Forest productivity mitigates human disturbance effects on late-seral prey exposed to apparent competitors and predators

Primary production can determine the outcome of management actions on ecosystem properties, thereby defining sustainable management. Yet human agencies commonly overlook spatio-temporal variations in productivity by recommending fixed resource extraction thresholds. We studied the influence of forest productivity on habitat disturbance levels that boreal caribou – a threatened, late-seral ungulate under top-down control – should be able to withstand. Based on 10 years of boreal caribou monitoring, we found that adult survival and recruitment to populations decreased with landscape disturbance, but increased with forest productivity. This benefit of productivity reflected the net outcome of an increase in resources for apparent competitors and predators of caribou, and a more rapid return to the safety of mature conifer forests. We estimated 3-fold differences in forest harvesting levels that caribou populations could withstand due to variations in forest productivity. The adjustment of ...

初级生产力（Primary Production）可决定生态系统属性相关管理措施的实施效果，进而明确可持续管理的核心内涵。然而当前人类管理机构常采用固定的资源开采阈值，忽视了生产力的时空变异特征。本研究探讨了森林生产力对北方针叶林驯鹿（boreal caribou）可承受的栖息地干扰水平的影响——该物种为受胁的晚演替有蹄类动物，受自上而下控制（Top-down Control）调控。基于为期10年的北方针叶林驯鹿监测数据，本研究发现：种群成年个体存活率与种群补充率随景观干扰程度加剧而下降，随森林生产力提升而升高。生产力的这一增益效应，实则是两种对立过程共同作用的净结果：一方面为驯鹿的表观竞争者与捕食者提供了更多可利用资源，另一方面使驯鹿能够更快返回成熟针叶林的安全生境。研究估算显示：受森林生产力变异的影响，不同种群的驯鹿可承受的森林采伐水平存在3倍差距。对……的调整。