Preface: Speciation research in ancient lakes – classic concepts and new approaches

Abstract

Ancient lakes harbor some of the most formidable aquatic ecosystems on earth. Most of the long-term stable lakes are large and extraordinarily deep, and their biotas have evolved under more or less pronounced isolation. This isolation, and the often restricted number of lineages of organisms that successfully invaded their waters, have set the stage for some of the most impressive cases of adaptive radiation, local endemism, and highly adapted organismal communities. It has for long been recognized that the biotas of ancient lakes offer outstanding opportunities for testing hypotheses in evolutionary biology, ecology, climatic history, and geology (Brooks, 1950). In the continuously expanding field of speciation research, much of the knowledge available to date rests upon studies performed in radiations restricted to isolated lakes of varying ages (Martens, 1997; Rossiter & Kawanabe, 2000). This present Special Issue of Hydrobiologia is devoted to recent progresses in the field of speciation in ancient lakes, arising from the 6th SIAL Conference (‘‘Speciation in Ancient Lakes: Classic concepts and new approaches’’), held in Cibinong, Indonesia, in August 2012. Beyond its extraordinarily rich riverine freshwater faunas, distributed over thousands of islands, Indonesia harbors on Sulawesi two ancient water bodies, namely Lake Poso and the Malili Lakes system. It is hence little surprising that several contributions at SIAL 6 were devoted to Indonesia’s native lakes and to the evolution of their endemic species flocks. The range of research presented was however much broader, highlighting the patterns of speciation, and its temporal as well as abiotic context, in ancient lakes from Baikal and Ohrid to Tanganyika. It is in the nature of the topic that the need for definitions stipulated some discussion on the question of the age of so-called ‘‘ancient lakes’’. Electronic supplementary material The online version of this article (doi:10.1007/s10750-014-2028-9) contains supplementary material, which is available to authorized users.