Key findings
- Not everything in the record was definitely there. For example, pine trees have highly mobile pollen and can sometimes be overrepresented in the pollen record.
- Not everything absent from the pollen record was absent on the ground. For example, insect-pollinated plants are often absent, or under-represented in the pollen record.
- The most important data you can collect is direct observation.
Evidence in the Dartmoor pollen record
It was amazing how many little nuances I bumped into when I was reading the research papers. For example, one of the first reports from the 1960s identified pollen from pine trees in the very earliest part of the record. We all assumed that meant there were actually pine trees here. One of the scientists from the original study, Ian Simmons, revisited the same location in the 1980s, but his conclusion the second time around, was that the pine tree pollen blew in from the lowlands. Apparently, pine tree pollen can get blown long distances and because it was only a very small percentage of the total pollen, it's more likely there weren't actually pine trees at the site, in the uplands of Dartmoor. Huh.
So the pollen record is an account of what happened right there in that little sliver of land, but it's more nuanced than that. For example, the record might not capture pollen from insect-pollinated plants whose pollen is mostly limited to transported by insects. Seems obvious, but if you don't know about this, it would be easy to think the insect pollinated plants hadn't been part of the landscape. But on the other hand, the pollen record sometimes captures information about plants that aren't right there, as in the case of our pine tree friends.
Getting outside and going for a walk, on the other hand, tells you what's here right now. There is nothing more accurate than boots on the ground, eyes on the trees. By walking a regular route, you'll come to know what's "normal" for your area. For example, I've never seen an oak apple gall on Dartmoor. I've seen marble galls, knopper galls, spangle galls, cherry galls, and oyster galls. (Yup, these are galls that can be found on just on oak trees!) I've seen oak apple galls elsewhere in Devon, just not on the high moor. Strange.
The gap between what the pollen record predicts, and what you'll find on the ground is juicy! I always want science to be smarter, more perfect, more verified, more, well, better than what I can manage from simple observation. That puts a lot of pressure on science to get things right! Hopefully, though, you've seen over the last couple of days that even science isn't static. Scientists are learning, too. To get a better picture of the whole, we need to combine our own experience, with the best, most up-to-date research from scientists. We need to recognise the observations we're able to make, and the limitations of science in deciphering the past. Both will improve and become more refined over time.
Keep looking, and watching, and reading, and learning!