Climate space, bioclimatic envelopes and coexistence methods for the reconstruction of past climates: a method using Australian beetles and significance for Quaternary reconstruction

If Quaternary palaeoclimatic reconstructions are to be adequately contextualised, it is vital that the nature of modern datasets and the limitations this places on interpreting Quaternary climates are made explicit – such issues are too infrequently considered. This paper describes a coexistence method for the reconstruction of past temperature and precipitation parameters in Australia, using fossil beetles. It presents the context for Quaternary palaeoclimatic reconstruction in terms of climate space, bioclimatic envelope data derived from modern beetle distributions, and the palaeoclimatic limitations of bioclimatic envelope-based reconstructions. Tests in modern climate space, using bioclimatic envelope data for 734 beetle taxa and 54 site-based assemblages from across the continent, indicate that modern seasonal, especially summer, temperatures and precipitation are accurately and, in the case of temperature, precisely reconstructed. The limitations of modern climate space, especially in terms of the limited seasonal variation in thermal regimes and subsequent lack of cold winters in the Australian region, renders winter predictions potentially unreliable when applied to the Quaternary record.