Rapid evolution and the convergence of ecological and evolutionary time

Abstract

Recent studies have documented rates of evolution of ecologically important phenotypes sufficiently fast that they have the potential to impact the outcome of ecological interactions while they are underway. Observations of this type go against accepted wisdom that ecological and evolutionary dynamics occur at very different time scales. While some authors have evaluated the rapidity of a measured evolutionary rate by comparing it to the overall distribution of measured evolutionary rates, we believe that ecologists are mainly interested in rapid evolution because of its potential to impinge on ecological processes. We therefore propose that rapid evolution be defined as a genetic change occurring rapidly enough to have a measurable impact on simultaneous ecological change. Using this definition we propose a framework for decomposing rates of ecological change into components driven by simultaneous evolutionary change and by change in a non-evolutionary factor (e.g. density dependent population dynamics, abiotic environmental change). Evolution is judged to be rapid in this ecological context if its contribution to ecological change is large relative to the contribution of other factors. We provide a worked example of this approach based on a theoretical predatorprey interaction [Abrams, P. & Matsuda, H. (1997). Evolution, 51, 1740], and find that in this system the impact of prey evolution on predator per capita growth rate is 63% that of internal ecological dynamics. We then propose analytical methods for measuring these contributions in field situations, and apply them to two long-term data sets for which suitable ecological and evolutionary data exist. For both data sets relatively high rates of evolutionary change have been found when measured as character change in standard deviations per generation (haldanes). For Darwin's finches evolving in response to fluctuating rainfall [Grant, P.R. & Grant, B.R. (2002). Science, 296, 707], we estimate that evolutionary change has been more rapid than ecological change by a factor of 2.2. For a population of freshwater copepods whose life history evolves in response to fluctuating fish predation [Hairston, N.G. Jr & Dillon, T.A. (1990). Evolution, 44, 1796], we find that evolutionary change has been about one quarter the rate of ecological change -less than in the finch example, but nevertheless substantial. These analyses support the view that in order to understand temporal dynamics in ecological processes it is critical to consider the extent to which the attributes of the system under investigation are simultaneously changing as a result of rapid evolution.

Beyond the Black Queen Hypothesis

“…Metabolic dependencies are potentially a major driver of species co-occurrence (Zelezniak et al, 2015). Until recently, the repercussions of such evolution at the community level were mostly overlooked, whereas it is now becoming evident that they are an integral part of community systems (Hairston et al, 2005;Johnson and Stinchcombe, 2007;Schoener, 2011) implying that evolutionary dynamics should systematically be taken into account when characterizing communities.…”

Fine-scale local adaptation in an invasive freshwater fish has evolved in contemporary time

“…Much of what we have learned about the conditions that promote adaptive divergence, and the speed and form of that divergence, has emerged from the opportunistic natural experiments afforded by biological invasions (reviewed by earlier studies [8,9]) or natural range expansions into new habitats [10,11]. It is increasingly clear that rapid evolutionary change can influence ecological dynamics in invaded ecosystems [12], and that adaptive evolution can create positive feedbacks on the ability of invaders to successfully disperse and colonize novel environments [13,14]. Despite its obvious importance, adaptation in recently established populations, and especially among vertebrates, is rarely assessed and even less frequently in situ.…”

Food web properties of the recently constructed, deep subtropical Fei-Tsui Reservoir in comparison with the ancient Lake Biwa

“…In the FTR, by contrast, its lentic history may be too short for the native fish to adapt well to the pelagic habitat. However, evolutionary biologists have recently reported numerous cases studying rapid evolution, which occurs on an ecological time scale much shorter than expected from conventional evolutionary process (Stockwell et al, 2003;Hairston Jr. et al, 2005). For instance, the bluegill sunfish Lepomis macrochirus Rafinesque, 1810 was introduced into Lake Biwa from the United States in the 1960s.…”