Transport and metabolic fate of sewage particles in a recipient stream

Although the implementation of wastewater treatment plants (WWTP) has dramatically increased the quality of surface waters in urbanized areas, WWTPs can still discharge noticeable amounts of solutes and particles to recipient streams. Although the fate of WWTP nutrients has received considerable attention, transport and in-stream transformation of sewage-derived particulate organic matter (SDPOM) have not. To investigate the transport and transformation of SDPOM in recipient streams, we experimentally injected fluorescently labeled SDPOM into a headwater stream and tracked its downstream fate at baseflow. Most SDPOM disappeared from the streamwater within a 160-m long reach with an average deposition velocity of 0.14 mm s(-1). We further coupled hydrometric measurements of specific water fluxes through the streambed interface with a mixing model to estimate streambed oxygen removal, and found significantly higher oxygen removal in the deposition (0.75 g O2 m(-2) d(-1)) than in the downstream post-deposition (0.36 g O2 m(-2) d(-1)) subreach. Contrary to our expectations, we did not detect any apparent effect of SDPOM deposition on streambed clogging. Our results show the capacity of a recipient stream to retain SDPOM and to reduce its downstream export, and thus contribute to a better understanding of ecosystem services of human-altered streams.     

Applicability of the Transient Storage Model to the hyporheic exchange of metals

Stream-subsurface exchange results from a complex ensemble of transport mechanisms that require different modeling approaches. Field and laboratory experiments show that advective exchange through the underlying sediments is an important mechanism of solutes transport and storage in riverine systems. Here, Transient Storage Model parameters are obtained for reactive solute exchange driven by bedform-induced advection. Consideration of exchange induced by this single mechanism allows specific relationships between model parameters and system properties like solute reactivity to be identified. This work shows that when a simplified model like the Transient Storage Model is applied to analyze metal storage in river sediments, particular attention must be devoted to the choice of modeling parameters.     

Is the participatory formulation of policy strategies worth the effort? The case of climate change adaptation in Austria

Participation is usually regarded as a good practice in environmental policymaking, but its effects on policy strategies are unclear. Based on literature research, surveys, and interviews with participants, the present paper assesses whether decisional participation in formulating Austria’s National Adaptation Strategy (NAS) was worth the effort. Assessed against the goals of the participation process, we find that it raised awareness for adaptation and facilitated an exchange among the participants and that it improved the content of the NAS. However, regarding the goal of enhancing the acceptance of and commitment to the NAS, we find that this has been achieved among those who participated but not among high-level policymakers who are responsible for implementing the NAS. We conclude that (decisional) participation has its benefits in formulating comprehensive policy strategies but that it is most likely not able to overhaul their well-documented weaknesses, among them weak political commitment and implementation failures.

     

Assessment of noise level and noise propagation generated by light-lift helicopters in mountain natural environments

The use of helicopter rises discussion about environmental noise propagation especially when it operates in proximity of environmentally sensitive areas (ESAs) for an extended period because of its potential implications in wildlife behaviours. In order to support decisions on helicopter logging operation management in proximity of ESAs, this study focused on (i) analysing the noise spectrum of a light-lift helicopter during logging operations and on (ii) assessing the noise propagation in the surrounding environments. This study investigated a helicopter logging operation for wood fuel extraction in the eastern part of the Italian Alps. The potential disturbance area covered for the entire helicopter logging operation was evaluated by a specific GIS application according to hearing sensitivity of the most sensitive wildlife species in the study area (different strigiform species). The noise level at the ground appeared to be affected by the location regardless both the use of equivalent continuous sound pressures level dB(A) (LAeq) and the single-event level (SEL) noise metrics. The lowest values were recorded when the helicopter was flown over the sound meter level located under the forest canopy, while the highest was recorded when the helicopter was unhooking the loads at the landing. The GIS application highlighted the consistent of the exceeded noise area (weighted to strigiform hearing range and sensitivity) for the lower frequency bands (0.016–0.250 kHz). A more restricted exceeded noise area concerned instead the most sensitive frequency bands" for the strigiform (1–2 kHz).

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Diverging response patterns of terrestrial and aquatic species to hydromorphological restoration

Although experiences with ecological restoration continue to accumulate, the effectiveness of restoration for biota remains debated. We complemented a traditional taxonomic analysis approach with information on 56 species traits to uncover the responses of 3 aquatic (fish, macroinvertebrates, macrophytes) and 2 terrestrial (carabid beetles, floodplain vegetation) biotic groups to 43 hydromorphological river restoration projects in Germany. All taxonomic groups responded positively to restoration, as shown by increased taxonomic richness (10–164%) and trait diversity (habitat, dispersal and mobility, size, form, life history, and feeding groups) (15–120%). Responses, however, were stronger for terrestrial than aquatic biota, and, contrary to our expectation, taxonomic responses were stronger than those of traits. Nevertheless, trait analysis provided mechanistic insights into the drivers of community change following restoration. Trait analysis for terrestrial biota indicated restoration success was likely enhanced by lateral connectivity and reestablishment of dynamic processes in the floodplain. The weaker response of aquatic biota suggests recovery was hindered by the persistence of stressors in the aquatic environment, such as degraded water quality, dispersal constraints, and insufficient hydromorphological change. Therefore, river restoration requires combined local- and regional-scale approaches to maximize the response of both aquatic and terrestrial organisms. Due to the contrasting responses of aquatic and terrestrial biota, the planning and assessment of river restoration outcomes should consider effects on both components of riverine landscapes.     

Applying the zoo model to conservation of threatened exceptional plant species

Maintaining a living plant collection is the most common method of ex situ conservation for plant species that cannot be seed banked (i.e., exceptional species). Viability of living collections, and their value for future conservation efforts, can be limited without coordinated efforts to track and manage individuals across institutions. Using a pedigree-focused approach, the zoological community has established an inter-institutional infrastructure to support long-term viability of captive animal populations. We assessed the ability of this coordinated metacollection infrastructure to support the conservation of 4 plant species curated in living collections at multiple botanic gardens around the world. Limitations in current practices include the inability to compile, share, and analyze plant collections data at the individual level, as well as difficulty in tracking original provenance of ex situ material. The coordinated metacollection framework used by zoos can be adopted by the botanical community to improve conservation outcomes by minimizing the loss of genetic diversity in collections. We suggest actions to improve ex situ conservation of exceptional plant species, including developing a central database to aggregate data and track unique individuals of priority threatened species among institutions and adapting a pedigree-based population management tool that incorporates life-history aspects unique to plants. If approached collaboratively across regional, national, and global scales, these actions could transform ex situ conservation of threatened plant species.     

Echolocation behavior of the bat <Emphasis Type="Italic">Vespertilio murinus</Emphasis> reveals the border between the habitat types “edge” and “open space”

We test the hypothesis that echolocation behavior can be used to find the border between bat habitats. Assuming that bats react to background targets in “edge space” but not in “open space”, we determined the border between these two habitat types for commuting individuals of the parti-colored bat Vespertilio murinus. We recorded sequences of bats’ echolocation signals while they flew parallel to the walls of large buildings and to the ground and determined the signals’ average bandwidth, duration, and pulse interval. These parameters varied systematically with the estimated horizontal and vertical distances between the bats and the background. A distinct effect of horizontal distance to the background on echolocation behavior was found for horizontal distances of less than 6 m, thus indicating the border between edge and open space. Only a few bats flew at vertical distances below 5 m. However, enough passages at vertical distances of 5 m and above indicated that the vertical border is somewhere below a distance of 5 m. Within edge space, V. murinus reacted to the background by reducing signal duration, increasing bandwidth at closer distances, and often emitting one signal per wing beat. In open space, signal parameters did not vary as a function of distance to the background. There, V. murinus emitted the longest signals with the narrowest bandwidth and often made one or two wing beats without emitting a pulse. With our data we support with statistical methods the hypothesis that echolocation behavior reveals the border between the habitat types “edge” and “open space”.     

Temporal variation in protein, carbohydrate, and lipid concentrations in Paramuricea clavata (Anthozoa, Octocorallia): evidence for summer–autumn feeding constraints

Temporal variations in protein, carbohydrate, and lipid levels were studied in a passive suspension feeder, the gorgonian Paramuricea clavata. The samples were collected every month for mature and immature colonies over a three-year period (1997–2000). The relationship between biochemical composition and reproductive output was examined on the basis of the 1998 and 1999 data. In female and male P. clavata colonies, the tissue displayed differences in lipid concentrations only in winter–spring, due to the high lipid levels attained by female colonies in this period. Immature colonies showed significant differences in lipid concentration only with respect to mature females in spring. There were clear seasonal trends in the lipid and carbohydrate levels in P. clavata, with maximum values in winter–spring [male lipid 212±75 SD μg mg⁻¹ of organic matter (OM) and female lipid 274±103 SD μg mg⁻¹ of OM; male and female carbohydrate 68±14 SD μg mg⁻¹ of OM], coinciding with maximum food concentration/quality, and minimum values in summer–autumn (male and female lipid 155±57 SD μg mg⁻¹ of OM; male and female carbohydrate 56±14 SD μg mg⁻¹ of OM), coinciding with low food concentration/quality. The relationship between reproductive output and tissue concentrations of lipids, carbohydrates, and proteins was not straightforward, although there was an evident overlap of the lipid accumulation and the gonadal development. The results of this study show that protein, carbohydrate, and lipid levels may provide a record of episodes in the ecological cycle bearing on the trophic aspects of the target species. The results indicate that information on seasonal biochemical levels may explain benthopelagic coupling processes, provided factors such as natural diet, feeding rates, reproduction, and growth are well understood.