Implementing environmentally sound management of inland waters

While it is now widely accepted that the harnessing of water resources can make a major contribution to economic progress in various parts of the world, there is also increasing concern about the adverse environmental effects that such development may produce. Reviewing experiences in several countries, however, it seems that it may be possible to reconcile the management of water resources and the maintenance of environmental integrity. The paper assesses the likelihood of a reconciliation taking place in the light of a number of trends in contemporary water management. While many of these trends are in the direction of harmonious development, the pace of accommodation has typically been slow and erratic. The authors offer some suggestions as to how this might be overcome through modifications in legislation, policies, procedures and administrative structures.     

Prey selection by the hogchoker, Trinectes maculatus (Pisces: Soleidae), along summer salinity gradients in Chesapeake Bay, USA

We investigated feeding by the hogchoker, Trinectes maculatus (Bloch and Schneider), in freshwater, oligohaline, mesohaline, and polyhaline regions of Chesapeake Bay, USA, and examined prey selection in relation to food availability. Otter trawling for fish and Van Veen grab sampling for benthic macrofauna occurred in July and August 1992 and August and September 1993. Hogchokers exhibited both opportunistic and selective feeding patterns along the estuarine salinity gradient in four tributaries (Potomac, Rappahannock, York, and James Rivers) and in the mainstem Chesapeake Bay. Major prey taxa included annelids, arthropods, and tellinid siphons. In polyhaline habitat, polychaetes dominated both the benthos and gut contents numerically and gravimetrically. On the other hand, oligochaetes were numerically dominant in freshwater/oligohaline areas but were rarely eaten, perhaps because of their burial depth. Arthropods (mostly amphipods) occurred at most salinities, were common in gut contents in low-salinity areas, and were replaced as prey by larger proportions of polychaetes in polyhaline regimes. Although hogchokers ate tellinid siphons, they rarely consumed whole bivalves or gastropods. These diet patterns (and especially the importance of siphon nipping) are similar to those of juvenile or small flatfish elsewhere in Europe, Africa, and North America. A size–salinity relationship for hogchokers occurred along the summer salinity gradient, with smaller fish predominating upstream and larger fish downstream. It was not clear from our data if variation in diet composition reflected changes in prey composition along the salinity gradient rather than changes in fish size. Received: 14 June 1997 / Accepted: 27 June 1997     

Five approaches to producing actionable science in conservation

The knowledge produced by conservation scientists must be actionable in order to address urgent conservation challenges. To understand the process of creating actionable science, we interviewed 71 conservation scientists who had participated in 1 of 3 fellowship programs focused on training scientists to become agents of change. Using a grounded theory approach, we identified 16 activities that these researchers employed to make their scientific products more actionable. Some activities were more common than others and, arguably, more foundational. We organized these activities into 3 nested categories (motivations, strategies, and tactics). Using a co-occurrence matrix, we found that most activities were positively correlated. These correlations allowed us to identify 5 approaches, framed as profiles, to actionable science: the discloser, focused on open access; the educator, focused on science communication; the networker, focused on user needs and building relationships; the collaborator, focused on boundary spanning; and the pluralist, focused on knowledge coproduction resulting in valuable outcomes for all parties. These profiles build on one another in a hierarchy determined by their complexity and level of engagement, their potential to support actionable science, and their proximity to ideal coproduction with knowledge users. Our results provide clear guidance for conservation scientists to generate actionable science to address the global biodiversity conservation challenge.     

Aligning the logics of inquiry and action to address the biodiversity crisis

Despite an abundance of research reaffirming biodiversity's importance to the health of the planet and society, species continue to go extinct at an alarming rate. Why has continued research on the value of biodiversity not had the intended effect and what can be done about it? We considered biodiversity loss as a public value failure and the result of a misalignment between the logic of inquiry (which guides scientists) and the logic of action (which guides practitioners). We drew lessons from our own research to propose the creation of a national biodiversity strategy designed to link the logic of inquiry with the logic of action and coordinate the production of actionable conservation science and informed conservation action.     

Transport of oxytetracycline,chlortetracycline, and ivermectin in surface runoff from irrigated pasture

The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.     

Using fisher-contributed secondary fins to fill critical shark-fisheries data gaps

Developing-world shark fisheries are typically not assessed or actively managed for sustainability; one fundamental obstacle is the lack of species and size-composition catch data. We tested and implemented a new and potentially widely applicable approach for collecting these data: mandatory submission of low-value secondary fins (anal fins) from landed sharks by fishers and use of the fins to reconstruct catch species and size. Visual and low-cost genetic identification were used to determine species composition, and linear regression was applied to total length and anal fin base length for catch-size reconstruction. We tested the feasibility of this approach in Belize, first in a local proof-of-concept study and then scaling it up to the national level for the 2017–2018 shark-fishing season (1,786 fins analyzed). Sixteen species occurred in this fishery. The most common were the Caribbean reef (Carcharhinus perezi), blacktip (C. limbatus), sharpnose (Atlantic [Rhizoprionodon terraenovae] and Caribbean [R. porosus] considered as a group), and bonnethead (Sphyrna cf. tiburo). Sharpnose and bonnethead sharks were landed primarily above size at maturity, whereas Caribbean reef and blacktip sharks were primarily landed below size at maturity. Our approach proved effective in obtaining critical data for managing the shark fishery, and we suggest the tools developed as part of this program could be exported to other nations in this region and applied almost immediately if there were means to communicate with fishers and incentivize them to provide anal fins. Outside the tropical Western Atlantic, we recommend further investigation of the feasibility of sampling of secondary fins, including considerations of time, effort, and cost of species identification from these fins, what secondary fin type to use, and the means with which to communicate with fishers and incentivize participation. This program could be a model for collecting urgently needed data for developing-world shark fisheries globally. Article impact statement: Shark fins collected from fishers yield data critical to shark fisheries management in developing nations.     

Production and uptake of dissolved carbon,nitrogen, and phosphorus in overlying water of aquaculture shrimp ponds in subtropical estuaries,China

Environmental Science and Pollution Research - Water quality deterioration can adversely affect the long-term sustainability of aquaculture industry. Understanding the processes of nutrient...     

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

Ex situ soil washing with synthetic extractants such as, aminopolycarboxylate chelants (APCs) is a viable treatment alternative for metal-contaminated site remediation. EDTA and its homologs are widely used among the APCs in the ex situ soil washing processes. These APCs are merely biodegradable and highly persistent in the aquatic environments leading to the post-use toxic effects. Therefore, an increasing interest is focused on the development and use of the eco-friendly APCs having better biodegradability and less environmental toxicity. The paper deals with the results from the lab-scale washing treatments of a real sample of metal-contaminated soil for the removal of the ecotoxic metal ions (Cd, Cu, Ni, Pb, and Zn) using five biodegradable APCs, namely [S,S]-ethylenediaminedisuccinic acid, imminodisuccinic acid, methylglycinediacetic acid, DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA), and 3-hydroxy-2,2′-iminodisuccinic acid. The performance of those biodegradable APCs was evaluated for their interaction with the soil mineral constituents in terms of the solution pH and metal-chelant stability constants, and compared with that of EDTA. Speciation calculations were performed to identify the optimal conditions for the washing process in terms of the metal-chelant interactions as well as to understand the selectivity in the separation ability of the biodegradable chelants towards the metal ions. A linear relationship between the metal extraction capacity of the individual chelants towards each of the metal ions from the soil matrix and metal-chelant conditional stability constants for a solution pH greater than 6 was observed. Additional considerations were derived from the behavior of the major potentially interfering cations (Al, Ca, Fe, Mg, and Mn), and it was hypothesized that use of an excess of chelant may minimize the possible competition effects during the single-step washing treatments. Sequential extraction procedure was used to determine the metal distribution in the soil before and after the extractive decontamination using biodegradable APCs, and the capability of the APCs in removing the metal ions even from the theoretically immobilized fraction of the contaminated soil was observed. GLDA appeared to possess the greatest potential to decontaminate the soil through ex situ washing treatment compared to the other biodegradable chelants used in the study.     

Montane meadows in the Sierra Nevada: comparing terrestrial and aquatic assessment methods

We surveyed montane meadows in the northern Sierra Nevada and southern Cascades for two field seasons to compare commonly used aquatic and terrestrial-based assessments of meadow condition. We surveyed (1) fish, (2) reptiles, (3) amphibians, (4) aquatic macroinvertebrates, (5) stream geomorphology, (6) physical habitat, and (7) terrestrial vegetation in 79 meadows between the elevations of 1,000 and 3,000?m. From the results of those surveys, we calculated five multi-metric indices based on methods commonly used by researchers and land management agencies. The five indices consisted of (1) fish only, (2) native fish and amphibians, (3) macroinvertebrates, (4) physical habitat, and (5) vegetation. We compared the results of the five indices and found that there were significant differences in the outcomes of the five indices. We found positive correlations between the vegetation index and the physical habitat index, the invertebrate index and the physical habitat index, and the two fish-based indices, but there were significant differences between indices in both range and means. We concluded that the five indices provided very different interpretations of the condition in a given meadow. While our assessment of meadow condition changed based on which index was used, each provided an assessment of different components important to the overall condition of a meadow system. Utilizing a multimetric approach that accounts for both terrestrial and aquatic habitats provides the best means to accurately assess meadow condition, particularly given the disproportionate importance of these systems in the Sierra Nevada landscape.     

WILLOW POSTS BANK STABILIZATION1

ABSTRACT: Harland Creek, in east-central Mississippi, is a rapidly migrating, meandering stream that is experiencing severe bank erosion. More than 9,000 willow (Salix nigra) posts were emplaced in February 1994 by the U.S. Army, Corps of Engineers in an effort to stabilize eroding stream banks using an experimental bioengi-neering technique. Monitoring of this stream reach and the willow post bank stabilization has resulted in a data base to assess willow mortality as related to bank aspect, post diameter, cover, and base elevation above low water. Monitoring has also resulted in the development of revised construction guidelines. Survivability of the posts, a necessary condition for long-term success, was found to average 81 percent in May 1994, 43 percent in October 1994, and 41 percent in August 1995. Even with survivability as low as 29 percent to 34 percent at specific bend reaches, willow posts are documented to be successful in bank stabilization for the period of monitoring, in comparison with more traditional riprap stabilization methods. Guidelines for improved survivability and recommended site selection are presented. Cost of willow post bank stabilization is less than traditional riprap, and willow posts can be emplaced using readily available equipment and materials.