When higher carrying capacities lead to faster propagation

Marjorie Haond (1) , Thibaut Morel-Journel (1) , Eric Lombaert (1) , Elodie Vercken (1) , Ludovic Mailleret (1, 2) , Lionel Roques (3)

1 ISA - Institut Sophia Agrobiotech
2 BIOCORE - Biological control of artificial ecosystems
3 BioSP - Biostatistique et Processus Spatiaux

This preprint has been reviewed and recommended by Peer Community In Ecology (https://dx.doi.org/10.24072/pci.ecology.100004). Finding general patterns in the expansion of natural populations is a major challenge in ecology and invasion biology. Classical spatio-temporal models predict that the carrying capacity (K) of the environment should have no influence on the speed (v) of an expanding population. We tested the generality of this statement with reaction- diffusion equations, stochastic individual-based models, and microcosms experiments with Trichogramma chilonis wasps. We investigated the dependence between K and v under different assumptions: null model (Fisher-KPP-like assumptions), strong Allee effects, and positive density-dependent dispersal. These approaches led to similar and complementary results. Strong Allee effects, positive density-dependent dispersal and demographic stochasticity in small populations lead to a positive dependence between K and v. A positive correlation between carrying capacity and propagation speed might be more frequent than previously expected, and be the rule when individuals at the edge of a population range are not able to fully drive the expansion.

Mots clés: expansion dynamics; invasion biology; propagation speed; density-dependent dispersal; Allee effect; demographic stochasticity; experimental microcosms; small populations; pushed invasion

Domaines: Evolution [q-bio.PE]

Marjorie Haond, Thibaut Morel-Journel, Eric Lombaert, Elodie Vercken, Ludovic Mailleret, et al.. When higher carrying capacities lead to faster propagation. Peer Community In Ecology, 2018, pp.e57. ⟨10.24072/pcjournal.66⟩. ⟨hal-01877823⟩