Reconstruction of the abiotic characteristics of past biomes: An example from the last glacial-interglacial cycle in France

The abiotic conditions (soil properties, water balance) associated with ter restrial biomes in France during the last climatic cycle have been quantifi ed using an indirect method. A set of potential modern climatic analogues a cross the world was first selected for each biome type. The edaphic feature s corresponding to the chosen analogue vegetation were then taken from a gl obal soil database and attributed to the biomes. Finally, the hydrological parameters were simulated for these analogues using a vegetation model. Rie have identified five groups of modern analogues with tither higher latitud es or higher elevations than the average present environment of France. Fro m these five groups of analogues, the first two represent boreal forest, tw o others are steppic, and the last one represents tundra. The first group o f analogues represents boreal forests at high latitudes (averaged latitude: 61 degrees N, average elevation: 300 m) with mainly sandy podzolized soils and intermittent permafrost, high precipitation and rapid drainage. The se cond group of analogues represents boreal forests at higher elevations and lower latitudes (44 degrees N, 2100 m) with stony soil and lower precipitat ion as well as poorer drainage. The first group of steppes at low elevation s and high latitudes (64 degrees N, 500 m) is characterized by cambisol or gleysol soils. The second group of steppes at high elevations and relativel y low latitudes (41 degrees N, 2900 m) has a hydrological regime with high evapotranspiration and poor drainage that is compatible with presence of xe rosols and yermosols. The tundra group (57 degrees N, 1400 m) has lithosoli c, cambisolic and gleysolic soils, The approach used here can be applied on a global scale and could provide useful boundary conditions for simulating past climate with general circulation models.