CHIRONOMID RECORDS | Africa

Abstract

Paleoecological research in Africa using fossil Chironomidae is still relatively uncommon, and continuous records spanning the entire postglacial period are thus far lacking. Until recently, all African chironomid studies (dealing with climate history or human impact on aquatic ecosystems) used the indicator-species approach, combining autecological information on the few African species with known larval morphology with genus-level ecological typology transferred from the Holarctic region. Paleoclimatologists have exploited the relative abundance of freshwater and salt-tolerant chironomid taxa as water-balance indicator in closed-basin lakes, and the relative abundance of (semi)terrestrial, lake, and stream taxa as indicators of hydrological variation in high-altitude peat bogs. Recent lake surveying efforts have now produced the paleoenvironmental calibration data sets required to develop statistically robust inference models for reconstruction of paleosalinity and a range of other environmental variables (temperature, lake trophic status, oxygen regime). Earlier attempts at quantitative chironomid-based paleoenvironmental reconstruction in Africa were founded on species distribution data compiled from regional surveys of the living fauna. This stimulated identification of fossil chironomid remains at the species level, such that the new paleoenvironmental calibration data sets now becoming available for various African regions can also be used to address questions about biodiversity and biogeography.