A Brief Introduction to Paleoecology.

Duria Antiquior famous watercolor by the geologist Henry de la Beche based on fossils found by Mary Anning. From Wikimedia Commons.

Duria Antiquior famous watercolor by the geologist Henry de la Beche based on fossils found by Mary Anning. From Wikimedia Commons.

Paleocology is a multidisciplinary science. It involves the reconstruction of past environments from geological and fossil  evidence. A more exhaustive definition was given by Valentí Rull in 2010: “the branch of ecology that studies the past of ecological systems and their trends in time using fossils and other proxies”. Paleoecology can be used to investigate (1) the rates of speciation and extinction, (2) biome shifts and ecosystem development and (3) adaptation, migration, and population change (Seppä, 2009).

Charles Lyell (1797–1875) and Roman Fedorovich Gekker (1900-1991)

Charles Lyell (1797–1875) and Roman Fedorovich Gekker (1900-1991)

The major philosophical concepts in paleoecology are uniformitarianism, analogy, and parsimony. The concept of uniformitarianism was created by James Hutton (1726–97) and  Charles Lyell (1797–1875). It can be summarized as ‘the present is the key to the past’ and is the basic principle of paleoecology. The concept of analogy involves the application of modern organismic features to ancient organisms, and of course parsimony is a central rule for any scientific inquiry. In 1933, the Russian paleontologist Roman Gekker published the first book dedicated to paleoecology: “Manual to Paleoecology”, based in his lectures about the Devonian Period. In this book he established the main objectives of Paleoecology. Later, in 1954, he wrote “Directions for Research in Paleoecology” and in 1957, he published “Introduction to Paleoecology”.

Scanning electron microscope image of different types of pollen grains. Image from Wikipedia.

Scanning electron microscope image of different types of pollen grains. Image from Wikipedia.

There are two major types of paleoecology: Quaternary paleoecology, concerned with the last 2.6 million years of Earth’s history, and Deep-time paleoecology, based on fossils from pre-Quaternary sediments over a wide range of timescales (Birks, 2013). In the last four decades, quantitative methods for reconstructing environmental variables have been developed from a range of biological proxies such as pollen, plant macrofossils, insects (chironomids, coleopterans), molluscs, ostracods, diatoms, chrysophycean cysts, testate amoebae, and cladocerans preserved in lake sediments and peat profiles, or dinoflagellate cysts, diatoms, pollen, foraminifera, coccolithophores, and radiolarians preserved in marine sediment records.

Lago Sarmiento in Southern Patagonia. Sediment cores recovered from lakes like this, help to reconstruct environmental changes. Photo credit: R. Dunbar.

Lago Sarmiento in Southern Patagonia. Sediment cores recovered from lakes like this, help to reconstruct environmental changes. Photo credit: R. Dunbar.

The dominant technique in Quaternary terrestrial paleoecology is the pollen analysis. Pollen analysis involves the quantitative examination of spores and pollen at successive horizons through a core, particularly in bog, marsh, lake or delta sediments (Armstrong, 2005). This method was created by Lennart von Post (1884–1950), a Swedish geologist and presented at the 16th Scandinavian meeting of natural scientists in Oslo. Since the 1980s, many fossil pollen data sets were developed specifically to reconstruct past climate change.

Reference:

Seddon, A. W. R., Mackay, A. W., Baker, A. G., Birks, H. J. B., Breman, E., Buck, C. E., Ellis, E. C., Froyd, C. A., Gill, J. L., Gillson, L., Johnson, E. A., Jones, V. J., Juggins, S., Macias-Fauria, M., Mills, K., Morris, J. L., Nogués-Bravo, D., Punyasena, S. W., Roland, T. P., Tanentzap, A. J., Willis, K. J., Aberhan, M., van Asperen, E. N., Austin, W. E. N., Battarbee, R. W., Bhagwat, S., Belanger, C. L., Bennett, K. D., Birks, H. H., Bronk Ramsey, C., Brooks, S. J., de Bruyn, M., Butler, P. G., Chambers, F. M., Clarke, S. J., Davies, A. L., Dearing, J. A., Ezard, T. H. G., Feurdean, A., Flower, R. J., Gell, P., Hausmann, S., Hogan, E. J., Hopkins, M. J., Jeffers, E. S., Korhola, A. A., Marchant, R., Kiefer, T., Lamentowicz, M., Larocque-Tobler, I., López-Merino, L., Liow, L. H., McGowan, S., Miller, J. H., Montoya, E., Morton, O., Nogué, S., Onoufriou, C., Boush, L. P., Rodriguez-Sanchez, F., Rose, N. L., Sayer, C. D., Shaw, H. E., Payne, R., Simpson, G., Sohar, K., Whitehouse, N. J., Williams, J. W., Witkowski, A. (2014), Looking forward through the past: identification of 50 priority research questions in palaeoecology. Journal of Ecology, 102: 256–267. doi: 10.1111/1365-2745.12195

Seppä, H. 2009. Palaeoecology. eLS DOI: 10.1002/9780470015902.a0003232

Walker, Mike J. C., and John J. Lowe. 2007. Quaternary science 2007: A 50-year retrospective.Journal of the Geological Society 164.6: 1073–1092. DOI: 10.1144/0016-76492006-195

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