Temporal evolution of ecosystem services in Sierra Nevada
Lead Author: UGR
Anthropogenic activities and land use changes are the main drivers of global change in our target ecosystems. It is estimated that land use change is the second cause of biodiversity loss at global scale and the first in the Mediterranean basin. Human activities have heavy consequences on ecosystem structure and function decades or centuries after they have occurred. The variation in anthropogenic use have conditioned the capacity of mountain ecosystems to produce ecosystem services over time, resulting in trade-offs between provisioning, regulating and cultural services.
Historical information showing land use changes in some parts of Sierra Nevada since XVIII century has been collected. These datasets show how human activities have shaped the structure of forests in Sierra Nevada. History of land use changes will be described by quantifying changes and trade-offs in some ecosystem services. Similarly,we will analyze how different beneficiaries and stakeholder value these trade-offs over time.
This is a local scale study focused on a small basin in a municipality of Sierra Nevada where the historical information was collected. This storyline considers several ecosystem types. Thus, there is a set of ecosystem services provided either by individual ecosystems or by the basin a whole.
We hypothesize that provisioning services have been declining over time in favor of an increase in regulating and cultural services. In this context, it is natural to wonder how some issues have affected this evolution:
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“We have to be able to identify a specific benefit or beneficiary to be able to say clearly what is, or is not, a service” (Hynes-Young and Potschin, 2010). This is more relevant in the case of historical evolution of ecosystem services, where the socio-economic context has changed the type of natural resources used and the way and intensity of the this use. In other words, some services provided formerly, nowadays are not profitable and there are not beneficiaries of them.
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In some cases, as regulatory services, their provision is physically separated from the place where the beneficiaries are (for example, retention of erosion). Thus, we postulate that different stakeholders will value differently these trade-offs.
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Another issue is related with the different types of beneficiaries. Will different beneficiaries (local population, managers, tourists, etc) value regulation and cultural services in the same way?
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Finally, we will assess how past response actions have influenced the supply rate of ecosystem services.
In order to answer these questions, we propose a storyline where the main subject would be ecosystem services. For this purpose we have adapted the DPSIR framework to an ecosystem service based schema (Fig.1).
Fig. 1: A framework for linking state variables, pressures, impacts and responses with the sections of this storyline document. Adapted from Hynes-Young and Potschin (2010).
The sections “State of the Environment/Ecosystem” and “Most important (abiotic and biotic) control factors on the ecosystem” give information about the descriptors and indicators to characterize and monitor the state of the focal ecosystem, control factors and critical ecosystem processes for provisioning focal ecosystem services. The sections “Pressures”, “Impacts” and “Responses” describe how these terms may affect the increase or reduction on ecosystem services provision.
Methodology
Historical information will be used to evaluate the evolution of the ecosystem services and trade-offs over time since XVIII century.
There are several and heterogeneous historical data sources (Fig. 2). We will collect information about land uses, anthropogenic activities and natural and human events from old cadastral documents, local knowledge based on GIS participatory workshops, a variety of gazetteers, statistical information, among many ones.
Fig. 2: Chronological distribution of historical sources.
In order to quantify the different types of ecosystems services we propose the following methodologies.
For provisioning services, we will quantify the production of the variety of agricultural, livestock and other materials collected in the last centuries by the rural economy. Furthermore, we will analyze the market price over time to evaluate final benefits.
Regulating services will be evaluated with WiMMed model. WiMMed (Watershed Integrated Model in Mediterranean Environments) is a physically-based, fully distributed hydrological model. It uses hourly and daily meteorological data, along with certain physical properties of the soil and subsoil to perform the spatial interpolation and temporal distribution of meteorological variables, rainfall interception, snowmelt, infiltration, runoff, surface slope circulation, calculation of the water in aquifers, and basin flow circulation. It thus provides instantaneous value or evolution of the principal flows and state variables, such as water flow volumes, amount of stored water, flooded surfaces, etc. A detailed description of this model is given by Herrero et al. (2009), and examples of the application of this model to the Guadalfeo River basin can be found in Herrero (2007), Ávila (2007), Millares (2008) and Aguilar (2008). WiMMed deals with climate and meteorological particularities with special consideration to Mediterranean environments (Herrero et al., 2014). Processes as spring and autumn torrential rain storms, high risk of persistent droughts, or high rates of sediment generation and soil loss can be correctly reproduced by the model. Knowing the physical and the hydrological properties of a watershed, WiMMed incorporates the meteorological inputs (rain, snow, solar radiation, wind…) and simulates the water cycle and the generation and transport of sediment associated to it. The outputs of the model comprise a large amount of variables at different space and time scales. The current user-level version of WiMMed 2.0 includes all the functionalities for the simulation of every aspect related to water fluxes and hillslope sediment generation and transport.
WIMMed is already calibrated for Sierra Nevada (Spain) for its present climate using the complete dataset of meteorological data, approximately available since 2000. This calibration of WiMMed also uses detailed topographical, soil and land use information, as well as some remote sensing data like albedo, vegetation cover fraction or snow cover fraction, used as input or as assimilated variables. The model has also been used to assess the effect over the hydrology of different IPCC scenarios with a modified meteorology, or under different hypothesis of changes in soil uses. The simulations of the past weather were performed using some simplification hypothesis to make use of the reduced available datasets. In general, systematic temperature records are only available since 1960 while precipitation records are available since 1945.
For cultural ecosystem services, we propose the method of willingness to pay to preserve the landscape quality using old and current photos. We have collected a wide set of antique photographs and have taken current photos at the same place (Fig. 3). We propose the valuation of the cultural services through the comparison between the two views of the same landscape but with a gap of 70 years. For this purpose, we will ask for the increase in the taxes that people are willing to pay for the recovering of the landscape through anthropogenic restoration.
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Fig. 3: Landscape view of a village in Sierra Nevada in the 1940´s and currently.
References
Aguilar, C. 2008. Efectos de escala en procesos hidrológicos. Aplicación a la cuenca del río Guadalfeo (Granada). Tesis doctoral. Grupo de Hidrología e Hidráulica Agrícola. Universidad de Córdoba.
Ávila Armella, A. 2007. Procesos de múltiple escala en la evolución de la línea de costa. Tesis Doctoral. Grupo de Dinámica de Flujos Ambientales. Universidad de Granada.
Herrero, J. 2007 Modelo físico de acumulación y fusión de la nieve. Aplicación a Sierra Nevada (España). Tesis Doctoral. Grupo de Dinámica de Flujos Ambientales. Universidad de Granada.
Herrero, J., Milares, A., Aguilar, C., Díaz, A., Polo, M.J., Losada, M. 2009. WiMMed 1.0. Base teórica. Grupo de dinámica de Flujos Ambientales. Universidad de Granada. Grupo de Hidrología e Hidráulica Agrícola. Universidad de Córdoba.
Herrero, J., Millares, A., Aguilar, C., Egüen, M., Losada, M.A., Polo, M.J. 2014. Coupling spatial and time scales in the hydrological modelling of Mediterranean regions: WiMMed. 11th International Conference on Hydroinformatics. New York City, USA.
Millares, A. 2008 Integración del caudal base en un modelo distribuido de cuenca. Estudio de las aportaciones subterráneas en ríos de montaña. Tesis Doctoral. Grupo de Dinámica de Flujos Ambientales. Universidad de Granada.