Miocene climate and vegetation changes in the Cape Peninsula, South Africa: Evidence from biogeochemistry and palynology

Dung beetle conservation biogeography in southern Africa: current challenges and potential effects of climatic change

“…Endemism has presumably been driven by eco-climatic evolution since the late Miocene. In the southwest, tropical coastal forest has been replaced by cool winter rainfall shrubs and forest patches with aridity developing to the north (Diekmann et al 2003;Dupont et al 2011;Hoetzel et al 2015;Sciscio et al 2016). This is consistent with the evolution of Pachysoma (tribe Scarabaeini) along the arid west coast that has been dated to the Plio/Pleistocene (Sole et al 2005).…”

“…However, there is potential for radical change at the southern tip of Africa in the context of evolution of the regional eco-climatic system during the late Cenozoic. Although reversion to the tropical southern climate of the early Miocene (Dupont et al 2011;Sciscio et al 2016) currently seems remote, Steffen et al (2018) have recently considered potential for development of a "hothouse earth". Such predictions are consistent with those for a 1.5 o southwards latitudinal movement of the westerlies by 2100 (Swart & Fyfe 2012) and irreversible ice loss from some parts of Antarctica by 2070 (Rintoul et al 2018).…”

“…Climatic change in the southwest Cape is supported by biogeochemical and palynological evidence for early to mid-Miocene subtropical climate (Sciscio et al 2016) followed by late Miocene (10-6 Ma) transition from tropical to semi-arid vegetation (Dupont et al 2011).…”

“…Consequently, there are many current challenges for conservation of dung beetle species across southern Africa, particularly those showing the smallest overall ranges and/or those showing specialist ecological associations within areas under the greatest pressures from urbanization, resource exploitation or conversion to agro-ecosystems (Fairbanks et al 2000;Davis et al In press). In the southwest, additional, future conservation challenges could result from predicted climatic change (Giorgi 2006;Scheiter & Higgins 2009;Rintoul et al 2018), particularly if it drives reversion from the present winter rainfall climate (Dieppois et al 2016) to the earlier more tropical system (Sciscio et al 2016) that preceded permanent glaciation in polar regions from the mid-Miocene (Zachos et al 2001).…”

African geoxyles evolved in response to fire; frost came later

“…Utescher et al (2009) estimated that annual ground frost days in northern Germany, with a temperature regime not unlike the mountain ranges where some SG proteas occur , were close to zero from 15 Ma (mean temperature of coldest month >10°C) and only began to rise substantially from 4 Ma when > 50 % of SG lineages had already arisen (Table 2). Thus, Sciscio et al (2016) determined a mean annual temperature of 21 °C at 11.6 Ma in the Cape Peninsula (possessing several SGs) compared with a current temperature of 17 °C that even now is frost-free. The mean age of shrubland SGs coincided with the Miocene Pliocene boundary and the grassland SGs with the Pliocene Pleistocene boundary, so climates must have been less warm and only frost-prone during evolution of some upland grassland proteas (Fig.…”