Projects

MICROCLIM A micro-scale perspective on alpine floras under climate change

2020-2026, ERC Advanced Grant (P.I.: Stefan Dullinger)

The diversity of organisms, one of the most striking features of life on Earth, is under threat, and climate change may become a major driver of the biodiversity crisis in the decades to come. However, climate effects on species will vary across ecosystems and regions. The fate of the rich and peculiar alpine flora in a warming world is particularly contentious. While some researchers expect massive loss of cold-adapted plants because they have few options to escape the heat (‘mountaintop extinction’), others assume low sensitivity of high-mountain floras due to widespread microclimatic refugia in the topographically complex alpine terrain. MICROCLIM aims to assess the evidence for these contradictory expectations by linking so far separated research strands of monitoring and predictive modelling of alpine plant distribution. In particular first, MICROCLIM provides a comprehensive evaluation of standard modelling approaches by comparing their predictions with Europe-wide monitoring of mountain top floras and analyse the role of spatial scale for possible mismatches between models and observations of change. Second, it includes the development of a novel modelling framework that simulates the simultaneous range dynamics of many interacting species. The model is parameterised by means of experiments and observational data and evaluated against monitoring data on an exemplary mountain. It will be then applied to simulate the dynamics of the flora of this mountain over the 21st century at a very fine spatial resolution to evaluate the proposed rescue effect of microclimatic variation in alpine terrain. The results achieved will be generalized in these dynamic simulations to all summits included in the European mountaintop monitoring network. The results of MICROCLIM will help understand how threatened the unique alpine flora of Europe actually improve our understanding of the future of European high mountain plants. Field Pictures

GLORIA GLobal Observation Research Initiative in Alpine environments

1994-Present, Austrian Academy of Sciences (IGF) & University of Natural Resources and Life Sciences Vienna (P.I: Harald pauli)

Global climate warming will affect all ecosystems on the planet. High mountain biota, however, are particularly sensitive to warming because they are determined by low-temperature conditions. Accelerating climate change can lead to a decline of cold-adapted species and thus to drastic biodiversity losses. GLORIA aims to establish and maintain a worldwide network of long-term observation sites in alpine environments. It will act as a warning system to detect and assess critical changes in the species composition and habitat stability. Monitoring data are a crucial requirement for making reliable predictions about future impacts on alpine ecosystems worldwide. Field Pictures

TRAPA Multitrophic functional integration of C sequestration in High Arctic Soils

2017-2019, Czech Science Foundation Fellow (P.I.: P. Macek, M. Devetter & F. de Bello)

Ongoing global changes challenge the carbon (C) sink status of Arctic soils and loops of positive feedback are seriously feared. A switch from C sink to source would cascade from the response of Arctic terrestrial ecosystems to global changes and warming in particular. To assess the sustainability and sensitivity of Arctic soils' C sequestration service, TRAPA  investigates the links among plants, soil invertebrate and microbial communities, and the C biogeochemical cycle in high Arctic terrestrial habitats. The project combines samplings along environmental gradients to investigate the variability of functional relationships, field and lab experiments testing the contribution of the communities to soil organic matter (SOM) transformation, and a modelling approach to outline the multitrophic web of interactions underlying Arctic soil sequestration. In the field, the project illustrates the breakthrough in functional ecology where a multidisciplinary approach truly integrates the holistic aspect of the ecosystem. The correlations among functional divergences and variations of the communities associated with a change in the C cycle characterize the complexity of the network and the strength of the functional relationships. Manipulative experiments investigate threshold dynamics and keystone structure of the ecosystem. I managed the fieldwork, the processing of the samples and the standardization of the data among the teams and eventually, I am in charge for the modelling approach to translate the conceptual framework of multi-diversity to a quantitative assessment of the ecosystem functional structure . Field pictures

DeVeSh Decadal time-scale vegetation shifts at high latitudes: causes and consequences

2012-2016, Academy of Finland fellow (P.I.: R. Virtanen)

High-latitudes ecosystems are facing strong and rapid climate and land-use changes inducing contrasting responses in plant community composition and functioning. In such slow-growing system, long-term approaches, both experimental and observational, are susceptible to improve our understanding of the causes and consequences of the ongoing vegetation dynamic. The present project combines analyses of long-term experiments in arctic tundra and regional resampling in northern Scandinavia to address at diverse spatial scales the relative modulating role of the main biotic and abiotic drivers of plant communities. In the surroundings of Kilpisjärvi, northern Finland, several experiments were set up since the end of the 80’s and maintained through the time until nowadays. They test the roles of browsing and grazing disturbances, nutrient and soil water content and environmental perturbation for the composition and dynamics of shrub and dwarf-shrub dominated tundra communities. The effects of decadal treatments are analyzed to produce new knowledge on the interdependence between biotic and abiotic factors in a long-term perspective. In parallel, old vegetation analyses (sampled from 20 to 100 years) from the northern Finland are collected, geographically positioned and resampled to quantify the shifts in vegetation at a larger scale. Vegetation changes will be compared to environmental, climate and land-use data to identify the main correlations. Finally, the project includes a meta-analyses approach to compare results from the project data sets to those from collaborators in the Scandinavian area.  My main involvement in the project concerns the analyses of data set from the long-term experiments.     Field pictures

 PHENOALP Toward a monitoring protocol of alpine plant phenology.

2009-2012, European Interreg project (P.I.: U. Morra di Cella, E. Cremonese & A. Delestrade)

PhenoAlp is a EU co-funded project aiming to get a better understanding of phenological changes in the Alps. Concerning plants, the main goal is to define the better phonological indicator in the field data set.After two growing seasons, my work consisted in the preliminary analyses of data and in the correction of the grassland protocol iregarding to the field difficulties met. As a result we wrote a simplified protocol for the field managers.   

VERTICAL ECOLOGY (ECOVER) Structuration of communities associated to cushion plants of high mountain.

2008-2011, LECA transversal fellow (P.I.: C. Albert, S. Ibanez, S. Lavergne & P. Saccone)

We developed a multi-approach project at the intersection of community ecology, phylogeny and microbial ecology to explore the structure of a community associated to cushion plants of high mountain cliffs. Because they are strongly isolated at small scales such as natural mesocosms, and because they occupy the end of environmental constraints gradients, these communities constitute a unique study model. The first results highlight the variable modulating role of cushion plants on the establishment of fungal and bacterial communities (Roy et al. 2013) and the genotypic extension of cushion plants on fungal communities (Roy et al. 2018) . I was one of the initiators of the project, I developed the sampling design, led the research and co-authored the publications.        Field pictures, TV report (in French), and project’s page on the Parc National des Ecrins’ web site         

NEVE Snow, plant litter and soil micro-organisms relationships.

2008-2009, LECA, LGGE, LEM collaborative project (P.I.: J.C. Clement, F. Domine, S. Morin & P. Saccone)

In cold ecosystems, winter activities represent an important part of total ecosystem functioning and the effects of climate changes on snow cover brought up some questions. However, subnivean processes structuring the ecosystem remain poorly known. It is the case, for example, for the litter decomposition in subalpine meadows for which agricultural practices also affect litter material. We developed a simple litter bag experiment to monitor all over the winter the effect of the snowpack and litter quality on the plant litter decomposition process. The results underline the importance of spatial and temporal persistence of the snowpack for decomposition on the top of simple snow depth (Saccone et al. 2013b). Moreover, higher microbial activity under thinner snowpack indicated a counterintuitive negative effect of snowpack insulation on soil microbiota (Jusselme et al. 2016). As co-initiator of the project, I developed the experimental design, I managed the field works, analysed the data and co-authored the publications.      Field pictures

VALIDATE Response of subalpine meadows to simulated climate and land-use changes.

2007-2010, ANR project (P.I.: J.F Soussana & S. Lavorel)

The project aimed at evaluating for France the vulnerability of grasslands and livestock to climate change and extreme events, combining ecosystem manipulation experiments and modelling at scales ranging from the plot, to the field and to the region. High-resolution climatic model was used to predict future rainfall and temperature site-specific scenario. The simulation of climate changes included roller blinds to intercept natural rainfall (precipitation is controlled by a watering system) and night time soil infra-red emission (simulating a global warming to +1°C) and infra-red ceramics heating plant canopy to + 6°C and simulating a heatwave event. The complete design crosses land-use (mown and unmown) and climate treatments. Plant responses to treatments were measured by physiological and morphological traits. We observed a subalpine community rather resistant to climate changes compared to the effect of land use change (Benot et al. 2014), but also how extreme climatic event can alleviate the vulnerability of dominant species to mowing (Benot et al. 2013). As postdoc on the project, I designed and installed the microclimate instrumentation, managed the whole experiment on the Lautaret Pass site, supervised the master students, participated to the analyses of the data and co-authored the publications.      Field pictures, and TV report (in french, from 19' 20")

BIOCATCH Alpine Biodiversity and Catchment value in a land use context

2007-2012, International volunteer collaboration (P.I.: J.C. Clément, C. Körner, S. Lavorel, E. Tasser & U. Tappeiner).

The project aims at documenting the significance of biodiversity and land-use for the hydrological catchment value. The experimental design is based on mesocosms ( Soil + Plant) from several agricultural practices transplanted in lysimeters allowing to collect deep seepage water for chemical analyses. Data from sites in the Western, Central and Eastern Alps will be complemented by data from the Southern Alps and the Central Caucasus through our associated partners. My contribution to this project consisted in the management of the French field site during one year and in the set-up of the rain simulator. I also participated to the analyses of the data and to the writing of the papers and supervised some students in the field.       Field pictures

GUISANE 2080 Experimental test of climate and biotic interactions effects on tree seedlings recruitment in alpine meadows.

2006-2009, (P.I.: W. Thuiller)

Current global warming induces changes in species distributions. Predictions of future distributions were mainly based on global climatic models and species average responses. In contrasted temperature and sun radiation meadows of the Guisane valley, we sowed seeds and transplanted one-year-old seedlings of Larix decidua and Pinus unicinata, with and without herbaceous neighbours. This designs allowed us to explore i) the variability of the specific response traits to environmental conditions ii) The local filter effect of biotic interactions for the specific response to global warming. We expect the results to improve predictive models relevance. I designed and setup the field experimentation.           Field pictures

CONTRACER Acer negundo invasiveness vs. Middle Rhone floodplain communities’ resistance

2005-2007, Local council fellow -CG38 Biodiv- (P.I.: J.J. Brun & P. Saccone)

In the context of biological invasion, the management of floodplain communities represents a crucial tool for biodiversity conservation. To help managers, we performed an observational study to evaluate the risk of the spread of the invasive Acer negundo along the Rhone River riparian forests. The project completed the experimental approach developed for INVABIO and was part of my PhD. I developed the proposal, led the research and supervised the master student recruited on the project.

INVABIO Floodplain functional composition, disturbance regimes and Acer negundo invasion

2004-2007, French Environment Ministry (P.I.: R. Michalet, E. Tabbacchi, J.J. Brun & P. Saccone)

Acer negundo, a North-American maple introduced in Europe, has invaded the lower and middle parts of the Garonne and Rhone rivers. The invasive species occurs in the successional dynamic at the ecotone between pioneer willows and mature ash communities. The project focused on the local processes shaping the invasive process on both river floodplains combining field and common garden designs. The main question was to assess to what extent the invasion of the lower parts of the rivers could be imputable to a particular functional composition of the recipient community in regards to the competitive effects or the disturbance tolerance of the invader. Rhone results did not show any obvious colonisation towards the upper part of the valleys (Saccone et al 2013a). Overall community richness was not negatively affected by the alien. The success of the alien was due to both a strong morphological plasticity in full resource conditions and a high shade-tolerance (Saccone et al 2010b). Its ability to tolerate both shade and disturbance allows the species to arrive in advance to ash species below the canopy of willows where it is facilitated. Later on, A. negundo outcompetes the willows and facilitates itself (Saccone et al. 2010a). The alien remains in the succession in the lower and middle parts of the rivers together with F. angustifolia which exhibited a similar competitive ability. This project was a part of my PhD. I participated in the selection of study site and I designed and set up the field experimentation. I was in charge of the Rhone field designs, I designed and managed the field experiments, collected, analysed and published the data.             Field pictures

 PhD in forest ecology Role of plant-plant interactions and place of exploitative competitor species in forest dynamics under global changes: a mountain and a riparian case

2002-2007, Cemagref Grenoble. Supervised by J.J. Brun and R. Michalet (Bordeaux I University)

Most of abiotic and biotic factors structuring plant communities have been identified, but their relative importance and their potential joint effects remain unclear (Brooker et al. 2008) as are their role in the plant response to global changes.

This study focused on the role of plant-plant interactions and plant strategies as structuring factors of temperate forest communities. The study sites were a post-cultural mountain forest dominated by Acer pseudoplatanus et Fraxinus excelsior in the Northern French Alps (field pictures) and a riparian forested system in the Rhone River floodplain under Acer negundo invasive pressure. A first descriptive approach allowed us to highlight the importance of these mid-successional species within the studied forested landscapes. Through experimental designs, we have compared the seedling responses of these trees to those of other dominant or potentially dominant trees. Our results showed that these species have developed an exploitative competitor strategy associating strong competitive abilities to high resource acquisition abilities. In the mountain system, A. pseudoplatanus and F. excelsior did not have better performances than the late-successional species tested which reject the hypothesis of a succession locking. In the riparian system, the exploitative competitor strategy of A. negundo was an invasive advantage in the downstream section of the system while the biotic resistance occurring in the upstream section limits its propagation. Moreover, our results highlighted the major role of biotic interactions in the responses of plant communities to global changes. A. negundo performances were facilitated in the downstream section of the riparian system by the direct or indirect effects of the tree canopy (Saccone et al. 2010a) while they were reduced in the upstream section by the neighborhood of trees and herbs (Saccone et al 2013a). In the mountain system, the trees canopy of the mesoxeric sites increased the negative impacts of 2003 European heatwave on A. pseudoplatanus and P. abies seedlings while the trees canopy of mesohygric sites have buffered these impacts on the survival of A. alba seedlings (Saccone et al. 2009). Finally, our results revealed the memory of target individuals in their responses to biotic interactions. The PhD included the management of the Rhone River part of the INVABIO project and the CONTRACER project (see above) Field pictures from the mountain forest, and the short report for users.

BIOSOL Human and Climate effects on the terrestrial biodiversity of French Subantarctic Islands

1999-2001, French Polar Instute (IPEV, P.I: Y. Frenot)

BIOSOL is a long-term program of the French Polar Institute monitoring the terrestrial biodiversity on the French Subantarctic Islands (Kerguelen, Crozet, St-Paul and Amsterdam). I have been recruited as a research assistant under the National Service program to over winter on Kerguelen from Dec. 1999 to April 2001. I was in charge of maintaining and collecting insect trap designs, monitoring introduced plant populations, completing bi-annual survey of primary succession on glacier valley, sorting insect samples and coordinating extra temporary experiments. I also analysed the long-term population dynamics of the introduced blow fly, Calliphora vicina, highlighting the synergetic effect of global changes where Global warming allowed the establishment and invasion of the introduced species on the islands.