Search results for "Desertification"

Using hydrological connectivity to detect transitions and degradation thresholds: Applications to dryland systems

2020

In arid and semi-arid ecosystems, shortage of water can trigger changes in landscapes’ structures and function leading to degradation and desertification. Hydrological connectivity is a useful framework for understanding water redistribution and scaling issues associated with runoff and sediment production, since human and/or natural disturbances alter surface water availability and pathways increasing/decreasing connectivity. In this paper, we illustrate the use of the connectivity framework for several examples of dryland systems that are analysed at a variety of spatial and temporal scales. In doing so, we draw particular attention to the analysis of coevolution of system structures and …

Key features of bacterial communities in Southern Europe soils vulnerable to desertification

2019

Mediterranean soils are experiencing increasingly negative effects of climate change due to drought and extreme weather phenomena that negatively affect agriculture, already suffering social and economic constraints. The LIFE project DESERT-ADAPT - Preparing desertification areas for increased climate change - (http://www.desert-adapt.it/index.php/en/) focuses on agricultural adaptation measures aimed at reverting ongoing desertification trends, while improving the socioeconomic conditions of farmers. The soil microbiota is recognized as key player in both diversity and productivity of terrestrial ecosystems and it is mandatory to include its role in sustainable agronomic management. In ord…

Patterns of soil microbial biomass and diversity across Mediterranean agroecosystems in areas under desertification risk

2022

Properties and erosional response of soils in a degraded ecosystem in Crete (Greece)

2013

To study desertification processes relating to soil erosion, a climatological and altitudinal gradient from south to north was selected in Crete (Greece) and four locations were selected along the gradient. At the locations precipitation ranged from 1400 mm/year at the highest location to 400 mm/year at the lowest. All locations are affected by the actual land use: intensive grazing, small controlled fires, and abandoned agricultural terraces. Representative soil profiles were described in the field and analyzed in the laboratory, and rainfall simulation experiments in the field measured soil erosion over different soil surfaces and land uses. Data on physical and chemical properties were o…

Vegetation cover seasonal changes assessment from TM imagery in a semi-arid landscape

2004

This work evaluates the suitability of spectral mixture analysis (SMA) methods to assess vegetation cover seasonal changes in a desertification context. Our main interest is to produce remotely sensed derived maps, sensitive to vegetation activity and quite independent of the soil background. A further aim is to analyse the inter-annual variations of this magnitude for different natural vegetation species, in response to seasonal and climatic changes. Fractional vegetation cover (FVC) was obtained using a Variable Endmember Spectral Mixture Analysis (VESMA) technique. The aim is to identify the main vegetation cover and lithological units and decompose them in separate stages. The use of sp…

Vulnerability of Mediterranean ecosystems to Climatic Change, study of soil degradation under different climatological conditions in an altitudinal t…

1995

Abstract To investigate the potential response of soils to climatic change, measurements of soil physical and chemical properties were carried out during a year in a mountain zone in Alicante (Spain), along an altitudinal and climatological gradient. Hydrological properties (infiltration runoff and sediment concentration) were measured under winter and summer conditions. Chemical and physical soil properties were analyzed for reference soil profiles along the transect. The erosional response of the soils as well as soil properties like organic matter and CEC are found to be under the direct influence of the climate, and as a result they have to be considered as important factors in the dese…

Irrigation, salinization and desertification. Evolution of Cropping Systems as Affected by Climate Change

2009

Monitoring Soil Salinisation as a Strategy for Preventing Land Degradation: A Case Study in Sicily, Italy

2010

Water demand is increasing worldwide. In regions affected by water scarcity such as those located in the Mediterranean basin, water supplies are already degraded, or subjected to degradation processes, which worsen the water shortage. In Sicily, the increasing scarcity of good quality water is expanding irrigation with saline-sodic waters, thus enhancing the risk of secondary salinization and sodification. Adequate management practices are urgently needed for sustainable use of saline/sodic waters. This chapter illustrates how the Geonics EM-38 probe was used for monitoring salinization in a Sicilian area where irrigation with saline water is increasingly practiced, and the risk of salinisa…

An operatorial description of desertification

2016

We propose a simple theoretical model for desertification processes based on three actors (soil, seeds, and plants) on a two-dimensional lattice. Each actor is described by a time dependent fermionic operator, and the dynamics is ruled by a self-adjoint Hamilton-like operator. We show that even taking into account only a few parameters, accounting for external actions on the ecosystem or the response to positive feedbacks, the model provides a plausible description of the desertification process, and can be adapted to different ecological landscapes. We first describe the simplified model in one cell. Then, we define the full model on a two-dimensional region, taking into account additional…

Effects of afforestation with four unmixed plant species on the soil–water interactions in a semiarid Mediterranean region (Sicily, Italy)

2012

Purpose An assessment of the effect of plant cover on the properties of four afforested soils in central Sicily was performed with the aim of discriminating among them after 60 years of afforestation. Materials and methods Chemical and biochemical soil analyses were coupled to fast field cycling (FFC) NMR relaxation investigations in order to monitor surface interactions of water in water-saturated soils. Results and discussion The traditional soil analyses revealed that the most stable soil properties such as soil texture and pH are not affected by 60 years of afforestation. Soils developed under eucalyptus trees showed larger amounts of hydrophilic organic matter as compared to the soils …