An observational study on changes in biometry and generation time of <Emphasis Type="Italic">Odontophora villoti</Emphasis> (Nematoda,Axonolaimidae) related to petroleum pollution in Bizerte bay,Tunisia

Introduction  

We conducted a yearly polluted-reference sampling to assess the effects of petroleum pollution on life cycle characteristics of the meiobenthic nematode Odontophora villoti. Samples were taken every 15 days between 26 November 2004 and 25 November 2005 from two beaches of Bizerte bay (Tunisia), Rimel and Tunisian Refining Industries Company (TRIC). The latter site is located in front of the “Tunisian Refining Industries Company” runoff.     

Pesticide removal from waste spray-tank water by organoclay adsorption after field application: an approach for a formulation of cyprodinil containing antifoaming/defoaming agents

Purpose  

Many reports on purification of water containing pesticides are based on studies using unformulated active ingredients. However, most commercial formulations contain additives/adjuvants or are manufactured using microencapsulation which may influence the purification process. Therefore, the main objective of this work was to develop and test a pilot scheme for decontaminating water containing pesticides formulated with antifoaming/defoaming agents.     

Response surface optimization of a dynamic dye adsorption process: a case study of crystal violet adsorption onto NaOH-modified rice husk

The adsorption of crystal violet from aqueous solution by NaOH-modified rice husk was investigated in a laboratory-scale fixed-bed column. A two-level three factor (2³) full factorial central composite design with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for optimisation of the dynamic dye adsorption process and evaluation of interaction effects of different operating parameters: initial dye concentration (100–200 mg L^?1), flow rate (10–30 mL min^?1) and bed height (5–25 cm). A correlation coefficient (R ²) value of 0.999, model F value of 1,936.59 and its low p value (<0.0001) along with lower value of coefficient of variation (1.38 %) indicated the fitness of the response surface quadratic model developed during the present study. Numerical optimisation applying desirability function was used to identify the optimum conditions for a targeted breakthrough time of 12 h. The optimum conditions were found to be initial solution pH?=?8.00, initial dye concentration?=?100 mg L^?1, flow rate?=?22.88 mL min^?1 and bed height?=?18.75 cm. A confirmatory experiment was performed to evaluate the accuracy of the optimised procedure. Under the optimised conditions, breakthrough appeared after 12.2 h and the column efficiency was determined as 99 %. The Thomas model showed excellent fit to the dynamic dye adsorption data obtained from the confirmatory experiment. Thereby, it was concluded that the current investigation gives valuable insights for designing and establishing a continuous wastewater treatment plant.     

Influence of biochar on nitrogen fractions in a coastal plain soil

Interest in the use of biochar from pyrolysis of biomass to sequester C and improve soil productivity has increased; however, variability in physical and chemical characteristics raises concerns about effects on soil processes. Of particular concern is the effect of biochar on soil N dynamics. The effect of biochar on N dynamics was evaluated in a Norfolk loamy sand with and without NHNO. High-temperature (HT) (≥500°C) and low-temperature (LT) (≤400°C) biochars from peanut hull ( L.), pecan shell ( Wangenh. K. Koch), poultry litter (), and switchgrass ( L.) and a fast pyrolysis hardwood biochar (450-600°C) were evaluated. Changes in inorganic, mineralizable, resistant, and recalcitrant N fractions were determined after a 127-d incubation that included four leaching events. After 127 d, little evidence of increased inorganic N retention was found for any biochar treatments. The mineralizable N fraction did not increase, indicating that biochar addition did not stimulate microbial biomass. Decreases in the resistant N fraction were associated with the high pH and high ash biochars. Unidentified losses of N were observed with HT pecan shell, HT peanut hull, and HT and LT poultry litter biochars that had high pH and ash contents. Volatilization of N as NH in the presence of these biochars was confirmed in a separate short-term laboratory experiment. The observed responses to different biochars illustrate the need to characterize biochar quality and match it to soil type and land use.     

Evolution of a Mediterranean Coastal Zone: Human Impacts on the Marine Environment of Cape Creus

This study presents an integrated analysis of the evolution of the marine environment and the human uses in Cape Creus, a Mediterranean coastal area where intense commercial fisheries and recreational uses have coexisted over the last fifty years. The investigation synthesizes the documented impacts of human activities on the marine environment of Cap de Creus and integrates them with new data. In particular, the evolution of vulnerable, exploited species is used to evaluate the fishing impacts. The effects of area protection through the establishment of a marine reserve in the late 1990s and the potential climate change impacts are also considered. The evolution of the human uses is marked by the increasing socioeconomic importance of recreational activities (which affect species and habitats) in detriment to artisanal and red coral fisheries (which principally affect at a species level). Overall, populations of sedentary, vulnerable exploited species, hard sessile benthic invertebrates, and ecologically fragile habitats, such as seagrass meadows, the coralligenous and infralittoral algal assemblages have been the most negatively impacted by anthropogenic activities. Albeit human uses currently constitute the largest negative impact on the marine environment of Cap de Creus, climate change is emerging as a key factor that could have considerable implications for the marine environment and tourism activities. The establishment of the marine reserve appears to have had little socioeconomic impact, but there is some evidence that it had some positive biological effects on sedentary, littoral fishes. Results demonstrate that the declaration of a marine reserve alone does not guarantee the sustainability of marine resources and habitats but should be accompanied with an integrated coastal management plan.     

Making Capacity Building Meaningful: A Framework for Strategic Action

This paper aims to give practical meaning to ‘capacity building’ through (a) identifying a suite of practical measures, such as mentoring or best practice guidelines, that have been shown to or are considered to build human, social, institutional, and economic capital; (b) placing these measures within a broader systems framework; and (c) exploring stakeholder feedback on specific measures to inform framework implementation. The 29 measures described provide actors, whether government or nongovernment, with a suite of practical investment choices for building capacity. These measures are then clustered into eight groups according to their primary purpose and placed within a systems framework. The framework provides a tool for actors with responsibilities for or an interest in capacity building to inform more holistic and strategic targeting of effort and investment. Stakeholder feedback gathered through surveys and workshops is subsequently reported to further inform implementation of specific measures within the framework’s eight groupings. The framework presented may be built upon through the identification and inclusion of further capacity building measures. The research is conducted within the context of decentralized governance arrangements for natural resource management (NRM), with specific focus on Australia’s recently formalized 56 NRM regions and their community-based governing boards as an informative arena of learning. Application of the framework is explored in the Australian setting through the identification and comparison of measures supported and most preferred by four major stakeholder groups, namely board members, regional NRM organization staff, policy/research interests, and Indigenous interests. The research also examines stakeholder perceptions of capacity issues, and whether these issues are likely to be addressed through implementing their preferred measures.

Influences on Wood Load in Mountain Streams of the Bighorn National Forest,Wyoming, USA

We documented valley and channel characteristics and wood loads in 19 reaches of forested headwater mountain streams in the Bighorn National Forest of northern Wyoming. Ten of these reaches were in the Upper Tongue River watershed, which has a history of management including timber harvest, tie floating, and road construction. Nine reaches were in the North Rock Creek watershed, which has little history of management activities. We used these data to test hypotheses that (i) valley geometry correlates with wood load, (ii) stream gradient correlates with wood load, and (iii) wood loads are significantly lower in managed watersheds than in otherwise similar unmanaged watersheds. Statistical analyses of the data support the first and third hypotheses. Stream reaches with steeper valley side slopes tend to have higher wood loads, and reaches in managed watersheds tend to have lower wood loads than reaches in unmanaged watersheds. Results do not support the second hypothesis. Shear stress correlated more strongly with wood load than did stream gradient, but statistical models with valley-scale variables had greater explanatory power than statistical models with channel-scale variables. Wood loads in stream reaches within managed watersheds in the Bighorn National Forest tend to be two to three times lower than wood loads in unmanaged watersheds.     

River-Stream Connectivity Affects Fish Bioassessment Performance

Stream fish bioassessment methods assume that fish assemblages observed in sample sites reflect responses to local stressors, but fish assemblages are influenced by local factors as well as regional dispersal to and from connected streams. We hypothesized that fish movement to and from refugia and source populations in connected rivers (i.e., riverine dispersal) would weaken or decouple relations between fish community metrics and local environmental conditions. We compared fish-environment relations between streams that flow into large rivers (mainstem tributaries) and streams that lack riverine confluences (headwater tributaries) at multiple spatial grains using data from the USEPA's Environmental Monitoring and Assessment Program in the mid-Atlantic highlands, USA (n = 157 sites). Headwater and mainstem tributaries were not different in local environmental conditions, but showed important differences in fish metric responses to environmental quality gradients. Stream sites flowing into mainstem channels within 10 fluvial km showed consistently weaker relations to local environmental conditions than stream sites that lacked such mainstem connections. Moreover, these patterns diminished at longer distances from riverine confluences, consistent with the hypothesis of riverine dispersal. Our results suggest that (1) the precision of fish bioassessment metrics may be improved by calibrating scoring criteria based on the spatial position of sites within stream networks and (2) the spatial grain of fish bioassessment studies may be manipulated to suit objectives by including or excluding fishes exhibiting riverine dispersal.     

Detecting Temporal Change in Watershed Nutrient Yields

Meta-analyses reveal that nutrient yields tend to be higher for watersheds dominated by anthropogenic uses (e.g., urban, agriculture) and lower for watersheds dominated by natural vegetation. One implication of this pattern is that loss of natural vegetation will produce increases in watershed nutrient yields. Yet, the same meta-analyses also reveal that, absent land-cover change, watershed nutrient yields vary from one year to the next due to many exogenous factors. The interacting effects of land cover and exogenous factors suggest nutrient yields should be treated as distributions, and the effect of land-cover change should be examined by looking for significant changes in the distributions. We compiled nutrient yield distributions from published data. The published data included watersheds with homogeneous land cover that typically reported two or more years of annual nutrient yields for the same watershed. These data were used to construct statistical models, and the models were used to estimate changes in the nutrient yield distributions as a result of land-cover change. Land-cover changes were derived from the National Land Cover Database (NLCD). Total nitrogen (TN) yield distributions increased significantly for 35 of 1550 watersheds and decreased significantly for 51. Total phosphorus (TP) yield distributions increased significantly for 142 watersheds and decreased significantly for 17. The amount of land-cover change required to produce significant shifts in nutrient yield distributions was not constant. Small land-cover changes led to significant shifts in nutrient yield distributions when watersheds were dominated by natural vegetation, whereas much larger land-cover changes were needed to produce significant shifts when watersheds were dominated by urban or agriculture. We discuss our results in the context of the Clean Water Act.     

Social Networks and Community-Based Natural Resource Management

We conducted case studies of three successful examples of collaborative, community-based natural resource conservation and development. Our purpose was to: (1) identify the functions served by interactions within the social networks of involved stakeholders; (2) describe key structural properties of these social networks; and (3) determine how these structural properties varied when the networks were serving different functions. The case studies relied on semi-structured, in-depth interviews of 8 to 11 key stakeholders at each site who had played a significant role in the collaborative projects. Interview questions focused on the roles played by key stakeholders and the functions of interactions between them. Interactions allowed the exchange of ideas, provided access to funding, and enabled some stakeholders to influence others. The exchange of ideas involved the largest number of stakeholders, the highest percentage of local stakeholders, and the highest density of interactions. Our findings demonstrated the value of tailoring strategies for involving stakeholders to meet different needs during a collaborative, community-based natural resource management project. Widespread involvement of local stakeholders may be most appropriate when ideas for a project are being developed. During efforts to exert influence to secure project approvals or funding, however, involving specific individuals with political connections or influence on possible sources of funds may be critical. Our findings are consistent with past work that has postulated that social networks may require specific characteristics to meet different needs in community-based environmental management.