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1.
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.  相似文献   
2.
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.  相似文献   
3.
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.  相似文献   
4.
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.  相似文献   
5.
6.
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.  相似文献   
7.
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.  相似文献   
8.
Due to the complexity of factors that influence species density on a large geographical scale, the effectiveness of the species distribution model (SDM) is still debatable. That is why the buffer zone (the area within 100 m from the outside edge of the patch), the core, i.e. (patches excluding the 100 m buffer zone from the patch’s edge) and patch shape are explored in this study to see how they affect the density of habitat specialist and generalist bird species. Two sets of generalised additive models were generated separately for each of the four bird species: One set of models contained landscape configuration metrics as an additional predictor variable, and the other did not. The results showed that models including the core, the buffer zone and the shape of patches turned out to be definitely better than models without them. Specialist species, the Corn bunting and the Wood nuthatch, are more likely to occur in the core of the preferred patches, and they choose those of a simple shape; while generalist species, the Whinchat and the Tree pipit, are more probable to be present in the buffer zone of a more complicated shape. Thus, the results clearly show that specific landscape configuration models can improve the predictive power of SDMs and can be used as an effective tool for predicting species density and functional bird diversity (specialist and generalist). Furthermore, from the applied ecology perspective, detailed landscape configuration metrics can be considered as a surrogate of elusive habitat conditions.  相似文献   
9.
Small-scale fisheries are an important livelihood and primary protein source for coastal communities in many of the poorest regions in the world, yet many are overfished and thus require effective and scalable management solutions. Positive ecological and socioeconomic responses to management typically lag behind immediate costs borne by fishers from fishing pressure reductions necessary for fisheries recovery. These short-term costs challenge the long-term success of these interventions. However, social marketing may increase perceptions of management benefits before ecological and socioeconomic benefits are fully realized, driving new social norms and ultimately long-term sustainable behavior change. By conducting underwater visual surveys to quantify ecological conditions and by conducting household surveys with community members to quantify their perceptions of management support and socioeconomic conditions, we assessed the impact of a standardized small-scale fisheries management intervention that was implemented across 41 sites in Brazil, Indonesia, and the Philippines. The intervention combines TURF reserves (community-based territorial use rights for fishing coupled with no-take marine reserves) with locally tailored social-marketing behavior change campaigns. Leveraging data across 22 indicators and 4 survey types, along with data from 3 control sites, we found that ecological and socioeconomic impacts varied and that communities supported the intervention and were already changing their fishing practices. These results suggest that communities were developing new social norms and fishing more sustainably before long-term ecological and socioeconomic benefits of fisheries management materialized.  相似文献   
10.
The geochemical model MAGIC was applied to estimate streamwater and soil chemistry between 1851 and 2030 at the Lysina catchment, an acid-sensitive granitic catchment covered by planted Norway spruce monoculture in the western Czech Republic. The total deposition of sulfur to the catchment was 164 meq m(-2) in 1991, but had declined to 52 meq m(-2) by 2000. Although SO2 emissions in the region declined by 90% compared to the 1980s, acidification recovery was small within the period 1990-2000. Stream pH increased only slightly (from 3.92 to 4.07), although SO4 concentration declined sharply from 568 microeq l(-1) (1990) to 232 microeq l(-1) (2000). Organic acids played an important role in streamwater buffering. According to the MAGIC prediction using deposition measured in 1999-2000, streamwater pH will increase to 4.3 and soil base saturation will increase to 6.2% by 2030 (from 5.7% in 2002). Pre-industrial pH was estimated to be 5.5 and soil base saturation 24.7%. The loss of base cations (Ca, Mg, Na, K) was caused predominantly by atmospheric acidity, but intensive forestry was responsible for approximately one third of the net base cation loss via accumulation in harvested biomass. Severely damaged sites, under continued pressure from forestry, will not return to a good environmental status in the near future (if ever) when the acid deposition input is only partially reduced.  相似文献   
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