Măsuri de întărire a capacității de adaptare la schimbările climatice a ecosistemelor acvatice

The current article presents a bibliographic overview of green infrastructures and their role in strengthening the adaptive capacity of aquatic ecosystems to the adverse effects of climate change (high temperatures, heavy rains, droughts). Different types of ecological infrastructures are presented: forest buffer strips, rain gardens, permeable pavement, drainage ditches; bioengineering structures for bank stabilization. Also the functions performed by green infrastructures to maintain ecosystem services were presented: mitigating the effects of floods, stabilizing banks, preventing landslides and water caused erosion, stormwater management, reducing the load of pollutants. For the implementation of this approach in the hydrographic basin of Dniester River or the Prut River a more detailed study is necessary on the state of habitats, identification of hotspot areas of aquatic biodiversity, particularly those species important for maintaining of ecosystem functions, highlighting of the areas at high risk of floods or erosion.

Soil N2O and CH4 Emissions From Fodder Maize Production With and Without Riparian Buffer Strips of Differing Vegetation

Purpose: Nitrous oxide (N2O) and methane (CH4) are some of the most important greenhouse gases of the 21st century. Vegetated riparian buffers are primarily implemented for their water quality functions in agroecosystems and their location in the agricultural landscape allows them to intercept and process pollutants from immediately adjacent agricultural land. They recycle increase soil carbon (C), intercept nitrogen (N)-rich runoff from adjacent croplands, and are seasonally anoxic, promoting processes producing environmentally harmful gases including N2O and CH4. Against this context, the study quantified these atmospheric losses between a cropland and vegetated riparian buffers that serve it.Methods: We used the static chamber to measure N2O and CH4 emissions simultaneously with soil. Gas measurements were done simulataneously with soil and environmental variables for a 6-month period in a replicated plot-scale facility comprising of maize cropping served by three vegetated riparian buffers, namely: (i) a novel grass riparian buffer; (ii) a willow riparian buffer, and; (iii) a woodland riparian buffer. These buffered treatments were compared with a no-buffer control. Results: The no-buffer control generated the largest cumulative N2O emissions of 18 929 g ha-1 (95% confidence intervals: 524.1 - 63 643) whilst the maize crop upslope generated the largest cumulative CH4 emissions of 5 050 ± 875 g ha-1. Soil N2O and CH4-based global warming potential (GWP) were lower in the willow (1223.5 ± 362.0 and 134.7 ± 74.0 kg CO2-eq. ha-1 year-1, respectively) and woodland (1771.3 ± 800.5 and 3.4 ± 35.9 kg CO2-eq. ha-1 year-1, respectively) riparian buffers.. Conclusions: Our results suggest that maize production in general, and situations where such cropping is not undertaken in tandem with a riparian buffer strip, result in atmospheric CH4 and N2O concerns.

Status of forest soil and necessity of sustainable soil conservation practices of Nepal

Forests are the fundamental natural resource regarded as the crucial aspect to uplift rural livelihood in Nepal. Forest, not only acquaints us with ecosystem services but also deals with carbon sequestration and nutrient cycling in forest soil, serving the most crucial part of human welfare. However, several human forces such as construction of roads, deforestation, shifting cultivation, overgrazing, and forest fires have decreased the organic matter content and contributed to landslides, erosion and sedimentation in forest. Frequent landslides, soil erosion on the landscape of Nepal is degrading the environment and soil, where 1.7mm of fertile topsoil is lost annually. Considering the fact, present study points to recognize the status of forest soil, its relationship and necessity of sustainable soil conservation practices. Secondary sources of data were used to assemble the related information. Hence, Involvement of different institutions, policy, law, local participation and community-based approach is significantly important in adopting forest soil conservation approaches. Different strategies of carbon sequestration should be maintained by increasing plant cover, enhancing microbes, utilizing agricultural inputs and slowing down the amount of soil disturbances. Likewise, strengthening different thematic areas of Forest Policy 2015 is indispensable in effective implementation of sub sectoral programmes. Forest management strategies incorporating the concepts of carbon storage, buffer strips, terracing, windbreaks, agroforestry, conservation tillage are the major areas highlighted through this paper for further researchers on preserving forest land.

Event-scale flow and sediment generation responses to agricultural land cover change in lowland UK catchments

Agricultural land use can increase runoff and erosion leading to detrimental downstream impacts. This paper examines the impact of agricultural land cover change on runoff and sediment generation at event scales using a model-based approach. SHETRAN, a physically based, spatially distributed model, was applied in two southwest England catchments to represent: (a) changes in the land cover (cropland extent and spatial arrangement), (b) changes in crop type, and (c) use of riparian buffer strips. A total of 84 simulated events within a 4-year period were used to quantify flow and sediment generation impacts. We found past changes in land cover resulted in significant differences in sediment yield (p < 0.05). Linear regression showed an increase in flow and sediment yield proportional to increases in arable crop area (p < 0.001). The spatial arrangement of cropped fields and riparian buffer strips produced no significant differences in event flow or sediment yield (p > 0.05). However, buffer strip scenarios compared with the base run showed sediment load reductions in specific events, up to 20% and 15% for woodland and grass riparian buffers, respectively. When comparing crop types with and without the use of post-harvest cover crops, we observed non-significant differences (both Qv and Sy). However, large reductions in modelled sediment yields occurred for some events (e.g., up to 60% for winter cereals, 50% for maize and 74% for spring cereals). For these scenarios, examination of rainfall event magnitude emphasized the importance of ground cover in mitigating soil erosion for maize and spring cereals, but not for winter cereals. Our findings indicate that significant changes in sediment delivery at the event scale are associated with cropland extent and crop types, depending on rainfall magnitude, but not on the spatial arrangement of cropped fields or the use of riparian buffer strips.

The Effects of Pedestrian Environments on Walking Behaviors and Perception of Pedestrian Safety

We investigated the effects of pedestrian environments on parents’ walking behavior, their perception of pedestrian safety, and their willingness to let their children walk to school. This study was a simulated walking environment experiment that created six different pedestrian conditions using sidewalks, landscape buffers, and street trees. We used within subjects design where participants were exposed to all six simulated conditions. Participants were 26 parents with elementary school children. Sidewalks, buffer strips, and street trees affected parents’ decisions to: walk themselves; let their children walk to school; evaluate their perception whether the simulated environment was safe for walking. We found that the design of pedestrian environments does affect people’s perceptions of pedestrian safety and their willingness to walk. The presence of a sidewalk, buffer strip, and street trees affected parents’ decision to walk, their willingness to let their children walk to school and perceived the pedestrian environment as safer for walking. The effects of trees on parents’ walking and perception of pedestrian safety are greater when there is a wide buffer rather than a narrow buffer. It was found that parents are more cautious about their children’s walking environments and safety than their own.

Horizontal ridging with mulching as the best tillage practice to reduce surface runoff and erosion in a Mollisol hillslope at the maize seedling stage

Soil erosion features and ideal tillage practices are not very clear at the crop seedling stage in Chinese Mollisols. Simulated rainfall experiments were conducted at the rainfall intensities of 50 and 100 mm h-1 to investigate the differences in soil erosion of a 5° hillslope during the maize seedling stage between conservation and conventional tillage measures, including cornstalk mulching (Cm), horizontal ridging (Hr), horizontal ridging + mulching (Hr+Cm), vertical ridging + mulching (Vr+Cm), flat-tillage (CK), and vertical ridging (Vr). The results demonstrated that crops could remit soil erosion at the seedling stage by reducing the kinetic energy and changing the distribution of raindrops. The conservation tillage measures significantly alleviated total runoff (11.7%–100%) and sediment yield (71.1%–100%), postponed runoff-yielding time (85 s–26.1 min), decreased runoff velocity (71.5%–96.7%), and reduced runoff and soil loss rate, compared to the conventional tillage measures. Practices with mulching showed better performance than Hr. Mulching reduced sediment concentration by decreasing runoff velocity and soil particle filtration in a manner similar to buffer strips. The contour ridge ruptured earlier at 100 mm h-1 than at 50 mm h-1 and changed the characteristics of the soil erosion by providing a larger sediment source to the surface flow. Runoff strength, rather than soil erodibility, was the key factor affecting soil erosion. Decreasing runoff velocity was more important than controlling runoff amount. The Hr + Cm treatment exhibited the lowest soil erosion and is, thus, recommended at the corn seedling stage.