This is a task of the LECA – Laboratoire d’écologie alpine.

WP3 will apply a dynamic vegetation model across the European mountain regions at 100m resolution. In the highly variable terrain of mountains, biodiversity-climate feedbacks are more complex, as high terrain heterogeneity leads to complex terrain-climate interactions. We will extend the dynamic landscape vegetation model FATE-HD developed at LECA with input from WP4 & WP5. FATE-HD7 simulates interactions between species or plant functional groups, the dynamics of cohorts, and dispersal, and considers disturbance regimes (e.g. fire, mowing or grazing) and environmental variation. In- and excluding these processes in the overall feedback loop (Fig. 1) will allow us to better understand their respective influence on the biodiversity-climate feedback. The processes that can be investigated in detail using the FATE-HD model are as follows.

1. Plant functional group classification: to reduce the dimensionality of the simulations, we will first build functionally consistent and climatically classified PFGs using species data occurring in the Alps and their functional traits24.
2. Succession: FATE-HD implements both interaction for light and for soil resources that directly impact germination, survival and mortality.
3. Habitat suitability: The suitability of the pixel of each defined PFG will be modelled using species distribution modelling methods calibrated using the data from WP4 and WP5.
4. Dispersal: FATE-HD uses a system similar to continuous kernel function but requires only a few parameters.
5. Disturbances: Several disturbance models will be parameterized to remove vegetation, affect fecundity, kill seeds or activate dormant seeds. As high thematic complexity (many PFTs, dispersal, etc.) prevents this model from being run across Europe, but can represent the vegetation dynamics in complex terrain with more detail than e,g, LPJ-GUESS (WP2).

Tasks

1. Optimisation of FATE-HD for the European Mountain ranges: We will extend FATE-HD regarding computing efficiency to allow running it over the European Mountain ranges at 100m resolution for about 50 PFGs. We will use the vegetation plot data from WP4 and traits (e.g. light response, seed mass, longevity) from WP5 to build the PFGs following our optimized protocol24. Climatic layers will be provided by WP1. Particular attention will be paid to gather relevant climatic variables such as snow cover and length of the vegetation period for realistic vegetation dynamics simulation. Data on land use, especially mowing for grazing will be gathered from local sources and satellite imageries.
2. Simulation of vegetation dynamics across the entire European Mountain ranges: We will simulate the dynamics of PFGs across the European Mountain ranges under past and current conditions until we reach an equilibrium state. The equilibrium state will be validated against remotely-sensed databases such as Sentinel-2A. Once validated or/and fine-tuned, we will simulate future plant dynamics, yearly, across the next century, using the climate change scenarios provided in downscaled form by WP1.
3. Disentangling the drivers of vegetation dynamics and providing scenarios for climate-biodiversity feedbacks: The simulations as in T3.2 are run, but some of the processes and influencing biodiversity-climate feedbacks are switching off/on. We will specifically investigate combination relevant for co-existence theory:
   1. neutral simulations, where only dispersal will be integrated (no effect of interactions);
   2. habitat filtering, where only habitat suitability will drive the whole dynamics;
   3. competition tradeoffs, where only interactions for light or soil resources will be switched on.
4. The different simulation experiments will be evaluated using the same protocols as for T3.2 and outcomes will be given to WP1 for processing for WP6.

Milestones

1. FATE-HD optimized to run across the entire European Mountain ranges;
2. Plant functional group classification completed for the European Mountain ranges;
3. Pilot runs of vegetation dynamics across the European Mountain ranges and validation of simulation dynamics;
4. Model experiments completed for input in WP1 & WP6.

Deliverables

1. Paper on vegetation dynamics simulations under current conditions;
2. Paper on vegetation dynamics simulations under future conditions;
3. Paper on vegetation dynamics under various scenarios of assembly rules.

Cover image: Marco Meyer, Unsplash.