A Match Made in Heaven: Pollen and Plant Macrofossils

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The importance of recognising the weaknesses and limitations of using pollen analysis as the only tool in a research investigation was highlighted in my previous post. I’m sure most of you are familiar with these, but here’s a quick reminder:

• Incomplete or differential preservation of pollen grains can influence data
• Low taxonomic resolution and or damage to pollen grains can make identification difficult
• Differential pollen production and dispersal rates can influence the pollen found at a particular site
• Defining the pollen source area can be problematic, leading to the issue of long-distance dispersal affecting data sets
• Pollen percentage diagrams can give inaccurate representations of changes in vegetation as all plant taxa are constrained to 100%

Birks and Birks (2000), therefore, highlight the importance of combining pollen and plant macrofossil data in future palaecological studies. They note that plant macrofossils can significantly add to the information from pollen analysis in treeless situations, macrofossils can usually be identified with higher taxonomic resolution than pollen grains (probably because they are usually much larger!), and they tend not to be transported great distances from their source, giving a much more accurate representation of past vegetation at a given site. Plant macrofossils are also ideally suited to AMS 14C dating which can help overcome some of the issues with pollen sample sizes. As Scourse (2010) noted, the studies that rely solely on pollen data to put forward the case for the cryptic Northern refugia hypothesis would have much more clout if they could incorporate some plant macrofossil data!