Ecology of the past

Having recently traveled to South Africa as part of the Landscape Dynamics field course run by our graduate school, and to be thinking again about trying to obtain funding to further research in Africa, I thought it might be fun to turn to the journals in which I have an editorial hand (Plant Ecology & Diversity, Vegetation History & Archaeobotany, and The Holocene) and see what new work was coming out on African ecosystem dynamics. From each of these journals I have selected two recent papers to highlight here.

The papers come from across the continent and all have a component of the ecology of the past, but they range in focus from developing methods to extract new insights about past ecological change (Le Moyne et al., 2023) through to the application of our understanding of past ecosystems to the management of conservation areas (Wilkinson et al., 2022).

The study by Le Moyne et al. (2023) examined modern reference material of nine grass species to determine how they might be better identified in the archaeological and palaeoecological record from the phytoliths they produce. Three of the studies use different lines of evidence of past ecological dynamics to explore change over the last few thousands of years.

• Champion et al. (2023) shed light on past agricultural practices in western Africa (Nigeria) through the examination of macro-botanical evidence from 50 archaeological sites and dating back c. 3500 years, hypothesizing a new route for the spread of pearl millet out of the central Sahara into the central Nigerian savannahs.
• Prader et al. (2023) present a c. 4000 year geochemical, palynological and and charcoal record from Table Mountain National Park in South Africa, showing changes in the abundance of fynbos and forest plants and how this was modified by people.
• Hildebrand et al. (2022) collated multiple lines of evidence of past environmental change from eastern Africa to assess changes in human activity during and after the African Humid Period (15,000-5000 years ago), highlighting the complex relationship between changes in human resource acquisition practice (fishing, hunting, gathering, and pastoralism) and environmental change.

The longest timescale perspective is provided by Milton et al. (2022) who investigated plant speciation in the Namib Desert. They combined a phylogenetic, morphometric and experimental genetic approaches to explore the evolutionary history of Senecio flavus and S. engerianus and produce palaeo-distribution models. From these data they suggest that the wider ranged species (S. flavus) is in fact derived from the smaller ranged parent (S. engerianus) and that this separation was caused by aridification during the Pleistocene.

The final paper, Wilkinson et al. (2022), take evidence for past abundances of elephants and compare them with the abundances in national parks today. They argue that modern elephant densities in national parks could be higher than the historical levels and that this could be detrimental to the flora and other fauna in the parks.

References