A Step Forward in Geology and Beetle Data
Beetles as Past Paleoenvironmental Indicators
Aug 24, 2009
Beetles are an abundant, diverse group of species. Their hard chitinous shells are virtually insoluble in most fluids, including acids, so they preserve well. Geologists have been able to ascertain that beetles found in the geologic record were not only host-specific but moved around with the climate as it changed (Marra, 2002). They may not only be the key to the past but also the future.
Beetle Analysis
Geologists in the past have concentrated on pollen analysis in paleoclimatic research. Whilst this has given good data analysis, more recent analysis shows that beetle fossil information may be more consistent. Using beetle fossils as paleoenvironmental markers is relatively new, with data having been collected from various places around the world including Northern America and New Zealand.
Studies of fossil beetle data from New Zealand indicate climate conditions just after the Last Glacial Maximum (LGM) and the rate of temperature changes, 25-22ka (Marra, 2005). (The abbreviation "ka" means "thousands of years ago".)
Most species of fossil beetle taken from New Zealand's South Island are found today in similar climatic conditions to which they were 25ka but are now living in locations further north. Climate data from the area or original habitat for the beetles show temperatures were a few degrees warmer than where the beetles exist today, thus indicating the beetles followed the climate, probably because their food source had moved to similar climatic conditions. Plant and pollen fossils were found to be consistent with beetle fossils found in the same areas (Marra 2005).
Fossil data from North America have given better climatic reconstruction data than New Zealand data. This is mainly because modern beetle data has not been studied to any great extent i.e., there are big gaps in modern fauna knowledge and there is a predominance of phytophagus species thus, little information on dispersal of other species in New Zealand (Marra, 2005).
Future Reference
This type of information is important in today's environment for scientists trying to interpret and understand the rate of climate change earth is experiencing at present. Although changes in climate happen over thousands of years, geologically speaking, this is a relatively short period of time. As the earth warmed after and between periods of glaciation, paleoenvironments adapted with the changes, changing habitats and long established niches.
Although in the early stages of development, the study of beetles as climatic indicators could be even more important than originally expected. The scientific world could do with a breakthrough on modern day climate change and perhaps the humble beetle holds the clue.
References
Maureen J Marra (2005). Lecture notes - New Zealand examples - paleoclimate. Lecture held at University of Auckland, New Zealand.
Maureen J Marra., (2003). Late Interglacial beetle fauna from New Zealand. Quaternary Research Vol 59: p 122-131.
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