Examining the processes that generate, maintain, and threaten biological diversity

Project Description:

Research in my group addresses one of the fundamental questions in evolutionary ecology: what are the ecological and evolutionary processes that generate, maintain, and constrain/threaten biological diversity? In particular, we are interested in population divergence and ecological speciation as a result of divergent natural selection between ecologically different environments (both natural and human-induced). Using integrative and highly collaborative approaches, we try to answer the questions of (i) how and why organisms diversify phenotypically, (ii) what ecological and evolutionary forces shape reproductive barriers important in facilitating an initial reduction in gene flow between diverging populations, and (iii) what role human-induced environmental change has on biodiversity in general, and the stability of population differentiation among diverging populations in particular. Hence, our research further emphasizes the dynamic nature of evolving biological systems also in the context of conservation. To that end, we combine behavioural, chemical ecological, population genetic, life-history, and morphological techniques that include observational studies, manipulations in the field, and laboratory experiments. We put great emphasis on comparative analyses among species and populations, and make use of different study systems (mainly livebearing fishes, mammals, and insects) that span a range of biological diversity. Combined, these systems span the full spectrum of the speciation continuum from panmixis to complete reproductive isolation, allowing examination of the different mechanisms driving or constraining the formation of new species. There are always on-going and potential research projects available to PhD students in my lab, so for further information please contact me (rudiger.riesch@rhul.ac.uk).

Policy Impact of Research:

Projects within this framework have the potential to significantly contribute to our understanding of patterns of speciation in animals as well as how human-induced habitat alterations affect biodiversity. The student will be trained in various different cutting-edge methods of quantifying phenotypic and genetic diversity.

Research Relating to this Project:

1. Riesch R, M Plath, I Schlupp, M Tobler & RB Langerhans (2014) Colonization of toxic environments drives predictable life-history evolution in livebearing fishes (Poeciliidae). Ecology Letters 17(1): 65-71.
2. Riesch R, T Easter, CA Layman & RB Langerhans (2015) Rapid human-induced divergence of life-history strategies in Bahamian livebearing fishes (family Poeciliidae). Journal of Animal Ecology 84(6): 1732-1743.
3. Riesch R, RA Martin & RB Langerhans (2013) Predation’s role in life-history evolution of a livebearing fish and a test of the Trexler-DeAngelis model of maternal provisioning The American Naturalist 181(1):78–93.