About Waterlands

River systems (entire catchments containing features such as streams, wetlands and lakes that are drained by their river networks) provide critical provisioning (e.g., clean water, fisheries), regulating (e.g., flood control, waste assimilation) and cultural services (e.g., recreation), all essential to human societies (Millenium Ecosystem Assessment 2005). At this regard, Integrated Catchment Management (ICM) faces today and highlight the considerable risk of losing important river ecosystem functions and associated services in the actual scenario of global change and major targets focus on maximizing societal returns from fluvial landscapes while ensuring resilience and aquatic biodiversity conservation. Thus, water managers need immediate assistance and new integrative tools to guide them through complex decisions that seek meeting multiple objectives in order to achieve desired conditions (habitat restoration, good ecological status, low flooding risk), including trade-offs even between riverine and terrestrial ecosystems.

In response to the current consequences of global change and to halt the current biodiversity loss and associated provisioning of relevant ecosystem services, the European Union adopted the Biodiversity Strategy in May 2011. This strategy is built around six mutually supportive targets, one of which represents the first normative reference related to Green Infrastructure Networks: “by 2020, ecosystems and their services should be maintained and enhanced by establishing green infrastructure and restoring at least 15% of degraded ecosystems”. Responding to this political ambition the European Commission published a new strategy in May 2013 to promote the use of Blue and Green Infrastructure networks (BGIN) across Europe. The strategy aims to create a robust framework in order to promote and facilitate BGIN implementation within existing legal, policy and financial instruments.

A BGIN can be broadly defined as “a strategically planned network of high quality natural and semi-natural ecosystems/habitats that is designed and managed to deliver a wide range of ecosystem services and to protect biodiversity in both rural and urban settings” (Own definition see HERE).

Many barriers emerge when specific nature based solutions are considered for real implementation. In this regard, the main challenges that ICM and Landscape Planning face today for a broader application of these techniques are related to:
(1) The need for evidence-based knowledge on the design and efficiency of nature based solutions.
(2) The need to develop integrated modelling approaches accounting for the main drivers of change.
(3) Building credible future scenarios in which a range of solutions could be evaluated.
(4) Inter-administrative cooperation and a change on the management culture towards more participative learning approaches.

WATERLANDS is conceived to cast light on all the above challenges by addressing water-land cover relationships and focusing specially on the relationship between rivers and forests. The world’s primary bodies dealing with climate change (IPCC and UNFCCC) have viewed the role of forests and trees exclusively as carbon sinks and, in contrast, water and the role of forests and trees as modulators of the hydrological cycle and of water temperatures have not received the explicit attention in adaptation to climate change policies (e.g., Díaz et al., 2015; Maier and Feest, 2016; Pascual et al., 2017). The uncertainties concerning the relationship between forests and river flow and water temperatures will increase as the rate of climate and LULC change increase as well (Thornton et al., 2014). Would it help to plant more trees? Would this make water scarcity worse? Does it matter what type of trees? Does it matter where and how they are integrated into the landscapes? (Creed and van Noordwijk, 2018).

Recent studies (e.g. Belmar et al., 2018) and extensive and updated reviews on forest-water relationships (Creed and van Noordwijk, 2018), have pointed to the need of addressing the role of different types of forests, of land cover dynamics and of secondary succession processes on forests (Figure). The differential responses that water amount and temperature might have to changes on land cover or forests of different age or between natural forest and tree plantations are related to a whole array of characteristics that affect key hydrological processes and microclimatic conditions. In relation to strict water-forest relationships, important changes on water fluxes have been identified theoretically on a forest maturation gradient (Chapin III et al., 2002) and on empirical studies (Vertessy et al., 1998).

Figure. Evolution of fluxes or pools of Carbon-Water from Gross Primary Production (GPP), Biomass-water storage in soils or plants and Net Primary Production (NPP) and Evapotranspiration along the lifetime of a natural forest plot (A; Adapted from Chapin III et al., 2002).

Hydrological and temperature regimens are among the most important drivers of river system processes and biodiversity (Poff et al., 2010). Both drivers are seriously modified by LULC and climate change. Thus, any decision support tool for catchment managers aiming at reflecting which are the best possible solutions to secure freshwater resources in the actual scenario of global change will need to explicitly integrate models that link LULC and climate change predictions to stream hydrology and water thermal regimens.

Climate change predictions are nowadays available for many parts of the world accounting mainly for precipitation and air temperature in a set of different scenarios (e.g., Collins et al., 2013), however, global LULC scenarios are still lagging far behind. The main reason for this is that land cover dynamics are generated by changes on land uses, which are mainly related to macro-economic drivers, but with a high dependence on local socio-economic ones (e.g., population, wealth, consumption preferences, agricultural productivity, land-use regulation, and trade; Stehfest et al., 2019). In this regard, different land cover transitions might emerge from land abandonment or land use intensification depending on the natural and socioeconomic environment in which these changes occur (Figure).

Figure. Land Use and Land Cover transitions on the Cantabrian Cordillera generated by human abandonment of traditional practices (green arrow) or by a more intensification of the landscape (orange arrow). Tree plantations could be developed from any of the other land cover types except for denuded land, and are very rarely restored to natural conditions

WATERLANDS aims at investigating which are the main differences on certain attributes among land cover (pastures, shrubs and forest) and forest (young forests, mature forests and tree plantations) types that modulate the effect they have on stream flow and water temperature, so as to have those differences into account when generating future scenarios of global change for water resource management.

Most of the available methods to evaluate the effect of human activities on river systems are based on the deviation of structural elements in comparison with a reference condition, being these elements biological groups (algae, macrophytes, macroinvertebrates, fishes or riparian vegetation) or other river components (hydrology, river morphology or water quality). However, using structural elements to evaluate river condition does not inform about the functional quality of the river system, as environmental stressors might affect composition and structure of biological communities but species replacement might keep river functioning rates unaltered (Young & Huryn, 1999). Thus, WATERLANDS will use river metabolism as an endpoint to evaluate the response of river systems to climate and LULC change in a given set of scenarios. This will allow investigating how the key drivers of global change might affect river processes and also how different nature base solutions could be implemented in the landscape to ameliorate these effects on river systems.