Should I Stay or Should I Go: Partially Sedentary Populations Can Outperform Fully Dispersing Populations in Response to Climate-Induced Range Shifts

Abstract

Global mean temperatures have increased by 0.72 • C since the 1950s, and climate warming is resulting in geographical shifts in the range limits of many species. Climate velocity is estimated to be 0.42 km/year, and if a species fails to adapt to the new climate, it must track the location of its climatically constrained niche in order to survive. Dispersal has an important role to play in enabling a population to shift is geographical range limits, but many species are partially sedentary, with only a fraction of the population dispersing each year. We ask, can partially sedentary populations keep pace with climate or will such populations be more vulnerable to extinction? Through the development of a moving-habitat integrodifference equation model, we show that, provided climate velocity is not too large, partially sedentary populations can outperform fully dispersing populations in one of two ways: (i) by persisting at climate speeds where a fully dispersing population cannot, and (ii) exhibiting higher population densities. Moreover, we find that positive density-dependent dispersal can further improve the likelihood a population can persist. Our results highlight the positive role that non-dispersers may play in mitigating the effects of overdispersal and facilitating population persistence in a warming world.

Local Interactions Affect Spread of Resource in a Consumer-resource System With Group Defense

“…In a general integrodifference framework, the spread rate of a population is calculated by analyzing when the extinction equilibrium of the travelling wave solution of the system becomes unstable [35]. This also works in the case of a single-population dynamics system with sessile stages [10]. In the case of System 2, the extinction equilibrium of resource is always unstable, which implies that the resource is always able to invade when rare.…”