@article{VelzenGaedkeKlauschies2022,
  author    = {Velzen, Ellen van and Gaedke, Ursula and Klauschies, Toni},
  title     = {Quantifying the capacity for contemporary trait changes to drive intermittent predator-prey cycles},
  series = {Ecological monographs : a publication of the Ecological Society of America},
  volume    = {92},
  journal   = {Ecological monographs : a publication of the Ecological Society of America},
  number    = {2},
  publisher = {Wiley},
  address   = {New York},
  issn      = {1557-7015},
  doi       = {10.1002/ecm.1505},
  pages     = {29},
  year      = {2022},
  abstract  = {A large and growing body of theory has demonstrated how the presence of trait variation in prey or predator populations may affect the amplitude and phase of predator-prey cycles. Less attention has been given to so-called intermittent cycles, in which predator-prey oscillations recurrently disappear and re-appear, despite such dynamics being observed in empirical systems and modeling studies. A comprehensive understanding of the conditions under which trait changes may drive intermittent predator-prey dynamics, as well as their potential ecological implications, is therefore missing. Here we provide a first systematic analysis of the eco-evolutionary conditions that may give rise to intermittent predator-prey cycles, investigating 16 models that incorporate different types of trait variation within prey, predators, or both. Our results show that intermittent dynamics often arise through predator-prey coevolution, but only very rarely when only one trophic level can adapt. Additionally, the frequency of intermittent cycles depends on the source of trait variation (genetic variation or phenotypic plasticity) and the genetic architecture (Mendelian or quantitative traits), with intermittency occurring most commonly through Mendelian evolution, and very rarely through phenotypic plasticity. Further analysis identified three necessary conditions for when trait variation can drive intermittent cycles. First, the intrinsic stability of the predator-prey system must depend on the traits of prey, predators, or both. Second, there must be a mechanism causing the recurrent alternation between stable and unstable states, leading to a "trait" cycle superimposed on the population dynamics. Finally, these trait dynamics must be significantly slower than the predator-prey cycles. We show how these conditions explain all the abovementioned patterns. We further show an important unexpected consequence of these necessary conditions: they are most easily met when intraspecific trait variation is at high risk of being lost. As trait diversity is positively associated with ecosystem functioning, this can have potentially severe negative consequences. This novel result highlights the importance of identifying and understanding intermittent cycles in theoretical studies and natural systems. The new approach for detecting and quantifying intermittency we develop here will be instrumental in enabling future study.},
  language  = {en}
}
@article{MillesDammhahnJeltschetal.2022,
  author    = {Milles, Alexander Benedikt and Dammhahn, Melanie and Jeltsch, Florian and Schl{\"a}gel, Ulrike and Grimm, Volker},
  title     = {Fluctuations in density-dependent selection drive the evolution of a pace-of-life syndrome within and between populations},
  series = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences},
  volume    = {199},
  journal   = {The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences},
  number    = {4},
  publisher = {Univ. of Chicago Press},
  address   = {Chicago},
  issn      = {0003-0147},
  doi       = {10.1086/718473},
  pages     = {E124 -- E139},
  year      = {2022},
  abstract  = {The pace-of-life syndrome (POLS) hypothesis posits that suites of traits are correlated along a slow-fast continuum owing to life history trade-offs. Despite widespread adoption, environmental conditions driving the emergence of POLS remain unclear. A recently proposed conceptual framework of POLS suggests that a slow-fast continuum should align to fluctuations in density-dependent selection. We tested three key predictions made by this framework with an ecoevolutionary agent-based population model. Selection acted on responsiveness (behavioral trait) to interpatch resource differences and the reproductive investment threshold (life history trait). Across environments with density fluctuations of different magnitudes, we observed the emergence of a common axis of trait covariation between and within populations (i.e., the evolution of a POLS). Slow-type (fast-type) populations with high (low) responsiveness and low (high) reproductive investment threshold were selected at high (low) population densities and less (more) intense and frequent density fluctuations. In support of the predictions, fast-type populations contained a higher degree of variation in traits and were associated with higher intrinsic reproductive rate (r(0)) and higher sensitivity to intraspecific competition (gamma), pointing to a universal trade-off. While our findings support that POLS aligns with density-dependent selection, we discuss possible mechanisms that may lead to alternative evolutionary pathways.},
  language  = {en}
}