Temporal changes in Mediterranean forest ecosystem services are driven by stand development, rather than by climate-related disturbances
Introduction
Forests are key terrestrial ecosystems because of their extension (Crowther et al., 2015), their role in sustaining biodiversity (Butchart et al., 2010), and the multiple ecosystem services (ES) they provide to humanity (Ninan and Inoue 2013). However, in the last decades they have been subjected to an increasing amount of pressures related to global change, including changes in land-use and management, and climate-related stress factors (e.g. Smith et al., 2016, Li et al., 2018). For example, climate anomalies and extreme events, such as droughts, are driving episodes of forest decline in many areas (Allen et al., 2015), affecting multiple ES (Anderegg et al., 2013). Other disturbances and natural hazards, such as wildfires, pests and diseases, are also increasingly important for forest dynamics, impacting the provision of different ES (Seidl et al., 2014, Thom and Seidl, 2016). It is hence necessary for the future development of management and conservation policies to quantify forests vulnerability to global change-related factors, and the capacity of forests to maintain the provision of essential ES (Mori et al., 2017). The development of adaptive guiding approaches for decision-making within the ES framework also require the integration of spatially explicit assessments of ES temporal dynamics that account for multiple environmental and site-related drivers (Rau et al., 2018).
Climate has been identified as a relevant driver for the supply of forest ES at multiple scales (Runting et al., 2017). From the regional to the global level, climatic conditions drive the geographic distribution and functioning of forest ecosystems, and control ES provision (Yu et al., 2008, Roces-Díaz et al., 2018). European forests have doubled their canopy mortality in the last decades (Senf et al., 2018) due to the combined effect of natural disturbances and forest-use. The same study reported that higher biomass was associated to higher levels of canopy mortality (Senf et al., 2018).
Forest ES are largely influenced by aspects related with the type and intensity of use, which affects their tree species composition but also ecosystem structure (Baeten et al., 2019, Mina et al., 2017). For example, multiple studies have analysed the complex relationship between forest diversity and its ecological functioning and services (e.g. Gamfeldt et al., 2013, Felipe-Lucia et al., 2018), including e.g. the link between biomass productivity (and derived ES) and tree species richness (e.g., Zhang et al., 2012, Liang et al., 2016). In addition, the spatial structure of forest stands is also relevant for determining the provision of ES such as climate regulation, habitat quality or resistance against disturbances (McGarvey et al., 2015, Yuan et al., 2018). Recent findings revealed that a high intensity in management can negatively impact multiple ES (Sing et al., 2017), while other studies found that common management practices enhance forest productivity in our study area (Garcia-Valdes et al., under review). In fact, the specific role of different management practices on forest community dynamics and derived ES is still unknown for most forest biomes (Pohjanmies et al., 2017).
Mediterranean forests and their derived ecosystem services have been influenced by human activities for millennia (Blondel, 2006), and more recently they have been increasingly affected by multiple global change factors (Doblas-Miranda et al., 2017, Peñuelas et al., 2017). In the last decades, these forests have showed lower levels of human pressure, i.e. less intensive forest management, with lower levels of timber extraction and firewood harvesting. In addition, Mediterranean landscapes are affected by the abandonment of traditional agricultural and livestock uses (Améztegui et al., 2010, Gauquelin et al., 2018). These processes combined with the change in the climatic conditions, have led to forest and tree species expansion (García-Valdés et al., 2013, Cervera et al., 2019, LCMC, 1993-2009), and to changes in forests structure, growth and productivity (Ruiz-Benito et al., 2014, MAPA, 1990-2015). These changes have generally resulted in increasing carbon stocks (Vayreda et al., 2012a), which could strongly impact the provision of ES. A recent analysis based on forest inventory data showed general increases in stand basal areas as well as reductions in ingrowth and growth, and increases in tree mortality in Spanish forests over the past 25 years (Astigarraga et al., 2020). According to some studies, these changes have made Mediterranean forests more vulnerable to hazards such as drought stress (De Cáceres et al., 2015). However, other studies found that changes in forest composition are also increasing the local diversity of drought-tolerance traits, which is buffering negative impacts on productivity (Garcia-Valdes et al., under review).
Furthermore, the supply of a specific service is rarely independent from other ES, and positive (synergies) and negative (trade-offs) pairwise relationships between ES are common (e.g., Duncker et al., 2012, Roces-Díaz et al., 2018, Sing et al., 2017, Schwaiger et al., 2019). However, these relationships have been usually assessed from a purely spatial (i.e. static) perspective (e.g., Roces-Díaz et al., 2018), and the temporal dimension of these relationships, which is critical for management and planning, has rarely been tackled (Tomscha and Gergel, 2016, Willemen, 2020).
In this study, we examined the dynamics of five ES (provision of wild mushrooms, timber volume increment, water provision, carbon sequestration and erosion mitigation) in Catalonia’s forests (North-Eastern Spain) along the past 25 years. We explored their spatial and biogeographical patterns, and their relationships with multiple environmental and site factors, including: the historical climatic conditions and their recent anomalies, disturbances, stand structure and management legacies. The specific objectives of this study were to: i) assess the changes in each forest ES values during the 1990–2015 period for the whole study area, and for its different ecological regions; ii) understanding the causal factors that drive observed dynamics of ecosystem services in the study area; and iii) determine the relationships between different ES over space and time (potential synergies and trade-offs). We hypothesize a dominant role of stand structure in driving recent changes in forest ES in the study area, consistent with previous studies assessing changes in forest dynamics and species composition (e.g., Vayreda et al., 2016). Based on recent findings describing lower levels of stand growth of Iberian forests during the last three decades (Astigarraga et al., 2020), we expect declining trends in timber volume increment and carbon sequestration, whereas increased vegetation cover would result in lower levels of water provision but increased erosion mitigation. We do not have specific expectations regarding changes in wild mushroom production. Finally, we also anticipate a negative impact of recent drought events, in agreement with recent episodes of drought-induced mortality in the study area (e.g., Chaparro et al., 2017).
Section snippets
Study area and outline of the experimental approach
This study focuses on forest ecosystems in Catalonia (North-eastern Spain; Fig. 1A), a region that covers 32,114 km2 and has a population of ~7.5 M people (2015). Most of its area belongs to the European Mediterranean Biogeographical Region, although its northern part, the Pyrenees mountain range, belongs to the Alpine bioclimatic zone. Catalonia has a marked altitudinal gradient from the sea level to more than 3000 m above sea level. According to the Eco-regional classification by Dinerstein
General changes in forest ecosystem services
Our results showed different temporal dynamics for the five forest ES analysed, with different levels of spatial heterogeneity (Fig. 2) and a predominantly declining trend in timber volume increment (overall reduction of 7.08%), water provision (−29.73%) and carbon sequestration (−16.52%; Supplementary material Table B1). Wild mushrooms production and erosion mitigation did not show consistent changes and their average values changed <1.5% for the whole study area during the 1990–2015 period.
Discussion
To our knowledge, this study provides one of the first assessments of forest ES change at regional level (32,114 km2) spanning across different ecoregions (sensu Dinerstein et al., 2017). Our results revealed a general temporal decline (from 1990 to 2015) in three of the five studied ES across our study region, which encompasses large topographic and climatic gradients. Our study was based on a large database (n = 3417) with direct field information resampled using standard protocols (Alberdi
Conclusions and implications
This study analyses the spatiotemporal dynamics of five key forest ES during the 1990–2015 period in a Mediterranean region, by combining a series of spatially explicit indicators, ecological models, and information derived from a large network of NFI plots. Our results showed a general decline of three ES, particularly large for water provision and carbon sequestration. Declines in all ES were driven by variables describing the forest structure and management legacies, being particularly
Funding
Funding was obtained from the Catalan Office for Climate Change (OCCC) through project FOREStime, from EU FORESTERRA program (INFORMED project) and from the Spanish government (CGL2013-46808-R, AGL2015-66001-C3-1-R, CGL2014-59742, CGL2017-89149-C2-2-R, CGL2017-89999-C2-1-R and C2-2-R, and RTI2018-099315-A-I00). We also thank the ECOMETAS (CGL2014-53840-REDT) network for support. JVRD was supported by the Government of Asturias and the FP7-Marie Curie-COFUND program of the European Commission
CRediT authorship contribution statement
Jose V. Roces-Díaz: Conceptualization, Writing - original draft, Writing - review & editing. Jordi Vayreda: Conceptualization, Data curation, Writing - review & editing. Miquel De Cáceres: Conceptualization, Data curation, Writing - review & editing. Raúl García-Valdés: Conceptualization, Data curation, Writing - review & editing. Mireia Banqué-Casanovas: Conceptualization, Data curation, Writing - review & editing. Alejandra Morán-Ordóñez: Data curation, Writing - review & editing. Lluís
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank Sergio Vicente-Serrano and Albert Alvarez for providing part of the data used, and Victor Granda for helping us with data processing.
References (96)
- et al.
Using the USLE: Chances, challenges, and limitations of soil erosion modelling
Int. Soil Water Conserv. Res.
(2019) - et al.
Bird community response in mountain pine forests of the Pyrenees managed under a shelterwood system
For. Ecol. Manage.
(2018) - et al.
Synergistic effects of past historical logging and drought on the decline of Pyrenean silver fir forests
For. Ecol. Manage.
(2011) - et al.
Understanding the long-term dynamics of forest transition: From deforestation to afforestation in a Mediterranean landscape (Catalonia, 1868–2005)
Land Use Policy
(2019) - et al.
Estimating daily meteorological data and downscaling climate models over landscapes
Environ. Modell. Software
(2018) - et al.
Impact of forest management intensity on landscape-level mushroom productivity: a regional model-based scenario analysis
For. Ecol. Manage.
(2014) - et al.
MedREM, a rainfall erosivity model for the Mediterranean region
J. Hydrol.
(2010) - et al.
A review of the combination among global change factors in forests, shrublands and pastures of the Mediterranean Region: Beyond drought effects
Global Planet. Change
(2017) - et al.
Trees, forests and water: cool insights for a hot world
Global Environ. Change
(2017) - et al.
An assessment of soil erosion prevention by vegetation in Mediterranean Europe: current trends of ecosystem service provision
Ecol. Ind.
(2016)
Drought-induced mortality and hydraulic architecture in pine populations of the NE Iberian Peninsula
For. Ecol. Manage.
Valuing forest ecosystem services: what we know and what we don't
Ecol. Econ.
Soil erodibility in Europe: a high-resolution dataset based on LUCAS
Sci. Total Environ.
Temporal dynamics of ecosystem services
Ecol. Econ.
Assessing the distribution of forest ecosystem services in a highly populated Mediterranean region
Ecol. Ind.
Ecosystem service trade-offs for adaptive forest management
Ecosyst. Serv.
Stand structure and plant species diversity in managed and abandoned silver fir mature woodlands
For. Ecol. Manage.
It’s about time: advancing spatial analyses of ecosystem services and their application
Ecosyst. Serv.
The Spanish National Forest Inventory, a tool for the knowledge, management and conservation of forest ecosystems
Ecosistemas
On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene
Ecosphere
Land-use changes as major drivers of mountain pine (Pinus uncinata Ram.) expansion in the Pyrenees
Glob. Ecol. Biogeogr.
Consequences of widespread tree mortality triggered by drought and temperature stress
Nat. Clim. Change
Evidence of non-stationary relationships between climate and forest responses: increased sensitivity to climate change in Iberian forests
Glob. Change Biol.
Identifying the tree species compositions that maximize ecosystem functioning in European forests
J. Appl. Ecol.
Forest stand structure, productivity, and age mediate climatic effects on aspen decline
Ecology
A review of the (Revised) Universal Soil Loss Equation ((R) USLE): with a view to increasing its global applicability and improving soil loss estimates
Hydrol. Earth Syst. Sci.
The ‘design’ of Mediterranean landscapes: a millennial story of humans and ecological systems during the historic period
Human Ecol.
Modelling the production and species richness of wild mushrooms in pine forests of the Central Pyrenees in northeastern Spain
Can. J. For. Res.
Global biodiversity: indicators of recent declines
Science
The role of climatic anomalies and soil moisture in the decline of drought-prone forests
IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens.
Climate change and interconnected risks to sustainable development in the Mediterranean
Nat. Clim. Change
Mapping tree density at a global scale
Nature
Quantifying ecosystem service trade-offs for plantation forest management to benefit provisioning and regulating services
Ecol. Evol.
Coupling a water balance model with forest inventory data to predict drought stress: the role of forest structural changes vs. climate changes
Agric. For. Meteorol.
An ecoregion-based approach to protecting half the terrestrial realm
Bioscience
How forest management affects ecosystem services, including timber production and economic return: synergies and trade-offs
Ecol. Soc.
Multiple forest attributes underpin the supply of multiple ecosystem services
Nat. Commun.
Drought-induced multifactor decline of Scots pine in the Pyrenees and potential vegetation change by the expansion of co-occurring oak species
Ecosystems
Higher levels of multiple ecosystem services are found in forests with more tree species
Nat. Commun.
Chasing a moving target: Projecting climate change-induced shifts in non-equilibrial tree species distributions
J. Ecol.
Mediterranean forests, land use and climate change: a social-ecological perspective
Reg. Environ. Change
Characterization of forest fires in Catalonia (north-east Spain)
Eur. J. Forest Res.
Cited by (34)
Nature's Contributions to People (NCPs) and biodiversity hotspots: a step towards multifunctionality of conservation areas in Peru
2023, Perspectives in Ecology and ConservationA flexible framework for cost-effective fire management
2023, Global Environmental ChangeExploring the effects of various rotation lengths on the ecosystem services within a multiple-use management framework
2023, Forest Ecology and ManagementInfluence of climate fluctuations on Pinus palustris growth and drought resilience
2023, Forest EcosystemsExploring the effects of management intensification on multiple ecosystem services in an ecosystem management context
2022, Forest Ecology and ManagementCitation Excerpt :The differences among the output of management scenarios, however, expand towards the end of simulation due to the increasing levels of afforestation, thinning and harvesting with a better performed future stand development after regeneration and thinning. This result is consistent with the fact that increase of forest area or stand development shows lower levels of runoff or ground water (Bentley and Coomes 2020; Roces-Díaz et al., 2021). Thus, temporal changes of ES are mainly driven by stand or forest development, requiring extensive studies to explore the causes of changes in forest structure over time in relation to various ES (Roces-Díaz et al., 2021).