Restoring free-flowing rivers: Planning for longitudinal and lateral connectivity recovery
Spatial–temporal connectivity is a key feature defining functional freshwater ecosystems but has been deeply transformed worldwide by longitudinal barriers, like dams, weirs or culverts and lateral barriers such as levees or channels, which have interrupted longitudinal continuity and disconnected r...
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/399757 |
| Acceso en línea: | http://hdl.handle.net/10261/399757 https://api.elsevier.com/content/abstract/scopus_id/105008750860 |
| Access Level: | acceso abierto |
| Palabra clave: | Lateral barrier Longitudinal barrier Marxan Opportunity cost River restoration Spatial prioritisation |
| Sumario: | Spatial–temporal connectivity is a key feature defining functional freshwater ecosystems but has been deeply transformed worldwide by longitudinal barriers, like dams, weirs or culverts and lateral barriers such as levees or channels, which have interrupted longitudinal continuity and disconnected rivers from their floodplains, respectively. There is growing interest in restoring the natural functionality of rivers and streams recovering free-flowing rivers, as these infrastructures threaten the maintenance of ecological processes that sustain biodiversity and ecosystem services. This recovery must be supported by adequate planning, often in entire catchments, to overcome the limitations of traditional opportunistic decisions, which have dragged the effectiveness of past river restoration. Most of the restoration planning efforts have focused on longitudinal connectivity. However, the recovery of free-flowing rivers demands that future restoration efforts also consider other dimensions of connectivity. I demonstrate how to plan for the recovery of longitudinal and lateral connectivity by identifying priority longitudinal and lateral barriers for restoration, to recover connectivity between populations of freshwater fish and floodplain habitats, while minimising the opportunity cost of restoration efforts. I test the approach under four alternative scenarios, including a coordinated vs. an uncoordinated scenario, where both types of barriers are simultaneously or individually prioritised. I also explored a null cost scenario where all barriers had the same opportunity cost, and a locked out scenario where barriers with a high opportunity cost were not allowed for selection, both under coordinated conditions. The results show that coordinated planning taking into account the opportunity costs of barriers leads to recommendations with the best perspective for the ecological recovery of free-flowing rivers, with lateral barriers selected in combination with longitudinal barriers upstream to allow recovery of the functionality of floodplains reconnected to rivers, while minimising the opportunity cost of restoration. Synthesis and Applications. Adequate planning should guide decision making in complex scenarios like river restoration, where opportunistic approaches have proven ineffective. This includes setting clear objectives and constraints and using adequate data. Restoring free-flowing rivers will also need the restoration of more than longitudinal connectivity, which will benefit from integrated planning of multiple types of barriers simultaneously. |
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