The complexity of an ecological community can be distilled into a network, where diverse interactions connect species in a web of dependencies. Species interact directly with each other and indirectly through environmental effects, however to our knowledge the role of these ecosystem engineers has not been considered in ecological network models. Here we explore the dynamics of ecosystem assembly, where species colonization and extinction depends on the constraints imposed by trophic, service, and engineering dependencies. We show that our assembly model reproduces many key features of ecological systems, such as the role of generalists during assembly, realistic maximum trophic levels, and increased nestedness with mutualistic interactions. We find that ecosystem engineering has large and nonlinear effects on extinction rates. While small numbers of engineers reduce stability by increasing primary extinctions, larger numbers of engineers increase stability by reducing primary extinctions and extinction cascade magnitude. Our results suggest that ecological engineers may enhance community diversity while increasing persistence by facilitating colonization and limiting competitive exclusion.

可以将生态社区的复杂性提炼成一个网络，其中各种相互作用将物种连接成一个依赖网络。物种之间直接相互影响，并通过环境影响间接相互作用，但是据我们所知，生态网络模型中并未考虑这些生态系统工程师的作用。在这里，我们探讨了生态系统装配的动力学，其中物种的定殖和灭绝取决于营养，服务和工程依赖性所施加的约束。我们表明，我们的装配模型重现了生态系统的许多关键特征，例如通才在装配过程中的作用，现实的最大营养水平以及通过相互影响而增加的嵌套。我们发现，生态系统工程对灭绝速率具有很大的非线性影响。少数工程师通过增加主要物种的灭绝来降低稳定性，而大量工程师则通过减少主要物种的灭绝和灭绝级联幅度来提高稳定性。我们的结果表明，生态工程师可以通过促进殖民化和限制竞争排斥来增强社区多样性，同时增加持久性。