THE USE OF ECOLOGICAL TOLERANCES FOR THE RECONSTRUCTION OF TERTIARY PALEOCLIMATES

The major vegetation types may be recognised from the pollen assemblag e being deposited beneath them, hence the palaeovegetation may be reco nstructed from fossil pollen assemblages. The climatic parameters of t he vegetation may then be used to reconstruct palaeoclimates. The resu lt, however, is very general. Most pollen types can only be affiliated with a family, a genus or a group of species and the ecological toler ances within these groups may not be uniform. There are, however, some distinctive pollen types that can be identified with a single living species and this paper examines the potential of these types in the re construction of palaeoclimates. Lagarostrobos franklinii (J.D.Hook) Qu inn, Huon pine, has a long history and the fossil occurrences of it ar e compatible with the hypothesis that its ecological tolerances have n ot changed and it has always required very high humidity. Two scleroph yllous taxa, Eucalyptus spathulata Hook. and Dodonaea triquetra Wendl. , however, coexisted with rainforest and then other vegetation types a s the climate became drier, adapting to the prevailing conditions. The evidence suggests that the salt-tolerant E. spathulata may have evolv ed in small patches of coastal scrub, subjected to marine influence, w ithin the dominant rainforest vegetation.