TY  - JOUR
A1  - van Velzen, Ellen
T1  - Predator coexistence through emergent fitness equalization
JF  - Ecology : a publication of the Ecological Society of America
N2  - The competitive exclusion principle is one of the oldest ideas in ecology and states that without additional self-limitation two predators cannot coexist on a single prey. The search for mechanisms allowing coexistence despite this has identified niche differentiation between predators as crucial: without this, coexistence requires the predators to have exactly the same R* values, which is considered impossible. However, this reasoning misses a critical point: predators' R* values are not static properties, but affected by defensive traits of their prey, which in turn can adapt in response to changes in predator densities. Here I show that this feedback between defense and predator dynamics enables stable predator coexistence without ecological niche differentiation. Instead, the mechanism driving coexistence is that prey adaptation causes defense to converge to the value where both predators have equal R* values ("fitness equalization"). This result is highly general, independent of specific model details, and applies to both rapid defense evolution and inducible defenses. It demonstrates the importance of considering long-standing ecological questions from an eco-evolutionary viewpoint, and showcases how the effects of adaptation can cascade through communities, driving diversity on higher trophic levels. These insights offer an important new perspective on coexistence theory.
KW  - coexistence
KW  - competition
KW  - competitive exclusion
KW  - defense
KW  - eco-evolutionary feedbacks
KW  - emergent facilitation
KW  - predator
KW  - prey
KW  - dynamics
Y1  - 2020
U6  - https://doi.org/10.1002/ecy.2995
SN  - 0012-9658
SN  - 1939-9170
VL  - 101
IS  - 5
PB  - Wiley
CY  - Hoboken
ER  -