Streams and rivers act as landscape-scale bioreactors processing large quantities of terrestrial particulate organic matter (POM). This function is linked to their flow regime, which governs residence times, shapes organic matter reactivity and controls the amount of carbon (C) exported to the atmosphere and coastal oceans. Climate change impacts flow regimes by increasing both flash floods and droughts. Here, we used a modelling approach to explore the consequences of lateral hydrological contraction, that is, the reduction of the wet portion of the streambed, for POM decomposition and transport at the river network scale. Our model integrates seasonal leaf litter input as generator of POM, transient storage of POM on wet and dry streambed portions with associated decomposition and ensuing changes in reactivity, and transport dynamics through a dendritic river network. Simulations showed that the amount of POM exported from the river network and its average reactivity increased with lateral hydrological contraction, due to the combination of (1) low processing of POM while stored on dry streambeds, and (2) large shunting during flashy events. The sensitivity analysis further supported that high lateral hydrological contraction leads to higher export of higher reactivity POM, regardless of transport coefficient values, average reactivity of fresh leaf litter and differences between POM reactivity under wet and dry conditions. Our study incorporates storage in dry streambed areas into the pulse-shunt concept (Raymond and others in Ecology 97(1):5\uffe2\uff80\uff9316, 2016. https://doi.org/10.1890/14-1684.1), providing a mechanistic framework and testable predictions about leaf litter storage, transport and decomposition in fluvial networks.Interactions among nitrogen (N) management and water resources quality are complex and enhanced in transboundary river basins. This is the case of Tagus River, which is an important river flowing from Spain to Portugal in the Iberian Peninsula. The aim was to provide a N assessment review along the Tagus River Basin regarding mostly agriculture, livestock, and urban activities. To estimate reactive nitrogen (Nr) load into surface waters, emission factor approaches were applied. Nr pressures are much higher in Spain than in Portugal (~13 times), which is mostly because of livestock intensification. Some policy and technical measures have been defined aiming at solving this problem. Main policy responses were the designation of Nitrate Vulnerable and Sensitive Zones, according to European Union (EU) directives. Nitrate Vulnerable Zone comprise approximately one third of both territories. On the contrary, Sensitive Zones are more extended in Spain, attaining 60% of the watershed, against only 30% in Portugal. Technical measures comprised advanced urban and industrial wastewater treatment that was designed to remove N compounds before discharge in the water bodies. Given this assessment, Tagus River Basin sustainability can only be guaranteed through load inputs reductions and effective transnational management processes of water flows.
", "keywords": ["STRATEGIES", "SURFACE", "IMPACT", "Tagus river basin", "01 natural sciences", "nitrogen", "12. Responsible consumption", "11. Sustainability", "PORTUGAL", "FIELD", "agriculture", "0105 earth and related environmental sciences", "LAND-USE", "Sensitive Zones", "measures", "15. Life on land", "Tagus River Basin", "6. Clean water", "Vulnerable Zones", "PHOSPHORUS", "WATER-QUALITY", "13. Climate action", "impact", "SOIL-CROP ENVIRONMENT", "sensitive zones", "AGRICULTURAL DOMINATED CATCHMENTS", "vulnerable zones"]}, "links": [{"href": "http://www.mdpi.com/2073-4441/10/4/406/pdf"}, {"href": "https://doi.org/10.3390/w10040406"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Water", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/w10040406", "name": "item", "description": "10.3390/w10040406", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/w10040406"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-03-30T00:00:00Z"}}, {"id": "10.1080/02508061003660714", "type": "Feature", "geometry": null, "properties": {"updated": "2026-06-26T16:19:55Z", "type": "Journal Article", "created": "2010-04-09", "title": "Forests And Floods In Latin America: Science, Management, Policy And The Epic Force Project", "description": "The EPIC FORCE project aimed to develop science-based policy recommendations for integrated forest and water resources management, relevant to extreme events for Costa Rica, Ecuador, Chile and Argentina. Data analysis and model application support the hypothesis that, as the size of the flood peak increases, the effect of forest cover becomes less important. Guidelines for integrated water and forest resources management are developed which recognize this effect but emphasize the role that forests play in reducing the flood levels of more moderate events. The research findings are transferred to policy-making for the four focus countries via a set of policy briefs, taking into account the institutional frameworks, achievable policy objectives and key stakeholders.", "keywords": ["Latin America", "Policy", "13. Climate action", "0208 environmental biotechnology", "0207 environmental engineering", "02 engineering and technology", "Ingenier\u00eda Hidr\u00e1ulica", "Forests", "15. Life on land", "Floods", "River catchments", "6. Clean water"]}, "links": [{"href": "https://doi.org/10.1080/02508061003660714"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Water%20International", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1080/02508061003660714", "name": "item", "description": "10.1080/02508061003660714", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1080/02508061003660714"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-04-13T00:00:00Z"}}, {"id": "10261/309237", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-06-26T16:28:14Z", "type": "Journal Article", "created": "2022-12-29", "title": "Spatial variability of soil organic carbon stock in an olive orchard at catchment scale in Southern Spain", "description": "Orchards have a high potential for carbon sequestration. However, little research is available on the spatial variability at catchment scale and on the difference between the tree area and the lanes. We analyzed theik spatial variability of soil organic carbon stock, SOCstock at 90\u00a0cm depth in an 8-ha catchment in Southern Spain with olives on a vertic soil. Results showed higher soil organic carbon concentration, SOC, in the tree area as compared to the lane up to 60\u00a0cm depth, but its impact on SOCstock was negligible since it was compensated by the higher soil bulk density in the lane. SOC at different depths was correlated with that in the top 0\u20135\u00a0cm. The overall SOCstock of the orchard was 4.14\u00a0kg\u00a0m\u22122, ranging between 1.8 and 6.0\u00a0kg\u00a0m\u22122. This SOCstock is in the mid-lower range of values reported for olive orchards, measured at smaller scale, and similar to those other intensive field crops and agroforestry under comparable rainfall conditions. The spatial variability in SOCstock was correlated to several geomorphological variables: elevation, cumulative upstream area, topographic wetness index, sediment transport index, and tillage erosion. Differences in SOC and SOCstock are driven by the sediment redistribution downslope, mainly by tillage erosion, and higher soil water availability in lower areas allowing higher biomass production. These topographic indexes and the correlation between SOC in the topsoil and SOCstock up to 90\u00a0cm should be further explored in other typology of olive orchards for facilitating the mapping of SOCstock.", "keywords": ["Carbon sequestration", "2. Zero hunger", "Vertic soils", "Mediterranean crops", "Catchments", "0401 agriculture", " forestry", " and fisheries", "04 agricultural and veterinary sciences", "TA1-2040", "15. Life on land", "Engineering (General). Civil engineering (General)", "Catchment", "Spatial variability"]}, "links": [{"href": "https://doi.org/10261/309237"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Soil%20and%20Water%20Conservation%20Research", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10261/309237", "name": "item", "description": "10261/309237", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10261/309237"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2023-06-01T00:00:00Z"}}, {"id": "10278/5031900", "type": "Feature", "geometry": null, "properties": {"updated": "2026-06-26T16:28:22Z", "type": "Journal Article", "created": "2022-12-12", "title": "Pulse, Shunt and Storage: Hydrological Contraction Shapes Processing and Export of Particulate Organic Matter in River Networks", "description": "AbstractStreams and rivers act as landscape-scale bioreactors processing large quantities of terrestrial particulate organic matter (POM). This function is linked to their flow regime, which governs residence times, shapes organic matter reactivity and controls the amount of carbon (C) exported to the atmosphere and coastal oceans. Climate change impacts flow regimes by increasing both flash floods and droughts. Here, we used a modelling approach to explore the consequences of lateral hydrological contraction, that is, the reduction of the wet portion of the streambed, for POM decomposition and transport at the river network scale. Our model integrates seasonal leaf litter input as generator of POM, transient storage of POM on wet and dry streambed portions with associated decomposition and ensuing changes in reactivity, and transport dynamics through a dendritic river network. Simulations showed that the amount of POM exported from the river network and its average reactivity increased with lateral hydrological contraction, due to the combination of (1) low processing of POM while stored on dry streambeds, and (2) large shunting during flashy events. The sensitivity analysis further supported that high lateral hydrological contraction leads to higher export of higher reactivity POM, regardless of transport coefficient values, average reactivity of fresh leaf litter and differences between POM reactivity under wet and dry conditions. Our study incorporates storage in dry streambed areas into the pulse-shunt concept (Raymond and others in Ecology 97(1):5\uffe2\uff80\uff9316, 2016. https://doi.org/10.1890/14-1684.1), providing a mechanistic framework and testable predictions about leaf litter storage, transport and decomposition in fluvial networks.