Electric power transmission lines both cause and are impacted by wildfires and fuel breaks are crucial to mitigate wildfire hazard along and in conjunction with these infrastructures. Information about fuel dynamics is crucial for planning and maintaining fuel treatments, namely, to define their frequency. We sampled mechanically treated power line corridors representative of wide variation in climate, soil, and plant communities in Portugal and at different times since treatment. Non-destructive methods were used to assess ground cover and height per fuel stratum and the corresponding phytovolumes and fine fuel loads were calculated. Variability in fuel metrics was described by fitting logistic generalized linear models or linearized power functions based on time since disturbance and categorical variables for the effect of regeneration strategy, soil-richness structure, and climate. Time since treatment dominated fuel abundance and recovery was faster in communities of obligate resprouters in comparison with obligate or facultative seeders and in light- versus heavy-textured soils. No apparent effect of local climate was found given the short-lived impact of fuel treatments under the productive regional Mediterranean climate. The results provide a decision-making basis to refine the current treatment periodicity. Mechanical-treatment intervals of 3-5 years or 6-10 years are advised, respectively, for wildfire control and to minimize infrastructure damage.
Context Invasive plants are one of the most significant threats to woodlands globally. Methods of invasive plant control include manual removal and herbicide application. While the impacts of control methods on invasive and off-target native plant species are often explored, the impacts on below-ground organisms, such as fungi, are less well understood.Aims We conducted a glasshouse trial to investigate the responses of soil fungal communities to herbicides and manual removal that are used to control common invasive plant species in Banksia woodland in south-western Australia.Methods Broad spectrum (glyphosate and pelargonic acid) and grass-specific (fluazifop-p-butyl) herbicides were separately applied to pots containing either Ehrharta calycina, a key invasive grass species or Eucalyptus todtiana, a native woodland tree at the recommended woodland rate. After six weeks, samples of treated soils were subjected to high throughput sequencing to determine fungal community diversity, richness, relative abundance, composition and putative ecosystem function.Key results Pelargonic acid induced the widest range of changes including decreased fungal richness and Shannon diversity but all herbicides affected community composition. Within functional groups, fluazifop-p-butyl led to a significant decrease of symbiotrophs in the mycorrhizal species.Conclusions We show that invasive species management, in the manner applied, can lead to immediate changes in fungal community composition.Implications Observed patterns require further exploration, particularly repeat testing under different environmental conditions, to better determine the impact and mode of action of herbicides on below-ground organisms. The functional changes in the soil fungal community could further disturb the soil fungal community and complicate subsequent management considerations.
The ruined landscapes of the Mediterranean littoral are a consequence of millennia of human impact and include abandoned agricultural lands, deforested areas, and degraded coastal areas. One of the drivers is the historical pattern of land use, which has resulted in the clearing of vegetation, soil erosion, and overgrazing. These have caused significant damage to natural ecosystems and landscapes leading to soil degradation, loss of biodiversity, and the destruction of habitats. The UN Sustainable Development Goal 15 Life on Land recommends a substantial increase in afforestation (SDG 15.2). Whilst this goal is certainly necessary in places, it should be implemented with caution. The general perception that certain ecosystems, such as forests, are inherently more valuable than grasslands and shrublands contributes to afforestation drives prioritising quick and visible results. This, however, increases the possibility of misguided afforestation, particularly in areas that never supported forests under the present climatic conditions. We argue that in areas that have not supported forest ecosystems, targeted reinforcement of existing populations and recreation of historical ones is preferable to wholesale ecosystem modification disguised as afforestation. We present a possible strategy for targeted reinforcement in areas that never supported forests and that would still achieve the goals of SDGs 15.5 and 15.8.
This study investigated using rare earth elements as tracers to study wildfire impacts. The study area was Antalya, located in the Mediterranean region of T & uuml;rkiye. This region is known for the frequent occurrence of wildfires, which cause significant damage to the flora and fauna of the area. A series of wildfires occurred in the region in 2016. Soil samples were collected from the affected areas to understand these wildfires' impact better. Instrumental neutron activation analysis was used to analyze the samples. The study found that the north-facing aspect had higher concentrations of rare earth elements. This could be because north-facing aspects are cooler and more humid, with less erosion, leading to better ecological restoration and less transportation of rare earth elements.
Forests provide multiple ecosystem services including water and soil protection, biodiversity conservation, carbon sequestration, and recreation, which are crucial in sustaining human health and wellbeing. Global changes represent a serious threat to Mediterranean forests, and among known impacts, there is the spread of invasive pests and pathogens, often boosted by climate change and human pressure. Remote sensing can provide support to forest health monitoring, which is crucial to contrast degradation and adopt mitigation strategies. Here, different multispectral and SAR data are used to detect the incidence of ink disease driven by Phytophthora cinnamomi in forest sites in central Italy, dominated by chestnut and cork oak respectively. Sentinel 1, Sentinel 2, and PlanetScope data, together with ground information, served as input in Random Forests to model healthy and disease classes in the two sites. The results indicate that healthy and symptomatic trees are clearly distinguished, whereas the discrimination among disease classes of different severity (moderate and severe damage) is less accurate. Crown dimension and sampled spectral regions are a critical factors in the selection of the sensor; better results are obtained for the larger chestnut crowns with Sentinel 2 data. In both sites, the red and near infra-red bands from multispectral data resulted well suited to monitor the spread of the ink disease.
Background and aims Decline in tree species is a complex phenomenon involving multiple factors, among edaphic conditions are assumed to play an important role as factor of predisposition of forests to this process. In this regard, scarce information exists on the effects of the internal variability of the soil with depth on the predisposition to decline, an aspect that requires further evaluation. Methods Characterization of the internal variability of soil was carried out at 20 sites (10 with evidence of decline and 10 with no signs of decline) and the results analyzed to determine their role in modulating the effect of drought, which is the main cause of the observed decline in Aleppo pine stands in the Comunidad Valenciana (Spain). Results The soil properties found to be the most explanatory were those associated with soil quality in terms of available space for root exploration, which is vital for nutrition and, above all, water uptake. Episodes of decline are associated with stands where soils have a shallow effective depth due to a low degree of profile development or through marked textural anisotropy because of particularly clayey horizons that cause abrupt changes in permeability and aeration. Conclusion The internal variability of the soil, closely linked to the degree of pedogenetic development, is identified as a factor that plays an important role in predisposing the vegetation to the effects of drought.
Flooding is a recurring natural phenomenon that can have both life-giving and destructive aspects. In natural environments, floods are often an important element of the seasonal hydrologic cycle that provides water and nutrients to soil, supporting unique, rich and diverse ecosystems. However, flood events can also represent a destructive force that can endanger lives and cause significant damage in urban areas. Karst areas, in particular, are unique because of their special hydraulic characteristics in terms of flood occurrence, the dependence of ecosystems on such events, and attempts to actively store and manage floods. In this article, the hydraulic response of karst aquifers to heavy precipitation events, flood generation, and engineering interventions for flood control are discussed using several examples from karst areas in the Mediterranean region. Flooding mechanisms and regulatory structures in karst poljes are considered using several typical examples from the Dinaric mountain range. In addition, different variants of groundwater abstraction for increasing storage capacity and flood control are presented using examples from France and Montenegro. Managed aquifer recharge in karst areas and adjacent aquifers is demonstrated with examples from Jordan and Algeria. Finally, failed attempts at flood storage in karst reservoirs are presented with examples from Spain and Montenegro. These examples of flood retention in karst areas show the wide range of planning and technical measures and remind us of possible risks and failures in implementation as well as some positive and negative impacts on the environment and especially on ecosystems.
Soil erosion is caused by increased agricultural activities and a lack of necessary measures to prevent erosion. This leads to the destruction of soil, which takes thousands of years to regenerate. The study area in the Mediterranean Basin is one of the subbasins most affected by global climate change. Erosion in burned areas, especially after large forest fires, occurs as water can wash away the soil and increase the risk of erosion. Burned vegetation also reduces the soil's erosion resistance. The increase in erosion in burned areas can lead to a series of problems, such as water source pollution, damage to agricultural areas, and environmental pollution. The study aims to determine that the Google Earth Engine (GEE) platform is an effective tool for combating erosion after fire lands. Erosion is predicted using the RUSLE model on GEE in pre-fire (2020) and post-fire (2022). This study determined areas at risk of erosion, and preventative measures were taken to prevent environmental problems like soil loss, water pollution, habitat loss, and biodiversity loss. In the results of the study, it was determined that the average soil loss after forest fires in the Manavgat River Basin was 9.47 ton-1 ha-1 year-1. According to the study, changes in soil loss were found depending on land use during the pre-fire and post-fire periods, and there was a general increase in soil loss of 0.10 ton-1 ha-1 year-1 after the fire. It was found that soil loss was lower before the fires. The study area experienced soil loss higher than the Turkiye average. The RUSLE-GEE method used in the study and other methods for estimating soil loss emphasizes the need to use strategies such as changing agricultural methods, using sediment trapping systems, protecting soil cover, and implementing policies and laws together to reduce soil erosion.
Biomass burning is a major source of Brown Carbon (BrC), strongly contributing to radiative forcing. In urban areas of the climate-sensitive Southeastern European region, where strong emissions from residential wood burning (RWB) are reported, radiative impacts of carbonaceous aerosols remain largely unknown. This study examines the absorption properties of water-and methanol-soluble organic carbon (WSOC, MeS_OC) in a city (Ioannina, Greece) heavily im-pacted by RWB. Measurements were performed during winter (December 2019 - February 2020) and summer (July - August 2019) periods, characterized by RWB and photochemical processing of organic aerosol (OA), respectively. PM2.5 filter extracts were analyzed spectrophotometrically for water-and methanol-soluble BrC (WS_BrC, MeS_BrC) absorption. WSOC concentrations were quantified using TOC analysis, while those of MeS_OC were determined using a newly developed direct quantification protocol, applied for the first time to an extended series of ambient sam-ples. The direct method led to a mean MeS_OC/OC of 0.68 and a more accurate subsequent estimation of absorption efficiencies. The mean winter WS_BrC and MeS_BrC absorptions at 365 nm were 13.9 Mm-1 and 21.9 Mm-1, respec-tively, suggesting an important fraction of water-insoluble OA. Mean winter WS_BrC and MeS_BrC absorptions were over 10 times those observed in summer. MeS_OC was more absorptive than WSOC in winter (mean mass absorption efficiencies - MAE365: 1.81 vs 1.15 m2 gC-1) and especially in summer (MAE: 1.12 vs 0.27 m2 gC-1) due to photo -dissociation and volatilization of BrC chromophores. The winter radiative forcing (RF) of WS_BrC and MeS_BrC rela-tive to elemental carbon (EC) was estimated at 8.7 % and 16.7 %, respectively, in the 300-2500 nm band. However, those values increased to 48.5 % and 60.2 % at 300-400 nm, indicating that, under intense RWB, BrC forcing becomes comparable to that of soot. The results highlight the consideration of urban BrC emissions in radiative transfer models, as a considerable climate forcing factor.
An 8-year dataset from 7 AERONET (Aerosol Robotic Network) sites is used to analyzed the variation characteristics of aerosol optical and microphysical properties over the Middle East (ME) and Eastern Mediterranean Sea (EMS) regions. The aerosol optical properties, including aerosol optical depth (AOD), Angstrom exponent (AE), volume size distribution (VSD), aerosol absorption optical depth (AAOD), single scattering albedo (SSA), dominant types, aerosol radiative forcing (ARF) and its efficiency (ARFE), are presented and analyzed over the two regions. The regional mean AODs (AEs) are 0.31 (0.69) and 0.19 (1.10) over ME and EMS, respectively. Although the linear trend of annual averages is not significant at these sites, the variations of seasonal and annual AODs and AEs are remarkable. The mean AODs are generally higher over ME than over EMS, while the AEs show the opposite pattern. AOD appears the maximum in summer and the minimum in winter both at ME and EMS sites. AE shows the maximum in autumn and winter over ME, while in summer over EMS. The lowest AE appears in spring over both regions due to the frequent dust events. The AAOD ranges from 0.03 to 0.04 and the SSA from 0.89 to 0.93 at these sites. The seasonal AAOD presents very different features over the two regions. The AAOD appears its minimum in winter at most ME sites, while the maximum appears in the same season at EMS sites. The differences of seasonal SSAs at ME sites are relatively small, while at EMS sites the SSAs are much higher in summer and autumn than those in spring and winter. The aerosol types are discussed based on four selected classification methods. It shows that the desert dust (DD) and the mixtures (Mix) are the two dominant aerosol types at most sites except ERD which is dominated by urban industry aerosol (UI). To the radiative forcing, the ARF at bottom of atmosphere (BOA) is generally larger at ME sites than at EMS sites, while the ARFs at top of atmosphere (TOA) are numerically similar at most sites. The ARFE shows higher value at sites in Arabian Peninsula both at BOA and TOA.