Jörgen Ripa Ph.D.

Researcher jorgen.ripa <at> biol.lu.se +46-46 222 3770   Graduate students: Jesper Sörensson (co-supervising)

Research Interests

Adaptive radiations in α and β niche dimensions

I theoretically investigate the ecological drivers of adaptive radiations - a rapid burst of speciations within a single lineage, filling up available niche space. A focal question is what type of traits diverge first - traits associated with adaptation to different habitat types (β-traits) or traits assocaited with local competition, which make local coexistence possible (α-traits). Examples of α-traits are diet preference traits or microhabitat adaptations. β-traits are typically adaptations to the physical environement, such as heat, cold or drought adaptiations. Is it possible to predict what traits are evolutionary conserved, or vice versa, if we find that one type of trait evolves more readily, what conclusions can we draw from such a pattern? These are fundamental questions for the intrepretation of current biogeographic and phylogenetic data, and our understanding of the emergence of species on earth.

Species evolution in variable environments

All organisms have to cope with a variable physical environment. However, such variation also generates fluctuating population densities, which in itself imposes a variable selection pressure. Moreover, the fluctations in population size will depend on what type or life history strategy is currently dominating the population. I am interested in this feedback loop between the short-term ecological time-scale and the long-term evolutionary time-scale. How do species and in particular species interactions evolve when all interacting species vary in abundance over time as well as space?

Population and community dynamics in variable, stochastic, environments

I also have a long time interest in the interplay between endogenous dynamics, driven by ecological interactions, and structured (temporally or spatially) environmental fluctuations.

Selected Publications (CV and complete list)

Evolution

Ripa, J. and Dieckmann, U. 2013. Mutant invasions and adaptive dynamics in variable environments. Evolution (in press)

Pontarp, M., Ripa, J. & Lundberg, P. 2012. On the origin of phylogenetic structure in competitive metacommunities. Evol. Ecol. Res. 14: 269-284

Johansson, J., Ripa, J., Kuckländer, N. 2010. The risk of competitive exclusion during evolutionary branching: effects of resource variability, correlation and autocorrelation. Theor. Pop. Biol. 77: 95-104.

Nilsson, J.& Ripa, J. 2010. Adaptive branching in source-sink habitats. Evol. Ecol. 24(2): 479-489.

Ripa, J., Olofsson, H., Jonzén, N. 2010. What is bet-hedging, really? Proc. R. Soc. B 277: 1153-1154.

Olofsson, H., Ripa, J., Jonzén, N. 2009. Bethedging as an evolutionary game: the trade-off between egg size and number. Proc. R. Soc. Lond. B 276: 2963-2969.

Ripa, J., Storlind, L., Lundberg, P. and Brown. J. S. 2009. Niche coevolution in consumer–resource communities. Evolutionary Ecology Research 11(2): 305–323

Ripa, J. 2009. When is sympatric speciation truly adaptive? An analysis of the joint evolution of resource utilization and assortative mating. Evolutionary Ecology 23(1): 31-52.

Bach, L., Ripa, J., Lundberg, P. 2007. On the evolution of conditional dispersal under environmental and demographic stochasticity. Evolutionary Ecology Research 9(4): 663-673.

Johansson, J. and Ripa, J. 2006. Will sympatric speciation fail due to stochastic competitive exclusion? The American Naturalist 168(5): 572-578.

Population dynamics

Ruokolainen, L. & Ripa, J. 2012. The strength of species interactions modifies population responses to environmental variation in competitive communities. J. Theor. Biol. 310: 199-205

Wikström, A., Ripa, J., Jonzén, N. 2012. The role of harvesting in age-structured populations: Disentangling dynamic and age truncation effects. Theor. Pop. Biol. 82: 348–354.

Abbott, K, Ripa, J., Ives, A. R. 2009. Environmental variation in ecological communities and inferences from single-species data. Ecology 90(5): 1268-1278.

Ripa, J. & Ranta, E. 2007. Biological filtering of correlated environments: towards a generalised Moran theorem. Oikos 116(5): 783-792.

Ripa, J. & Ives, A. R. 2003. Food web dynamics in correlated and autocorrelated environments. Theoretical Population Biology 64: 369-384.

Ripa, J. 2000. Analysing the Moran effect and dispersal: their significance and interaction in synchronous population dynamics. Oikos 89(1): 175-187.

Ripa, J. & Heino, M. 1999. Linear analysis solves two puzzles in population dynamics: the route to extinction and extinction in coloured environments. Ecology Letters 2: 219-222.

Ripa, J. & Lundberg, P. 1996. Noise colour and the risk of population extinctions. Proceedings of the Royal Society, London, Ser. B 263:1751-1753.

Teaching

Head teacher of:

• Theoretical Ecology (BIOR30)
• Evolutionary Processes (postgraduate course)

Other courses (recent):

• Modelling of Biological Systems (BIOS02)
• Biologiska system (TEK292)
• Conservation Biology (BIOR37)
• Ecology - Advanced course (BIOR13)
• Biology, Introductory Course (TEK 290)