Sprecher
Beschreibung
Pollen is the most common terrestrial fossil with extensive use in paleoenvironmental and palaeoecological studies. Given that pollen from anemophilous taxa can be transported considerable distances there is a need to assess how well the niche of taxa can be modelled using pollen distribution data. The aim of this study is to test whether pollen records can be used in niche models to predict tree ranges using climate variables and elevation data. Which can then be applied to our understanding of using fossil pollen records to model the potential distribution of taxa in the past. Here we examine whether maximum entropy (MaxEnt) modelling can be used to predict comparable niche estimates using modern pollen distribution data and known species distribution records. Eight conifer genera were selected: Cathaya, Cryptomeria, Cunninghamia, Keteleeria, Pseudotsuga, Sciadopitys, Sequoia and Tsuga. Based on the measure of overlap between the modelled ranges using the different distribution records, the models show high comparability for Pseudotsuga, Sequoia and Tsuga, some comparability for Cathaya and Keteleeria and no comparability for Cryptomeria, Cunninghamia and Sciadopitys. Differences in comparability between the models runs using pollen distribution and genus distribution records are present and likely driven by pollen dispersal mechanisms and deforestation. The results of this study indicate that caution must be taken when interpreting the most likely niche space (MLNS) predicted using fossil pollen distributions due to differences in pollen dispersal and levels of deforestation.