The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape
The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape
复制标题
DOI：
10.1073/pnas.1202894110
复制
发表时间：
2013-03-05
影响因子：
11.1
通讯作者：
Higuchi, Niro
中科院分区：
文献类型：
--
作者：
Chambers, Jeffrey Q.;Negron-Juarez, Robinson I.;Higuchi, Niro
原始森林生态系统由不同演替阶段的斑块组成，在大的时空尺度上，处于任何特定状态的景观比例相对恒定。扰动事件的大小分布和返回频率，以及随后的恢复过程，在很大程度上决定了这种古老稳定状态发展的空间尺度。在这里，我们通过整合野外样地数据、遥感干扰概率分布函数和基于个体的模拟建模来表征亚马逊中部森林的这种马赛克。结果表明，在相对较大的空间尺度上，不同演替年龄的斑块呈现稳定状态，这对探测一小部分景观样本的时间趋势具有重要意义。长期高度显著的随机运行平均1.0 Mg生物量。ha（-1）。Y（-1）经常被偶发性干扰事件打断，导致公顷尺度树木生物量的锯齿形时间序列。为了最大限度地检测该亚马逊中部地区的时间趋势（例如，由二氧化碳施肥驱动），大于10公顷的地块将提供最大的灵敏度。基于模型的各种林隙死亡率分数分析表明，基于样地的方法遗漏了9.1-16.9%的树木死亡率，这强调了将样地和遥感方法结合起来估算净景观碳平衡的必要性。热带原生林在扰动和恢复周期的驱动下表现出复杂的大尺度结构，公顷尺度样地的生态系统和群落属性表现出从稳态状态持续的动态偏离。
Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. The size distribution and return frequency of disturbance events, and subsequent recovery processes, determine to a large extent the spatial scale over which this old-growth steady state develops. Here, we characterize this mosaic for a Central Amazon forest by integrating field plot data, remote sensing disturbance probability distribution functions, and individual-based simulation modeling. Results demonstrate that a steady state of patches of varying successional age occurs over a relatively large spatial scale, with important implications for detecting temporal trends on plots that sample a small fraction of the landscape. Long highly significant stochastic runs averaging 1.0 Mg biomass.ha(-1).y(-1) were often punctuated by episodic disturbance events, resulting in a sawtooth time series of hectare-scale tree biomass. To maximize the detection of temporal trends for this Central Amazon site (e.g., driven by CO2 fertilization), plots larger than 10 ha would provide the greatest sensitivity. A model-based analysis of fractional mortality across all gap sizes demonstrated that 9.1-16.9% of tree mortality was missing from plot-based approaches, underscoring the need to combine plot and remote-sensing methods for estimating net landscape carbon balance. Old-growth tropical forests can exhibit complex large-scale structure driven by disturbance and recovery cycles, with ecosystem and community attributes of hectare-scale plots exhibiting continuous dynamic departures from a steady-state condition.