SSS8.10 | Coevolution of landforms, soils and vegetation: advances in the study of patterns, feedbacks and ecosystem stability thresholds

The present context of accelerated changes in both climate and land use imposes an unprecedent pressure on a number of vulnerable ecosystems including wetlands, forests and rangelands, in which vegetation closely interacts and coevolves with soils and landforms. Complex interactions between climate, soils and biotic factors are involved in the development of landform-soil-vegetation feedbacks and play an important role in making ecosystems resilient to disturbances. In addition, large shifts in the distribution of vegetation and soils are associated with losses of ecosystem services (including carbon capture), frequently involving thresholds of ecosystem stability and nonlinear responses to both human and climatic pressures.

This session looks back on the successful and exciting sessions on landform-soil-vegetation coevolution and ecosystem stability annually held at EGU since 2013 and will focus on ecogeomorphological and ecohydrological aspects of landscapes and wathersheds (including their connectivity), the conservation of both soil and water resources, and the restoration of ecosystem services and functions.

We welcome theoretical, modelling and empirical studies as well as scaling approaches from the soil profile to the landscape scale addressing soil structure and its functions, including carbon and nutrient cycling, the distribution of vegetation and their coevolving landforms, and also contributions with a wide appreciation of the soil erosion-vegetation relationships that rule the formation of broad, landscape-level spatial organization. We also welcome studies describing the implications of these spatial patterns for the resilience, stability and restoration of ecosystems under the pressure of climate change and/or human disturbances.

We are proud to announce that Prof. Susana Bautista (Head of the Ramon Margalef Multidisciplinary Institute for Environmental Studies, University of Alicante, Spain) has agreed to participate in the session with the invited talk "Within-patch plant diversity modulates the hydrological source-sink dynamics of dryland landscapes".

Co-organized by BG3/GM3
Convener: Mariano Moreno de las Heras | Co-conveners: Patricia Saco, Peng ShiECSECS, Omer Yetemen, Siyu CaiECSECS, Hu Liu, Jose Rodriguez
Orals
| Mon, 24 Apr, 08:30–12:30 (CEST)
 
Room -2.20
Posters on site
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
Hall X3
Posters virtual
| Attendance Mon, 24 Apr, 14:00–15:45 (CEST)
 
vHall SSS
Orals |
Mon, 08:30
Mon, 14:00
Mon, 14:00

Orals: Mon, 24 Apr | Room -2.20

Chairpersons: Omer Yetemen, Patricia Saco
Climate and anthropogenic effects on vegetation, coevolving soil-landscape systems and both runoff and soil erosion processes
08:30–08:35
08:35–08:45
|
EGU23-4627
|
SSS8.10
|
ECS
|
Virtual presentation
Jiongchang Zhao, Jianjun Zhang, and Yang Yu

Land-use and rainfall characteristics are two crucial influencing factors that affect the surface runoff and soil loss process; however, less attention has been paid to nested watersheds in vulnerable geo-ecosystems. In this study, we analyzed rainfall characteristics impacts on runoff and sediment in one of the nested watersheds, which contains six sub-watersheds with different land uses (secondary forest watershed, mixed forest watershed, closed watershed, plantation watershed, farmland watershed and farming-pastoral watershed) on the Loess Plateau, China. According to rainfall amount, rainfall duration and maximum rainfall intensity within 30 min (I30), 180 rainfall events during 2004–2019 were categorized into four types using K-means clustering method, and different hydrological years were distinguished. The runoff coefficient and sediment yield under the rainfall regime I (little precipitation, moderate duration of precipitation, low intensity of precipitation) were the lowest; under the rainfall regime IV (high precipitation, short duration of precipitation, high intensity of precipitation), these values were the largest. The average runoff coefficient among the six sub-watersheds analyzed varied as follows: farmland watershed (2.42%) > farming-pastoral watershed (2.38%) > closed watershed (1.11%) > secondary forest watershed (1.08%) > mixed forest watershed (0.73%) > plantation watershed (0.43%). The closed watershed had the lowest average sediment yield, while the farming-pastoral watershed showed the highest one. In addition, the runoff coefficient and sediment yield also changed differently in various hydrological years. The results of this study suggest that natural restoration measures are the optimal choice for coordinating the relationship between surface runoff and sediment yield. In future research, enhanced long-term monitoring is needed to accurately describe watershed processes.

 

How to cite: Zhao, J., Zhang, J., and Yu, Y.: Effects of land uses and rainfall regimes on surface runoff andsediment yield in a nested watershed of the Loess Plateau, China , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4627, https://doi.org/10.5194/egusphere-egu23-4627, 2023.

08:45–08:55
|
EGU23-6057
|
SSS8.10
|
ECS
|
On-site presentation
Manel Llena, Javier Zabalza, Melani Cortijos-López, Teodoro Lasanta, and Estela Nadal-Romero

During the second half of the 20th century the mountain areas of the Mediterranean region undergone an intense process of rural abandonment. This process together with a transition to warmer and drier climatic conditions caused a decrease in runoff and sediment yield, which have several consequences from hydrological, geomorphological and ecological points of view. Land use management of these areas has become a target of environmental authorities and stakeholders to ensure the sustainability of ecosystem services. An active management has been applied in some areas through the reduction of vegetation density or by human afforestation, while other areas have not been managed, undergoing a natural process of revegetation. In this context, assessing the contribution of different land use management on runoff is fundamental for addressing water management at the catchment and regional scales, especially in a context of climate change. The main objective of this work is to analyse the relative effects of land use management techniques to hydrological connectivity and water yield in a Mediterranean mid-mountain basin. To pursue this objective, we applied hydrological connectivity (IC index) and ecohydrological (RHESSys) models to different sub-catchments of the Leza Valley (Iberian System, Spain), representative of three different scenarios: (i) natural revegetation, (ii) human afforestation, and (iii) shrub clearing. Results show how hydrological connectivity tends to decrease when vegetation cover increases (i.e., natural revegetation and human afforestation) while tends to increase when shrub clearing takes place. Runoff coefficient followed a similar pattern, decreasing in basins where vegetation increases and decreasing where there is vegetation clearing. Important differences were observed in terms of the distribution of connectivity changes, their location in relation to the outlet and the effects on surface runoff.

This research project was supported by the MANMOUNT (PID2019-105983RB-100/AEI/ 10.13039/501100011033) project funded by the MICINN-FEDER and the PRX21/00375 project funded by the Ministry of Universities of Spain from the “Salvador de Madariaga” programme. Manel Llena has a “Juan de la Cierva Formación” postdoctoral contract (FJC2020-043890-I/AEI/ 10.13039/501100011033) from the Spanish Ministry of Science and Innovation, while Melani Cortijos-López is working with an FPI contract (PRE2020-094509) from the Spanish Ministry of Economy and Competitiveness associated to the MANMOUNT project.

 

How to cite: Llena, M., Zabalza, J., Cortijos-López, M., Lasanta, T., and Nadal-Romero, E.: Land use management effects on water yield and hydrological connectivity after rural abandonment in a mid-mountain basin: Leza Valley (Iberian System, Spain), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6057, https://doi.org/10.5194/egusphere-egu23-6057, 2023.

08:55–09:05
|
EGU23-6540
|
SSS8.10
|
ECS
|
Virtual presentation
Kun-xia Yu, Lu Jia, Guoce Xu, Peng Li, and Zhanbin Li

The widespread occurrence of soil erosion reflects the accelerated deterioration of the surface ecological environment. The spatiotemporal variation of rainfall erosivity is the key driving factor for soil erosion by water, especially in the Loess Plateau in China. The Fenhe River basin in the Loess Plateau was selected as a case study based on the daily rainfall data from 1962 to 2019. Using a rainfall erosivity model based the daily rainfall, we studied the changing pattern. Furthermore, the impact of rainfall erosivity on sediment load was evaluated, and the possible causes for changes in sediment load were discussed. The results showed that the annual rainfall erosivity of the 12 weather stations experienced an insignificant change (p > 0.05). Moreover, before the 1980s, the decrease in annual watershed average rainfall erosivity may be the main reason for the decrease in annual sediment load, while after the 1980s, the construction of check dams may be the main factor leading to annual sediment load reduction, especially around 1993. However, the increase of vegetation was a main reason for the reduction of annual sediment load after 1999. Given Fenhe River basin as a typical watershed of the Loess Plateau, the study of rainfall erosivity and its impacts on the sediment in this area can provide a useful reference for further ecological construction and soil erosion control in the Loess Plateau.

How to cite: Yu, K., Jia, L., Xu, G., Li, P., and Li, Z.: The changing pattern of rainfall erosivity and its impact on sediment load in the Loess Plateau, China: A case study of a typical watershed, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6540, https://doi.org/10.5194/egusphere-egu23-6540, 2023.

09:05–09:15
|
EGU23-3559
|
SSS8.10
|
On-site presentation
Olivier Cerdan, Valentin Landemaine, Anthony Foucher, Jean-François Desprats, Olivier Evrard, Thomas Grangeon, Clément Chabert, and Sébastien Salvador-Blanes

At continental and geological time scales, tectonic forces and climate are the first landscape evolution drivers. However, since the Neolithic, human is recognised as being a new geomorphic agent, indirectly or directly moving significant amount of materials across landscapes. In a context of global changes, when both climate and human activities are rapidly evolving, the question of the relative contribution of climate variability and anthropogenic activities to soil erosion remains poorly quantified. Understanding this contribution is however key to the design of appropriate soil erosion management plans. Based on two catchment-scale hydrosedimentary observatories, the objective of this study is to quantify the relative importance of climate variability and land use change on the erosive response of two headwater catchments located in contrasted environments. The first study area is in a volcanic tropical island and the second one is in a lowland, intensively cultivated plain under an oceanic temperate climate. More particularly, we will investigate the importance of rainfall and associated flood events intensity and frequency on the water and sediment fluxes. The influence of these temporal dynamics (i.e. frequency/intensity of events) will be studied according to different land uses, as the two questions (spatial/temporal variabilities) are closely interlinked.

How to cite: Cerdan, O., Landemaine, V., Foucher, A., Desprats, J.-F., Evrard, O., Grangeon, T., Chabert, C., and Salvador-Blanes, S.: Climatic against land use variability impact on soil erosion in two contrasting environments, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3559, https://doi.org/10.5194/egusphere-egu23-3559, 2023.

09:15–09:25
|
EGU23-15029
|
SSS8.10
|
ECS
|
On-site presentation
Andrea Román-Sánchez, Tom Vanwalleghem, Ana Laguna, Adolfo Peña, Juan Vicente Giraldez, and Luca Brocca

Influence of the Mediterranean climate, relief and geology can shed light on the most important processes that affect the mechanisms and rate of bedrock weathering. Despite the effort dedicated to exploring the processes of soil formation, little is known about the quantitative aspects of these processes. This research is based on developing a spatially explicit model of soil water and climate dynamics to explain the processes in soil formation. This model includes a simple soil water balance model, climatic data, topographic variables and runs a daily time step. The model calibration is performed with satellite soil moisture data for the Mediterranean basin. The model highlights the importance of soil water flux at different topographic positions on soil formation on long-term time scales.

How to cite: Román-Sánchez, A., Vanwalleghem, T., Laguna, A., Peña, A., Giraldez, J. V., and Brocca, L.: Modelling soil water and climate dynamics to understand soil formation in Mediterranean landscapes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15029, https://doi.org/10.5194/egusphere-egu23-15029, 2023.

09:25–09:45
|
EGU23-8480
|
SSS8.10
|
solicited
|
Highlight
|
On-site presentation
Veerle Vanacker, Rose Paque, Ilia Alomia Herrera, Jean Dixon, Yessenia Montes Anchali, Frantz Zeheter, and Armando Molina

Understanding the complex interactions between climate, vegetation and soils is important for the sustainable management of soil ecosystems in the context of climate and land use change. Few benchmark data exist on soil-landscape and vegetation interactions, as most soil ecosystems have a legacy of past land use and management.

By working in the Galapagos Islands, a UNESCO World Heritage Site, we have the opportunity to better constrain the coevolution of soils and vegetation over millennial timescales for pristine soil ecosystems. Five monitoring sites are located on the Pacific Island of Santa Cruz, and they cover a ~10 km long NW-SE stretch. Along this gradient with a 10-fold increase in mean annual precipitation, the climate effects on the coevolution of soils and vegetation were quantified. Soil weathering extent was assessed through geochemical proxies, and these data were then related to time-series of precipitation, air and soil temperature, and humidity to explore the relationships between soil and vegetation development, and climate. Then, by contrasting the data from five pristine soil ecosystems with data from agricultural soils, new information was obtained on the anthropogenic effects on soil ecosystems.

Soil weathering indices and elemental mass balances were used as a measure of soil development and were derived from the soil's physical and chemical properties measured at soil profiles. For the pristine sites, there is a nonlinear relationship between the degree of soil and vegetation development and (hydro)climatic data. Forest conversion into agricultural land leads to measurable effects on soil ecosystem services and functions.

How to cite: Vanacker, V., Paque, R., Alomia Herrera, I., Dixon, J., Montes Anchali, Y., Zeheter, F., and Molina, A.: Climate and anthropogenic effects on the coevolution of soils and vegetation: A case-study in the Pacific island of Santa Cruz (Galapagos, Ecuador), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8480, https://doi.org/10.5194/egusphere-egu23-8480, 2023.

09:45–09:55
|
EGU23-1955
|
SSS8.10
|
Virtual presentation
Zhun Zhao and Peng Shi

Soil aggregates are important for improving the soil quality and structure. Soil erosion causes the fragmentation and migration of soil aggregates. Vegetation restoration is an effective method for controlling soil erosion, and the vegetation distribution on the slope changes the hydrological processes. However, there is a lack of studies on the regulation of vegetation patterns with respect to soil aggregate loss. In this study, four different vegetation patterns were used to study the loss characteristics of soil aggregates during erosion: no vegetation (pattern A), upslope vegetation (pattern B), middle-slope vegetation (pattern C), and downslope vegetation (pattern D). The results show that the proportions of microaggregates (<0.25 mm) in the sediments during erosion are 65.2%, 72.4%, 77.7%, and 87.7% for patterns A, B, C, and D, respectively. The loss of macroaggregates (>0.25 mm) in the sediment is significantly higher in pattern A than in the other patterns (P < 0.05): A (34.8%) > B (27.6%) > C (22.3%) > D (12.3%). Vegetation on the slope reduces the mean weight diameter (MWD) of aggregates in the sediments by 66.0%–70.0% and the fractal dimension increases by 0.42%–0.96%. The vegetation pattern has different effects on the enrichment rate of aggregates in sediments: the enrichment ratio of macroaggregates decreases by 20.9%–64.7% and the enrichment ratio of microaggregates increases by 11.1%–34.5%. These results indicate that downslope vegetation effectively reduces soil erosion and the loss of soil macroaggregates.

How to cite: Zhao, Z. and Shi, P.: Vegetation patterns affect soil aggregate loss during water erosion, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1955, https://doi.org/10.5194/egusphere-egu23-1955, 2023.

09:55–10:05
|
EGU23-10293
|
SSS8.10
|
On-site presentation
Arnaud Temme, Mostafa Sadeghnejad, Harsimran Singh Sodhi, and Jalal Samia

The spatial pattern of landslide susceptibility is a key input for decision making by many natural hazard agencies. Therefore, the estimation of landslide susceptibility maps has received much attention in the last decades. Increasingly, such maps are produced by statistical methods that relate the locations of observed landslides to geofactors such as slope steepness or vegetation density. Almost without exception, these susceptibility assessments are entirely spatial. At the same time, recent studies of large multitemporal landslide datasets have shown empirically that landslide susceptibility changes over time as well as space, as a result of the impact of recent nearby landslides. In at least two study sites, places near previous landslides are temporarily more susceptible to landsliding, sometimes substantially so. Several candidate mechanisms underlie this form of complexity (called path-dependency) in the landslide system, and targeted field measurements in landslide-prone study sites should be recorded to fully understand which mechanism is most important.

Awaiting such measurements, physically-based mechanistic modelling of landslide impacts in the soil-landscape system can help explore the possible mechanisms. Here, we report on our development of landslide simulation capabilities in soil-landscape evolution model LORICA. In this model, landslides affect not only surface elevation, but also local soil and vegetation properties. Since other processes in the model also affect these properties, the impact of landslides is not permanent. Applied to a hypothetical soil-landscape, this model allows us to explore whether a) local topographic effects such as oversteepening, b) temporarily changed soil hydraulic parameters, or c) disruption of vegetation and roots, are the most likely mechanisms behind landslide path-dependency.

How to cite: Temme, A., Sadeghnejad, M., Singh Sodhi, H., and Samia, J.: The search for path-dependency mechanisms using physically-based soil-landscape modelling of landslides, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10293, https://doi.org/10.5194/egusphere-egu23-10293, 2023.

10:05–10:15
Coevolution of landforms, vegetation and soils in drylands and coastal wetlands
Coffee break
Chairpersons: Patricia Saco, Jose Rodriguez
10:45–10:50
10:50–11:00
|
EGU23-10408
|
SSS8.10
|
ECS
|
Virtual presentation
Eliana Jorquera, Patricia Saco, Danielle Verdon-Kidd, and Jose Rodriguez

Coastal mangroves are essential areas for the habitat of coastal and marine ecosystems, which are under constant anthropogenic and climatic pressure. Sediment and biological accretion can attenuate the effects of sea-level rise by rising the ground level. The balance between the soil accretion and the sea-level rise under climate change conditions will determine the response of the mangrove and its adaptation/survival.

This contribution presents the ecogeomorphological assessment of the Dreketi river wetland (northern coast of Vanua Levu - Republic of Fiji). This mangrove wetland belongs to the central area of the Great Sea Reef, which was declared as Ramsar site in 2018. The Dreketi river catchment is the main contributor of water and sediments to the wetland. The amount of water and sediments generated in the catchment were determined using a hydro-sedimentological, physically based watershed scale model (SWAT). Then, the response of the Dreketi mangrove wetland to sea-level rise and climate change was analysed using an eco-geomorphological (EGM) model.

The hydro-sedimentological model proved to be suitable to represent the sediment concentration in the Dreketi river catchment with a good performance against sediment concentrations obtained using remote sensing products. The EGM was able to represent the spatial distribution of suitable areas for mangrove habitats, given the current conditions. Under sea-level rise events, after 100 years, a significant amount of the suitable area could disappear for a sea-level rise. The model showed the profound effect that sea-level rise and sediment accretion have on the wetland's future evolution, highlighting the importance of the sediment input from the contributor catchment.

How to cite: Jorquera, E., Saco, P., Verdon-Kidd, D., and Rodriguez, J.: Ecogeomorphological assessment of a mangrove wetland in the Pacific Islands, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10408, https://doi.org/10.5194/egusphere-egu23-10408, 2023.

11:00–11:10
|
EGU23-12589
|
SSS8.10
|
On-site presentation
Tegan Blount, Andrea D'Alpaos, Sonia Silvestri, and Marco Marani

Salt marshes provide a multitude of ecosystem services while simultaneously being susceptible to habitat loss and degradation in response to climatic and anthropogenic disturbances. Thus, the spatially explicit characterisation, monitoring and sustainable management of these environments is crucial. Particularly as salt marshes are considered a blue carbon ecosystem due to their enhanced ability to produce and sequester organic carbon, acting as long-term reservoirs with a role in climate change mitigation. Since tidal wetlands are bio-geomorphologically intricate, biotic and abiotic coevolution is a key factor in the landscape development. Given the complexity of the processes and the interactions which underlie the system, research in this field requires a multidisciplinary approach. Remote sensing is a facet of this approach, which can enable the cost-effective analysis of salt marsh systems across a range of temporal and spatial scales.

Herein we analyse the application of unmanned aerial vehicle (UAV) based light detection and ranging (LiDAR) and optical sensors as tools to derive salt marsh biomass spatial distribution and structure in the Venice Lagoon (Italy). All validation and empirical relations are based on in situ data. Our results allow us to (1) derive digital terrain and vegetation models (DTM and DVM) and canopy structure using an efficient and open-access procedure; (2) examine the effect which scan angle, post-processing and variation in ecogeomorphological characteristics have on the accuracy of remote sensing results and; (3) further elucidate good practice guidelines for UAV based remote sensing of salt marsh topography and biomass. The results indicate that a linear feedback exists between the LiDAR scan angle and the DTM elevation error, notable for angles above 10 degrees. Furthermore, there is a dialogue between the accuracy of the remote sensing derived data and the spatial patterns driven by salt marsh ecogeomorphological complexity. Thus, characteristics such as vegetation density, elevation transitions between geomorphological structures and differences along the marsh gradient result in spatially variable levels of uncertainty. Overall, our analyses support salt marsh sustainable management as well as enhance the understanding of salt marsh ecogeomorphological complexity.

How to cite: Blount, T., D'Alpaos, A., Silvestri, S., and Marani, M.: Remote sensing salt marsh biomass: a dialogue between technical approach and spatial patterns of ecogeomorphological complexity, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12589, https://doi.org/10.5194/egusphere-egu23-12589, 2023.

11:10–11:30
|
EGU23-15228
|
SSS8.10
|
solicited
|
On-site presentation
Susana Bautista, Valeriia Nazarova, David Fuentes, and Francisco Rodríguez

Source-sink processes and feedbacks are critical for ecosystem function and dynamics in dryland landscapes. In patchy-vegetation drylands, the runoff generated on bare-soil inter-patches provides resource inputs to downslope patches, enhancing plant growth and increasing patch cover, which in turn controls the size of the bare-soil areas, completing a source-sink feedback loop. Both the efficiency of vegetation patches in capturing and storing runoff-driven resources and the response of the patch vegetation to such resource inputs depend on the functional traits of the species in the patch. We hypothesized that increasing within-patch plant diversity enhances the sink function of the patch, and thus reinforces the strength of the source-sink feedback. To test such hypothesis, we established over 600 vegetation patches on a 0.5 ha bare-soil experimental slope, resulting in six replicated treatments that combined different numbers of species and individuals per patch (up to 8 species and 8 individuals per patch). Based on drone surveys conducted five years after the establishment of the vegetation patches, we estimated the area, height, volume and normalised difference vegetation index (NDVI) of each patch, as well as a variety of metrics that captured the size and shape of the upslope bare-soil inter-patch draining into each patch. We found that increasing the size of the drainage area resulted in a general increase in NDVI and patch growth. For a given patch size (number of plant individuals), increasing within-patch plant diversity increased the overall strength of the positive relationships between patch performance and drainage area. Our results demonstrate that within-patch plant diversity controls eco-hydrological source-sink dynamics in drylands, and highlight the potential of establishing functionally-diverse plant patches for the restoration of degraded drylands.

How to cite: Bautista, S., Nazarova, V., Fuentes, D., and Rodríguez, F.: Within-patch plant diversity modulates the eco-hydrological source-sink dynamics of dryland landscapes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15228, https://doi.org/10.5194/egusphere-egu23-15228, 2023.

11:30–11:40
|
EGU23-5817
|
SSS8.10
|
ECS
|
On-site presentation
Karl Kästner, Christoph Hinz, Daniel Caviedes-Voullième, Nanu Frechen, and Roeland C van de Vijsel

Fascinating spatial patterns are found in many ecosystems. For example, patterns in Dryland ecosystems often consist of vegetation patches which alternate with bare soil. The patterns appear strikingly regular, when their formation is driven by scale-dependent feedbacks. Because of their regularity, such patterns are conceptually understood to be periodic. The formation of periodic patterns has been reproduced with idealized numerical models and the vulnerability of pattern forming ecosystems to environmental pressure has been preferentially studied with such models. However, natural patterns appear far from periodic. So does the distance between and the size of the patches vary systematically and the fringes of the patches are ragged. Previously, we revisited tests for periodicity and demonstrated that the large majority of regular patterns found in nature are not periodic. We also introduced a method to quantify the regularity of patterns, and found that natural patterns are of intermediate regularity, in-between uncorrelated noise and periodic functions, which can best be described by stochastic processes, where the irregularity is intrinsic to the pattern and not due to added noise. Here, we corroborate our previous results with a comprehensive metastudy, where we analyze natural and computer-generated patterns found in the leading literature. Furthermore, we extend our theory for the formation of stochastic patterns with arbitrary regularity to two dimensions. We find that our theory captures well the spectral properties of both isotropic, i.e. spotted, labyrinthic and gapped, as well as of anisotropic, i.e. banded patterns.

Figure 1: a) Normalized spectral density averaged over the natural and model generated patterns found in the literature. The density of the natural patterns consists of a wide and low lobe, while the density of the model generated patterns consists of a narrow and high peak. b) Median regularity and interquartile range for the natural and model generated patterns. The modelled patterns are 3-5 times as regular as the natural patterns. Number of samples indicated next to the median.

How to cite: Kästner, K., Hinz, C., Caviedes-Voullième, D., Frechen, N., and van de Vijsel, R. C.: A metaanalysis of the regularity of environmental spatialpatterns and a theory relating them to stochastic processes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5817, https://doi.org/10.5194/egusphere-egu23-5817, 2023.

11:40–11:50
|
EGU23-10976
|
SSS8.10
|
ECS
|
Virtual presentation
Carlos Brieva, Patricia Saco, Steven Sandi, and Jose Rodriguez

Arid and semi-arid ecosystems are under the pressure of climate change and are facing overgrazing and logging, which has led to increased degradation and desertification processes. The Drylands of Mendoza, Argentina, are fragile ecosystems devoted to cattle breeding on native bushes and rangelands. Livestock farming relies on the productivity of natural resources, closely related to the monthly, annual, and seasonal rainfall, which is a critical driver of vegetation productivity and dynamics. This study aims to determine the relationship between NDVI and Accumulated Antecedent Precipitation (AAP) in natural dryland as a basis for decision support in cattle grazing. NDVI from MODIS-Terra (MOD13Q1 V6.1) and AAP estimated by satellite using GPM (Global Precipitation Measurement) were correlated using Pearson's Correlation Coefficient at monthly timesteps over a period of 20 years (June 2000 to May 2020) considering 0 APP (monthly) and 1, 3-, 6-, 9- and 12-months AAP. The analysis was carried out spatially (pixel-to-pixel) in 5 points of each of 4 primary vegetation types of the interest area (Bush steppe with low land cover; Open Bush; Forest of Prosopis Flexuosa; and Psammophilious Grassland). NDVI responses to 3 months of AAP were significant for all vegetation types in the study area. Tracking vegetation responses to rainfall in this region is of outmost importance for management of the limited water resources.

How to cite: Brieva, C., Saco, P., Sandi, S., and Rodriguez, J.: NDVI and Accumulated Antecedent Precipitation (APP) in four different vegetation types in drylands of Mendoza, Argentina, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10976, https://doi.org/10.5194/egusphere-egu23-10976, 2023.

11:50–12:00
|
EGU23-11363
|
SSS8.10
|
Highlight
|
On-site presentation
Angeles G. Mayor, Susana Bautista, Fernando Maestre, and Francisco Rodríguez

Bare-soil connectivity and vegetation cover have proven to be good indicators of dryland function. The two properties are closely correlated and reflect the combined role of both the amount and spatial distribution of vegetation, making it difficult to disentangle the relative importance of each. Using partial correlation analyses between bare-soil connectivity, vegetation cover and soil function data from 109 dryland plots distributed worldwide, we have investigated the independent explanatory role of the two vegetation metrics along a variety of environmental gradients. Our results show that bare-soil connectivity and vegetation cover swap their relative importance as indicators of dryland function along most of the environmental gradients considered, with bare-soil connectivity increasing its independent explanatory role for both the milder and harder end of the gradients, and pattern-independent vegetation cover being a better predictor for medium-moderate  conditions.

How to cite: G. Mayor, A., Bautista, S., Maestre, F., and Rodríguez, F.: The relative importance of the amount and spatial distribution of vegetation as indicators of dryland function, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11363, https://doi.org/10.5194/egusphere-egu23-11363, 2023.

12:00–12:10
|
EGU23-2220
|
SSS8.10
|
On-site presentation
Aaron Yair

Dryland areas are regarded as highly sensitive to climatic changes. A positive relationship between average annual rainfall, and environmental factors is often assumed for areas with an average annual rainfall of 100-400 mm. The above assumption disregards the fact that a climate change in some dry-land areas is not limited to climatic factors. In addition, the climatic models, based on average annual rainfall, disregard the rainfall characteristics at the rain-shower level, which greatly influence the degree to which rainwater will percolate, thereby significantly affecting the spatial redistribution of water resources. The present work deals with the complex relationships between average annual rainfall, and environmental variables in sandy areas, along a rainfall gradient of  90-450 mm, in the south eastern Mediterranean area, Israel. Data obtained clearly show that average annual rainfall is not a good indicator of water resources, and ecosystem characteristics. The controlling factors vary from one site to another.

How to cite: Yair, A.: Landscapes of sandy areas along a rainfall gradient of 90-450 mm, average annual rainfall, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2220, https://doi.org/10.5194/egusphere-egu23-2220, 2023.

12:10–12:20
|
EGU23-16576
|
SSS8.10
|
On-site presentation
Tonggang Zha, Haiyan Yu, Xiaoxia Zhang, and yang Yu

Understanding the spatial distribution and controlling factors of soil organic carbon(SOC) at different scales is essential for an accurate estimation of soil organic carbon stocks. Furthermore, this understanding is vital for evaluating the impact of soil managemen to both soil quality and climate change. Our study were conducted in a Loess revegetated small watershed and the effects of topography, vegetation, soil properties factors on SOC distribution and redistribution at surface and different depths were evaluated, the results were as follows:

(1) The interactions between vegetation type and topography and soil depth significantly impacted SOC(P<0.05) in 0-200cm. The relative contribution of topographic factors to the SOC content exceeded that of vegetation type in entire soi lprofile, which implied that topography was the dominant factor controlling the spatial distribution of SOC in the studied small watershed.

(2) SOC stock in deep soil layer(200–500cm) was 7.62kgm−2, accounting for 40% of the total carbon, soil factors(including soil clay, soil water content, and soil bulk density) were dominant in deep soil layers(200–500cm), averagely accounting for 44.3%.

(3) Vegetation restoration alleviated the redistribution and spatial heterogeneity of SOC by reducing the migration of soil active organic carbon and soil erosion. thus, our research presented some new insights for SOC evaluating in loess-gully regions with their complicated terrain and short recovery time, but with wide distribution in the Loess Plateau of China.

How to cite: Zha, T., Yu, H., Zhang, X., and Yu, Y.: Distribution and influencing factors of soil organic carbon in a revegetated small watershed in the Chinese Loess Plateau, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16576, https://doi.org/10.5194/egusphere-egu23-16576, 2023.

12:20–12:30

Posters on site: Mon, 24 Apr, 14:00–15:45 | Hall X3

Chairpersons: Jose Rodriguez, Patricia Saco
X3.100
|
EGU23-4348
|
SSS8.10
Vilim Filipović and Thomas Baumgartl

Rehabilitation in the mining context refers to restoring the natural characteristics such as land stability, vegetation, soil functions, biodiversity and hydrological cycle. The main aim of mine rehabilitation is to construct environmentally sustainable landforms and to restore their ecosystem services, either to a site specific stable equilibrium or ideally to its previous state. The objective of this work is to build a predictive and decision making tool using hypothetical modelling to simulate water fluxes for two different scenarios in terms of different soil cover depth including vegetation (grass). Hypothetical hydrological modelling was performed using the HYDRUS-1D with one-dimension water flow modelling based on the Richards equation and hydraulic functions of van Genuchten-Mualem model. The soil and coal hydraulic parameters were derived from laboratory tests using the extended evaporation method. Water flux modelling was performed for 2021 using the climatic data from Latrobe Valley (Victoria, Australia) meteorological station, where the coal and soil samples were collected. Two scenarios were selected which varied in the depth of soil cover and coal layer, both with grass vegetation on top of the soil columns. The first scenario (S1) had 50 cm of soil cover, while the second scenario (S2) had 100 cm of soil cover on top of coal material, respectively. Modelling results revealed that soil water content and fluxes were directly reflecting the precipitation pattern and the most limiting factor in downward water flow was the low permeability of the coal layer. The hydraulic parameters for coal show large water retention capacity at very low hydraulic conductivity. The shallower soil cover in the S1 scenario resulted in higher soil water content during the period of intense rainfall and resulted in larger and faster initiation of surface runoff. The thicker soil cover layer resulted in larger infiltration rate and root water uptake which was however limited when the soil was fully saturated in both scenarios. Interestingly, very similar bottom flux in both scenarios even with two different coal layer depth (i.e., 30 cm vs 80 cm) were recorded. Water balance results indicate increase in potential of storing water in the S1 scenario which has a thicker coal layer due to its high water retention capacity. However, at this point it is not clear to what extent stored water from coal can be available for plants. Beside valuable research insights in terms of soil cover design, hypothetical modelling will assist in preventing experimental design flaws and providing a more efficient, robust controlled experiment performed in a next study phase.

How to cite: Filipović, V. and Baumgartl, T.: Hydrological performance of soil and vegetation covers impact in mine rehabilitation: results of a preliminary modelling study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4348, https://doi.org/10.5194/egusphere-egu23-4348, 2023.

X3.101
|
EGU23-7488
|
SSS8.10
Erich Inselsbacher, Helene Gerzabek, Ursula Nopp-Mayr, and Martin Gerzabek

Forests are critically influenced by game animals since the browsing and peeling by these animals has a detrimental effect on forests by affecting a broad range of processes in forest ecosystems. Further, plants that are browsed by herbivorous game animals show stress reactions which can lead to a change in plant species composition and in belowground interactions between roots and soil microorganisms. On the other hand, a high game population density leads to high nutrient and carbon (C) inputs via excrement and, in case of feeding, via fodder inputs. These inputs can have positive effects on plant nutrition and growth as well as soil organic C build-up. While previous studies have focused on various topics related to the effects of game animals on forest ecosystems, an overarching understanding of soil-plant-wildlife interactions and feedback reactions is still missing. In this study, we aim at tackling this short-coming and elucidating the effect of long-term enhanced game population density on soil physical, chemical, and microbial properties. The study site includes different forest types located in the vicinity of Vienna, Austria, and consists of a fenced area with high game animal population density and a directly adjacent, open forest area with lower animal density, serving as a control. Soil samples were taken from three depths (0-10 cm, 10-20 cm, 20-50 cm) from ten sub-sites differing in plant species composition and underbrush density. In the laboratory, we analyzed soil density, particle size distribution, pH, electric conductivity, total C and N, microbial biomass C and N, plant-available nutrients, and root density to study the effect of a high density of game animals (wild boars, deer) in the study area. The results gained in this study will serve as a scientific basis for a subsequent, long-term research and monitoring strategy. Here, we present results from the first sampling campaign and discuss implications of environmental impacts of wildlife animals on a larger scale.

How to cite: Inselsbacher, E., Gerzabek, H., Nopp-Mayr, U., and Gerzabek, M.: Effects of long-term enhanced game population density on soil physical, chemical, and microbiological properties, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7488, https://doi.org/10.5194/egusphere-egu23-7488, 2023.

X3.102
|
EGU23-9126
|
SSS8.10
|
ECS
Pascal Sibomana, Matthias Vanmaercke, Deogratias Nahayo, Arthur Depicker, Bernard Tychon, Aurélia Hubert, Emmanuel Rukundo, and Olivier Dewitte

The tropical mountainous environments of the Northern-western provinces of Rwanda in Africa are often referred to as the breadbasket of the country and are also densely populated. This high demographic pressure is associated with significant land management practices. In particular, agricultural practice of terracing has been promoted as soil and water conservation measure on the steep hillslopes of the region. However, the region is also landslide prone and the  potential effect of terracing on landslides occurrence has never been considered in the land management strategy. In this work, we assess this  potential effect through the analysis of more than 4000 recent landslides that were triggered by intense rainfall events. Exploring the role of slope, lithology, regional landslide susceptibility patterns and the types of terraces (typology, age), we show that, overall, terracing increases the odds of landsliding when compared to non-terraced hillslopes. Although the terraces are implemented as soil and water conservation measures in the region, we find that they result into higher hillslope hazard.

How to cite: Sibomana, P., Vanmaercke, M., Nahayo, D., Depicker, A., Tychon, B., Hubert, A., Rukundo, E., and Dewitte, O.: Potential effect of agricultural terraces on landslide occurrence: the tropical mountains of Rwanda, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9126, https://doi.org/10.5194/egusphere-egu23-9126, 2023.

X3.103
|
EGU23-9891
|
SSS8.10
|
ECS
Kristine Afanasjeva, Raimonds Kasparinskis, and Olgerts Nikodemus

During the last few decades significant amount of agricultural land in Latvia have been abandoned and overgrown, due to various factors. It is considered that abandonment is strongly influenced by socioeconomic and political factors, however, soil quality should be taken into consideration, as it plays a very important role in the development of vegetation. The aim of the research is to clarify spatial relationship of soil properties with different land use change scenarios.
The study was conducted in the polygon (310 ha) characterized by slightly undulated topography in the southeast part of Latvia, where over the last 60 years, abandonment of agricultural land and overgrowth with forest has been observed.
For the spatial assessment of land use change, aerial photo materials between 1954 and 2014 were digitized, where three types of land use were determined: arable land, grassland and forest. From 1954 till 2014 land use in the study area has changed significantly, therefore several scenarios were distinguished: a) arable land → forest; b) grassland → forest; c) arable land → grassland; d) grassland → grassland. In the study area 36 soil profiles were established, samples were collected and physical and chemical analyses (soil texture (sand, silt, clay (%), pHKCl, total carbon (%), total nitrogen (%), exchangeable cations (Ca2+, Mg2+, K+, Fe3+, Al3+) (cmol(+) kg-1)) according to standard methods were conducted in the laboratory. To estimate statistically significant (p<0.05) differences between land use scenarios and soil properties was used One-Way ANOVA.
The study results shows that the area covered by forest increased from 11% to 62%, between 1954 and 2014, but arable land decreased from 33% to 0,1% and grassland area decreased by 20%. In 2014 agricultural lands are mainly overgrown with Alnus incana (48.6%), Salix caprea (19%) and Betula pendula (14%), as well with Populus tremula and Picea abies. Statistical analyses showed significant differences of soil textural classes: content of sand and silt fraction, pHKCl value, and exchangeable cations (Ca2+, Al3+) between former arable land that changed to forest and arable land that changed to grassland. Arable land overgrows faster in areas of poorer soil and lighter soil textural classes, in contrast longer agricultural activity was found in areas, characterized by relatively heavier soil textural classes. Soil was more acidic and concentration of Al3+ was significantly higher in areas that have been overgrown by trees. 
Statistical analysis revealed that soil texture, acidity and nutrient availability significantly influence further development of land, either area will be transformed to forest or kept as grassland. Although, overgrowth is considered as reasonable land use option of abandoned agricultural lands, preliminary results showed that investigated marginal lands are suitable for farming. Further study will be conducted in a wider region for deeper understanding of mechanisms responsible for land use changes.

How to cite: Afanasjeva, K., Kasparinskis, R., and Nikodemus, O.: Spatial relationships between soil properties and land use change after agricultural land abandonment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9891, https://doi.org/10.5194/egusphere-egu23-9891, 2023.

X3.104
|
EGU23-10518
|
SSS8.10
|
Highlight
Jose Rodriguez, Patricia Saco, Angelo Breda, Steven Sandi, and Neil Saintilan

Predictions of the fate of coastal wetlands under the effects of sea-level rise (SLR) vary widely due to uncertainties on environmental variables, but also due to unavoidable simplifications in the models. Here, we present a simplified domain ecogeomorphic model that includes all relevant hydrodynamic, sedimentation and vegetation dynamics mechanisms that affect wetland evolution, it does not require detailed information and it is efficient enough computationally to allow the simulation of long time periods. We test this framework and apply it in different settings typically found in coastal wetlands around the world, comprising different geomorphic configurations, vegetation types, sediment characteristics and tidal regimes. Most of the wetland settings analysed are unable to cope with the high SLR rates expected by the end of the century, in agreement with results using paleo-records during periods of high SLR rates.

How to cite: Rodriguez, J., Saco, P., Breda, A., Sandi, S., and Saintilan, N.: Predicting the fate of coastal wetlands using a simplified domain ecogeomorphic model., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10518, https://doi.org/10.5194/egusphere-egu23-10518, 2023.

X3.105
|
EGU23-11301
|
SSS8.10
Rossano Ciampalini, Amandine Pastor, Frédéric Huard, Stéphane Follain, Feliciana Licciardello, Armand Crabit, and Damien Raclot

Soil erosion is a balance between forces acting to detach and transport sediment and those resisting, such as soil cohesion or protection of vegetation cover. The amount of eroded particles is proportional to the acting forces, but the feedback, as is widely acknowledged, has a non-linear behaviour. Moreover, most of the erosion is concentrated in the strongest events, as evidenced by many authors.
Here, in a long-term simulation, we investigate the occurrence of the size of the erosion events in a vineyard catchment area. We analysed around 700 rainfall events over 20 years  from two climate series (historical 1985-2005, and and future 2040-2060), and four contrasted land use and management scenarios.
The results confirmed that the erosion is driven by a limited number of strong events with an increment in future series due to an increase in frequency of the more severe rainfall events. We observed that: 1) Size of erosion events VS return time exhibit different logarithmic trends in each LU scenario; 2) Long-term erosion series show that the few major erosion phases are due to a limited number of events, the most severe; 3) The concentration of erosion events towards the highest values is more pronounced in intensified landscape indicating more reactive erosion than in protected landscapes.
This suggests that controlling the state of intensification of a landscape (i.e. intensified or preserved) can mitigate soil erosion even if climate change tends to increase erosion rates.

How to cite: Ciampalini, R., Pastor, A., Huard, F., Follain, S., Licciardello, F., Crabit, A., and Raclot, D.: Modelling soil erosion focusing on event-size occurrences under global change in a vineyard catchment, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11301, https://doi.org/10.5194/egusphere-egu23-11301, 2023.

X3.106
|
EGU23-13424
|
SSS8.10
|
ECS
Xiaopan Pang, Xueting Xu, and Yimo Wang

Plateau pika (Ochotona curzoniae) is a small, common burrowing herbivore with average 150 g, native to grassland in the Asia, especially to alpine meadows in the Qinghai-Tibetan Plateau. Termed as bioturbator herbivores, this animal can create extensive soil disturbance through digging and burrowing activities. In the process of disturbing the soil, these animals break the soil surface layer, increasing water infiltration, soil moisture, and the capture of organic matter, which leads to change in soil ecological processes. This small burrowing herbivore can shape alpine meadows, even contributes to alpine meadow degradation because its density can range up to 300 individuals per hectare. Consequently, plateau pika is generally considered as a pest in China and extensive control efforts have been conducted to eradicate it. However, several studies have argued that plateau pika is a keystone species for alpine meadow ecosystem. To date, no consensus about the role of plateau pika in alpine meadow ecosystem has emerged among policy makers, professionals and herders, and more studies are needed to examine the impact of plateau pika on soil process. Therefore, take plateau pika as an example, our study focuses on accurately evaluating the service functions of the alpine grassland ecosystem including productivity, soil conservation, and C sequestration under the bioturbation by small burrowing herbivore.

How to cite: Pang, X., Xu, X., and Wang, Y.: Soil disturbance: Responses of soil carbon to plateau pika bioturbation in alpine grasslands on the Qinghai Tibetan Plateau, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13424, https://doi.org/10.5194/egusphere-egu23-13424, 2023.

X3.107
|
EGU23-14554
|
SSS8.10
|
ECS
Longshuai Ma

Rainfed agriculture is conducted on 80% of the world's arable land and provides 60% of the world's food, therefore playing an important role in ensuring food security for a growing population. Climate change impacts are predicted to be harmful for rainfed agriculture all over the world, which will face future yield reductions of up to 30%, so more attention should be given to the efficient use of agricultural water in agricultural production, especially under rainfed conditions. Intercropping is a traditional sustainable planting system having advantages of increased production and improved yield stability, which is widely valued and has attracted increasing interest as a strategy to deal with climate change. Clarify the water consumption process of the intercropping system, especially the complementary and competition mechanism of soil water between species, is necessary for optimizing the field management and improving the water use efficiency of the intercropping system. The Loess Plateau is a typical rainfed farming area in northern China, the limitation of water resources and soil erosion are two major problems for efficient agricultural production. Therefore, we focuses on water consumption process of the intercropping system on the Loess Plateau, and the research results can provide theoretical support for the healthy and sustainable development of agriculture in rainfed area.

How to cite: Ma, L.: A strategy to deal with climate change: Intercropping system has attracted increasing interest., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14554, https://doi.org/10.5194/egusphere-egu23-14554, 2023.

X3.108
|
EGU23-15745
|
SSS8.10
Omer Yetemen, Aydogan Avcioglu, Orkan Ozcan, Ibrahim Simsek, Mesut Kolbuken, In-Young Yeo, Kwok Pan Chun, Tolga Gorum, and Omer Lutfi Sen

Microclimatic variations in semi-arid ecosystems can cause topographic asymmetry over geologic time scales due to uneven distribution of incoming solar radiation as a function of slope aspect. This phenomenon has long been recognized in geomorphology and has been studied primarily in catchments with high spatial heterogeneity in climate forcing and underlying lithology. Due to fluctuations in prevailing climate and lithological differences in the studied catchments, the formation age and size of the catchments add another level of complexity and uncertainty. Due to their small size, uniform lithology, well-constrained initial morphology, and relatively young age, cinder cones are natural laboratories for better understanding the eco-hydro-geomorphic evolution caused by nonlinear interactions between vegetation, climate, and soil. The Sandal Divlit cinder cone located in the Kula volcanic field, western Turkey, is an inactive volcano and formed in the last stage of volcanism in the region. The climax vegetation in the primary succession following the volcanic eruption can be seen on north-facing slopes with trees. North-facing slopes have deeper soils than south-facing slopes, which have sparsely herbaceous plants and shrubs and thin, weakly developed soils. Airborne-LiDAR surveys and the digital elevation models having 5 m and 12.5 m spatial resolution were used to analyze the geomorphic descriptors and canopy structure of the cone as a function of aspect. In the summer and winter seasons, the surface temperatures of the cone were measured using a thermal-imaging drone. The results show that north-facing slopes are much cooler and have less evaporative demand than south-facing ones. As a result of denser vegetation attributed to relatively more available soil moisture, they are steeper than south-facing ones due to better erosion protection. Despite its young age (<30 ka), the cone has developed topographic asymmetry and is imprinted with the signature of aspect-related vegetation difference. This finding is further evaluated and with the results of landscape evolution models to assess the role of microclimate due to vegetation on the development of asymmetric geomorphological features.

This study has been produced benefiting from the 2232 International Fellowship for Outstanding Researchers Program of the Scientific and Technological Research Council of Turkey (TUBITAK) through grant 118C329. The financial support received from TUBITAK does not indicate that the content of the publication is approved in a scientific sense by TUBITAK.

How to cite: Yetemen, O., Avcioglu, A., Ozcan, O., Simsek, I., Kolbuken, M., Yeo, I.-Y., Chun, K. P., Gorum, T., and Sen, O. L.: Influence of Hillslope Aspect on a Cinder Cone Evolution: The Sandal Divlit example, Kula, Turkey, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15745, https://doi.org/10.5194/egusphere-egu23-15745, 2023.

X3.109
|
EGU23-16963
|
SSS8.10
Eduardo Vicente, Mariano Moreno de las Heras, Luis Merino-Martín, José Manuel Nicolau, and Tíscar Espigares

Ecohydrologically suitable microsites, such as surface depressions and micro-topographical barriers acting as sink patches intercepting and infiltrating runoff, as well as nurse shrubs have largely been proposed as tools to improve the establishment of tree vegetation in Mediterranean reclaimed landscapes and other degraded dryland environments. We analyze the impact of sink patches and nurse (Genista scorpius) shrubs developed in Mediterranean-dry reclaimed mining hillslopes (Utrillas field site, central Spain) on seedling performance up to 8 years after plantation of two tree species with contrasted water-use strategies: Pinus nigra, a drought avoider species, and Quercus ilex, a drought tolerant species. Nurse shrubs enhanced early establishment of seedlings in shaded spots under its canopy. Further, sink patches ameliorated the survival of both species, although only increased plant growth during wet years that promoted source-to-sink transference of surface water resources as surface runoff. The survival and growth of P. nigra seedlings were strongly constrained during dry periods, resulting in a high cumulative mortality after 8 years regardless of microsite. Q. ilex showed a better performance during the experiment, keeping the positive effects of suitable microsites on plant survival after 8 years of plantation. Overall, our results encourage the use of ecohydrologically suitable microsites that concentrate water resources and nurse shrubs that ameliorate local conditions as key spots for introducing late-successional tree species in Mediterranean-dry reclaimed mining sites. Our results also indicate that seedling functional strategy to cope with drought is a critical factor conditioning plantation performance, therefore constituting a fundamental species selection criterion for restoration actions in Mediterranean areas, especially under effects of climate change.

How to cite: Vicente, E., Moreno de las Heras, M., Merino-Martín, L., Nicolau, J. M., and Espigares, T.: Sink patches, nurse shrubs and plant water-use strategies control the establishment of tree seedlings in Mediterranean-dry reclaimed mining hillslopes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16963, https://doi.org/10.5194/egusphere-egu23-16963, 2023.

Posters virtual: Mon, 24 Apr, 14:00–15:45 | vHall SSS

Chairpersons: Omer Yetemen, Jose Rodriguez
vSSS.4
|
EGU23-1823
|
SSS8.10
|
ECS
Lulu Bai and Peng Shi

Soil degradation of the spoil ground generated during the construction of expressways is a serious concern, and the ecological environment of the mound created by the unplanned piling of abandoned soil is poor. Revegetation could quickly and efficiently restore the ecological environment of the spoil ground. This study aimed to explore the direct and indirect effects of different fertilization treatments on the remediation of spoil ground soil using vetiver grass, and determine the most appropriate combination of fertilizers to help repair the ecological environment of the spoil ground. To study the changes in the physicochemical properties, enzyme activity, microorganisms in rhizosphere soil, and plant characteristics of vetiver grass, 12 treatments were set up, including no fertilization (CK), a single application of nitrogen fertilizer (N1:150 kg/ha, N2:300 kg/ha, and N3:450 kg/ha), a single application of phosphorus fertilizer (P1:350 kg/ha and P2:700 kg/ha), and a chemical fertilizer combination (NP: N1P1, N2P1, N3P1, N1P2, N2P2, N3P2). Compared with CK, combined nitrogen and phosphorus fertilization improved the physicochemical properties, enzyme activities, microbial diversity of rhizosphere soil and the plant traits, more significantly than the treatment with nitrogen or phosphorus fertilization alone. Path analysis showed significant differences between the direct and indirect paths of plant characteristics under the N, P, and NP treatments. NP treatment was more helpful in improving the soil environment of spoil ground, because NP treatment had a higher path coefficient for plant traits (NP (0.807) > N (0.703) > P (-0.993)) and enzyme activities (NP (0.897) > P (0.767) > N (0.373)). N2P2 had the highest comprehensive score (34), indicating that N2P2 could be used as an effective fertilizer combination.  These results indicate that the benefits of appropriate cultivation and fertilization practices to help restore degraded soil. Combined fertilization treatment (NP) improved the path coefficient of soil physicochemical properties to plant traits and soil enzyme activities, and thus better restored the habitats of spoil ground.

How to cite: Bai, L. and Shi, P.: Rapid restoration of spoil ground along expressways through a combination of vetiver grass cultivation and fertilization, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1823, https://doi.org/10.5194/egusphere-egu23-1823, 2023.

vSSS.5
|
EGU23-2215
|
SSS8.10
|
ECS
Xi Zhou, Wei Chen, Qingtao Liu, Hongxia Shen, Siyu Cai, and Xiaohui Lei

 In order to comprehensively consider the impact of human activities on runoff simulation and improve the accuracy of runoff simulation, so as to make a more accurate prediction of the future runoff of the Hanjiang River Basin, this study improved the reservoir module of the Wespa model, adding two parts: reservoir inflow data correction and water storage and outflow data calculation without measured data. Use the improved model to verify its applicability to the Hanjiang River Basin, then, choose the ones who has the most familiar trend with the historical data in the future climate model data (CMIP6). Put the selected data in the model to predict the runoff of Hanjiang River from 2021 to 2060. By analyzing the future runoff trend of Ankang, Huangjiagang and Huangzhuang in the Hanjiang River Basin from 2021 to 2060 and the changes of average runoff, seasonal runoff and monthly runoff compared with the historical period (1981-2020), the conclusions drawn are as follows: (1) The improved Wetspa model has good applicability in the Hanjiang River Basin; (2) The future runoff of Ankang section is decreasing, while that of Huangjiagang and Huangzhuang sections is increasing; (3) Compared with the reference period, the average runoff of the three sections in the future shows an increasing trend, which indicates that there will be flood risk in the future; (4) Compared with the reference period, the runoff proportion of the three sections will increase in spring and winter, and decrease in autumn. Attention should be paid to the risk of drought in autumn. In terms of months, the proportion of runoff from April to June increases, decreases from September to November, and increases and decreases in other months are uncertain.

How to cite: Zhou, X., Chen, W., Liu, Q., Shen, H., Cai, S., and Lei, X.: Future runoff forecast in Hanjiang River Basin based on Wetspa model and  CMIP6 model, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2215, https://doi.org/10.5194/egusphere-egu23-2215, 2023.

vSSS.6
|
EGU23-3101
|
SSS8.10
Yiyang Yang and Siyu Cai

The hydrological conditions are key factors in ensuring the health of water ecosystems. The lack of runoff data constrains the assessment of the basin's evolutionary pattern of the eco-hydrological conditions. The Yongding River Basin (YDRB) is a typical water-scarce basin in northern China, where the changing environment has led to widespread water scarcity and ecosystem degradation problems. In response to the shortage of information at the upper reaches of the YDRB at the Xiangshuibao gauging station, this study adopted a distributed hydrological model, WetSpa, to simulate the daily runoff data in this station from 1960 to 2019. Then, Indicators of Hydrologic Alteration (IHA) was used to identify the most ecologically relevant hydrological indicators (ERHIs) and further determine the "true" eco-hydrological variation point in the basin. Finally, the evolution rule of the eco-hydrological conditions in the basin was analyzed and the overall hydrological alteration degree of the Xiangshuibao Section was determined. The results showed that the rising rate, decline rate, annual maximum 1-day flow, annual minimum 1-day flow, annual maximum flow occurrence time, and July flow were the ERHIs. The variation period was from 1980 to 1986. Except for the annual maximum 1-day flow and decline rate were moderate variation indicators, all others were low variation indicators. The overall hydrological variability of the Xiangshuibao section was low. The results of this study were intended to provide a reference for ecological management construction in the YDRB and other similar areas.

How to cite: Yang, Y. and Cai, S.: Analysis of the hydrological conditions based on hydrological model in a data-scarce basin: A case study in the Yongding River Basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3101, https://doi.org/10.5194/egusphere-egu23-3101, 2023.

vSSS.7
|
EGU23-3395
|
SSS8.10
|
ECS
|
Yihang Li and Xiangzhou Xu

Abstract

Reservoir-bank avalanche is a common hydrogeological problem whether in China or other countries, and analysis for the mechanism of collapse on reservoir bank is an important issue in the field of disaster prevention and mitigation. This paper reviews the methods which had been used to study the mechanism of reservoir-bank avalanche, including field monitoring, field investigation, model or field experiment, and numerical simulation. In virtue of many advantages, e.g., high efficiency and automation, field monitoring has become a powerful tool in evaluating reservoir-bank collapse. Nevertheless, field monitoring is also subject to some external factors related to remote sensing technology, such as weather conditions, environment, and other factors. Field investigation has the characteristics of flexibility and maneuverability. However, a field investigation is a sampling method based the observation in the representative area, and the hazard information cannot be comprehensively obtained via field investigation in the study area. A common merit for the field monitoring and investigation is that data observed with the methods mentioned above may be used to calibrate the results of the model experiment and numerical simulation, but field monitoring or investigation are not applicable to track the process of bank collapse. Different from the monitoring or investigating method, an experiment of reservoir-bank collapse under closely monitored or controlled experimental conditions focuses on the regularities of bank collapse from a micro perspective. The model experiment may be conducted in a laboratory far away from the study area, and the experimental scenario may be freely designed if needed. Yet the researchers should consider the similarity of the cumulative effect while designing the downscaled model experiment for reservoir bank failure. Maybe it is easy to simulate and observe the complicated topographical conditions of bank collapse in the field experiment, because no change exists in the scale of the underlying surface and properties of erosion material. In fact, usually to make accurate observations and simulations is relatively difficult in the field. Numerical simulations have been widely used to analyze and predict the reservoir-bank avalanche from a macro perspective all over the world, whereas the result of the numerical simulation has to be verified with that obtained from monitoring, investigation or experiment. In summary, each research method presents its own characteristic set of advantages and limitations. Scientists may use an appropriate route for analysis according to objectives and contents of a specific project.

Key words: Reservoir-bank avalanche; Field monitoring; Field investigation; Model experiment; Numerical simulation

How to cite: Li, Y. and Xu, X.: How to study mechanism of avalanche on reservoir bank: a retrospective study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3395, https://doi.org/10.5194/egusphere-egu23-3395, 2023.

vSSS.8
|
EGU23-4031
|
SSS8.10
Lina Zhang, Xaohui Lei, Chao Wang, Yi Ji, and Jiahui Sun

The project of the Yangtze-to-Huaihe River diversion focuses on urban and rural water supply, taking into both irrigation and water supply as well as improving the ecology of Chaohu Lake. It is a major strategic water resource allocation project across river basins and across provinces. This study used a combination of a simulation model and optimization technology to establish an annual water dispatch model based on the principle of water balance for the Yangtze-to-Huaihe River diversion project and employs genetic algorithms to optimize the proportion of the two-line river diversion for the section of Yangtze River-to-Chao lake. The possible scenarios of the annual water dispatching model were analyzed from two aspects of runoff water condition and water use planning, and typical years scheduling scenarios were established, including short-term planning and long-term planning of low flow years, short-term planning and long-term planning of normal flow years, and short-term planning and long-term planning of high flow years. The annual water dispatch model was used to simulate the annual scheduling schemes for these different scenarios, and the results of water diversion and water supply, divisional scheduling, and lake storage conditions were compared and analyzed for scheduling schemes. The simulation results showed that the water shortage in the near-term planning level year (2030) and the long-term planning level year (2040) was basically zero in the flat water year and the abundant water year, and there was a large water shortage in the dry water year in both the near-term and long-term planning level years, mainly in agriculture. The total amount of water diversions for each typical year in the scheduling scheme was thus significantly reduced compared with that in the design plan. In the far and near future planning, the abandoned water was less in the dry water year and relatively more in the rich water year and the flat water year, and the abandoned water was similar in the two lakes in the flat water year, while the abandoned water mainly occurs in Chaohu Lake in the rich water year. The northern section of the river was the main object of the water supply of the river-supply project, and the supply of this section accounts for about 57% of the total amount in the dry water year, more than 75% of the total amount in the flat water year, and more than 97% of the total amount in the rich water year. From the viewpoint of the whole section of the project, the water supply in the dry water year was the largest, the lake utilization in the flat water year was the largest, and the abandonment rate in the abundant water year is the largest under the near and long term planning. The results of this study can provide a certain foundation and reference value for the construction of project scheduling operation and scheduling system.

How to cite: Zhang, L., Lei, X., Wang, C., Ji, Y., and Sun, J.: Research on the Annual Water Dispatch Model of the Yangtze-to-Huaihe River, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4031, https://doi.org/10.5194/egusphere-egu23-4031, 2023.

vSSS.9
|
EGU23-4222
|
SSS8.10
|
ECS
Peng Liu, YanQing Li, and Yang Yu

In fragile karst watershed, landscape pattern mainly affects evapotranspiration, interception, surface runoff, soil water infiltration and groundwater formation through spatiotemporal variation of land use, vegetation pattern, and then influences the discharge and sediment transport. A new Vegetation-Topographic factor (VTF)was constructed by NDVI and DEM data from 2000 to 2018. Based on VTF classification , Vegetation-Topographic landscape index(VTLI) was calculated by FRAGSTATS to analyze the impact of VTLI change on runoff and sediment yield in Nandong underground river system(NURS). The results showed that :(1) PD, IJI, LSI, SHDI were significantly positively correlated with runoff and sediment, while AI, CONNECT were significantly negatively correlated with runoff and sediment yield(P<0.05). LPI and DIVISION indices were not significantly correlated with discharge, but positively correlated with sediment yield. (2) PD, IJI, LSI and SHDI were the main promoting factors for runoff, while LSI and SHDI were the main promoting factors for sediment yield. CONNECT and AI were the main restrain factors of sediment yield, Which showed a downward trend. (3) In urban areas, VTF was decreased and has persistence trend. In basin-mountain margin areas, VTF was increased and has persistence trend. In mountain area, VTF was unchanged or not significantly increased but was anti-persistence trend. The change of landscape pattern indexes varied the runoff and sediment yield of NURS. The trend and persistence of VTF vary greatly in different geomorphic positions of NURS. These results will provide theoretical basis for watershed management and soil conservation of karst fragile ecosystem in southwest China. 

How to cite: Liu, P., Li, Y., and Yu, Y.: Landscape pattern change affect runoff and sediment yield in Nandong underground river system, Southwest China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4222, https://doi.org/10.5194/egusphere-egu23-4222, 2023.

vSSS.10
|
EGU23-5218
|
SSS8.10
Hu Liu, Chan Liu, Wenzhi Zhao, Yang Yu, and Omer Yetemen

Groundwater-dependent ecosystems (GDEs) exist all over the world, especially in water-limited regions. To achieve better water management, it is necessary to map and identify GDEs. Central Asia (CA) is one of the most arid regions in the mid-latitudes and one of the major regions with shallow groundwater tables. However, the role of groundwater in the impacts of climate change and regional anthropogenic activities on environmental risks, especially regional desertification, is inadequately understood due to the limited available research on GDEs. In the present study, a remote sensing-based method was used for mapping GDEs in regional CA, and three means—overlay analysis, correlation analysis, and the water balance method—were adopted to validate the accuracy of the mapping outcomes. Our results indicated that: 1) GDEs were concentrated around large lakes and in central Kazakhstan (between 46°N and 50°N latitudes), and areas "Very Likely" and "Likely" to be GDEs accounted for 36.89%, and 28.85% of the total natural vegetation areas, respectively; 2) at the watershed scale, the Sarysu Basin had the largest proportion (94.02% of the area) of potential GDEs while the Ysyk-Kol Basin had the lowest proportion (17.84%); 3) all the three validation methods indicated a good performance for our GDE mapping results. We concluded that the remote sensing-based GDE identification method can be considered a potential approach for mapping GDEs regionally. Better recognition of relationships among groundwater availability, ecosystem health and groundwater management policies should be developed by conducting further studies, to protect GDEs and to prevent regional land degradation.

How to cite: Liu, H., Liu, C., Zhao, W., Yu, Y., and Yetemen, O.: Mapping Groundwater-dependent Ecosystems in Arid Central Asia: Implications for Controlling Regional Land Degradation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5218, https://doi.org/10.5194/egusphere-egu23-5218, 2023.

vSSS.11
|
EGU23-16505
|
SSS8.10
|
ECS
Ruoxiu Sun, Li Ma, Jianjun Zhang, and Yawei Hu

Vegetation distribution are of great significance to control soil erosion and water and soil loss on slope.  In order to further explore the influence of slope vegetation distribution on the process of sediment yield and discharge, and quantitatively analyze the relationship between vegetation distribution and sediment yield and discharge. Through field rainfall simulation, under the condition of 15° slope, the sediment yield and runoff were observed under the conditions of different vegetation coverage (40%, 60%), different rainfall intensity (30, 60, 90 mm/h) and different vegetation distribution positions (relative distance 0, 0.2, 0.4, 0.6, 0.8, 1). The results showed that: (1) under a certain slope and rainfall intensity, the runoff yield and sediment yield increased rapidly at first and then tended to be stable under different vegetation distribution conditions. (2) In this study, the average runoff yield and sediment yield firstly decreased and then increased with the increase of the relative distance. The average runoff yield of the slope with the relative distance of 0.2 was the minimum. (3) The random forest algorithm shows that rainfall intensity and vegetation coverage have important effects on runoff yield, and rainfall intensity and vegetation relative distance have important effects on sediment yield. (4) When the vegetation coverage was 40%, the optimal vegetation relative positions were 0~0.36 and 0~0.31, respectively, with the main objective of reducing runoff and sediment. When the vegetation coverage was 60%, the optimal relative vegetation positions were 0~0.43 and 0~0.22, respectively, to reduce runoff and sediment. This study shows that slope vegetation distribution has an important effect on sediment yield and runoff. Under the same vegetation coverage, the smaller the relative distance of the grass belt, the better the effect of reducing runoff and sediment. The research results can provide theoretical basis and data support for optimal allocation of vegetation in the process of ecological restoration.

How to cite: Sun, R., Ma, L., Zhang, J., and Hu, Y.: Evaluation of the effects of grassland distribution on erosion processes of the loess hillslopes under simulated rainfall, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16505, https://doi.org/10.5194/egusphere-egu23-16505, 2023.