The importance of residual ecological legacies for extinction debts in managed forests

栖息地丧失是北方森林和许多其他生态系统物种丧失的主要原因。然而，最近的理论进展表明，这些影响可能被大大低估，物种灭绝可能会通过一种称为灭绝债务的过程持续到未来很久。尽管有这种可怕的预测，但几乎没有关于物种灭绝债务的经验例子，这些例子提供了预测何时以及哪些物种将灭绝所需的信息。因此，目前尚不清楚灭绝债务是否会转化为生态系统功能的长期损失(“功能债务”)，以及什么样的保护或恢复努力可以限制或扭转这些损失。 在这里，我提出了一个综合研究计划，该计划将确定在北方森林通过密集采伐和生物量移除大规模清除枯木后，灭绝债务的可能性、程度和持续时间。通过这个研究项目，我将培训12名以上的HQP。我还将提供一种概念上和实验上独特的方法，基于直接测量与枯木相关的昆虫和真菌在个别枯木栖息地和跨复制的、日益受影响的景观中的定居-灭绝动力学。我将利用正在进行的三个实验，它们的栖息地丧失发生在不同的时间，从而提供了跨越15年的景观的时间序列，其中灭绝债务的影响可以直接测量。然后，我将使用殖民-灭绝动态的经验估计来参数化灭绝债务模型，并在大量现实的管理情景下评估长期物种丧失的风险。通过关注枯木中的群落和食物网及其在分解和碳储存中的作用，我将进一步将灭绝债务的任何长期影响扩展到与功能债务相关的更大的生态系统影响。 这个框架提出了一种新的方法，通过明确考虑殖民灭绝动力学来整合保护和恢复生态学。有了这些信息，我们可以根据更大的地貌条件，‘定制’有利于特定类型的枯木的缓解策略。我还提供了一种方法，将枯木管理与生态弹性的概念统一起来。这些信息对于土地管理者、养护利益攸关方和政策制定者来说至关重要，他们目前正在根据有限的(如果有的话)生态信息规划指导方针和具有约束力的立法，以便密集清除生物质。

Habitat loss is the principal cause of species loss in boreal forests and many other ecosystems. However, recent theoretical advances suggest these impacts may be greatly underestimated and species loss may continue far into the future through a process called extinction debt. Despite this dire prediction, there are few empirical examples of extinction debt that provide the information necessary to predict when and which species will go extinct. As a consequence, it is unclear whether extinction debts will translate into long-term losses in ecosystem functions (‘functional debt’) and what kinds of conservation or restoration efforts could limit or reverse these losses. Here, I present an integrated research program that will determine the likelihood, extent and duration of extinction debts following large-scale removal of deadwood by intensive harvesting and biomass removal in boreal forests. Through this research program I will train more than 12 HQPs. I will also provide a conceptually and experimentally unique approach based on direct measurement of colonization-extinction dynamics of deadwood-associated insects and fungi in individual deadwood habitats and across replicated, increasingly impacted landscapes. I will capitalize on three ongoing experiments where habitat loss occurred at different times thus providing a chronosequence of landscapes that spans 15 years and where the effects of extinction debt can be measured directly. I will then use empirical estimates of colonization-extinction dynamics to parametrize extinction debt models and evaluate the risks of long-term species loss under a large number of realistic, management scenarios. By focusing on communities and food webs in deadwood and their role in decomposition and carbon storage, I will further extend any long-term impacts of extinction debt to larger ecosystem impacts related to a functional debt. This framework presents a novel means to integrate conservation and restoration ecology through explicit consideration of colonization-extinction dynamics. With this information we can ‘customize’ mitigation strategies that favour specific types of deadwood depending on the condition of the larger landscape. I also provide a means to unify deadwood management with notions of ecological resilience. This information is essential for land-managers, conservation stakeholders and policy makers who are currently planning guidelines and binding legislation for intensive biomass removal based on limited (if any) ecological information.