Negrín Dastis Jorge Octavio, Milne Russell, Guichard Frédéric, Derry Alison Margaret
Départment des sciences biologiques Université du Québec à Montréal (UQAM) Montréal Québec Canada.
Groupe de recherche interuniversitaire en limnologie et en environnement aquatique (GRIL) Montréal Canada.
Evol Appl. 2019 Jul 25;12(7):1475-1486. doi: 10.1111/eva.12833. eCollection 2019 Aug.
Maladaptation is widespread in natural populations. However, maladaptation has most often been associated with absolute population decline in local habitats rather than on a spectrum of relative fitness variation that can assist natural populations in their persistence at larger regional scales. We report results from a field experiment that tested for relative maladaptation between-pond habitats with spatial heterogeneity and (a)symmetric selection in pH. In the experiment, we quantified relative maladaptation in a copepod metapopulation as a mismatch between the mean population phenotype and the optimal trait value that would maximize mean population fitness under either stable or fluctuating pH environmental conditions. To complement the field experiment, we constructed a metapopulation model that addressed both relative (distance from the optimum) and absolute (negative population growth) maladaptation, with the aim of forecasting maladaptation to pH at the regional scale in relation to spatial structure (environmental heterogeneity and connectivity) and temporal environmental fluctuations. The results from our experiment indicated that maladaptation to pH at the regional scale depended on the asymmetry of the fitness surface at the local level. The results from our metapopulation model revealed how dispersal and (a)symmetric selection can operate on the fitness surface to maintain maladaptive phenotype-environment mismatch at local and regional scales in a metapopulation. Environmental stochasticity resulted in the maintenance of maladaptation that was robust to dispersal, but also revealed an interaction between the asymmetry in selection and environmental correlation. Our findings emphasize the importance of maladaptation for planning conservation strategies that can support adaptive potential in fragmented and changing landscapes.
适应不良在自然种群中广泛存在。然而，适应不良通常与当地栖息地的种群绝对数量下降相关，而非与一系列相对适合度变化相关，而这种相对适合度变化有助于自然种群在更大的区域尺度上持续存在。我们报告了一项田间实验的结果，该实验测试了具有空间异质性和pH值（非）对称选择的池塘间栖息地之间的相对适应不良情况。在实验中，我们将桡足类集合种群中的相对适应不良量化为平均种群表型与在稳定或波动的pH环境条件下使平均种群适合度最大化的最优性状值之间的不匹配。为补充田间实验，我们构建了一个集合种群模型，该模型考虑了相对（与最优值的距离）和绝对（种群负增长）适应不良情况，目的是预测区域尺度上相对于空间结构（环境异质性和连通性）和时间环境波动的pH值适应不良情况。我们实验的结果表明，区域尺度上对pH值的适应不良取决于局部水平上适合度表面的不对称性。我们集合种群模型的结果揭示了扩散和（非）对称选择如何在适合度表面上起作用，以在集合种群的局部和区域尺度上维持适应不良的表型 - 环境不匹配。环境随机性导致了对扩散具有鲁棒性的适应不良的维持，但也揭示了选择不对称性与环境相关性之间的相互作用。我们的研究结果强调了适应不良对于规划保护策略的重要性，这些策略可以支持破碎化和不断变化的景观中的适应潜力。
