Mammal Research Institute, Polish Academy of Sciences, Waszkiewicza 1, 17-230, Białowieża, Poland.
Department of Wildlife, Fish and Environmental Studies, SLU, 901 83, Umeå, Sweden.
New Phytol. 2017 Apr;214(1):158-168. doi: 10.1111/nph.14345. Epub 2016 Nov 28.
Plant biomass consumers (mammalian herbivory and fire) are increasingly seen as major drivers of ecosystem structure and function but the prevailing paradigm in temperate forest ecology is still that their dynamics are mainly bottom-up resource-controlled. Using conceptual advances from savanna ecology, particularly the demographic bottleneck model, we present a novel view on temperate forest dynamics that integrates consumer and resource control. We used a fully factorial experiment, with varying levels of ungulate herbivory and resource (light) availability, to investigate how these factors shape recruitment of five temperate tree species. We ran simulations to project how inter- and intraspecific differences in height increment under the different experimental scenarios influence long-term recruitment of tree species. Strong herbivore-driven demographic bottlenecks occurred in our temperate forest system, and bottlenecks were as strong under resource-rich as under resource-poor conditions. Increased browsing by herbivores in resource-rich patches strongly counteracted the increased escape strength of saplings in these patches. This finding is a crucial extension of the demographic bottleneck model which assumes that increased resource availability allows plants to more easily escape consumer-driven bottlenecks. Our study demonstrates that a more dynamic understanding of consumer-resource interactions is necessary, where consumers and plants both respond to resource availability.
植物生物质消费者（哺乳动物食草和火灾）越来越被视为生态系统结构和功能的主要驱动因素，但温带森林生态学的主流范式仍然是，它们的动态主要是受底部资源控制的。利用来自热带稀树草原生态学的概念进展，特别是人口瓶颈模型，我们提出了一个新的观点，即整合消费者和资源控制对温带森林动态的影响。我们使用完全因子实验，改变有蹄类动物食草和资源（光）可利用性的水平，来研究这些因素如何塑造五种温带树种的繁殖。我们进行了模拟，以预测不同实验场景下的高度增量的种间和种内差异如何影响树种的长期繁殖。在我们的温带森林系统中，强烈的食草动物驱动的人口瓶颈发生了，而且在资源丰富的情况下与资源匮乏的情况下，瓶颈一样强烈。在资源丰富的斑块中，食草动物的过度啃食强烈抵消了这些斑块中小树苗逃脱的增强强度。这一发现是人口瓶颈模型的一个重要扩展，该模型假设资源的增加使植物更容易逃脱消费者驱动的瓶颈。我们的研究表明，需要对消费者-资源相互作用有更动态的理解，其中消费者和植物都对资源的可用性做出反应。
