Documentary data To get a more convincing assessment of a statement such as a regular occurrence of Frost Fairs on the River Thames we need sources that include records of frost dates, droughts, famine, the freezing of lakes, ponds and rivers, duration of snow and sea ice cover, and the dates of flowering of plants.Combined, these historical records can provide insight into past climate conditions.That's too general of a fact to be helpful in explaining our specific predicament.We want to know why the evidence seems to suggest that beetles returned to a glacial area sooner than pollen from plants did.By assembling a data matrix of pollen morphological characters from extant and fossil Myrtaceae, we were able to measure the fit of 26 pollen fossils to a molecular phylogenetic tree using parsimony optimisation of characters.We identified eight fossils as appropriate for calibration based on the most parsimonious placements of these fossils on the tree.B) suggests that once warm weather returns to an area, beetles will establish themselves sooner than plants (this fits both halves of our surprising data)C) suggests something very similar to (B), that beetles can return to a barren postglacial area sooner than plants can.
The warm-weather ones showed up later, with the warm-weather plant pollen, once the glacier had left.
A collage of several fossil pollen grains, spores, and algal cysts from the Hell Creek formation, viewed using scanning electron microscopy.
A scale bar is included in the lower right hand corner.
Documentary evidence is, however, generally limited to regions with long literary traditions, such as Britain and parts of Europe, China, and to a lesser extent North America.
In addition ship’s logs from Spanish, Dutch and English ships crossing the World’s oceans from the 16th through 20th centuries provide new insights into weather patterns and how these change over time (see CLIWOC project and podcast interview with Dennis Wheeler).