Spatial Patterns and Temporal Trajectories of the Bog Ground Layer Along a Post-Fire Chronosequence
Spatial Patterns and Temporal Trajectories of the Bog Ground Layer Along a Post-Fire Chronosequence
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DOI：
10.1007/s10021-008-9178-4
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发表时间：
2008-11-01
期刊：
影响因子：
3.7
通讯作者：
Vitt, Dale H.
中科院分区：
文献类型：
--
作者：
Benscoter, Brian W.;Vitt, Dale H.
泥炭地表层物种组成与生态系统功能(例如碳储存)有着错综复杂的联系。作为北方沼泽的主要干扰，野火选择性地移走了地表植被，创造了异质的栖息地条件，启动了演替。然而，人们对火灾后地面群落的演替轨迹知之甚少。在这里，我们评估了加拿大阿尔伯塔省中北部地区火灾后沼泽(火灾发生后1-105年)群落组成的时间和空间变化。我们在13个沼泽地建立了植被样地，并在2003-2006年对其进行了反复监测。我们发现了火后沼泽群落的三个阶段，从火后不久的先锋真苔藓(例如，狭叶多毛藓)优势(<；10ysf)到成熟地(20-80ysf)持续的泥炭藓优势，在较老的沼泽(>；80ysf)部分被羽毛苔藓(例如，施雷伯里侧耳)所取代。虽然物种均匀度较低，但以青海泥炭草为主的成熟沼泽群落物种丰富度最高。近地层群落组成的空间异质性呈双峰型，约为10ysf(真苔藓和泥炭藓共存)，当羽毛苔藓侵占和破坏泥炭藓优势时达到80ysf以上，导致群落物种丰富度和多样性沿火灾后恢复梯度的反相关关系。基于这些结果，我们发展了一个火后沼泽重新定居和演替的概念模型，在该模型中，微地形、土壤水分和燃烧强度相互作用，从而首次全面描述了火后沼泽近地层的时空演替轨迹。
Peatland ground layer species composition is intricately tied to ecosystem function (for example, carbon storage). As the primary disturbance in boreal bogs, wildfire selectively removes the ground layer vegetation, creating heterogeneous habitat conditions and initiating succession. However, the successional trajectory of the ground layer community following fire is poorly understood. Here we assess spatial and temporal changes in community composition along a chronosequence of post-fire bogs (1-105 years since fire) in north central Alberta, Canada. We established vegetation plots in 13 bogs and repeatedly monitored them from 2003-2006. We found three phases of the post-fire bog community, grading from pioneer true moss (for example, Polytrichum strictum) dominance soon post-fire (< 10 ysf) to persistent Sphagnum dominance in mature sites (20-80 ysf) with partial replacement by feathermosses (for example, Pleurozium schreberi) in older bogs (> 80 ysf). Mature bogs dominated by Sphagnum fuscum had the greatest species richness, although species evenness was low. Spatial heterogeneity of ground layer community composition was bimodal, peaking approximately 10 ysf (co-occurrence of true mosses and Sphagnum) and more than 80 ysf when feathermosses encroach and break-up Sphagnum dominance, resulting in inverse relationships of community species richness and diversity along the post-fire recovery gradient. Based on these results, we develop a conceptual model of post-fire bog recolonization and succession, in which microtopography, soil moisture, and combustion severity interact, thereby presenting the first comprehensive description of the spatio-temporal post-fire successional trajectory of the bog ground layer.