Leaf area index and precipitation estimates from present and past communities of large herbivorous mammals

To reconstruct past environments, it is necessary to be able to quantify environmental variables, like temperature and precipitation. There is also a growing need to provide numerical estimates of environmental variables for climate and ecosystem models. One of the key environmental variables used in modeling is Leaf Area Index (LAI). It is used for calculating evapotranspiration, precipitation, albedo and carbon exchange in the models.a
It is also routinely used for estimating other vegetation traits that are not taxon- or biome-specific (e.g. Plant Functional Types). Models typically use data from present-day biomes or ecosystem types to subscribe many of these variables. For modeling the pre-Quaternary past or the future, this is not possible. Here we show that it is possible to use the dental characteristics of large herbivorous mammals, readily available from the fossil data, to estimate Leaf Area Index and precipitation values for the Neogene. By using LAI of the lowest quarter of the year and annual average LAI we can quantify and track the increase of seasonality during the Late Miocene in space and time.