Protecting Monumental Stones with Graphene Oxide The coating of carbonated stones from our historical heritage with an aqueous graphene oxide suspension is an efficient and cost‐effective method to shield them from climatic erosion, as presented in article number 2101012 by María Fernández‐Raga, Jose Miguel González‐Domínguez, and co‐workers. By simply spraying such additive‐free aqueous colloids on surface, an outstanding protective effect against rainfall and temperature is revealed, without altering the stones' original aesthetics.

Image network geometry, including the number and orientation of images, impacts the error, coverage, and processing time of 3D terrain mapping performed using structure‐from‐motion and multiview‐stereo (SfM‐MVS). Few studies have quantified trade‐offs in error and processing time or ways to optimize image acquisition in diverse topographic conditions. Here, we determine suitable camera locations for image acquisition by minimizing the occlusion produced by topography. Viewshed analysis is used to select the suitable images, which requires a preliminary digital elevation model (DEM), potential camera locations, and sensor parameters. One aerial and two ground‐based image collections were used to analyse differences between SfM‐MVS models produced using: (1) all available images (ALL); (2) images selected using conventional methods (CON); and (3) images selected using the viewshed analysis (VIEW). The resulting models were compared with benchmark point clouds acquired by a terrestrial laser scanner (TLS) and TLS‐derived DEMs. The VIEW datasets produced denser point clouds (28–32% more points) and DEMs with up to 66% reduction in error compared with CON datasets due to reduction of gaps in the DEM. VIEW datasets reduced processing time by 37–76% compared with ALL, with no reduction in coverage or increase in error. DEMs produced with ALL and VIEW datasets had similar slope and roughness, while slight differences that may be locally important were observed for the CON dataset. The new method helps optimize SfM‐MVS image collection strategies that significantly reduce the number of images required with minimal loss in coverage or accuracy over complex surfaces. © 2020 John Wiley & Sons, Ltd.

Soil moisture has a direct influence on biomass production, food security, and ecosystem functioning, thus resources management in water‐limited environments could be improved if feedbacks between water and vegetation were fully understood. This study tries to define the sensitivity of annual pastures under the influence of different vegetation covers to soil water availability during two contrasting growing seasons, dry and wet. For this reason, soil water content was continuously monitored during two complete hydrological years using capacitance sensors, which were gathered in soil moisture stations located in open grasslands and beneath tree canopies. Pasture growth was recorded by measurements of its height and by biomass cuts. The study was conducted on three private farms located in savanna‐like ecosystems of Spain (dehesa) with Mediterranean climate. Results highlighted the importance of the topsoil (first 15 cm) as the main layer for water supply of natural grasses. Soils below canopies registered longer and more intense water deficits than those located in grasslands. This was reflected in biomass growth, given that when growing conditions were dry, pasture yield decreased more than 40% in grasslands and more than 50% below tree canopies. The studied ecosystems occupy millions of hectares in Spain and Portugal and present a canopy cover up to 40%. If dry episodes become more frequent in the present century due to climate change, important surface, especially under trees, could become drier, less productive, and therefore more prone to land degradation.

Changes in land use are common in Mediterranean areas and are reported as having produced changes in the intensity of soil erosion. Dehesas are rangelands with a disperse tree cover, widespread in the south-western part of the Iberian Peninsula and similar ecosystems are also common in other areas with a Mediterranean climate. The aim of the present study is to analyse temporal and spatial variations of soil erosion rates estimated along three hillsides, located in two farms (Buitrera and Parapuños) in southwest Spain. To understand the temporal variation, soil erosion rates were studied in light of land use-management changes that took place during the last few centuries. Results indicate very low erosion rates prior to the 18 th century in both farms. In Buitrera, a first increase of soil loss rates was identified during the period 1831-1897, amounting to 7.4 t ha -1 y -1 . A further increase took place during the 20 th century, reaching a mean erosion rate of 29.1 t ha -1 y -1 . In Parapuños, data points to a significant increase from 1881 onwards, with an estimated mean erosion rate of 18.5 t ha -1 y -1 . Those increases were presumably connected with an intensification of land use, such as cultivation and excessive livestock populations. Regarding spatial variation, the bare surface and the erosive power of run-off along the hillsides accounts for 76% of the soil erosion rates dispersion. At a local scale, the variability of erosion rates could not be explained, because of (i) uncertainty related to the micromorphology of the past soil surface and (ii) the role of tillage erosion in the past. However, the results obtained offer valuable data on the temporal and spatial variation of erosion rates in dehesas at the hillslope scale and a similar approach could be used for other rangelands with a disperse tree cover.