Rock Hyrax Middens and Climate Change in Southern Africa During the Last 50,000 Years

This presentation describes the work being undertaken by the European Research Council project HYRAX. This project is engaged in the development of a novel and extremely promising palaeoenvironmental archive from southern Africa: the rock hyrax (Procavia capensis) midden, stratified accumulations of urine and faecal pellets that preserve records of environmental change spanning upwards of 50,000 years. Despite the southern Africa’s sensitivity to climate change, and its position at a key juncture in hemispheric and global circulation systems, the environmental history of the region remains largely unknown. This is principally due to the region’s semi- to hyperarid climate, which is not conducive to the occurrence of lakes and wetlands that typically preserve long records of environmental change in temperate and tropical regions.

As a new palaeoenvironmental archive, rock hyrax middens offer the first opportunity to obtain reliable high-resolution records of past climate and vegetation change in the region. When coupled with high-precision chronologies, these records provide sub-annual to multi-decadal records of rapid environmental change spanning thousands of years. In comparison with other terrestrial palaeoenvironmental archives from the region, which can generally only be resolved to millennial to multi-millennial timescales, hyrax middens provide an improvement in resolution of three to four orders of magnitude.

This improvement in reliability and resolution makes hyrax middens ideal for acquiring records of long-term climate and vegetation change that: 1) can be directly calibrated and compared to instrumental records to obtain quantitative estimates of palaeoclimatic parameters, and 2) can be found across much of southern Africa, allowing for detailed synoptic palaeoclimatic reconstructions at scales that allow for detailed comparisons with general circulation model (GCM) simulations.

The eventual acquisition of an aggregate African hyrax midden dataset will allow us to evaluate, modify and improve GCM performance, and  use GCMs to study the drivers and dynamics of long-term climate change as observed in the hyrax midden data.