution of Cirolana harfordi (Lockington) populations is determined largely by the availability of loose boulders on sandy beaches. The isopods swim out from under the rocks at high tide to feed. Their diet consists primarily of minute polychaetes and crustaceans. In addition, the isopods locate and utilize any available dead animal matter in the surf zone. Breeding occurs throughout most of the year, except for a brief lull in the fall. Females produce 1 or 2 broods of 18 to 68 young during their 2-year life-span. Marsupial incubation lasts 3 to 4 months. The population size and structure remained relatively constant from one year to the next. Mortality rates estimated for juveniles, males and females showed that newly emergent young and post-reproductive females suffer the greatest losses (up to 75% mortality per month).     

Cumulative ecological and socioeconomic effects of forest policies in coastal Oregon.

Forest biodiversity policies in multi-ownership landscapes are typically developed in an uncoordinated fashion with little consideration of their interactions or possible unintended cumulative effects. We conducted an assessment of some of the ecological and socioeconomic effects of recently enacted forest management policies in the 2.3-million-ha Coast Range Physiographic Province of Oregon. This mountainous area of conifer and hardwood forests includes a mosaic of landowners with a wide range of goals, from wilderness protection to high-yield timber production. We projected forest changes over 100 years in response to logging and development using models that integrate land use change and forest stand and landscape processes. We then assessed responses to those management activities using GIS models of stand structure and composition, landscape structure, habitat models for focal terrestrial and aquatic species, timber production, employment, and willingness to pay for biodiversity protection. Many of the potential outcomes of recently enacted policies are consistent with intended goals. For example, we project the area of structurally diverse older conifer forest and habitat for late successional wildlife species to strongly increase. 'Other outcomes might not be consistent with current policies: for example, hardwoods and vegetation diversity strongly decline within and across owners. Some elements of biodiversity, including streams with high potential habitat for coho salmon (Oncorhynchus kisutch) and sites of potential oak woodland, occur predominately outside federal lands and thus were not affected by the strongest biodiversity policies. Except for federal lands, biodiversity policies were not generally characterized in sufficient detail to provide clear benchmarks against which to measure the progress or success. We conclude that land management institutions and policies are not well configured to deal effectively with ecological issues that span broad spatial and temporal scales and that alternative policies could be constructed that more effectively provide for a mix of forest values from this region.     

A pre/post evaluation of fatigue,stress and vigilance amongst commercially licensed truck drivers performing a prolonged driving task

Purpose. The main purpose of this research study was to evaluate changes in fatigue, stress and vigilance amongst commercially licensed truck drivers involved in a prolonged driving task. The secondary purpose was to determine whether a new ergonomic seat could help reduce both physical and cognitive fatigue during a prolonged driving task. Two different truck seats were evaluated: an industrial standard seat and a new truck seat prototype. Methods. Twenty male truck drivers were recruited to attend two testing sessions, on two separate days, with each session randomized for seat design. During each session, participants performed two 10-min simulated driving tasks. Between simulated sessions, participants drove a long-haul truck for 90 min. Fatigue and stress were quantified using a series of questionnaires whereas vigilance was measured using a standardized computer test. Results. Seat interactions had a significant effect on fatigue patterns. Conclusion. The new ergonomic seat design holds potential in improving road safety and vehicle accidents due to fatigue-related accidents.     

Temporal variation of recruits as a basis of ephemeral genetic heterogeneity in the western rock lobster Panulirus cygnus

Allozymes were examined in quantitative lunar monthly collections of larval recruits of the western rock lobster Panulirus cygnus George over three recruitment seasons at two sites nearly 350 km apart in Western Australia. At Alkimos, the southern site, recruitment occurs in a relatively narrow peak early in the spring, whereas at the northern Houtman Abrolhos Islands, recruitment extends into the summer months. In the 1995/1996 recruitment season, the frequency of the GPI ^* 100 allele increased from early to late in the season, but the frequencies were indistinguishable at the two sites in each monthly collection. The combination of this temporal variation in allelic frequencies with the contrasting patterns of recruitment at the Abrolhos Islands and Alkimos resulted in genetically different cohorts at the two sites. This pattern was ephemeral, as it was not repeated in the subsequent two years. Thus, ephemeral genetic patchiness in P. cygnus can be generated by the locally-specific genetic mix of recruits obtained from a common larval pool. This mechanism is the probable explanation of previously observed temporal and possible spatial genetic variation in adult P. cygnus, and highlights the importance of studying recruitment in order to understand the genetic structure of marine species. Received: 22 February 1999 / Accepted: 8 June 1999     

ENVIRONMENTAL IMPACT OF STREAM CHANNELIZATION1

ABSTRACT Geologic, engineering, and biological investigations of six Pennsylvania coldwater streams were undertaken to determine the impact of channel modifications instituted both prior to and following Hurricane Agnes. The primary focus of the study was on the ecological changes brought about by stream channelization. No long-term deleterious effects on water quality, attached algae, benthic fauna, or forage fish populations were found. Trout, however, were found to be greater in numbers and weight in natural than in channelized stream reaches. Lack of suitable physical habitat appears to be the primary cause of reduced trout populations in stream reaches which have been channelized.