An Assessment of the Ecological Condition of Long Island Sound, 1990–1993

Data from the Environmental Protection Agency's (EPA) Environmental Monitoring and Assessment Program (EMAP) from 1990 to 1993 were used to assess the condition of the Long Island Sound (LIS) estuary. Ambient water, sediment and biota were collected during the summer months from 53 LIS stations using an unbiased sampling design. The design consists of two LIS subunits, LIS proper, and small estuaries (<2.6 km2) at the margins of the Sound. Selected indicators of condition included: benthic species composition, abundance and biomass; fish species composition and gross external pathology; sediment physical and chemical characterization and sediment toxicity; and water clarity and quality. Results of the four-year sampling indicated that 28(±11)% of the areal extent of LIS proper had a benthic index < zero (impacted) and 51(±12)% of the area of small estuaries was impacted. Analysis of the results of other indicators also shows that small estuaries were particularly affected. For example, 42(±10)% of the areal extent of small estuaries exhibited sediment toxicity, and significant chemical contamination was evident in 22% of the area of small estuaries. Low dissolved oxygen (D.O.) concentrations (<5 ppm), however, appeared to affect only the deeper open waters of western LIS. Approximately 48(±12)% of the areal extent of LIS proper documented exposure to at least moderate D.O. stress (<5 ppm). The overall results of this monitoring study indicate that significant anthropogenic impacts have occurred in LIS and that if remediation was to take place, specific localized sediment problems would need attention. Point source and non-point source nutrient inputs to the Sound, which are believed to be the primary causative factor for the observed hypoxic conditions, would also need attention.     

C and N Content in Density Fractions of Whole Soil and Soil Size Fraction Under Cacao Agroforestry Systems and Natural Forest in Bahia,Brazil

Agroforestry systems (AFSs) have an important role in capturing above and below ground soil carbon and play a dominant role in mitigation of atmospheric CO₂. Attempts has been made here to identify soil organic matter fractions in the cacao-AFSs that have different susceptibility to microbial decomposition and further represent the basis of understanding soil C dynamics. The objective of this study was to characterize the organic matter density fractions and soil size fractions in soils of two types of cacao agroforestry systems and to compare with an adjacent natural forest in Bahia, Brazil. The land-use systems studied were: (1) a 30-year-old stand of natural forest with cacao (cacao cabruca), (2) a 30-year-old stand of cacao with Erythrina glauca as shade trees (cacao + erythrina), and (3) an adjacent natural forest without cacao. Soil samples were collected from 0-10 cm depth layer in reddish-yellow Oxisols. Soil samples was separated by wet sieving into five fraction-size classes (>2000 μm, 1000–2000 μm, 250–1000 μm, 53–250 μm, and <53 μm). C and N accumulated in to the light (free- and intra-aggregate density fractions) and heavy fractions of whole soil and soil size fraction were determined. Soil size fraction obtained in cacao AFS soils consisted mainly (65 %) of mega-aggregates (>2000 μm) mixed with macroaggregates (32–34%), and microaggregates (1–1.3%). Soil organic carbon (SOC) and total N content increased with increasing soil size fraction in all land-use systems. Organic C-to-total N ratio was higher in the macroaggregate than in the microaggregate. In general, in natural forest and cacao cabruca the contribution of C and N in the light and heavy fractions was similar. However, in cacao + erythrina the heavy fraction was the most common and contributed 67% of C and 63% of N. Finding of this study shows that the majority of C and N in all three systems studied are found in macroaggregates, particularly in the 250–1000 μm size aggregate class. The heavy fraction was the most common organic matter fraction in these soils. Thus, in mature cacao AFS on highly weathered soils the main mechanisms of C stabilization could be the physical protection within macroaggregate structures thereby minimizing the impact of conversion of forest to cacao AFS.     

A multilevel model of emotional skills,communication performance,and task performance in teams

There is increasing research regarding the influence of emotions on teamwork. In this study, we use a multilevel approach to examine how team members' use of emotion‐related skills affects team task performance and communication performance within the team. We measured individual self‐reported emotional skills prior to team formation and then collected peer‐rated individual communication performance and independently rated team task performance eight weeks later. Although there was no influence at the individual level between emotional skills and performance, team‐level emotional skills positively predicted team task performance scores. At the cross level, team‐level emotional skills predicted individual‐level communication performance. These findings emphasize the importance of distinct team emotional skills in shaping both team performance and individual team member performance. Copyright © 2011 John Wiley & Sons, Ltd.     

Choosing an appropriate soil-gas survey method

Three types of soil-gas surveys were performed over the same location at an industrial facility. The surveys performed were (1) a passive technique using buried collectors, (2) an active technique in which samples were collected in the field by pumping with subsequent analysis at a field laboratory, and (3) a screening technique that employed a hand-held survey instrument. Each of the surveys had desirable features, but there was considerable variability in the quality of data obtained, cost, and ease of performance. The passive and active surveys provided excellent detection limits, but the passive technique does not provide data in real time. The active survey was also time-consuming and required an analytical chemist in the field. Neither the active nor the passive survey were able to delineate the plume of contaminated groundwater. Consequently, the results from the rapid and inexpensive reconnaissance technique provided functionally equivalent data.Publication No. 3672, Environmental Sciences Division, ORNL.Operated by Martin Marietta Energy Systems, Inc. for the U.S. Department of Energy under Contract No. DE-AC05-840R21400.     

Is bird song a reliable signal of aggressive intent?

In this commentary, we discuss recent experiments on the reliability of bird song as a signal of aggressive intent during territorial conflicts. We outline relevant theoretical views on honest signaling, highlighting the vulnerability handicap hypothesis as a possible explanation for soft song’s reliability in predicting attack. We also sketch possible methods of testing whether soft song agrees with key predictions of the vulnerability handicap hypothesis. Finally, we suggest possible empirical refinements that may be useful in future studies of signals of intent, both in birds and in animals broadly. In particular, we argue that future studies of intent should strive to incorporate the following elements into their experimental design: (1) multi-modal signal components, (2) interaction dynamics, and (3) minimal time intervals. Simulated exchanges using dynamically interactive models may provide a powerful means of incorporating all three of these design features simultaneously.

Constitutive and induced defenses to herbivory in above- and belowground plant tissues

A recent surge in attention devoted to the ecology of soil biota has prompted interest in quantifying similarities and differences between interactions occurring in above- and belowground communities. Furthermore, linkages that interconnect the dynamics of these two spatially distinct ecosystems are increasingly documented. We use a similar approach in the context of understanding plant defenses to herbivory, including how they are allocated between leaves and roots (constitutive defenses), and potential cross-system linkages (induced defenses). To explore these issues we utilized three different empirical approaches. First, we manipulated foliar and root herbivory on tobacco (Nicotiana tabacum) and measured changes in the secondary chemistry of above- and belowground tissues. Second, we reviewed published studies that compared levels of secondary chemistry between leaves and roots to determine how plants distribute putative defense chemicals across the above- and belowground systems. Last, we used meta-analysis to quantify the impact of induced responses across plant tissue types. In the tobacco system, leaf-chewing insects strongly induced higher levels of secondary metabolites in leaves but had no impact on root chemistry. Nematode root herbivores, however, elicited changes in both leaves and roots. Virtually all secondary chemicals measured were elevated in nematode-induced galls, whereas the impact of root herbivory on foliar chemistry was highly variable and depended on where chemicals were produced within the plant. Importantly, nematodes interfered with aboveground metabolites that have biosynthetic sites located in roots (e.g., nicotine) but had the opposite effect (i.e., nematodes elevated foliar expression) on chemicals produced in shoots (e.g., phenolics and terpenoids). Results from our literature review suggest that, overall, constitutive defense levels are extremely similar when comparing leaves with roots, although certain chemical classes (e.g., alkaloids, glucosinolates) are differentially allocated between above- and belowground parts. Based on a meta-analysis of induced defense studies we conclude that: (1) foliar induction generates strong responses in leaves, but much weaker responses in roots, and (2) root induction elicits responses of equal magnitude in both leaves and roots. We discuss the importance of this asymmetry and the paradox of cross-system induction in relation to optimal defense theory and interactions between above- and belowground herbivory.     

Policy relevance of three integrated assessment tools—A comparison with specific reference to agricultural policies

The Common Agricultural Policy (CAP), a system of market support instruments, direct income transfers, and rural development measures, has been put through an ongoing reform process in recent decades. This paper introduces three policy impact assessment tools (SIAT, SEAMLESS-IF, MEA-Scope tool) and analyses how these tools have responded to a number of challenges for integrated assessment modelling as reported in the international literature. Significant progress has been made with regard to modelling linkages whereas other challenges, particularly those related to issues of scale and uncertainty management, require further efforts. It is also analysed which CAP instruments are represented and what kinds of effects can be analysed at different scales. Market instruments and direct payments are comparatively well represented, while the ability to model rural development measures is mostly beyond the scope of these tools. Because each tool has found a different solution for coping with the common challenges of integrated assessment modelling, the choice of one of the tools for a particular application depends strongly on the policy questions being asked. The SIAT provides the big picture via its ability to represent broad changes in policy instruments with EU-wide cross-sector impacts. The most comprehensive analysis of agricultural policy instruments can be obtained with SEAMLESS-IF. The MEA-Scope tool complements the other two approaches with detailed regional profiles.     

Mycorrhizal benefit differs among the sexes in a gynodioecious species

Both plant sex and arbuscular mycorrhizal (AM) symbiosis influence resource acquisition and allocation in plants, but the interaction between these two components is not well established. As the different plant sexes differ in their resource needs and allocation patterns, it is logical to presume that they might differ in their relationship with AM as well. We investigate whether the association with AM symbiosis is different according to the host plant sex in the gynodioecious Geranium sylvaticum, of which, besides female and hermaphrodite plants, intermediate plants are also recognized. Specifically, we examine the effects of two different AM fungi in plant mass allocation and phosphorus acquisition using a factorial greenhouse/common garden experiment. Cloned G. sylvaticum material was grown in symbiosis with AM fungi or in non-mycorrhizal condition. We evaluated both the symbiotic plant benefit in terms of plant mass and plant P content and the fungal benefit in terms of AM colonization intensity in the plant roots and spore production. Our results suggest that G. sylvaticum plants benefit from the symbiosis with both AM fungal species tested but that the benefits gained from the symbiosis depend on the sex of the plant and on the trait investigated. Hermaphrodites suffered most from the lack of AM symbiosis as the proportion of flowering plants was dramatically reduced by the absence of AM fungi. However, females and intermediates benefited from the symbiosis relatively more than hermaphrodites in terms of higher P acquisition. The two AM fungal species differed in the amount of resources accumulated, and the fungal benefit was also dependent on the sex of the host plant. This study provides the first evidence of sex-specific benefits from mycorrhizal symbiosis in a gynodioecious plant species.     

Black granite mining and the implications for the development of sustainability in Zimbabwe: the case of Mutoko communities

Small- and large-scale mining land acquisitions and mining establishments continue to grow in Zimbabwe, but the question about the development of sustainability remains problematic. While mining establishments can be regarded as vehicles for development, the evidence of positive effects in terms of sustainability in this case is weak. The mining-sustainability nexus is characterized by conflicts regarding livelihoods, the environment, culture, and social relations. The paper argues that local sustainability challenges generated by mining activities cannot be resolved as long as there is institutionalized exclusion of local communities, hence, aspects such as revision of the current Mines and Minerals Act, involvement of communities affected by the extraction of granite, opportunities for skills development and training involving traditional leaders, children, youth, and women, extending community driven share-ownership schemes to granite mining and enforcing site remediation should be considered as crucial steps toward the development of sustainability in the mining sector.     

PUBLIC PARTICIPATION IN WATERSHED MANAGEMENT: COMBINING NOMINAL GROUP PROCESS AND MICROCOMPUTERS1

ABSTRACT: The growing concern for public participation in water resource decision-making has invited researchers to improve and develop reliable, quick, and inexpensive techniques for measuring public preferences. It is increasingly clear that traditional participation mechanisms, though useful, are no longer sufficient in providing the level of participation desired by many. A combination of microcomputer technology with Nominal Group Process (a step-by-step process ending in ranked recommendations) offers numerous possibilities for active participatory planning. Efforts at participation occurring through a well developed and defined process cannot be successful without a sensitivity to the conceptual, methodological, and pragmatic problems involved. This paper prefaces presentation of an alternative active process technique with discussion of the theoretical basis of participatory democracy and the frustration with practical implementation procedures.