Adaptation of mountain regions to drought recurrence in a context of global change Sandra LAVOREL Pénélope Lamarque, LECA Benoît Courbaud, Laurent Dobremez, Baptiste Nettier, François Véron, Irstea, Grenoble Recent climatic trends in the Central French Alps The case of Vercors Precipitation T min T max Sylvain Bigot, Sandra Rome Jean-Paul Laurent Pierre-Eymard Biron Perception by farmers and shepherds of consequences of droughts since 2003 • • • • Signs of climate change - “Fewer storms in summer" Decrease in pastoral resources Decrease in water availability for summering herds Vegetation dynamics – “Invasions” by undersirable species, superficial soil degradation Adaptations at farm scale – Pastoral systems have integrated the hypothesis of increasingly frequent droughts into their fucntioning – BUT: tactic responses without long-term adaptation – Impacts and adaptation options differ widely across farming systems (level of reliance on winter fodder) – Given a scenario of increasing drought recurrence, only strong system transformations would allow persistance of livestock systems – Drought is only one risk among others for livestock systems: socio-économic context, structural constraints Nettier et al., Journal of Alpine Research 2010 Perception by foresters of consequences of droughts since 2003 2003 2004-5 • 2003: strong defoliation on drier / thinner soils, but not in productive stands; good recovery with only limited mortality • Beetle damage on sprice in 2004-5 • Foresters are aware of climate change and the risk of recurring droughts, but are yet to see climate change effects • Adaptation responses are limited: – Manage stands towards species and structural diversity – Reduce the share of spruce in regional plans – Infrastructure for increased fire risk – Inconclusive attemps to plant more southern species (frost) – No consideration of the forest – grassland interface A high uncertainty on expected climate trends Mean max summer T Number of days of heat wave Mean annual precipitation Length of drought SECALP project Objective: To analyse adaptation mechanisms for mountain regions in the face of climate change, especially recurring droughts – Mechanisms of ecosystem resilience and transformation – Processes of adaptation for livestock farming and forestry – Expected effects of climate change scenarios, in the context of social transformations Guidelines for supporting managers through policy and infrastructure Strategies for long term observation SECALP: An integrated conceptual framework Ecosystem adaptation Land use adaptation Scenarios and pathways to sustainable management Long-term observation system The Central French Alps LTSER Transdisciplinary network 40 scientists, 25 PhD & postdocs 1 national & 1 regional park Vercors high plateaux Villar d’Arène Queige 5 15 10 25 15 Lanslebourg 0 0 5 Mortality rate 35 Are there discernable effects of drought years on tree mortality? 1940 1960 1980 2000 mortality rate CI 1920 1940 1960 1980 2000 1940 1960 1980 2000 Méaudre 0.0 1 0.5 2 1.0 3 Engins 1900 1.5 1920 0 Mortality rate 4 1900 1900 1920 1940 1960 1980 2000 1900 1920 • Overall low mortality rates and no long term trend • Links to climate variables: – Strongly predominant effects of storms (yr n or n-1) – No effect of the Palmer Drought Severity Index (Climatic Research Unit, Norwich) – 2nd order effect of increased precipitation Seignobosc et al. in prep. Experimental simulation of the combined effects of drought and management - 80% reduction in summer precipitation + 1 C night time warming - One extreme event: one month of total drought + 6 C warming - Mowing (0/1) – split plot design within the climate manipulation Complex interactions and surprises ? Measurements over 3 years • Plant level: leaf senescence, photosynthetic stress, growth, leaf traits • Community structure: species diversity & composition • Ecosystem functioning: standing biomass, litter depth & decomposition Slow climate effects vs. rapid management effects CLIMATE CHANGE Limited impacts of climate manipulation on plantand community-level parameters # plant functions leaf senescence plant development # litter decomposition Longer term effects? MOWING Importance of competition Dominance by F. paniculata competition intensity above-ground biomass litter production changes in composition species diversity From field data to projections of ecosystem services Step 1 Environmental drivers Step 2 Response and effects traits Step 3 Ecosystem properties Step 4 Ecosystem services Plant Microbial NNI= LUT+ β1*Altitude VegHt = LUT+ β1*N Green biomass = β0 + β1 *NNI + β2 *VgHt – β3 *LDMC Stakeholders’ perceptions Lavorel, Grigulis, Lamarque et al (2011), J Ecol PLANT TRAITS (CWM and FD) Vegetative height LDMC, SLA LNC, LCC, C/N MICROBIAL TRAITS NEA : Km, Vmax AOB, AOA, Ns, nrxA DEA, nirS, nirK, Fungi:Bacteria REML ECOSYSTEM PROPERTIES Green herbage mass Litter mass Litter decomposition Microbial biomass N Potential Leached NO3 and NH4 N Mineralization Potential (NMP) Ecosystem services Linear mixed model with restricted maximum likelihood estimations Relative contributions of plant and microbial traits to a range of above- and belowground processes under complex field conditions with diverse plant communities Direct and indirect abiotic effects on C and N stocks across the landscape Altitude RESPONSE - EFFECT TRAITS e NNI CWM_VgHt PNI CWM_LNC e Green biomass Litter e e ECOSYSTEM FUNCTION e 0 - 0.2 0.2 - 0.4 0.4 - 0.6 0.6 - 0.8 Positive - Negative C N Propagation of ABIOTIC effects to TRAITS and ECOSYSTEM FUNCTION ENVIRONMENT e Lavorel & Grigulis J. Ecol. 2012 A functional continuum from plant to microbial control of ecosystem functioning, associated with plant responses to grassland management intensity Exploitative PLANTS Bacterial Dominance MICROBIAL ABUNDANCES Fast Conservative Fungal Dominance MICROBIAL PROCESSES Slow Microbial control Plant control Biomass Production Carbon sequestration Nutrient retention Lavorel & Grigulis J.Ecol. 2012; Grigulis et al. J. Ecol. in press Modelling framework for climate and management impacts on ecosystem services Plant and microbial functional traits VgHeight Ecosystem properties Ecosystem services Biomass Fodder quantity Fodder N concentration Fodder quality Soil fertility Leaf P Potential N mineralization Nitrif Vmax Nitrate retention Water quality Leaf N Leaf DM Denit DEA Abiotic parameters Soil organic matter Carbon sequestration Flowering date Pollination Litter mass Esthaetic value Plant diversity Plant diversity conservation WHC Sol NO3 Altitude Lamarque et al., in prep. Participatory scenario development 1 3 Co-building of 4 highly detailed storylines with regional experts - 2 drought frequencies x 2 socio-economic contexts => storylines Biophysical model parameter changes - Field experiments and scientific experts 4 2 Co-building of land management adaptation maps with farmers Modelling of effects on ecosystem services of DIRECT climate effects and INDIRECT effects through farmers adaptation Lamarque et al., submitted – see presentation by Pénélope Lamarque Wed. 2:40 p.m. Model parameterisation for ecosystem service projections Plant and microbial functional traits VgHeight Ecosystem properties Ecosystem services Biomass Fodder quantity Fodder N concentration Fodder quality Soil fertility Leaf P Potential N mineralization Nitrif Vmax Nitrate retention Water quality Leaf N v Leaf DM Denit DEA Abiotic parameters Soil organic matter Carbon sequestration Flowering date Pollination Litter mass Esthaetic value Plant diversity Plant diversity conservation WHC Sol NO3 v Altitude Ecosystem services supply according to stakeholder criteria Ecosystem properties Green biomass Fodder crude protein content + Ecosystem services = Agronomic value Plant diversity = Pollination Mean flowering onset date Litter Mass + += Cultural value Lavorel, Grigulis, Lamarque et al. J. Ecol. 2011 Projected ecosystem services change Scenarios Intermittent international Current Land use Intermittent local Drastic international Carbon sequestration Soil fertility Drastic local Water quality Plant diversity Green biomass Litter mass Flowering onset Carbon sequestration Soil fertility Water quality Plant diversity Green biomass Forage quality Litter mass Flowering onset Under more drastic scenarios, shift from provisioning and cultural services of local interest to regulation services of larger scale interest Forage quality Lamarque et al., in prep. Implications • Current climate impacts are difficult to detect through observations or experiments, especially for forests • Greater concern within the pastoral than the forestry sector, but limited adaptation / adaptability for both • Basic understanding of ecological constraints : – Guidelines for policy and management for the maintenance of multifunctional landscapes and of local livelihoods – Payments for non-marketed ecosystem services or subsidies – Need to take into account trade-offs between ES • Enhance adaptation and sustainable delivery of ES – An integrated observation system of (i) climate and extreme weather events, (ii) management systems and practices, and (iii) ecosystems – Training material tailored for managers and extension officers