Rapid evolution accelerates plant population spread in fragmented experimental landscapes

Abstract

Abstract:Predicting the speed of biological invasions and native species migrations requires understanding the ecological and evolutionary dynamics of spreading populations. Theory predicts that evolution can accelerate species' spread velocity, but how landscape patchiness, an important control over traits under selection, influences this process is unknown. We manipulated the response to selection in populations of a model plant species spreading through replicated experimental landscapes of varying patchiness. After six generations of change, evolving populations spread 11% further than non-evolving populations in continuously favorable landscapes, and 200% further in the most fragmented landscapes. The greater effect of evolution on spread in patchier landscapes was consistent with the evolution of dispersal and competitive ability. Accounting for evolutionary change may be critical when predicting the velocity of range expansions.One Sentence Summary: Evolution on ecological timescales increases the velocity of experimental plant populations spreading through patchy habitats. Main text:In an era of global environmental change, biological invasions and the movement of species ranges with climate change present two of the greatest threats to natural and managed ecosystems (1, 2). At the core of each dynamic is the spread of populations across landscapes fragmented by natural and anthropogenic barriers to movement. That habitat fragmentation slows the velocity of spread has long been appreciated (3, 4), but its influence on the potential for evolution to increase population expansion is unknown (5). Theory shows that natural selection at the low-density front of populations expanding through continuously favorable landscapes coupled with the spatial sorting of offspring favors traits contributing to fecundity and dispersal, both of which accelerate the invasion velocity (6-10). Whether this eco-evolutionary process operates similarly in systems fragmented by unsuitable habitat is uncertain because spread in these systems depends on the build-up of high density populations capable of dispersing over gaps (5, 11). Any factor that alters selection on an expanding population can influence spread, but whether evolution through selection or genetic drift predictably affects spread velocity on the rapid time scale of ecological dynamics remains an open question. Answering such questions has Page 2 of 10! important implications for predicting the future spread of biological invasions and climate change migrants.Empirical progress toward understanding evolution in populations spreading through fragmented landscapes is limited, largely because the process occurs over many generations and at geographic spatial scales. Due to these constraints, nearly all empirical evidence for evolution affecting spread comes from a few retrospective, observational analyses (12-16). The spread velocity of cane toads, for example, increased 6-fold after introduction to Australia, consistent with evolved changes in dispersal (14,17,18). No...

Climate and rapid local adaptation as drivers of germination and seed bank dynamics of Alliaria petiolata (garlic mustard) in North America

“…; Sultan et al . ; Oduor, Leimu & van Kleunen ; Williams, Kendall & Levine ). There is evidence for other rapid evolutionary changes involving A. petiolata , including root glucosinulate concentrations, which appear to be a function of residence time (Lankau et al .…”

“…). These investigations documented widespread local adaptation in introduced species that surprisingly matches local adaptations of native species (Flores‐Moreno & Moles ; Oduor, Leimu & van Kleunen ) and materializes within a few generations (Williams, Kendall & Levine ). These rapid adaptations do not involve morphological features but more often physiological or chemical changes in response to climate, competitors, mutualists or natural enemies (Faillace & Morin ; Kilkenny & Galloway ; Colautti et al .…”

Evolution of dispersal syndrome and its corresponding metabolomic changes

“…Furthermore, dispersal is known to be linked with several other ecological and evolutionary processes, such as, population stability (Dey and Joshi 2006), local adaptation (Gandon et al 1996;Lenormand 2002), speciation (reviewed in Barton 2001), coopera-tion and sociality (Le Galliard et al 2005), community dynamics (reviewed in Leibold et al 2004), species invasion (Shaw and Kokko 2015), range expansion (Travis and Dytham 2002), and disease spread (Rappole et al 2006). Not surprisingly, the causes and consequences of dispersal evolution have been a major focus of investigation for the past decade (Fronhofer and Altermatt 2015;Williams et al 2016;Fronhofer et al 2017;Ochocki and Miller 2017;Weiss-Lehman et al 2017). Not surprisingly, the causes and consequences of dispersal evolution have been a major focus of investigation for the past decade (Fronhofer and Altermatt 2015;Williams et al 2016;Fronhofer et al 2017;Ochocki and Miller 2017;Weiss-Lehman et al 2017).…”

The influence of time since introduction on the population growth of introduced species and the consequences for management

“…This might reflect a lack of data for populations that have recently been introduced because fecundity related processes may exert a relatively strong influence during the initial introduction stages. There is theoretical and empirical evidence that reduced intraspecific competition along the low density front of an invasion can select for traits such as fecundity that contribute to increased population growth and spread rate Perkins et al 2013;Williams et al 2016). We need more data of alien species at the early stage of introduction to detect any changes in elasticity to fecundity (F), although these types of data are usually not obtained until later in the invasion process and then often only if the species has become a management problem.…”