Congreso Internacional sobre Desertificación.

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Open Access
Estimación de volúmenes de suelo perdido por procesos de erosión por piping. Sureste de España.
(2020-03-30) Romero Díaz, María Asunción; Plaza Martínez, J.F; Sánchez Soriano, A.; Belmonte Serrato, F.; Ruiz Sinoga, J.D; Departamento de Geografía, Universidad de Murcia, Campus de La Merced; Departamento de Geografía, Universidad de Málaga, Campus de Teatinos
Piping processes have been widely studied in many countries and regions, but especially in arid environments, on marl soils, reach a great development. We studied eight areas affected by piping, located in the Basin of Mula (Murcia), on terraced farmlands and abandoned about 40 years ago. Have been evaluated sediments mobilized by this process and erosion rates. The erosion rate per plot is 287 t/ha/year, undoubtedly, a very high value of soil losses. For this it is necessary soil conservation practices when these fields are abandoned.
Open Access
El uso de parámetros edáficos como indicadores de riesgo de erosión. Rambla de Las Moreras, Murcia, SE de España
(2020-03-30) Romero Díaz, María Asunción; Quiñonero Rubio, J.M; Ortiz Silla, R.; Sánchez Navarro, Antonio; Fernández-Delgado Juárez, M.; Gil Vazquez, J.M.; Departamento de Geografía, Universidad de Murcia, Campus de La Merced; Centro de Edafología y Biología Aplicada del Segura (CEBAS), CSIC; Departamento de Química Agrícola, Geología y Edafología, Universidad de Murcia
Uno de los factores que más interviene en la erosión del suelo es su erodibilidad, es decir, la vulnerabilidad que el suelo tenga a la erosión. En este trabajo se estudian varios parámetros (textura, estructura, materia orgánica, profundidad, pedregosidad y cobertura vegetal) en la cuenca de la Rambla de Las Moreras (Murcia) con el objetivo de determinar si algunos de ellos pudieran servir de indicadores de riesgo de erosión. Los resultados muestran como la materia orgánica y la estabilidad de agregados pueden ser buenos indicadores de ello.
Open Access
Evaluación y seguimiento multitemporal de la desertificación en Andalucía
(2020-03-30) Rodríguez Surián, M.; Moreira Madueño, J.M; Quijada Muñoz, J.; Corzo Toscano, M.; Gíl Giménez, Y.; Dirección General de Planificación e Información Ambiental. Consejería de Medio Ambiente.; Desarrollo de la Red de Información Ambiental de Andalucía.
Desertification, as a process of degradation caused by the confluence of certain arid or semiarid climatic conditions together with aggressive and barely sustainable human activities in the natural and productive environment, and also bearing in mind the current context of climate change, is an environmental phenomenon whose monitoring would seem to be advisable, both with regard to its evolution in recent years and in relation to the changes that the new climatic scenarios may determine, in order to prepare mitigation or enhancement strategies, and also to raise greater awareness of the approaching problems. The availability of historical information in a Geographic Information System referring to land uses and land cover and to climatic data, together with other environmental information (relief, soils, geology, environment management.....), as well as decade-by-decade climatic information on possible future change scenarios until 2100 in the Andalusian Environmental Information Network (REDIAM), has permitted, within the framework the European projects DesertNet I and DesertNet II, the development of models for diagnosing the areas affected by historical desertification processes and the areas of present and future incidence, while at the same time a common methodology is applied to the European context for the delimitation of degradation-sensitive areas. These models have been applied to the entire territory of Andalusia, providing a view of the temporal and spatial incidence of this phenomenon.
Open Access
An evaluation of the MEDALUS ESA index (environmental sensitivity to land degradation), from regional to plot scale
(2020-04-03) Lavado Contador, J. F; Schnabel, S; Gómez Gutiérrez, A.; Grupo de Investigación GeoAmbiental, Universidad de Extremadura
An assessment of the sensitivity to land degradation have been carried out for the region of Extremadura, SW Spain, by means of the modelling approach developed in the European Commission funded MEDALUS project (Mediterranean Desertification and Land Use) which identifies such areas on the basis of an index (ESA index) that incorporates data on environmental quality (climate, vegetation, soil) as well as on anthropogenic factors (management). Two maps of environmental sensitivity to degradation with different legend resolution (4 and 8 classes of sensitivity) have been made. The results of the model were validated at different spatial scales, i.e.; regional and farm scales. True field data on degradation-related variables at the different spatial scales have been used in order to undertake the validation procedures. Selected farms covering different physiographical and socioeconomic characteristics were used to gather data at farm scale. Data gathered from the National Inventory of Soil Erosion was also used to validate the model at the regional scale.
Open Access
African and local wind-blown dust contributions at three rural sites in SE Spain: the aerosol size distribution
(2020-04-03) Orza, J.A.G.; Cabello, M.; Lidón, V.; Martínez, J.; SCOLAb, Física Aplicada, Universidad Miguel Hernández; Aeolian Erosion Research Group, Universidad Miguel Hernández
The entrainment of particulate material into the atmosphere by wind action on surface soils both disturbed and natural, as well as directly due to human activities like agricultural practices, mineral industry operations, construction works and traffic, is a significant contribution to the aerosol load in Mediterranean semi-arid areas. A further crustal contribution in the region comes from the frequent arrival of African mineral dust plumes. We summarize some of the results obtained after 4-6 -month campaigns at three rural sites in SE Spain where the aerosol number size distribution (31 size bins between 0.25 and 32 μm) was continuously measured. The influence of both local wind speed and the arrival of air masses loaded with African dust on the airborne particulate distribution is assessed. Similarities and differences between the three locations give information that allows a better understanding of the influence of both local wind speed and African dust outbreaks (ADO), while highlight what is mostly related to local features.
Open Access
Aplicación de técnicas hiperespectrales de imagen al estudio de la degradación de suelos en ambientes áridos (Los Monegros, España)
(2020-04-03) Gumuzzio Such, A.; Palacios Orueta, A.; Schmid, T.; Dominguez, J.A.; Gumuzzio, J.; E.T.S.I Montes de Madrid. Departamento de Silvopascicultura, Ciudad Universitaria; CIEMAT, Departamento de Medioambiente, Avda. Complutense; Centro de Estudios Hidrográficos CEDEX; Departamento de Geología y Geoquímica. Universidad Autónoma de Madrid
The aim of this work is to identify characteristics associated to soils affected by degradation within an arid area of Spain using optical hyperspectral airborne data. The methodological approach was developed to determine the spatial distribution of selected soils affected by degradation processes. A satisfactory spatial distribution is obtained where the corresponding soil characteristics are closely related to degradation processes.
Open Access
Agua y agricultura en sistemas áridos: un modelo dinámico del regadío de Mazarrón y Águilas
(2020-04-03) Martínez Fernández, j.; Esteve Selma, Miguel A.; Departamento de Ecología e Hidrología. Universidad de Murcia; Departamento de Ecología e Hidrología. Universidad de Murcia
The intensive use of groundwater resources in the new irrigated lands of Mazarron-Aguilas has led to the over-exploitation of the local aquifers and thus, to seawater intrusion, water salinization and falling off water tables, all of them key processes of desertification. The simulation results show that the unrealistic perceptions about the relationships between irrigated land and water resources constitutes a key factor to explain the highly unsustainable dynamics of irrigated lands in Mazarrón and Aguilas and the whole SE Spain. The increase in water resources does not eliminate the problem because the feedback loops and endogenous factors of the system lead to a further increase in irrigated land and continuation of the water deficit, which shows a highly counter-intuitive behaviour.
Open Access
A procedure to derive intra- and inter-annual changes on vegetation from NDVI time series. A case study in Spain.
(2020-04-03) Gilabert, M.A.; Martínez, B.; Meliá, J.; Departament de Física de la Terra i Termodinàmica, Universitat de València.
The NDVI time series are characterized by patterns like seasonality, trends and localized abrupt changes or discontinuities resulting from disturbance events. Therefore, they allow us to characterize vegetation dynamics on the basis of different temporal scales. In particular, the subtle, long-term changes convey relevant information on land degradation. The objective of this work is to study the spatial patterns of vegetation activity over Spain and its temporal variability throughout the period 1989-2002. A multi-resolution analysis (MRA) based on the wavelet transform has been implemented on NDVI time series from the MEDOKADS database. The MRA decomposes the original signal as a sum of series associated with different temporal scales. Specifically, the intra-annual series is processed to define several key features in relation with the vegetation phenology. In contrast, the interannual component of the signal is used to detect trends by means of a Mann-Kendall test and map the magnitude of the land-cover change. Finally, a comprehensive identification of the areas presenting a negative value of the magnitude of change is carried out to select those linked to land degradation processes. Results show a major presence of these areas the Southeast of Spain.
Open Access
Analysing the factors affecting gully development and their relationships with land-use changes in the east Alentejo (Portugal)
(2020-04-03) Roxo, M. J.; Calvo-Cases, A.; Departamento de Geografia e Planeamento Regional, Universidade Nova de Lisboa; Departament de Geografia, Universitat de Valencia
The land abandonment and land-use changes as a consequence of the implementation of the European Union Common Agricultural Policy (C.A.P.), in the SE of Portugal, have been generating, differences in the equilibrium of the geomorphic processes. The head waters catchments of some of the Guadiana River tributaries show in the study area several degrees of gully initiation and development both on the hillsides and valley bottom infill. This gully generation process is closely related with the changes in the soil and cover properties occurring when agricultural practises have been replaced by intensive grazing areas or by abandoned land. High resolution panchromatic and Landsat images, dating from the last 40 years have been analysed in combination with field observations and the analysis of the data from soil erosion plots series in the Estação Experimental de Vale Formoso, in order to establish and parameterise the sequence of changes in soil surface properties and vegetation cover and distribution. The results show the connection between the different degrees of gully development and their morphological characteristics with the land cover properties at different times and after different sequences of land-use changes
Open Access
Aportaciones de la teledetección y los SIG para la mejora de los modelos de evaluación de las pérdidas de suelo en Andalucía
(2020-04-03) Moreira Madueño, J.M.; Rodríguez Surián, M.; Ojeda Zújar, J.; Dirección General de Desarrollo Sostenible e Información Ambiental. Consejería de Medio Ambiente.; Departamento de Geografía Física y Análisis Geográfico Regional, Universidad de Sevilla,
The Regional Ministry of the Environment, through the Environmental Information Network (REDIAM), monitors the annual rate of land loss in Andalusia. This phenomenon, which is characterised by a high level of spatial and temporal variance, is particularly influenced by the amount and intensity of rainfall and land uses. The use of high and low resolution satellite images and regional ortophotographs has enabled continuous updating of information on plant cover and land uses, whilst the daily climate information from a network of automated weather and rainfall stations are used to generate monthly rain erosivity maps. This information on land loss is a useful tool for direct analysis or modelling, and provides the basis for identifying and implementing preventive and corrective actions enshrined in the various strategic plans developed by this agency.
Open Access
Análisis espacio-temporal de los cambios de usos del suelo en la Cuenca del Río Segura
(2020-04-03) Alonso Sarriá, Francisco; Gomariz Castillo, Francisco; Cánovas García, F.; Moreno Brotóns, J.; Instituto del Agua y Medio Ambiente, Universidad de Murcia, Campus de Espinardo
Land use change is a dynamic process that affects heavily to different environmental processes. In this work, a GIS application is designed to analyse land use changes from landsat imagery since 1976 to 2007, a period with important socioeconomic and land use changes in River Segura Basin. This work describes the methodology used to obtain a yearly series of land cover maps of the Demarcación Hidrográfica del Segura (River Segura basin in South East Spain). In order to analyze this great amount of information for a large (more than 18,000 km2) and heterogeneous area, a unified methodology has been developed. It has been used a supervised classification improved by a previous not supervised classification using both spectral (4 or 6 landsat solar spectrum bands depending on the sensor available, MSS or TM, ETM) and two textural variables. The last ones were obtained estimating the semivariogram frunction from the albedo and NDVI layers. Having used two images from different seasons, the total number of variables included in the classification is 12 or 16 depending on the year. Preliminary results show a reduction of the surfaces with traditional dry crop uses and the important increase of irrigation lands during the first half of the 1980s decade. The increase in bare soil areas also reflects the abandonment of traditional crops. Finally, it has been observed an increase in urban areas attributable to demographic trends.
Open Access
Aportaciones de la palinología en la reconstrucción del impacto ganadero, en los alrededores de Rascafría (Madrid), durante el Holoceno reciente
(2020-04-03) Gómez González, C.; Ruiz Zapata, M.B.; López-Saez, J.A.; Gil Garcia, M.J.; Departamento de Geología, Universidad de Alcalá,; Laboratorio de Arqueobotánica, Departamento de Historia CSIC
We present the results obtained from the palaeoecological studies about human impact on the vegetal landscape of a peatbog located in Rascafría (Lozoya Valley, Madrid, Central Spain). Palynomorph analysis allows to identify the kind and intensity of human activity and its relation to the trophic changes in the peatbog during the late Holocene (2455±35 BP). Pollen record reveals an anthropic Mediterranean landscape mainly composed by pastures used for grazing. Non Pollen Palynomorphs (NPP) and pH and conductivity sediment have revealed as useful tools for detection of trophic conditions and land use changes.
Open Access
Abandonment terraced hillside and answer of the fire system: some results from Mediterranean old fields
(2020-04-03) Llovet López, J.; Ruiz Valera, M.; Josa March, R.; Vallejo Calzada, V.R.; Fundación CEAM, Departament d’Ecologia (CEAM); Departament d’Enginyeria Agroalimentària i Biotecnologia
The abandonment of agricultural lands promotes temporal changes both in soil characteristics (i.e., increasing organic matter and other quality indicators) and in plant community (i.e., changing its composition and structure, and increasing the fuel load). As a consequence, we can expect differences in the resilience to fire as succession progresses. The aim of this work is to analyse the capacity of an ecosystem to return to pre-fire conditions as a function of the stage of abandonment of old agricultural lands. The study was carried out in the north of Alicante province (E Spain). In long-term abandoned lands, post-fire rainfall modulated plant response, which in turn determined soil crusting, runoff and erosion dynamics. In recently-abandoned lands, the plant community seemed less dependent on rain to recover. Results show a large increase in soil surface crusting in the short term after the fire and it remained high at medium term in long-abandoned lands colonised by pine forest. Fire scarcely modified runoff and erosion in recently-abandoned lands whereas in forest lands the post-fire values increased by some orders of magnitude and remained highly dependent on rain characteristics in the short and medium term after the fire. The results obtained show evidences of increased vulnerability to fire in long-abandoned lands colonised by pine forests
Open Access
El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-Efecto de la actividad agrícola en los contenidos de sales en suelos de Murcia: comparación con otros usos de suelo
Acosta Aviles, J.A.; Faz Cano, A.; Martínez-Martínez, S.; Universidad de Murcia
ABSTRACT Salinization is one of the main problems of soil degradation in arid and semiarid areas, causing a reduction of soil quality, declining yield and productivity, and even land abandonment. The aim of this study was to evaluate the effect of different land uses, particularly agricultural use in the salt content in soil. The study area is located in the surroundings of Murcia city (SE Spain), with an surface of 100 km2, with high agricultural productivity. In order to determine salt content in soil, E.C. was measured in the 1:5 ratio. The results showed that the study area is saline, being the salinity higher when anthropogenic activity is more severe. Agricultural lands present the widest range of data, probably due to the application of poor quality irrigation water, fertilizers and livestock waste. Supporting this hypothesis, spatial distribution showed that the salinity is clearly located in the agricultural area. Detailed studies will be useful to understand the salinization process in order to implement measures to control and reduce salinity.
Open Access
Erosión y desertificación.-DesertNet – Structure and Aims of an International Network for Desertification Research
Akhtar-Schuster, M.; San Juan Mesonada, C.; Universidad de Murcia
ABSTRACT DesertNet (http://www.european-desertnet.eu/) is an interdisciplinary scientific network which was established in October 2006 at the UN premises in Bonn, Germany, by a group of international scientists. The network strives to generate and enhance scientific knowledge and understanding of the biophysical and socio-economic processes of desertification. This international scientific network provides an international platform for scientifically based discussions and exchange of ideas, addressing knowledge gaps, and identifying research areas. DesertNet is also a think tank community which identifies issues and priorities for the sustainable development of drylands. The paper outlines the current role of DesertNet in the international scientific community and it delineates its role to strengthen the Science/Policy Interface.
Open Access
Erosión y desertificación.-Los procesos de erosión hídrica en el retroceso erosivo de acantilados sobre rocas blandas en la provincia de Cádiz
Rendón Aragón, J.J.; Gracia Prieto, F.J.; Del Río Rodríguez, L.; Universidad de Murcia
ABSTRACT The littoral cliffs on soft materials of the Atlantic Cadiz coast show an important activity of the fresh water erosion processes, sometimes even more significant than the marine erosion processes. The connection of the lower cliffs with sandy beaches favours aeolian sand invasion, which fills previous rills and reduces the water erosion intensity by increasing infiltration. Cliff retreat and rill erosion measurement by using erosion sticks has shown very variable values, most of them higher than the estimated error of the employed methods. This indicates the existence of other factors influencing the distribution of water erosion processes along these cliffs, which have to be studied through different techniques.
Open Access
Erosión y desertificación.-Land degradation of Taleghan drainage basin, Iran from saline and alkaline marly formations
Feiznia, S.; Hosseini, S.H.; Universidad de Murcia
ABSTRACT In Iran fine – grained, saline, alkaline and erodible Tertiary marly formations are exposed in many geological zones and play important role in the formation of present landforms. They also play important role in degradation of water resources and soils as diffuse sources, they are the main sources of suspension loads of many rivers and are endless sources of sediments for sand dunes. These marly formations are present in Zagros, Central Iran, Alborz and Kopeh – Dagh Geological Zones and consists of different geological formations such as Gachsaran, Mishan and Razak Formations(in Zagros), Lower Red and Upper Red Formations(in Central Iran) and Neogene Red Beds(in Albors and Kopeh-Dagh). In this research, Neogene marly formations of Taleghan Drainage Basin, located in Alborz Geological Zone are investigated for chemical, physical and mechanical characteristics and erosion and sediment yield potential. The studied area is located about 100 kilometers west of Tehran and is one of the subdrainages of sefid-Rood Dam. Runoff and sediment yield were measured using field rainfall simulator. According to their physical and chemical characteristics, Neogens fine grained Formations of Taleghan Drainage Basin were classified into six subunits: Siltstone (NgSi), Claystone (gy1C), marl(gy1M), haliferous siltstone (NgSiH), haliferous claystone (gy2CH) and gypsiferous claystone (gy1CG). From the view point of salinity and alkalinity, NgSi unit is alkaline and NgsiH, gy2CH, gy1C and gy1CC units are saline and alkaline. The order of the units in respect to sediment and runoff production is as follows: NgsiH>Ngsi>gy2Ch>gy1CC > gy1C.
Open Access
Erosión y desertificación.-Monitoreo de la salinidad en el Distrito de Riego 038 Río Mayo, Sonora, México, mediante sensores remotos
Pulido Madrigal, L.; González Meraz, J.; Universidad de Murcia
ABSTRACT A soil salinity survey was carried out in the Rio Mayo irrigation district (ID) in 1996, using satellite imagery along with an EM-38 electromagnetic (EM) device. Data from Landsat TM imagery were calibrated with field data, according to the Plant Indicator methodology. This methodology yielded a partial salinity map of the ID, but including only those areas where indicator crops were cultivated. The remaining non-mapped areas were surveyed with an EM-38 electromagnetic device, generating a second partial salinity map. Both partial maps were integrated to get a complete soil salinity map of the ID. In 2001, another soil salinity survey was carried out using solely the EM device. The results of both methodologies were analyzed, resulting in less affected areas in 2001 compared to those obtained in 1996.
Open Access
Erosión y desertificación.-Combating desertification strategies in arid land of India
Joshi, K.N.; Singh Solanki, Shailendra; Universidad de Murcia
ABSTRACT The present study deals with the current status and process of desertification due to over exploitation and mis-management of natural resources of the Rajasthan. The author try to make some observations on specific indicators of natural resources degradation that have strong impact on the process of desertification. The author have also looked into the climatological phenomenon such as drought. From the above study it is very much clear that to meet out the ever increasing demand of the man and society, the natural resources are being exploited at the rate where no regeneration is possible. Lastly, a brief account of the protective measures that have been taken by government is discussed.
Open Access
El impacto de la ganadería y la agricultura en los ecosistemas terrestres.-The availability of water in ranches of mediterranean type climate
S. Schnabel; Pulido Fernández, M.; Lavado Contador, J.F.; Universidad de Murcia
ABSTRACT A preliminary study on water resources for livestock rearing in SW Spain is presented. The objectives of this work were to assess the availability of water for domestic animals in farms and to explain whether water shortages are controlled by environmental factors or are also related with land management. The study was carried out in 54 private farms of wooded and treeless rangelands in Extremadura. Field work, digital topographic maps and aerial photographs were used to assess the potential hydrological resources of each farm. The water needs of livestock were estimated considering the number and species of animals per farm, as well as other factors influencing their water consumption. Furthermore, semistructured interviews were carried out in order to gather information about water management. Results indicate that almost 20% of the farms suffer problems of water availability in summer and almost 50% during droughts. Different solutions are adopted by the farmers, including construction of infrastructure, bringing water from outside or moving the animals to other areas. Data indicate a positive relationship between problems of water supply and the degree of aridity. Data also point to a relationship with water consumption by livestock and the availability of water by artificial ponds.