66 research outputs found
Thematic Workshop: Challenges, opportunities, and adaptation strategies to climatic changes in dryland forestry systems
No full textAs a part of networking activities of PEN-CAFoRR COST Action (CA19128), the combined meeting took place in Mitzpe Ramon, Israel from 15 to 16 March 2023. In addition to the Core Group and Working Groups Meeting, a Thematic Workshop was organized by the local organizer Dr Ilan Stavi
Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems
No full textSoil indicators may be used for assessing both land suitability for restoration and the effectiveness of restoration strategies in restoring ecosystem functioning and services. In
this review paper, several soil indicators, which can be used to assess the effectiveness of ecological restoration strategies in dryland ecosystems at different spatial and temporal
scales, are discussed. The selected indicators represent the different viewpoints of pedology, ecology, hydrology, and land management. Two overall outcomes stem from the review. (i) The success of restoration projects relies on a proper understanding of their ecology, namely the relationships between soil, plants, hydrology, climate, and land management at different scales, which are particularly complex due to the heterogeneous pattern of ecosystems functioning in drylands. (ii) The selection of the most suitable soil indicators follows a clear identification of the different and sometimes competing
ecosystem services that the project is aimed at restoring
A review of coupled hydrologic and crop growth models
No full textCoupling hydrologic and crop models is becoming an increasingly important approach in the development of agro-hydrologic theme. Scientists and decision makers working to address issues in the areas of resource conservation and agricultural productivity are interested in the complementary processing of the two coupled systems. The objective of the present work is to review relevant studies related to hydrologic and crop models coupling, and to analyze the domain applicability, limitations, and other considerations
Wildfires in Grasslands and Shrublands: A Review of Impacts on Vegetation, Soil, Hydrology, and Geomorphology
No full textWildfires are prevalent in grasslands and shrublands. The objective of this study is to provide land managers with a general overview, by assessing the main impacts of wildfire, including those on plant communities (e.g., secondary succession and species invasion), soil characteristics (e.g., water repellency (hydrophobicity), aggregation and structure stability, and contents of organic carbon and nutrients), and surface processes (e.g., ash deposition, ground surface clogging, water runoff, soil erosion, hillslope debris flow, and dry ravel). Additionally, the study discusses the effects of livestock grazing on the functioning of post-fire grasslands and shrublands. Although mesic regions are mentioned, this review focuses on drylands. The comparatively low-to-moderate fuel loads that characterize grasslands and shrublands generate wildfires of relatively moderate intensity, resulting in moderate burn severity. Yet, it seems that because of decreased soil aggregate stability following burning, the hoof action of livestock that access burnt lands shortly after the fire increases the shearing and detachment of mineral material from the ground surface; this increases soil erodibility, with the possible risk of accelerated land degradation. The review ends with an assessment of general implications for environmental sustainability and health, and provides recommendations on wildfire control in rangelands, and on restoration of burnt lands
Seeking Environmental Sustainability in Dryland Forestry
No full textForestry systems, including afforestation and reforestation land uses, are prevalent in drylands and aimed at restoring degraded lands and halting desertification. However, an increasing amount of literature has alerted potentially adverse ecological and environmental impacts of this land use, risking a wide range of ecosystem functions and services. The objective of this paper is to demonstrate the potentially adverse implications of dryland forestry and highlight the caution needed when planning and establishing such systems. Wherever relevant, establishment of low-impact runoff harvesting systems is favored over high-impact ones, which might cause extensive land degradation of their surroundings. Specifically, both in hillslopes and channels, scraping, removal, or disturbance of topsoil for the construction of runoff harvesting systems should be minimized to prevent the decrease in soil hydraulic conductivity and increase in water overland flow and soil erosion. In order to negate suppression of understory vegetation and sustain plant species richness and diversity, low-density savanization by non-allelopathic tree species is preferred over high-density forestry systems by allelopathic species. Wherever possible, it is preferable to plant native tree species rather than introduced or exotic species, in order to prevent genetic pollution and species invasion. Mixed-species forestry systems should be favored over single-species plantations, as they are less susceptible to infestation by pests and diseases. In addition, drought-tolerant, fire-resistant, and less flammable tree species should be preferred over drought-prone, fire-susceptible, and more flammable species
On-Site Use of Plant Litter and Yard Waste as Mulch in Gardening and Landscaping Systems
No full textPlant litter, such as fallen leaves, branch trimmings, and other yard waste, plays important roles in both natural and man-made ecosystems. However, due to common aesthetic perceptions, land-owners or managers of many residential gardening and municipal landscaping systems consider these organic residues a burden, and therefore, clear them from the ground and dispose of them off-site. The removal of these organic resources increases the system’s environmental footprint, decreases its sustainability, and negates the provision of important ecosystem services. At the same time, retaining these organic materials on-site could provide the system with substantial benefits. The most obvious effect is the ground surface shading, which decreases direct solar radiation to the soil, lowers soil temperature, lessens evaporation rates, decreases risk of soil salinization, and improves water-use efficiency. Ground surface mulching likewise prevents the raindrop splash impact, negates the formation of sealed mechanical crusts, improves water infiltrability, and reduces water runoff and soil erosion. Another benefit is the on-site decomposition of organic materials, which improves soil quality by elevating organic carbon concentration and contributing to nutrient cycling. Vegetation patches in such systems encompass "engineered fertility islands", which can be defined as highly productive, healthy, and functioning habitats. Further, over time, these systems require less maintenance. This management practice is crucial for tree- or shrub-dominated gardening and landscaping systems in drylands, where water availability is the major limiting factor of vegetation growth. However, global climate change, in which extended parts of the world experience increasing temperatures and decreasing precipitation rates, makes this practice relevant for other climatic regions as well
Urgent reduction in greenhouse gas emissions is needed to avoid irreversible tipping points: time is running out
No full textABSTRACTThis essay addresses climate change and its main causes over the last three decades. Between 1992–2021, global emissions of greenhouse gases (GHGs) have risen continually. Specifically, the major socioeconomic sectors – including (1) energy, (2) industry, (3) land-use/land-use change/agriculture, (4) transportation, (5) building/construction, and (6) waste treatment/disposal – have emitted enormous amounts of GHGs. Between 1992–2019, the combined annual GHG emissions have risen by 53% – from 32.6 to 49.8 Gt CO2 equivalent (CO2e). The combined GHG concentration has increased by 33% – from 382 ppm CO2e in 1992 to 508 ppm CO2e in 2021. The combined radiative forcing has surged by 45% – from 2.226 W m−2 in 1992 to 3.222 W m−2 in 2021. At the current emission rate, the entire GHG credit for limiting global warming to 1.5°C or 2.0°C – according to the Shared Socio-Economic Pathway (SSP) 1–1.9 or SSP1–2.6, respectively – in 2100 compared to preindustrial levels may be fully exploited by~2030. Limiting global warming to 1.5°C or 2.0°C will require total GHG emissions to peak before 2025 at the latest, and be reduced by 43% or 25%, respectively, in 2030 relative to 2019, followed by zero net emissions in the early 2050s or 2070s, respectively
Runoff Mitigation in Croplands: Evaluating the Benefits of Straw Mulching and Polyacrylamide Techniques
No full textWater loss through surface runoff is a significant constraint for rainfed agricultural lands across the Mediterranean region. Using straw-mulch cover (SMC) as a runoff mitigator has been successfully utilized to negate the impact of raindrop splashing. However, this practice is uncommon due to the high demand for crop residue as feed or fodder for livestock. Therefore, the application of synthetic polyacrylamide (PAM) has become a common practice. Although many studies have shown the positive impact of PAM on runoff control, most were conducted under laboratory conditions, where interactions with crop phenology and runoff dynamics were disregarded. In this study, on-site rainfall simulation was used to determine the efficiency of PAM and SMC to control runoff from foxtail millet (Setaria italica) fields under three seasonal conditions: (1) high-intensity rainfall, characteristic of autumn, on bare soil surfaces; (2) moderate-intensity rainfall, characteristic of winter, following crop tillering; and (3) high-intensity rainfall, characteristic of spring, following the flowering phase. The effect of SMC during the autumn and spring simulations was significantly better than that of the PAM and control treatments. For the winter simulation, runoff rates and runoff ratios were similar for all treatments. The most prominent finding was obtained for the spring simulation, where SMC yielded no runoff, whereas the PAM and control treatments yielded similar runoff rates and runoff ratios
- …
