Hot,Salty Water: A Confluence of Issues in Managing Stormwater Runoff for Urban Streams

Research increasingly highlights cause and effect relationships between urbanization and stream conditions are complex and highly variable across physical and biological regions. Research also demonstrates stormwater runoff is a key causal agent in altering stream conditions in urban settings. More specifically, thermal pollution and high salt levels are two consequences of urbanization and subsequent runoff. This study describes a demonstration model populated with data from a high gradient headwaters stream. The model was designed to explain surface water‐groundwater dynamics related to salinity and thermal pollution. Modeled scenarios show long‐term additive impacts from salt application and suggest reducing flow rates, as stormwater management practices are typically designed to do, have the potential to greatly reduce salt concentrations and simultaneously reduce thermal pollution. This demonstration model offers planners and managers reason to be confident that stormwater management efforts can have positive impacts.     

From Valuation to Governance: Using Choice Experiment to Value Street Trees

This paper reports a choice experiment used to estimate the value of street trees in the city center of Lodz, Poland, and the broader context of how valuation results helped to improve governance of urban ecosystem services in this city. Based on a simplified inventory of trees, we prepared a set of hypothetical programs which put varying emphasis on the different ways to increase the numbers of trees, along with different levels of a hypothetical tax that would have to be paid by respondents to implement a given program. Our study indicated that the 351 surveyed Lodz residents were willing to pay the highest price for greening those streets where currently there are few or no trees and confirmed the general importance of planting trees. The results provided an argument in the debate on the new development strategy for the city and helped to promote the concept of ecosystem services.     

The response of a mid- and high latitude peat bog to predicted climate change: methane production in a 12-month peat incubation

There are fears that global warming will lead to degradation of peatlands, higher emissions of greenhouse gases from peat, and accelerated warming. Anaerobic decomposition of organic soils produces methane (CH₄), a potent greenhouse gas. Two peat bogs differing in mean annual temperature, Velke Darko (VD, Czech Republic, 7.2 °C), and Stor Åmyran (SA, Sweden, 4.0 °C), were selected for a comparative study of how organic soils in different climatic zones will respond to warmer and drier conditions. Twenty peat cores from each bog were incubated in growth chambers. Under present-day summer conditions, VD produced 14 times more CH₄ than SA. Two different warming scenarios were used. Peat-core replicates were kept at temperatures of 11 versus 16 °C, and 11 versus 22 °C. From 11 to 16 °C, the CH₄ production slightly decreased at SA, and slightly increased at VD. From 11 to 22 °C, the CH₄ production increased 9 times at SA, but slightly decreased at VD. After an 8-month incubation, peat cores under drying conditions (water table at ?14 cm) were compared to samples with original water table (?2 cm). Drying conditions led to a steeper reduction in CH₄ production at VD, compared to SA. The CH₄ production decreased more than 100 times at VD. Then, the combined effect of simultaneous warming and drying at 11 and 22 °C was studied. We did not find any significant effect of interactions between increasing temperature and decreasing water table level. Overall, the warmer site VD responded more strongly to the simulated climate change than the colder site SA.     

Applicability of hydromorphological monitoring data to locate flood risk reduction measures: Blanice River basin, Czech Republic

This paper presents a new methodological approach, using hydromorphological monitoring data from river networks, to identify stream elements that may negatively influence the course of floods, as well as elements suitable for modifications that will reinforce the natural retention potential of the floodplain. The approach uses data derived from hydromorphological monitoring that conforms to the EN 14614 standard "Water quality--Guidance standard for assessing the hydromorphological features of rivers." Four major aspects of stream modifications that can potentially affect the course and consequences of floods, and that can be derived from hydromorphological monitoring, were identified. These are: (1) modifications that increase the speed of runoff, (2) modifications that restrict the retention potential of the floodplain, (3) potential obstacles to the flood course, and (4) improper alterations of stream route modifications. A GIS is used to identify and locate these critical aspects of stream and floodplain modification. This method was applied in the Blanice River basin, an area in central Europe hit by a severe flood in August 2002. The critical modifications identified were compared with geomorphological mapping to display the different effects of individual types of modifications.     

Changes in water quality in agricultural catchments after deployment of wastewater treatment plant

Insufficient wastewater remediation in small communities and nonpoint source pollution are the key factors in determining the water quality of small streams in an agricultural landscape. Despite the current extensive construction of municipal wastewater treatment facilities in small communities, the level of organic substances and nutrients in the recipient catchments has not decreased in many areas. This paper analyzes the changes in the water quality of the small streams after the deployment of wastewater treatment plants that were designed to address sources of pollution from small municipalities. The analysis is based on the results from a water quality monitoring network in the small watersheds in the Czech Republic. Five rural catchments with one dominant municipal pollution source, where a wastewater treatment plant was deployed during the monitoring period, were selected according to a predefined set of criteria, from a series of 317 profiles. Basic water quality indicators were selected for the assessment: O₂, BOD-5, COD, TOC, conductivity, NH₄-N, NO₂-N, NO₃-N, PT, and PO₄-P. Results of the analysis showed that the simple deployment of the water treatment facilities at these streams often did not lead to a reduction of contamination in the streams. The expected post-deployment changes, namely, a significant and permanent reduction of stream contamination, occurred only in one catchment, whereas in the remainder of the catchments, only marginal changes or even increased concentrations of the contaminants were detected. As the critical factors that determined the efficiency of wastewater treatment were studied, the need for the consideration of the local conditions during the design of the facility, particularly regarding the size of the catchments, initial level of contamination, proper system of operation, and process optimization of the treatment facility, emerged as the important factor.     

Indonesia's developing forest industry

Indonesia is a major exporter of tropical hardwoods. The country's goal is to establish integrated wood industries by reducing the export of unprocessed sawlogs. The value of hardwood sawlog exports has decreased by twothirds in 1986 dollars since 1978, while the value of hardwood sawnwood and plywood exports has increased sixfold. Sawlog exports are now banned. This article contrasts the official governmental policy on forest industry development with the operational realities of doing business in Indonesia.     

Generalist cuckoo bees (Hymenoptera: Apoidea: Sphecodes) are species-specialist at the individual level

Intensive and incessant arms races between a parasite and its host are generally expected to lead to parasite specialization. Nevertheless, some parasitic species still successfully attack wide spectra of hosts. One of the solutions to the evolutionary enigma of the long-term existence of generalist parasites is their specialization at an individual level, a phenomenon well known, e.g., in European common cuckoo. Over its range, it parasitizes a number of bird species; however, individual females are mostly specialists possessing adaptations to a particular host species. In this study, we test the possibility of individual specialization in generalist cuckoo bees, the insect counterparts of avian cuckoos. Females of cuckoo bees lay each egg into a single brood cell in the nests of other bee species. The host’s offspring is destroyed by the parasitic female or later by her larvae, which feed on pollen supplies accumulated by the host. Both studied cleptoparasitic bees (Sphecodes ephippius and Sphecodes monilicornis) are widely distributed in Europe, where they have been reported to use broad host spectra. We recorded several host species (including some previously unknown) for both cuckoo bee species, and confirmed that these parasites are indeed generalist even at a small local scale. However, we demonstrate that exactly as in the avian cuckoos, each female in both species of generalist bee parasites tends to attack just one host species.     

Limited scope for reproductive senescence in wild populations of a short-lived fish

Senescence in wild populations was long considered negligible but current evidence suggests that it is widespread in natural populations of mammals and birds, affecting the survival and reproductive output of older individuals. In contrast, little is known about reproductive senescence in species with asymptotic growth that can keep increasing their reproductive output as they grow older and larger. Using a cross-sectional study, we tested age-related decline in fecundity and relative allocation to reproduction in five wild populations of an annual killifish, Nothobranchius furzeri (Cyprinodontiformes). We did not detect any decline in absolute female egg production over their short lifespan in the wild. Relative fecundity (egg production controlled for female body mass) tended to decrease with age. This effect was driven primarily by a single population that survived 17 weeks, almost twice as long as the median persistence of the other four study populations. There was no decrease in relative ovary mass while in males, relative testes mass actually increased with age. Intra-population variation in relative ovary mass increased in older females suggesting heterogeneity in individual trajectories of female reproductive allocation. Overall, we demonstrate that annual killifish do not experience significant age-related decline in reproductive functions during their very short lifespan in the wild despite the marked deterioration of gonad tissue detected in captivity.