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Indirect evolutionary rescue: prey adapts, predator avoids extinction.

Yamamichi M, Miner BE - Evol Appl (2015)

Bottom Line: A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate.As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics.We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Cornell University Ithaca, NY, USA.

ABSTRACT
Recent studies have increasingly recognized evolutionary rescue (adaptive evolution that prevents extinction following environmental change) as an important process in evolutionary biology and conservation science. Researchers have concentrated on single species living in isolation, but populations in nature exist within communities of interacting species, so evolutionary rescue should also be investigated in a multispecies context. We argue that the persistence or extinction of a focal species can be determined solely by evolutionary change in an interacting species. We demonstrate that prey adaptive evolution can prevent predator extinction in two-species predator-prey models, and we derive the conditions under which this indirect evolutionary interaction is essential to prevent extinction following environmental change. A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate. As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics. We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

No MeSH data available.


Indirect evolutionary rescue in eqn (1). An abrupt environmental change occurs when t = 50 as indicated by arrows (the predator mortality, m, changes from 0.2 to 0.4). Without prey evolution, the predator goes extinct (A), whereas when prey can evolve, the predator population increases after its initial decline (B). Adaptive evolution lowers prey defense (B), which stays constant in the case of no evolution (A). Black solid lines: predator abundance, gray dashed lines: prey abundance, and gray solid lines: prey defense trait. Parameter values are a = 0.3, G = k = b = 1, and Vx = 0 (A) or 0.01 (B). The predator and prey abundances and the prey trait reached an equilibrium before the environmental change with Vx > 0.
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fig01: Indirect evolutionary rescue in eqn (1). An abrupt environmental change occurs when t = 50 as indicated by arrows (the predator mortality, m, changes from 0.2 to 0.4). Without prey evolution, the predator goes extinct (A), whereas when prey can evolve, the predator population increases after its initial decline (B). Adaptive evolution lowers prey defense (B), which stays constant in the case of no evolution (A). Black solid lines: predator abundance, gray dashed lines: prey abundance, and gray solid lines: prey defense trait. Parameter values are a = 0.3, G = k = b = 1, and Vx = 0 (A) or 0.01 (B). The predator and prey abundances and the prey trait reached an equilibrium before the environmental change with Vx > 0.

Mentions: We demonstrate indirect evolutionary rescue using numerical simulations with eqn (1) assuming that f(x) = Ge−x and r(x) = 1 – ax, where G is the attack rate coefficient and a is the defense cost coefficient. We chose a linear function for the intrinsic rate of increase as it can be negative or positive, and an exponential function for the attack rate because it should be always positive. The mechanism underlying indirect evolutionary rescue is as follows: consider a situation in which a predator and its prey experience environmental change that is detrimental to the predator (in this simulation, increased predator mortality) and results in its extinction in the absence of evolutionary change (Fig. 1A). When the prey species exhibits a trade-off between defense against predation and maximum population growth rate (i.e., intrinsic rate of increase), environmental change that is detrimental to the predator results in reduced predation pressure on the prey due to decreased predator abundance (Fig. 1B). Because of its defense/growth rate trade-off, the prey then evolves toward a less defended phenotype with a higher intrinsic rate of increase (Fig. 1B). The reduction in prey defense consequently permits the persistence of the predator, even though environmental conditions are not favorable to the predator, and the predator population itself has not evolved (Fig. 1B). Although at first counterintuitive, the result of this interaction is that adaptive evolution by a prey species to increase its population growth rate causes the persistence of its predator.


Indirect evolutionary rescue: prey adapts, predator avoids extinction.

Yamamichi M, Miner BE - Evol Appl (2015)

Indirect evolutionary rescue in eqn (1). An abrupt environmental change occurs when t = 50 as indicated by arrows (the predator mortality, m, changes from 0.2 to 0.4). Without prey evolution, the predator goes extinct (A), whereas when prey can evolve, the predator population increases after its initial decline (B). Adaptive evolution lowers prey defense (B), which stays constant in the case of no evolution (A). Black solid lines: predator abundance, gray dashed lines: prey abundance, and gray solid lines: prey defense trait. Parameter values are a = 0.3, G = k = b = 1, and Vx = 0 (A) or 0.01 (B). The predator and prey abundances and the prey trait reached an equilibrium before the environmental change with Vx > 0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561568&req=5

fig01: Indirect evolutionary rescue in eqn (1). An abrupt environmental change occurs when t = 50 as indicated by arrows (the predator mortality, m, changes from 0.2 to 0.4). Without prey evolution, the predator goes extinct (A), whereas when prey can evolve, the predator population increases after its initial decline (B). Adaptive evolution lowers prey defense (B), which stays constant in the case of no evolution (A). Black solid lines: predator abundance, gray dashed lines: prey abundance, and gray solid lines: prey defense trait. Parameter values are a = 0.3, G = k = b = 1, and Vx = 0 (A) or 0.01 (B). The predator and prey abundances and the prey trait reached an equilibrium before the environmental change with Vx > 0.
Mentions: We demonstrate indirect evolutionary rescue using numerical simulations with eqn (1) assuming that f(x) = Ge−x and r(x) = 1 – ax, where G is the attack rate coefficient and a is the defense cost coefficient. We chose a linear function for the intrinsic rate of increase as it can be negative or positive, and an exponential function for the attack rate because it should be always positive. The mechanism underlying indirect evolutionary rescue is as follows: consider a situation in which a predator and its prey experience environmental change that is detrimental to the predator (in this simulation, increased predator mortality) and results in its extinction in the absence of evolutionary change (Fig. 1A). When the prey species exhibits a trade-off between defense against predation and maximum population growth rate (i.e., intrinsic rate of increase), environmental change that is detrimental to the predator results in reduced predation pressure on the prey due to decreased predator abundance (Fig. 1B). Because of its defense/growth rate trade-off, the prey then evolves toward a less defended phenotype with a higher intrinsic rate of increase (Fig. 1B). The reduction in prey defense consequently permits the persistence of the predator, even though environmental conditions are not favorable to the predator, and the predator population itself has not evolved (Fig. 1B). Although at first counterintuitive, the result of this interaction is that adaptive evolution by a prey species to increase its population growth rate causes the persistence of its predator.

Bottom Line: A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate.As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics.We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Cornell University Ithaca, NY, USA.

ABSTRACT
Recent studies have increasingly recognized evolutionary rescue (adaptive evolution that prevents extinction following environmental change) as an important process in evolutionary biology and conservation science. Researchers have concentrated on single species living in isolation, but populations in nature exist within communities of interacting species, so evolutionary rescue should also be investigated in a multispecies context. We argue that the persistence or extinction of a focal species can be determined solely by evolutionary change in an interacting species. We demonstrate that prey adaptive evolution can prevent predator extinction in two-species predator-prey models, and we derive the conditions under which this indirect evolutionary interaction is essential to prevent extinction following environmental change. A nonevolving predator can be rescued from extinction by adaptive evolution of its prey due to a trade-off for the prey between defense against predation and population growth rate. As prey typically have larger populations and shorter generations than their predators, prey evolution can be rapid and have profound effects on predator population dynamics. We suggest that this process, which we term 'indirect evolutionary rescue', has the potential to be critically important to the ecological and evolutionary responses of populations and communities to dramatic environmental change.

No MeSH data available.