Plant-trait-based modeling assessment of ecosystem-service sensitivity to land-use change

Evidence is accumulating that the continued provision of essential ecosystem services is vulnerable to land-use change. Yet, we lack a strong scientific basis for this vulnerability as the processes that drive ecosystem-service delivery often remain unclear. In this paper, we use plant traits to assess ecosystem-service sensitivity to land-use change in subalpine grasslands. We use a trait-based plant classification (plant functional types, PFTs) in a landscape modeling platform to model community dynamics under contrasting but internally consistent land-use change scenarios. We then use predictive models of relevant ecosystem attributes, based on quantitative plant traits, to make projections of ecosystem-service delivery. We show that plant traits and PFTs are effective predictors of relevant ecosystem attributes for a range of ecosystem services including provisioning (fodder), cultural (land stewardship), regulating (landslide and avalanche risk), and supporting services (plant diversity). By analyzing the relative effects of the physical environment and land use on relevant ecosystem attributes, we also show that these ecosystem services are most sensitive to changes in grassland management, supporting current agri-environmental policies aimed at maintaining mowing of subalpine grasslands in Europe.     

Using revealed preferences to estimate the Value of Travel Time to recreation sites

The opportunity Value of Travel Time (VTT) is one of the most important elements of the total cost of recreation day-trips and arguably the most difficult to estimate. Most studies build upon the theoretical framework proposed by Becker (1965) by using a combination of revealed and stated preference data to estimate a value of time which is uniform in all activities and under all circumstances. This restriction is relaxed by DeSerpa's (1971) model which allows the value of saving time to be activity-specific. We present the first analysis which uses actual driving choices between open access and toll roads to estimate a VTT specific for recreation trips, thereby providing a value which conforms to both Becker's and DeSerpa's theoretical models. Using these findings we conduct a Monte Carlo simulation to identify generalizable results for subsequent valuation studies. Our results indicate that 3/4 of the wage rate provides a reasonable approximation of the average VTT for recreation trips, while the commonly implemented assumption of 1/3 of the wage rate generates downward biased results.     

Consequences of resource competition for sex allocation and discriminative behaviors in a hyperparasitoid wasp

Population-wide mating patterns can select for equal parental investment in both sexes, but limiting resources, such as mates or developmental substrates, can increase competition leading to biased sex ratios in favor of either sex. Such competition for resources typically occurs in spatially structured populations, where dispersal is limited. In this laboratory study, we investigate if and how resource competition affects sex allocation, discriminative behaviors and competitive interactions of the wingless hyperparasitoid Gelis acororum, which exploits patchily distributed hosts. We show that G. acororum sex ratios are male-biased and that this is not a consequence of constrained reproduction by virgin females. Our results suggest that this pattern of reproductive investment, which is only rarely observed in parasitoids, is a consequence of resource limitation, in terms of hosts rather than mates. Further, G. acororum appears not to respond to intrinsic host quality or to prior oviposition in its host. When competing inter-specifically for host resources, G. acororum outcompetes its congener Gelis agilis, but does so mainly when ovipositing on the host first. Overall, our results suggest that host resource limitation could be an important environmental factor shaping sex allocation in G. acororum, with competition taking place both intra- and inter-specifically.     

A blended hazard identification methodology to support process diagnosis

A novel hazard identification methodology applied to process systems is presented in this paper. This blended hazard identification (BLHAZID) methodology blends two different types of HAZID methods: the function-driven and component-driven approach. The BLHAZID method is based on a conceptual framework called the Functional Systems Framework, which describes structure–function–goal relationships in process systems.The goals of the BLHAZID methodology are to generate outcomes that contain a high coverage of hazards, describe detailed failure causality in process systems and express this knowledge in a structured form for effective reused in subsequent applications, such as fault diagnosis, operator training, design reviews, fault and event tree construction and hazard updates to satisfy major hazard facility requirements.Both the BLHAZID methodology and the Functional Systems Framework were developed with involvement and advice from two major industrial partners. An industrial case study of a benzene saturation unit is presented to illustrate how the BLHAZID methodology operates in practice.     

Stakeholder perspectives on the value proposition of enterprise-level natural capital accounting for three primary industries

Environment Systems and Decisions - Globally we are experiencing a decline in aggregate natural capital. Many primary industries and enterprises are highly dependent on renewable and non-renewable...     

Potentially toxic elements in some fresh water bodies in Ethiopia

A total of thirty three water samples were collected from Tinishu Akaki River, Lake Awassa, and Lake Ziway, Ethiopia. Multi-element determination of trace elements (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb) in water samples was carried out by inductively coupled plasma-mass spectrometry after acidification with 1% HNO₃. The concentration (in µg?L^?1) of the elements were in the range of 1.0–19, <0.42–83, 1.1–1580, <45–1760, <0.11–2.0, 0.43–13, 0.77–13, 6–300, <0.94–2.0, <0.3–1.5, <0.012–0.63, 0.13–4.8, <0.29, and 0.2–7.2 for V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Ag, Cd, Sn, Hg, and Pb, respectively. The concentrations of all the quantified elements, with the exception of Mn, were in the range of the permissible limits of the Ethiopian, European Community, and World Health Organization for both drinking water quality guidelines and irrigation water guidelines. The accuracy of the method was validated by analyzing trace elements in water standard reference material (SRM 1643e). The measured values of trace elements in the SRM agreed well with the certified values at the 95% confidence level.     

Distribution of mercury in the sediments of some freshwater bodies in Ethiopia

Sediment samples were collected from Tinishu Akaki River (TAR), Lake Awassa, and Lake Ziway, Ethiopia for determination of mercury. The air-dried samples were analyzed for mercury with a differential atomic absorption spectrometer after thermal evaporation of bound mercury converting it to its atomic form. Certified reference materials (CRMs) of sediments and soils were used to validate the method. The recovery of mercury from CRMs and sediments was in the range of 95–100%. The limit of detection for the determination of mercury was 50?ng?kg^?1. The concentration of total mercury in the sediments varied from 3.9 to 110?µg?kg^?1 for TAR, 14 to 67?µg?kg^?1 for Lake Awassa, and 17 to 110?µg?kg^?1 for Lake Ziway. It was found that the total mercury concentrations in all samples were below the United States Environmental Protection Agency guideline of 200?µg?kg^?1.     

Is Scotland sustainable? A the series of indicators of sustainable development

Seven measures of sustainable development for Scotland are examined for the period 1980-1993. These measures are green net national product, genuine savings, ecological footprint, environmental space, human appropriation of net primary production, the index of sustainable economic welfare and the genuine progress indicator. Very different messages concerning sustainable development in Scotland emerge from these measures.