Ontogenetic development underlies population response to mortality

Understanding demographic responses to mortality is crucial to predictive ecology. While classic ecological theory posits reductions in population biomass in response to extrinsic mortality, models containing realistic developmental change predict the potential for counterintuitive increase in stage-specific biomass, i.e., biomass overcompensation. Patterns of biomass overcompensation should be predictable based on differences in the relative energetic efficiencies of juvenile maturation and adult reproduction. Specifically, in populations where reproduction is the limiting process, adult-specific mortality should enhance total reproduction and thus juvenile biomass. We tested this prediction by inducing an array of stage-specific harvesting treatments across replicate populations of Daphnia pulex. In accordance with reproductive regulation, the greatest biomass response occurred in the juvenile Daphnia stage and this response occurred most strongly in response to adult mo...理解死亡率的种群统计响应，对预测生态学研究至关重要。经典生态学理论提出，外源性死亡率会引发种群生物量下降；但纳入真实发育动态的模型则预测，特定发育阶段的生物量可能出现反直觉的增长，即生物量过度补偿（biomass overcompensation）。生物量过度补偿的模式可依据幼体发育成熟与成体繁殖的相对能量效率差异进行预测。具体而言，在以繁殖为限制过程的种群中，成体特异性死亡率可提升总繁殖量，进而增加幼体生物量。我们通过在多组重复的大型溞（Daphnia pulex）种群中施加一系列阶段特异性捕捞处理，对该预测开展了验证。依据繁殖调控规律，最大的生物量响应出现在大型溞幼体阶段，且该响应在针对成体[原文截断]的处理下表现最为强烈。