You should look for species specific biomarkers and/or c isotopic signatures for their distribution with respect to space and time in the context of past changes in climate.
I guess most of the studies done from the perspective to understand species response in past in India is based upon carbon isotopic signature. The problem is that has been done too on the tree-ring forming plant species. If I have to investigate the response of oak (i.e. tree ring formation absent) let's take 50 years back I don't know how to do that. Distribution in space and time may not be solely individual response but it is certainly modulated by the species interactions (competition for resources, facilitation etc.) within the community.