François Gillet

Modeling Social-Ecological Feedback Effects in the Implementation of Payments for Environmental Services in Pasture-Woodlands

An effective implementation of payment for environmental services (PES) must allow for complex interactions of coupled social-ecological systems. We present an integrative study of the pasture-woodland landscape of the Swiss Jura Mountains combining methods from natural and social sciences to explore feedback between vegetation dynamics on paddock level, farm-based decision making, and policy decisions on the national political level. Our modeling results show that concomitant climatic and socioeconomic changes advance the loss of open grassland in silvopastoral landscapes. This would, in the longer term, deteriorate the historical wooded pastures in the region, which fulfill important functions for biodiversity and are widely considered as landscapes that deserve protection. Payment for environmental services could counteract this development while respecting historical land-use and ecological boundary conditions. The assessed policy feedback process reveals that current policy processes may hinder the implementation of PES, even though a payment for the upkeep of wooded pasture would generally enjoy the backing of the relevant policy network. To effectively support the upkeep of the wooded pastures in the Jura, concomitant policy changes, such as market deregulation, must also be taken into account.

Sustainable Land Use in Mountain Regions Under Global Change: Synthesis Across Scales and Disciplines

Mountain regions provide essential ecosystem goods and services (EGS) for both mountain dwellers and people living outside these areas. Global change endangers the capacity of mountain ecosystems to provide key services. The Mountland project focused on three case study regions in the Swiss Alps and aimed to propose land-use practices and alternative policy solutions to ensure the provision of key EGS under climate and land-use changes. We summarized and synthesized the results of the project and provide insights into the ecological, socioeconomic, and political processes relevant for analyzing global change impacts on a European mountain region. In Mountland, an integrative approach was applied, combining methods from economics and the political and natural sciences to analyze ecosystem functioning from a holistic human-environment system perspective. In general, surveys, experiments, and model results revealed that climate and socioeconomic changes are likely to increase the vulnerability of the EGS analyzed. We regard the following key characteristics of coupled human-environment systems as central to our case study areas in mountain regions: thresholds, heterogeneity, trade-offs, and feedback. Our results suggest that the institutional framework should be strengthened in a way that better addresses these characteristics, allowing for (1) more integrative approaches, (2) a more network-oriented management and steering of political processes that integrate local stakeholders, and (3) enhanced capacity building to decrease the identified vulnerability as central elements in the policy process. Further, to maintain and support the future provision of EGS in mountain regions, policy making should also focus on project-oriented, cross-sectoral policies and spatial planning as a coordination instrument for land use in general.

Integrated synusial phytosociology: some notes on a new, multiscalar approach to vegetation analysis

The integrated synusial approach of the vegetation is based on the differentiation of several spatio-temporal organization levels. A phytocoenosis (community of the second level) is considered as a complex of synusiae (communities of the first level) and is characterised by a strong tendency to self organization. At each level, a typology of the communities can be performed. Ecological indicator values as well as different diversity indices are calculated for each vegetation unit. They are useful for understanding the spatial and temporal organization of the phytocoenoses. As an example, this approach is applied to wooded meadows.

Effect of cattle activities on gap colonization in mountain pastures

Cattle influences gap dynamics in pastures in two ways: (1) by creating gaps and (2) by affecting the colonization process. This effect of cattle activity on gap revegetation can be subdivided in three main factors: herbage removal, trampling and dung and urine deposition. The objective of this study was to assess how these three effects moderate the plant succession following gap creation.In an exclosure, four controlled treatments simulating cattle activity (repeated mowing, trampling, manuring and untreated control) were applied on plots of 2 × 2 m. In the centre of each plot, one artificial gap of 60 × 60 cm was created. During three years, vegetation changes were monitored in spring and in autumn, with a square grid of 100 cells of 0.01 m2 centred on the gap.Our experiment confirmed that fine-scale gap creation may have a high impact on relative abundances of species in the community. The gap environment acts on species as a filter and this filtering was described in terms of regenerative attributes. Colonizers were species with small seeds, unspecialized seed dispersal, persistent seed bank and high vegetation spread. However, the role of dung deposition, herbage removal or trampling by cattle did not seem to be of primary importance in the revegetation process, but could moderate vegetation response. Therefore, the different cattle effects act as secondary filters that selectively favoured or disadvantaged different species from the gap-regenerating community. These complex interactions are probably keys to understand plant coexistence in perennial grasslands.

The Swiss Mountain Wooded Pastures: Patterns and Processes

Influenced by the combined action of grazing and forest management, wooded pastures represent a traditional form of multiple use of natural resources in some European mountains. This fragile semi-natural ecosystem is characterized by the coexistence of high biodiversity and extensive land use. Based on experimental and observational studies carried out at various spatial scales in the Swiss Jura Mountains, this chapter provides an insight into patterns and processes occurring in this typical silvopastoral ecosystem. Summer grazing by cattle is the main driving force affecting vegetation dynamics. Large herbivores influence vegetation in three ways: grazing and browsing, dung and urine deposition and trampling. Field observations reveal a high heterogeneity of cattle activities at both fine and large scales. Cattle habitat use controls the dynamics of plant species and functional groups in the herb layer. Natural tree regeneration is also closely affected by cattle activity and related to the heterogeneous environment. Distribution of tree seedlings is spatially associated with specific physical structures or nurse plants that facilitate their survival in the herb and the shrub layers. Moreover, the growth of tree saplings is related to grazing intensity. Knowledge of ecological functioning of wooded pastures has allowed the development of a novel, spatially explicit, mosaic compartment model of the dynamics of silvopastoral ecosystems. This model is able to explain some aspects of the origin of vegetation heterogeneity in pasture-woodland landscapes. The conservation of such ecosystems is an important challenge considering its complexity and the present change in agricultural practices in mountain regions. A better integration of ecological and socio-economic processes into predictive multi-level models will permit the exploration of the conditions for sustainable management schemes compatible with biodiversity conservation.

Past and future landscape dynamics in pasture-woodlands of the Swiss Jura Mountains under climate change

Silvopastoral systems are traditional components of the landscape in the Swiss Jura Mountains, and are promising approaches for the sustainable management of mountain areas worldwide. Due to complex vegetation dynamics, pasture-woodlands are very vulnerable to the currently occurring land use and climate changes. Therefore, management requires integrative long-term predictions of successional trends. We present a refined version of the spatially explicit, dynamic simulation model WoodPaM with improved climate sensitivity of simulated vegetation. We investigate pasture-woodland dynamics by applying an innovative combination of retrospective simulations starting in the Middle Ages with prospective simulations following two climate change scenarios. The retrospective simulations demonstrate the strong dependency of the landscape mosaic on both climate and management. In high elevation mountain pastures, climate cooling during the Little Ice Age hindered simulated tree regeneration and reduced forage production of grasslands. Both led to an increase in open grassland and to a structural simplification of the landscape. In turn, climate warming afterwards showed the opposite effect. At lower elevations, high cattle stocking rates generally dominate simulated succession, leading to a slow development of quite homogenous landscapes whose structures are hardly affected by historical climate variability. Aerial photographs suggest that logging and windstorms critically shaped the current landscape, both homogenizing mosaic structures that emerge from selective grazing. Simulations of climate change scenarios suggest delayed but inevitable structural changes in the landscape mosaic and a temporary breakdown of the ecosystem service wood production. The population of currently dominating Norway spruce collapses due to simulated drought. Spruce is only slowly replaced either by beech under moderate warming or by Scots pine under extreme warming. In general, the shift in tree species dominance results in landscapes of less structural richness than today. In order to maintain the mosaic structure of pasture-woodlands, we recommend a future increase in cattle stocking on mountain pastures. The (re-) introduction of mixed herds (cattle with horses, sheep, and goats) could mitigate the simulated trend towards structural homogenization of the forest-grassland mosaic because diverse browsing effects selectively control tree regeneration and would counteract simulated forest encroachment. This could prevent the loss of species-rich open grasslands and forest-grassland ecotones. Forest management should respect forest-grassland mosaics and ecotones by following the traditional selective felling of single trees instead of large clear-cutting. Additionally, beech regeneration should be promoted from now on in order to smoothen tree species replacement with warming and to ensure the continuous provision of forest ecosystem services.

Soil microbial community changes in wooded mountain pastures due to simulated effects of cattle grazing

The effect of cattle activity on pastures can be subdivided into three categories of disturbances: herbage removal, dunging and trampling. The objective of this study was to assess separately or in combination the effect of these factors on the potential activities of soil microbial communities and to compare these effects with those of soil properties and plant composition or biomass. Controlled treatments simulating the three factors were applied in a fenced area including a light gradient (sunny and shady situation): (i) repeated mowing; (ii) trampling; (iii) fertilizing with a liquid mixture of dung and urine. In the third year of the experiment, community level physiological profiles (CLPP) (Biolog Ecoplates™) were measured for each plots. Furthermore soil chemical properties (pH, total organic carbon, total nitrogen and total phosphorus), plant species composition and plant biomass were also assessed. Despite differences in plant communities and soil properties, the metabolic potential of the microbial community in the sunny and in the shady situations were similar. Effects of treatments on microbial communities were more pronounced in the sunny than in the shady situation. In both cases, repeated mowing was the first factor retained for explaining functional variations. In contrast, fertilizing was not a significant factor. The vegetation explained a high proportion of variation of the microbial community descriptors in the sunny situation, while no significant variation appeared under shady condition. The three components of cattle activities influenced differently the soil microbial communities and this depended on the light conditions within the wooded pasture. Cattle activities may also change spatially at a fine scale and short-term and induce changes in the microbial community structure. Thus, the shifting mosaic that has been described for the vegetation of pastures may also apply for below-ground microbial communities.

Influence of tree cover on the diversity of herbaceous communities in subalpine wooded pastures

. The relationships between several diversity indices and tree cover in subalpine wooded pastures with Larix de-cidua were analysed at two spatial scales: phytocoenoses (2500-m2 plots) and herbaceous synusia (1-m2 quadrats). Diversity indices have a non-linear relationship to Larix cover; the best fit was obtained with Gaussian regressions. Species richness was influenced by Larix cover more than evenness. At the phytocoenosis level, the optimum for species and synusial richness in the herb layer was near 25 % tree cover. At the synusia level, species richness of the herb layer showed an optimum when mean distance to the four nearest Larix trees was ca. 30 m, or when the potential number of sunshine hours between April and September was close to 1250 h. Canonical Correspondence Analysis confirmed the influence of Larix cover on the composition of phytocoenoses and herbaceous synusiae, but included also the role of altitude, slope and aspect.

Human exposure to allergenic pollens: A comparison between urban and rural areas

BACKGROUND Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient. METHODS Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria. RESULTS Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas. CONCLUSIONS Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens.

PATUMOD: a compartment model of vegetation dynamics in wooded pastures

A system of wooded pasture can be described by seven biological state variables (trees, shrubs, underwood grasslands, fallows, eutrophic meadows, oligrotrophic lawns and cattle) linked by a network of dynamic interactions, which are controlled by altitude and human activities. PATUMOD is a spatially implicit compartment model designed to simulate vegetation dynamics in such silvopastoral ecosystems at community level and according to an equilibrium paradigm. Computer simulations show that the state variables generally end up on a steady-state (one-point attractor), independent on their initial values but strongly dependent on cattle load. At a given altitude, to each value of the stock density is corresponding a stable equilibrium characterised by a given relative cover of each vegetation component. If the initial values are very far of the attractor, a long succession of intermediate stages is required before leading to the steady-state. A remarkable exception to this rule can occur at low altitude, with a repellor between switching trajectories towards two attractors, corresponding to a threshold between scarcely and densely wooded pastures. PATUMOD can be applied to simulate different management scenarios, which include changing global stock density and cutting trees or shrubs.