Much of the water and sediment fluxes in semi-arid catchments are found to be highly concentrated in localized pathways. Identifying the location of these pathways in the landscape is important for management and restoration. Measures can then be targeted so as to minimize the potential for erosion and sediment flux along these pathways. A method of repeat field mapping of flow and sediment pathways suitable for Mediterranean catchments is presented. Several small catchments in Cárcavo basin, SE Spain, differing in topographic and land use characteristics, were monitored under several events. Morphometric properties of pathways were analysed and compared with rainfall characteristics. Number and length of pathways varied with rainfall characteristics and also antecedent conditions. In low rainfall events, runoff sources and main pathways were disconnected, but in a larger event, the network of pathways became fully connected. The pathway patterns showed that man-made lines such as terrace embankments and tracks have a major influence on sediment connectivity. Microtopographic factors, soil moisture and the presence of vegetation are highly influential on pathways and the frequency of water and sediment fluxes. Runoff and erosion hotpots for the development of pathways were identified, which should be targeted for mitigation and restoration measures using vegetation. The relevance of local scale factors emphasizes the importance of repeat field observations to understand connectivity and pathways development in the landscape.
– The spawning period of brown trout (Salmo trutta L.) was studied in the river Castril, southern Spain, by means of redd counts. This mountain stream is located near to the southern limit of the species’ natural distribution range and it shows a highly unpredictable flow regime. The spawning period extended from December to mid‐April and the maximum reproductive activity was in February. These results represent the latest reproduction date and the longest spawning period reported in the literature along the natural distribution range of the species. However, belated spawning in the Castril is congruent with the known latitudinal cline: the lower the latitude, the later the spawning period. Our results, along with a review of the literature on natural populations, also showed that the duration of reproduction is the longer, the lower the latitude. Spawning lasted twice as long in the main stem of the river, which is connected with a reservoir, than in the isolated reaches. These differences may be linked to the influence of the reservoir and to habitat fragmentation. We discuss and support the hypothesis that a long spawning period is an advantage for survival in unpredictable habitats. The belated and protracted spawning period found in river Castril has important implications in fisheries management. A strong research effort is needed in order to fill the critical lack of data on southern brown trout populations.
Monitoring forest–agriculture mosaics is crucial for understanding landscape heterogeneity and managing biodiversity. Mapping these mosaics from remotely sensed imagery remains challenging, since ecological gradients from forested to agricultural areas make characterizing vegetation more difficult. The recent synthetic aperture radar (SAR) Sentinel-1 (S-1) and optical Sentinel-2 (S-2) time series provide a great opportunity to monitor forest–agriculture mosaics due to their high spatial and temporal resolutions. However, while a few studies have used the temporal resolution of S-2 time series alone to map land cover and land use in cropland and/or forested areas, S-1 time series have not yet been investigated alone for this purpose. The combined use of S-1 & S-2 time series has been assessed for only one or a few land cover classes. In this study, we assessed the potential of S-1 data alone, S-2 data alone, and their combined use for mapping forest–agriculture mosaics over two study areas: a temperate mountainous landscape in the Cantabrian Range (Spain) and a tropical forested landscape in Paragominas (Brazil). Satellite images were classified using an incremental procedure based on an importance rank of the input features. The classifications obtained with S-2 data alone (mean kappa index = 0.59–0.83) were more accurate than those obtained with S-1 data alone (mean kappa index = 0.28–0.72). Accuracy increased when combining S-1 and 2 data (mean kappa index = 0.55–0.85). The method enables defining the number and type of features that discriminate land cover classes in an optimal manner according to the type of landscape considered. The best configuration for the Spanish and Brazilian study areas included 5 and 10 features, respectively, for S-2 data alone and 10 and 20 features, respectively, for S-1 data alone. Short-wave infrared and VV and VH polarizations were key features of S-2 and S-1 data, respectively. In addition, the method enables defining key periods that discriminate land cover classes according to the type of images used. For example, in the Cantabrian Range, winter and summer were key for S-2 time series, while spring and winter were key for S-1 time series.
Please cite this article as: Martín, P.E., Herrera, G., Sacristán, M.M., Tomás, R., Béjar-Pizarro, M., Marín, R.M., A quasi-elastic aquifer deformational behavior: Madrid aquifer case study, Journal of Hydrology (2014), doi: http:// dx.doi.org/10. 1016/j.jhydrol.2014.08.040 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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