I´m a landscape ecologist studying the influence of natural and anthropogenic factors on landscape patterns and species distributions at different spatial and temporal scales. My research has a strong applied focus, developing innovative technical solutions to generate new knowledge that informs management. Currently I am a post-doctoral research fellow at the InForest Joint Research Unit (Centre Tecnològic Forestal de Catalunya - CREAF) in Spain. I am working on four projects (European and National) devoted (1) to the study of the ecosystem services provided by Mediterranean forests and (2) to forecast how the provision of these services may change under differentfuture soci o-economic and climate change scenarios.
Research Items (34)
- Nov 2018
Assessment of potential forests’ threats due to multiple global change components is urgently needed since increasing exposure to them could undermine their future persistence. We aim to assess the risks to the persistence of monospecific forests in Western Mediterranean Europe posed by climate change, fire, and land-use changes (i.e., deforestation) in the short and medium terms (horizon 2040). We specifically evaluate whether the degree of risk related to the likelihood of hazard occurrence varies depending on seral stage, tree species, and climate gradients. We performed the risk assessment on forests of Catalonia (NE Spain) through a combination of correlative and process-based modeling approaches and future global change scenarios. Overall, climate suitability of forests showed a general decrease by 2040, with the exception of xeric Pinus halepensis forests mainly distributed in the driest climate of the study area. Forest stands dominated by low drought-tolerant species were at higher risk of losing climatic suitability than forests dominated by Mediterranean species. The highest fire and deforestation risks were predicted for forest stands in dry climate where human pressures are higher. Nevertheless, high deforestation risk was also attained outside the driest areas. Deforestation risk was lower in old-growth than in younger stands, whereas old-growth forests in the Wet climate or dominated by Pinus sylvestris were projected to be at higher fire risk than younger forests. Our results suggest that conservation actions should target forest stands in dry climate. Moreover, old-growth forest stands should also be prioritized due to their particular sensitivity to disturbances and their high ecological value.
- Sep 2018
Science and society are increasingly interested in predicting the effects of global change and socio-economic development on natural systems, to ensure maintenance of both ecosystems and human well-being. The Intergovernmental Platform on Biodiversity and Ecosystem Services has identified the combination of ecological modelling and scenario forecasting as key to improving our understanding of those effects, by evaluating the relationships and feedbacks between direct and indirect drivers of change, biodiversity, and ecosystem services. Using as case study the forests of the Mediterranean basin (complex socio-ecological systems of high social and conservation value), we reviewed the literature to assess (1) what are the modelling approaches most commonly used to predict the condition and trends of biodiversity and ecosystem services under future scenarios of global change, (2) what are the drivers of change considered in future scenarios and at what scales, and (3) what are the nature and ecosystem service indicators most commonly evaluated. Our review shows that forecasting studies make relatively little use of modelling approaches accounting for actual ecological processes and feedbacks between different socio-ecological sectors; predictions are generally made on the basis of a single (mainly climate) or a few drivers of change. In general, there is a bias in the set of nature and ecosystem service indicators assessed. In particular, cultural services and human well-being are greatly underrepresented in the literature. We argue that these shortfalls hamper our capacity to make the best use of predictive tools to inform decision-making in the context of global change.
Public participation to monitoring programs is increasingly advocated to overcome scarcity of resources and deliver important information for policy‐making. Here, we illustrate the design of optimal monitoring networks for bird species of conservation concern in Catalonia (NE Spain), under different scenarios of combined governmental and citizen‐science monitoring approaches. In our case study, current government efforts, limited to protected areas, were insufficient to cover the whole spectrum of target species and species‐threat levels, reinforcing the assumption that citizen‐science data can greatly assist in achieving monitoring targets. However, simply carrying out both government and citizen‐science monitoring ad hoc led to inefficiency and duplication of efforts: some species were represented in excess of targets while several features were undersampled. Policy‐making should concentrate on providing an adequate platform for coordination of government and public‐participatory monitoring to minimize duplicated efforts, overcome the biases of each monitoring program and obtain the best from both.
Context: The Natura 2000 aims to promote the persistence of biodiversity and traditional uses. European landscapes have, however, undergone large transformations in the past decades, mainly associated with the abandonment of less productive lands concentration of intensive agriculture. These changes could pose management challenges and new opportunities to the achievement of the network´s goals. Objective: Evaluate changes in land cover within Natura 2000 in the last two decades. Methods: We use different Corine Land Cover datasets to construct transition matrices of land uses for measuring changes for each Natura 2000 site. We also explore the role of different drivers in observed changes and assess the impacts of these changes in the structure of landscape. Results: Landscape has been highly dynamic within Natura 2000 in the last two decades with more than 20% undergoing land cover changes. The most systematic transitions involved both, succession processes towards naturalisation in older and more abrupt protected areas (PAs) and anthropization in less steep and more recently designated PAs. Changes across land cover categories had also significant effects on the landscape configuration towards a higher homogenisation. Conclusions: Two different strategies would be needed to enhance the role of Natura 2000, i) tighter control to ensure anthropization, mainly intensive agriculture, does not compromise conservation goals within PAs and ii) tackle more effectively the ecological and socio-economic effects of abandonment in less productive areas to halt loss of key habitats. On the other hand, changes in composition and structure of landscape open new conservation opportunities derived from enhanced connectivity.
- Jan 2018
Diversifying selection between populations that inhabit different environments can promote lineage divergence within species and ultimately drive speciation. The mitochondrial genome (mitogenome) encodes essential proteins of the oxidative phosphorylation (OXPHOS) system and can be a strong target for climate-driven selection (i.e. associated with inhabiting different climates). We investigated whether Pleistocene climate changes drove mitochondrial selection and evolution within Australian birds. First, using phylogeographic analyses of the mitochondrial ND2 gene for 17 songbird species, we identified mitochondrial clades (mitolineages). Second, using distance-based redundancy analyses, we tested whether climate predicts variation in intraspecific genetic divergence beyond that explained by geographic distances and geographic position. Third, we analyzed 41 complete mitogenome sequences representing each mitolineage of 17 species using codon models in a phylogenetic framework and a biochemical approach to identify signals of selection on OXPHOS protein-coding genes and test for parallel selection in mitolineages of different species existing in similar climates. Of 17 species examined, 13 had multiple mitolineages (range 2-6). Climate was a significant predictor of mitochondrial variation in eight species. At least two amino acid replacements in OXPHOS complex I could have evolved under positive selection in specific mitolineages of two species. Protein homology modelling showed one of these to be in the loop region of the ND6 protein channel and the other in the functionally-critical helix HL region of ND5. These findings call for direct tests of the functional and evolutionary significance of mitochondrial protein candidates for climate-associated selection.
- Nov 2017
- II CONFERENCE OF THE PROGRAMME ON ECOSYSTEM CHANGE AND SOCIETY
Reporting for policy-science platforms (e.g. IPBES) relies on the use of published data to identify current and future trends for biodiversity and ecosystem services across biomes. Generated reports tend to ignore or underrepresent small social-ecological systems due to either their size or limited data availability. Data gaps or a lesser spatial extent of these systems do not, however, mean that they are less important or relevant for human-wellbeing and biodiversity conservation. Wetlands only occupy 9% of the land globally, but they provide proportionally significantly more ecosystem services, which are also of high importance (e.g. water provision, hazard protection). Especially in regions such as the Mediterranean Basin where wetland habitat extent is decreasing while the human population is increasing, the importance of wetlands for ecosystem services and biodiversity is increasingly disproportionate. Meanwhile, ongoing social and political instability in the region means progress towards Sustainable Development Goals is not a trivial challenge. This study uses a systematic literature review to identify the pathways, conditions and criteria for positive developments of Mediterranean wetlands under the current global change context. This information is used to develop specific recommendations towards positive futures (e.g. water security, safe coasts). These recommendations are not primarily directed to global platforms, but rather to national governments, NGOs and local citizens" organizations. These parties are most directly concerned with the benefits from a sustainable development path and the safeguarding of related ecosystem services and biodiversity.
Australia's northern savannas are one of the few remaining large and mostly intact natural areas on Earth. However, their biodiversity and ecosystem values could be threatened if proposed agricultural development proceeds. Through land-use change scenarios, we explored trade-offs and synergies among biodiversity conservation, carbon farming and agriculture production in northern Australia. We found that if all suitable soils were converted to agriculture, habitat at unique recorded locations of three species would disappear and 40 species and vegetation communities could lose more than 50% of their current distributions. Yet, strategically considering agriculture and biodiversity outcomes leads to zoning options that could yield >56,000 km2 of agricultural development with a significantly lower impact on biodiversity values and carbon farming. Our analysis provides a template for policy-makers and planners to identify areas of conflict between competing land-uses, places to protect in advance of impacts, and planning options that balance agricultural and conservation needs.
- Mar 2017
Conservation of species under climate change relies on accurate predictions of species ranges under current and future climate conditions. To date, modelling studies have focused primarily on how changes in long-term averaged climate conditions are likely to influence species distributions with much less attention paid to the potential effect of extreme events such as droughts and heatwaves which are expected to increase in frequency over coming decades. In this study we explore the benefits of tailoring predictor variables to the specific physiological constraints of species, or groups of species. We show how utilizing spatial predictors of extreme temperature and water availability (heat-waves and droughts), derived from high-temporal resolution, long-term weather records, provides categorically different predictions about the future (2070) distribution of suitable environments for 188 mammal species across different biomes (from arid zones to tropical environments) covering the whole of continental Australia. Models based on long-term averages-only and extreme conditions-only showed similarly high predictive performance tested by hold-out cross-validation on current data, and yet some predicted dramatically different future geographic ranges for the same species under 2070 climate scenarios. Our results highlight the importance of accounting for extreme conditions/events by identifying areas in the landscape where species may cope with average conditions, but cannot persist under extreme conditions known or predicted to occur there. Our approach provides an important step toward identifying the location of climate change refuges and danger zones that goes beyond the current standard of extrapolating long-term climate averages. This article is protected by copyright. All rights reserved.
Butterflies are arguably one of the most charismatic animal groups in the world and play a key role in plant-pollinators and plant-herbivore ecological networks. Although butterfly biodiversity and ecology has been thoroughly studied in most ecosystems, there is still very little recorded knowledge of their distribution and ecological interactions in urban areas. Particularly very little is known on which plant species butterflies are using as feeding resources or which plant species they contribute to pollinate. Using the City of Melbourne as a case study (Figure 5), we will address this gap by systematically surveying plant-butterfly interactions in a network of urban green spaces distributed across the municipality.
- Dec 2016
Managing and restoring faunal diversity across large areas requires an understanding of the roles of connectivity and dispersal in driving community patterns. We sought to determine the influence of connectivity, water regime, water source, geographical location, and dispersal traits on patterns of aquatic invertebrate diversity across a continent-wide arid biome. We compiled data on freshwater invertebrate assemblages from sites spanning the breadth of arid Australia. Univariate analyses (analysis of variance and rarefaction) revealed that alpha and gamma diversity across sites decreased as latitude increased. Multivariate analyses (ordination and analysis of similarity) revealed that community composition had considerable fidelity to geographic regions. Hydrological connectivity was strongly associated with riverine community composition although water rarely flowed (often less than annually). Hydrologically isolated sites (springs and rockholes) supported communities that were markedly dissimilar to hydrologically connected sites, and to each other. We investigated the influence of dispersal on diversity patterns by examining Distance Decay Relationships for each of four dispersal trait groups (obligate aquatic and passive, weak, and strong aerial dispersers) on the basis of geodesic (shortest path) distances between pairs of sites and Mantel tests. We did not detect clear differences between dispersal traits and distance decay relationships at the continental scale, even for the two groups with the lowest dispersal ability (obligate aquatics and passive dispersers.) Our results suggest that the loss of hydrological connectivity from water developments in arid lands (for example, the impoundment of intermittent rivers) is likely to affect macroinvertebrates. However, the exact flow mechanisms underlying such changes remain to be determined. This article is protected by copyright. All rights reserved.
Species distribution models (SDMs) are currently the most widely used tools in ecology for evaluating the suitability of environments for biodiversity in the face of future environmental change. In this study we seek to provide an assessment of the predictive performance of SDMs over time. How well do SDMs predict for future time periods and what factors influence predictive performance? We used a historical spatially explicit database of 1.8 million occurrence records for 318 tetrapod species from across continental Australia over the period 1950–2013. We fitted distribution models for each species to data from four multi-decadal time slices and used these to predict the species distributions up to 60 years after the data collection period for the fitted models. We evaluated predictions against observed data from the relevant time period. Predictions were made assuming either complete knowledge of changes in climatic and environmental conditions or assuming the environment and climate remained unchanged between the fitting and evaluation time periods. We used generalized linear mixed models to model variation in the predictive performance of SDMs over time in relation to a variety of factors, including the length of time between fitting and evaluation, species traits, taxonomic group and attributes of the dataset used to fit models. We found that most models provided useful predictions even when the period between model fitting and evaluation was 60 years (area under the receiver operator characteristic curve > 0.7 in 80% of the species evaluated). Variation in predictive performance over time was strongly related to the species range breadth (models for species with broad geographical ranges tended to perform worse than models for locally restricted species) and to the environmental coverage of occupancy data. Conversely, taxonomic group, habitat preferences and body size were not highly influential in describing the variation in predictive performance over time.
How did The Little Things that Run the City get its name? The Little Things that Run the City has been inspired by Edward O. Wilson’s famous quote: “…let me say a word on behalf of these little things that run the world” The quote was part of an address given by Wilson on occasion of the opening of the invertebrate exhibit of the National Zoological Park (Washington D.C., USA). It later appeared in writing format in the first volume of the journal Conservation Biology. The key objective of Wilson’s address was to stress the urgent need to recognise the importance of insects and other invertebrates for humanity. Almost 30 years ago he was keen to see that efforts aimed at the conservation of biodiversity were beginning to also include non-vertebrate animals. In his words: “A hundred years ago few people thought of saving any kind of animal or plant. The circle of concern has expanded steadily since, and it is just now beginning to encompass the invertebrates. For reasons that have to do with almost every facet of human welfare, we should welcome this new development.” In this research collaboration with the City of Melbourne we aim to expand the circle further to also encompass the conservation of insects and other invertebrates in urban environments. We are inspired to ‘say a word on behalf of the little things that run the city’.
The number of studies aimed at understanding the complexity of ecological patterns and processes and their interaction with human societies has dramatically increased in the last two decades, but especially since the publication of the Millennium Ecosystem Assessment reports in 2003 and 2005. Integrative models and scenarios are key tools to disentangle this complexity, forecast the ecological consequences of current and future states of societal development and support well-informed decision making. But, what's the state of the art in the development and application of these tools? We are conducting a review of the methods and scenarios in use for evaluating the future of biodiversity and ecosystem services provision in the context of forest systems across the Mediter-ranean basin. The review is framed within the international ERA-net Foresterra INFORMED project (INtegrated research on FOrest Resilience and Management in the MEDiterranean) that seeks to foster forest system resilience through biodiversity management (from genes to communities). Mediterranean forests represent a good example of biodiversity-rich and complex ecological systems, with a long history of human perturbations and management and currently threatened by ongoing global change. With our review, we aim to know which types of models are more widely used (correlative vs process-based) and how widespread is the implementation of integrated modelling approaches – those accounting for feedbacks across sectors (e.g. agriculture and forestry) and spatial scales within a single modelling framework. We also evaluate the prevalence of the use of multi-driver scenarios – those accounting for the simultaneous impacts of multiple direct and indirect drivers (e.g. climatic, land use, management) – and single-driver scenarios in literature. The overall goal is to understand the state of the art in how indicators of the state of Mediterranean forests are being developed/modelled, and to identify priority areas for future research. Preliminary results show that the number of studies that focus on a single biodiversity or ecosystem service indicator, use a single model or scenarios based on a single-driver outnumber the more integrative studies. Our study will directly inform the currently-in-progress regional Eu-ropean and Central Asia assessment of the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) on integrated assessment modelling and scenarios. * Speaker
- May 2016
Aim The ‘two sides of the same coin’ hypothesis posits that biological traits that predispose species to extinction and invasion lie on opposite ends of a continuum. Conversely, anthropogenic factors may have similar effects on extinction and invasion risk. We test these two hypotheses using data on more than 1000 reptile species. Location Global. Methods We used hierarchical Bayesian models to determine whether biological traits and anthropogenic factors were correlated with whether a species was: (1) listed as Threatened versus Least Concern on the IUCN Red List, and (2) successful versus unsuccessful at establishing a viable population once introduced outside of its native geographical range. The ‘two sides of the same coin’ hypothesis predicts that model coefficients for each trait should be opposite in sign between these two models. Results Seventy-three per cent of model coefficients describing 10 aspects of a species’ life history, ecology, biogeography and environmental niche breadth were opposite in sign between the two groups; however, most effect sizes for variables that showed contrasting relationships were small and/or uncertain. The only exception was body size: larger-bodied species were more likely to be threatened, whereas smaller-bodied species were more likely to be invasive. As predicted, human population density across a species’ native geographical range was positively correlated with both threat and invasion probabilities. Other anthropogenic variables did not have strong analogous effects. Main conclusions The assumption that threatened and invasive species lie on opposite ends of a continuum, while consistent with life-history theory, appears to be an oversimplification. Our results do suggest, however, that anthropogenic variables can be important predictors of a species’ fate, and should be more routinely incorporated in trait-based analyses of extinction and invasion risk.
1. Traditionally, dispersal of aquatic invertebrates has been thought to be very closely associated with river network structure, despite many species being capable of active or passive dispersal across the terrestrial matrix. However, recent studies of both population genetics and community structure from dryland regions indicate that aquatic species commonly disperse across catchments, implying that movement away from streams is more common than originally thought. This study investigated how aquatic invertebrate metacommunity structure in central Australia is influenced by interactions between species’ dispersal traits, dispersal routes and local environmental conditions. 2. We sampled community composition in 16 perennial and long-term inundated freshwater habitats in central Australia. Aquatic invertebrate taxa were allocated to one of four dispersal trait groups: obligate aquatic, passive aerial, weak flying and strong flying. We then used Mantel tests to examine correlations between trait group community dissimilarities, and four isolation models representing (i) local environmental conditions, (ii) geographical distances, (iii) landscape resistances restricted to river networks and (iv) landscape resistances incorporating overland dispersal ‘conduits’. 3. We found that the community composition of aquatic invertebrates in three of four dispersal trait groups, and all traits combined, was influenced primarily by topographic connectivity via overland dispersal conduits. 4. Our results suggest that rainfall events and their effect on the landscape as a whole, rather than river flow during these events, shape aquatic invertebrate metacommunity structure in central Australia. This study provides further support for the importance of overland dispersal conduits to aquatic invertebrates, particularly in arid environments with irregular rainfall.
- May 2015
AimTo understand how environmental conditions and landscape structure interact at different spatial scales to shape the community composition of arid zone aquatic invertebrates with different dispersal abilities.LocationAustralia.Methods For each of five drainage basins and for their encompassing region (Pilbara), we built matrices of dissimilarities in presence–absence patterns of aquatic invertebrate community composition. This was carried out for all taxa collectively and separately for five dispersal trait groups: obligate aquatics, passive aerial dispersers, animals moving by aerial phoresy, weak and strong fliers. We analysed correlations between community dissimilarities and (1) dissimilarities in local environmental conditions, (2) geographic distances and (3) landscape resistance distances among the sites from which invertebrates were sampled. Calculation of landscape resistances accounted for longitudinal connectivity along the river channels (least-cost-path), lateral connectivity between streams and the potential effects of rugged topography on invertebrate dispersal.ResultsLocal environmental factors and landscape resistances explained differences in community composition at the regional scale. In basins with complex topography, local environmental conditions were the main factor explaining community dissimilarities in most dispersal groups. Conversely, in basins where flatter topography meant that moderate to high lateral connectivity between streams is possible, the spatial configuration of the dendritic network determined the community composition of most dispersal trait groups. Geographic and least-cost-path distances were poor predictors of community composition. None of the groups showed a consistent correlation with environmental factors alone, or just landscape resistances, across all basins.Main conclusionsLocal environmental conditions, hydrological connectivity and landscape resistance to dispersal are all important influences on community composition of arid zone aquatic invertebrates. The impact of each of these factors varies with dispersal trait group and spatial configuration of basins: the importance of lateral connectivity for explaining a substantial proportion of community composition points to a major role of flooding regimes in maintaining biological communities.
- Aug 2013
Heathlands are considered biodiversity hotspots of high conservation interest. However, they are at risk of degradation and disappearance in most parts of Europe mainly due to land abandonment, degradation and conversion to other land uses. Heathlands are semi-natural systems: their maintenance and survival depends on specific practices such as extensive grazing or burning. Traditionally they provide a wide range of goods and services to societies. In this study we used the ecosystem services (ES) framework to analyse the changes in the demand for and delivery of ES for the heathland landscapes of the Cantabrian Mountains (NW Spain), since the 1950s. Particularly, we analysed how the social changes since the 1950s have determined changes in stakeholders’ demand for provisioning, cultural and regulating services and how these changes have influenced the vegetation dynamics and conservation status of these systems. We identified a general shift from the provisioning of grazing facilities and local products for the local-regional market to the provisioning of conservation services to satisfy national-international demand. For the present situation we found a clear mismatch between the conservation demand, management practices and land use forms. This mismatch threatens to lead to further landscape changes and loss of biodiversity. The results of our multi-scale and multi-services study can help to increase awareness of the value of currently obtainable benefits from heathlands among stakeholders and managers. The ES approach can improve understanding of the functioning of the socio-ecological heathland system, and inform the development of new management strategies for heathland protection.
This report describes the research undertaken to develop national guidelines for climate adaptation planning for arid zone aquatic ecosystems and freshwater biodiversity. The guidelines focus on the protection of habitats and processes that support the persistence of freshwater biota under a changing climate. They support policy development, planning and on-ground actions. The major climate adaptation goal is to reduce the risk of the loss of aquatic habitats, deteriorating water quality and the extinction of aquatic and water-dependent species. A portfolio of adaptation approaches to maintaining aquatic habitats, the water resources that support them, and the species that depend upon them, is proposed within a framework of strategic adaptive management. This approach best addresses the uncertainty that exists as to how climatic changes will play out across the arid zone with respect to water availability and ecological processes. Recommended climate adaptation actions include: combining a national mapping program that identifies the major types of arid zone aquatic ecosystems, their biological assets and the surface water and groundwater resources that sustain them, with vulnerability assessments that determine the climate sensitivity and likely persistence of key habitats; recognising the importance of evolutionary refugia and ecological refuges as priority sites for arid zone climate adaptation planning and policy; protecting a dynamic (spatial and temporal) mosaic of perennial, temporary and ephemeral waterbodies to provide the range of conditions needed to support aquatic and waterdependent species with varying life history traits and dispersal abilities; maintaining the integrity of the dry sediments of temporary and ephemeral waters to ensure the persistence of viable seed and egg banks; recognising the importance of key hydrological and ecological processes, particularly connectivity and dispersal; reducing the existing stressors on aquatic ecosystems and aquatic biota; identifying new and novel waterbodies created by arid zone industries (e.g. mining, pastoralism) that could provide valuable offsets for aquatic systems lost through climatic drying, and implementing climate adaptation actions within a strategic adaptive management framework accompanied by a dedicated program for indigenous, industry and local community engagement and education.
- Jan 2013
- Economy and Ecology of Heathlands
Chapter Summary This chapter reviews the evolution of heathlands in the Cantabrian Mountains and the drivers of these changes. It also describes how the value that societies attribute to heathlands have changed in the last decades and identifies key management strategies aimed at preserving heathlands while boosting the sustainable development of the human population in the Cantabrian Mountains. The benefits that Cantabrian Mountains' societies have obtained from heathlands have changed over time. These changes are linked to changes in social preferences and needs. In the Cantabrian Mountains, active management specifically aimed at heathland conservation has never been practised and it is still lacking nowadays. Maintenance of heathlands has always depended on traditional management which focused on increasing the availability of pastures for extensive grazing. European countries, such as England or Norway, could be the example to follow when designing management plans for heathlands management within the Natura 2000 network. Keywords: Cantabrian mountains heathlands; heathland economy; Natura 2000 network; South-West Europe 10.1163/9789004277946_008 /content/books/b9789004277946s008 dcterms_subject,pub_keyword 10 5
- Jun 2012
Aim We aim to map the distribution of four heath and shrub formations constituting habitats of high conservation priority in Europe, whose occurrence is strongly dependent on human activities. Specifically, we assess whether the use of LANDSAT data in habitat distribution modelling may account for land use management, allowing accurate mapping of real distribution patterns. In particular, we explore whether reflectance values may be a better alternative to other remote sensing data traditionally used in modelling approaches (i.e. spectral vegetation indices and classified land cover maps). Finally, we test whether modelling performance is affected by the ecological traits of the dominant species of the target formations.
Mountain systems often represent biodiversity hotspots. Due to a combination of their ecological characteristics (strong altitudinal gradients favouring small-scale diversity at short distances) and low intensity management practices (e.g. extensive livestock grazing and small scale agriculture), these areas can sustain a significant diversity of ecosystems and species. Such diversity represents the key factor that allows mountain systems to provide a wide range of ecosystem services, beneficial for both human societies and the species occurring within these landscapes. However, the depopulation of rural areas and the ensuing land abandonment, especially marked since the 1960s, has led to the loss of traditional management, in turn determining loss of semi-natural and natural habitats, homogenization of landscape patterns and loss of biodiversity in the short-medium term. In this Thesis I study land use and land cover changes in the southern slope of the Cantabrian Mountains (NW Spain), at different spatio-temporal scales, identifying the main biophysical and socio-economic factors driving the observed changes. Particular attention is paid to the analysis of the ecosystem services that landscape mosaics of heathlands, shrublands, grasslands and rocks, provide at different institutional scales (ranging from local to international), and to how to raise awareness of their values among the public, stakeholders and managers. This knowledge can represent valuable supporting information when designing current and future management strategies aimed at preserving the conservation values of these landscapes. Firstly we carried out an assessment of land cover changes at the regional scale between 1991 and 2004, a key period for the implementation of land conservation policies, on the basis of a temporal series of land cover maps created from LANDSAT images though supervised classification methods (accuracy >85%). The main changes were the increase of forest due to secondary succession and the loss of shrub related to shrub-cutting management practices. Spatially explicit models of landscape change were built to predict areas where future land cover changes may occur (i.e. forest recovery). Additionally, we evaluated whether the observed changes in forest and shrub cover and structure may have been determined by land protection status. We determined that in protected areas management measures allowed for decreasing shrub area and connectedness, while these increased in non-protected areas. As supervised classification outputs (land cover maps) did not prove useful for distinguishing among specific heath and shrub covers, we incorporated LANDSAT channels in distribution modelling algorithms to determine the current distribution patterns of four heath and shrub formations of high conservation interest, dominated by species with different life traits (specialist vs. generalist). We also evaluated whether including biotic interactions as covariates in distribution modelling approaches would increase the accuracy of predictions, and how the spatial variation of environmental limiting factors of individual species would determine the success of a species under a competition scenario. LANDSAT channels allowed the detection of the specific signal of the dominant species in the canopy of each habitat, improving the accuracy of the models (especially those of the generalist species) and showing some advantages over other remote sensing information traditionally used in species distribution modelling approaches (spectral indices and land cover maps). The most accurate models were those considering abiotic factors, biotic interactions and remote sensing data as predictors. We observed that when two species competed, the dominant species became the main limiting factor for the weakest species, restricting its distribution to competition free areas. Finally, we characterized the ecosystem services provided by heathlands landscapes (heterogeneous mosaics of heathlands, grasslands and rocks). In particular, we analysed how social changes undergone since the second half of the twentieth century (1950s-2010s) modified both the heathland landscape patterns and the stakeholders’ perception of ecosystem services provided by heathlands, at different institutional scales ranging from local to international. We defined the threats currently faced by heathlands and their services across multiple scales and discussed potential management measures. We observed that, in the last sixty years, the demand of provisioning services from heathland landscapes (at local and regional scales) has significantly declined in favour of cultural services, mainly demanded at national and international scales. Finally, we evaluated a practical case study regarding the interaction between ecosystem services (demand of grazing resources and suitability of habitat for breeding bird species). The results of this Thesis represent a significant improvement of our comprehensive ecological knowledge of the territory, and provide useful information for the implementation of management strategies in the Cantabrian Mountains.
- Apr 2011
Due to the high sensitivity of mountain landscapes to environmental changes, the study of land cover dynamics has become an essential tool for guiding management policies. Since the second half of the twentieth century, the Cantabrian Mountains (NW Spain) have been substantially altered by the loss of traditional management practices and, more recently, by the new environmental schemes developed by the Regional Government. This area is a biodiversity hotspot, representing the south-western-most distribution limit for a large number of species in Europe. Therefore, small changes in landscape patterns can result in biodiversity losses. In this study, we analyzed land cover changes in the Cantabrian Mountains from 1991 to 2004 by means of remote sensing techniques, identifying the main driving forces and classifying the territory according to its risk of land cover change. Forest expansion and loss of shrublands were the two major trajectories of change apparent during this period. When modeling the occurrence of these land cover changes, we found that performance of models was related to the nature of the change. The most accurate models were associated with processes of secondary succession, i.e. forest expansion (78.6%), while the least accurate models related to changes linked with management decisions, i.e. loss of shrubs (61.8%). The main drivers of change were variations in the number of goats (for the forest expansion model) and changes in the number of head of sheep and cattle (for the loss of shrubs model). Topographic conditions (altitude and slope) were relevant in both models. Our approach proposes an explicit decision support tool for landscape managers, allowing better identification of the areas where they should focus their attention.