scholarly journals Effects of vegetation succession and shrub clearing after land abandonment on the hydrological dynamics in the Central Spanish Pyrenees

CATENA ◽  
2021 ◽  
Vol 204 ◽  
pp. 105374
Author(s):  
M. Khorchani ◽  
E. Nadal-Romero ◽  
T. Lasanta ◽  
C. Tague
2020 ◽  
Author(s):  
Makki Khorchani ◽  
Estela Nadal-Romero ◽  
Teodoro Lasanta

<p>The Mediterranean mountains have been subject to significant land abandonment processes during the second half of the 20th century.  The subsequent natural revegetation following abandonment in rural areas has been widely documented to have significant implications on the hydrological cycle and the vegetation dynamics. The Spanish Pyrenees, are one of the most affected areas by these land transformations which could threaten their importance for water supply and agricultural activities in the downstream lowland areas.</p><p>Management strategies of these abandoned areas have been debatable during the last decades between scientists, policy-makers and stakeholders. Active Management strategy through shrub clearing is one of the proposed practices that have shown advantages to deal with land abandonment in some regions of Spain. Nevertheless, little is known on the effects of this practice on the hydrological cycle and water resources in abandoned areas. In this study we used the Regional Eco-Hydrological Simulation System RHESSys to estimate shrub clearing effects on water resources in the Aisa valley in the Central Spanish Pyrenees, subject to land abandonment and natural revegetation processes during the past decades. Our results show an increase of annual streamflow and a decrease of annual evapotranspiration following shrub clearing. Nevertheless, the magnitude of these changes may decrease with the age of abandonment and climate change.</p>


Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1841
Author(s):  
Luigi Sciubba ◽  
Martina Mazzon ◽  
Luciano Cavani ◽  
Elena Baldi ◽  
Moreno Toselli ◽  
...  

Agricultural land abandonment is an emerging problem in European Union (EU), and about 11% of agricultural EU land is at high risk of abandonment in the coming 10 years. Land abandonment may have both positive and negative effects in ecosystems. Due to the potential for land abandonment to increase soil fertility, the study of vegetation succession effects on soil quality is of great importance. In this study, we investigated an abandoned vineyard where, after a period of 30 years, rows and alleys were characterized by two different forms of vegetation succession: natural recolonization by trees along the rows and by herbaceous vegetation in the alleys. No-tilled alleys covered by herbaceous vegetation of a neighboring conventionally cultivated vineyard were used as a comparison. Soil samples were chemically characterized (pH, extractable element, and available and total metals), and analyzed for the determination of carbon (C) and nitrogen (N) pools; hydrolytic and phenol oxidizing (PO) enzyme activities involved in C, N, and phosphorus (P) cycles; and the enzyme ratios. Results highlighted that natural recolonization by trees increased the organic C and N soil pools by 58% and 34%, respectively, compared to the natural recolonization by herbaceous vegetation. Moreover, natural recolonization by trees reduced β-glucosidase by 79%, urease by 100%, alkaline phosphastase by 98%, acid phosphatase specific hydrolytic activities by 50%, and catechol oxidase and laccase specific oxidative activities by 127% and 119%, respectively, compared to the renaturalization by herbaceous vegetation. In addition, the natural recolonization by trees reduced the C (βglu):C (PO) enzymes ratio by 16% compared to that of the conventional vineyard. Comparing the natural recolonization by herbaceous vegetation with that of the conventional vineyard revealed little significant difference (15% of the measured and calculated parameters); in particular, PO activities significantly decreased in the renaturalized vineyard with herbaceous vegetation by 49% (catechol oxidase) and 52% (laccase), and the C (βglu):C (PO) enzyme ratio showed a reduction (−11%) in the vineyard naturally recolonized by herbaceous vegetation compared to the conventional vineyard. This highlights that the type of vegetation succession that takes place after land abandonment may have a significant impact in terms of soil fertility and C accrual potential. These results help to focus attention on the practices used in agro-forestry that should be adopted in abandoned agro-ecosystems to increase their biodiversity, soil C stock, and soil quality, because these indicators are affected by the type of vegetative coverage.


2001 ◽  
Vol 27 (0) ◽  
pp. 47 ◽  
Author(s):  
M. P. Errea ◽  
T. Lasanta ◽  
L. Ortigosa ◽  
A. Cerdá

CATENA ◽  
2021 ◽  
Vol 205 ◽  
pp. 105441
Author(s):  
Estela Nadal-Romero ◽  
Pablo Rubio ◽  
Vasiliki Kremyda ◽  
Samira Absalah ◽  
Erik Cammeraat ◽  
...  

2021 ◽  
Vol 13 (4) ◽  
pp. 616
Author(s):  
Rafael Alonso ◽  
José María García del Pozo ◽  
Samuel T. Buisán ◽  
José Adolfo Álvarez

Snow makes a great contribution to the hydrological cycle in cold regions. The parameter to characterize available the water from the snow cover is the well-known snow water equivalent (SWE). This paper presents a near-surface-based radar for determining the SWE from the measured complex spectral reflectance of the snowpack. The method is based in a stepped-frequency continuous wave radar (SFCW), implemented in a coherent software defined radio (SDR), in the range from 150 MHz to 6 GHz. An electromagnetic model to solve the electromagnetic reflectance of a snowpack, including the frequency and wetness dependence of the complex relative dielectric permittivity of snow layers, is shown. Using the previous model, an approximated method to calculate the SWE is proposed. The results are presented and compared with those provided by a cosmic-ray neutron SWE gauge over the 2019–2020 winter in the experimental AEMet Formigal-Sarrios test site. This experimental field is located in the Spanish Pyrenees at an elevation of 1800 m a.s.l. The results suggest the viability of the approximate method. Finally, the feasibility of an auxiliary snow height measurement sensor based on a 120 GHz frequency modulated continuous wave (FMCW) radar sensor, is shown.


Wetlands ◽  
2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Yu An ◽  
Yang Gao ◽  
Xiaohui Liu ◽  
Shouzheng Tong ◽  
Bo Liu ◽  
...  

2021 ◽  
Vol 11 (16) ◽  
pp. 7176
Author(s):  
Guillermo Cobos ◽  
Miguel Ángel Eguibar ◽  
Francisco Javier Torrijo ◽  
Julio Garzón-Roca

This case study presents the engineering approach conducted for stabilizing a landslide that occurred at “El Portalet” Pass in the Central Spanish Pyrenees activated due to the construction of a parking lot. Unlike common slope stabilization cases, measures projected here were aimed at slowing and controlling the landslide, and not completely stopping the movement. This decision was taken due to the slow movement of the landslide and the large unstable mass involved. The degree of success of the stabilization measures was assessed by stability analyses and data obtained from different geotechnical investigations and satellite survey techniques such as GB-SAR and DinSAR conducted by different authors in the area under study. The water table was found to be a critical factor in the landslide’s stability, and the tendency of the unstable slope for null movement (total stability) was related to the water table lowering process, which needs more than 10 years to occur due to regional and climatic issues. Results showed a good performance of the stabilization measures to control the landslide, demonstrating the effectiveness of the approach followed, and which became an example of a good response to the classical engineering duality cost–safety.


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