Biodiversity inhibits species’ evolutionary responses to changing environments

Abstract

Despite growing interplay between ecological and evolutionary studies, the question of how biodiversity influences evolutionary dynamics within species remains understudied. Here, using a classical model of phenotypic evolution in species occupying a patchy environment, but introducing global change affecting patch conditions, we show that biodiversity can inhibit species’ evolution during global change. The presence of several species increases the chance that one or more species are pre‐adapted to new conditions, which restricts the ecological opportunity for evolutionary responses in all the species. Consequently, environmental change tends to select for changes in species abundances rather than for changing phenotypes within each species. The buffering effects of species diversity that we describe might be one important but neglected explanation for widely observed niche conservatism in natural systems. Furthermore, the results show that attempts to understand biotic responses to environmental change need to consider both ecological and evolutionary processes in a realistically diverse setting.

Physiological tolerances account for range limits and abundance structure in an invasive slug

“…Brewer & Gaston 2002Klok et al 2003; and also Leibold et al 2004;de Mazancourt et al 2008). On Marion Island, the scope of interactions between slugs and other species is likely to be small.…”

“…Even where conditions are not favourable, individuals may still persist owing to a rescue effect, or temporal variation in conditions, frequently making range margins dynamic and diffuse, rather than sharp (Gaston 2003;Crozier 2004). Why populations often do not evolve to overcome local environmental constraints adds further complexity to the questions of how range margins are set and change (see Hoffmann et al 2003, Alleaume-Benharira et al 2006, Chown & Terblanche 2007, de Mazancourt et al 2008and Hoffmann & Willi 2008.…”

Evolutionary rescue beyond the models

“…The fourth core property is the amount of heritable genetic variation in absolute fitness segregating in the population, since this standing variation largely determines a population's short-term capacity to increase its mean absolute fitness through natural selection [29]. In addition to the four core properties, it would be helpful to have information about mutational contributions to genetic variation in absolute fitness, how traits (such as selfing rates) mediate absolute fitness in the stressful environment, behavioural or phenotypic plasticity affecting fitness, and ecological properties that affect population growth or decline such as density dependence, spatial heterogeneity or interspecific interactions [16,18,19].…”

“…Formal mathematical models of evolutionary rescue that join population genetics with demography appeared soon after and have since provided a rigorous foundation for evolutionary rescue [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These models consider both gradual [6] and abrupt [7,8] modes of environmental change, various sources of environmental, genetic and demographic stochasticity [9][10][11][12][13][14][15][16] and intra-and interspecific interactions [18,19]. The relative influences of the genetic details underlying fitness variation (number of loci, gene effect sizes, initial allele frequencies) on evolutionary rescue have also been analysed [20].…”

Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations

“…Although the quality of DNA being released into the environment is a matter of debate [13,14], resistance genes can be disseminated in soil and other environments rich in nucleic acids [15,16]. On the other hand, standing variation present among different species of bacteria might result in competition among functional classes, such that strains that are pre-adapted to new conditions will limit the opportunity for the evolution of novel traits in less well pre-adapted strains [17]. This functional interference should be especially important in soil and gut microbial communities where there are a high diversity and number of existing bacteria types, ecological functions and resistance determinants [18 -21].…”