dichotomum up to 18 000 years to migrate 650 kilometres poleward. During the mid-Holocene, about 6000 years ago, the available quiver tree range was more or less in the same location as the current range. As temperatures became more favourable, the trees started expanding their range polewards at a rate of 0.4 kilometres per decade. dichotomum was outside the current range – around 650 kilometres further to the north. ĭuring the Last Glacial Maximum (LGM) (22 000 years ago), the models predict that two-thirds of suitable habitat for A. ![]() The findings have recently been published in the journal Frontiers in Ecology and Evolution. She then used population genetic methods to test the results. In the latest study, Prof Midgley's postgraduate student Lara Brodie used species distribution modelling to reconstruct the likely spatial extent of the quiver tree's ranges during glacial periods. Repeated observational studies over the years are needed to confirm the findings that such a range shift may be underway. In 2007, Prof Wendy Foden was able to show signs of a coming southward and upward shift, with individual trees dying off in the warmer parts of the range towards the equator and at lower elevations throughout the northern half of the range. Over the past two decades, Prof Midgley and his postgraduate students have been observing and documenting quiver tree populations' response to climate change. It is therefore becoming imperative for the future conservation of endemic species such as the quiver tree, to try to understand and predict their response to ongoing and future climate change. In contrast, according to the latest report from the Intergovernmental Panel on Climate Change (IPCC), surface air temperatures in Africa is projected to rise in excess of 5☌ in the dry, subtropical areas in less than a century. In other words, while trees may have been able to migrate or adapt to previous changes in the paleo climate, taking place over thousands of years, they may not be able to adapt or migrate as fast as is needed to survive man-made climate change.įor example, over the past 10 000 years the surface air temperature in southwestern Africa likely rose by 5☌ during glacial to interglacial warming at the end of the Pleistocene. Globally, trees are the most vulnerable to man-made climate change, as they are long-lived with long generation times. In the case of long-lived trees, however, the adaptive options are limited. The non-adaptive outcome is local extinction," he explains. The other options are on site adaptation by genetic changes or changes in biology or behaviour. “A common prediction for plants is that they will shift their geographic ranges in response to warming, either poleward or upward in elevation. Prof Guy Midgley, head of the global change research group in SU's Department of Botany and Zoology, says worldwide a large body of research and observation show that biological systems and species are already responding to human-made climate change. The aim was to establish its response to past climate change, and how human-made climate change could affect this response into the future. Going 22 000 years into the past and projecting 50 years into the future, ecologists from Stellenbosch University (SU) simulated the paleo- and future geographic range of arid South Africa and Namibia's iconic quiver tree, Aloidendron dichotumum.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |