Long-term effects of pest-induced tree species change on carbon and nitrogen cycling in northeastern U.S. forests: A modeling analysis
Long-term effects of pest-induced tree species change on carbon and nitrogen cycling in northeastern U.S. forests: A modeling analysis
复制标题
害虫引起的树种变化对美国东北部森林碳和氮循环的长期影响：模型分析
DOI：
10.1016/j.foreco.2016.03.045
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发表时间：
2016
影响因子：
3.7
通讯作者：
K. Weathers
中科院分区：
文献类型：
--
作者：
K. Crowley;G. Lovett;M. Arthur;K. Weathers
入侵的昆虫和病原体可以通过改变树种组成引起森林生态系统的长期变化，从而从根本上改变森林的生物地球化学。为了研究树种变化如何改变美国东北部森林的长期碳(C)和氮(N)循环，我们开发了一种新的森林生态系统模型，称为Spe-CN，该模型允许物种组成随时间变化。本文模拟了三种入侵物种——山毛榉树皮病（BBD）、铁杉毛枝病（HWA）和橡树猝死病（SOD）对森林生产力、碳储量、氮保留和损失的影响。该模型预测了林分入侵后植被与土壤间碳氮循环速率和分布的变化，其变化幅度、方向和时间取决于树种特性。对于因BBD导致糖枫（Acer saccharumMarsh.）取代美洲山毛榉（Fagus 500foliaehrh .）的林分，该模型预测，随着植物C的增加（+36%）超过土壤（- 11%）和砍伐木材（- 24%）的C损失，碳的净损失（100年后- 13%）转变为净C储存（300年后+10%）。在替换东部铁杉（Tsuga canadensis(L.)）后黄桦（Betula alleghaniensis isbritt .）的早期森林地表C损失（100年后- 28%）超过了145年后植物和砍伐木材C的增加；300年时，入侵和未入侵林分的总碳含量差异不大。在红枫（Acer rubrumL.）因SOD而取代红橡树（Quercus rubraL.）的情况下，植物和土壤C的损失在100年后继续产生净C损失（- 29%）。与C相比，在不同的入侵情景中，C的储存和损失模式存在很大差异，但在所有三种入侵情景中，总氮最终都较低。入侵林分的预测硝态氮淋失量也相应高于未入侵林分（+0.3 g m−2年−1），但淋失量的增加滞后于HWA入侵后近100年。总之，这些结果表明，虫害诱导的树种变化对森林C和N循环的影响在大小、影响方向和入侵后响应时间上都有所不同，这取决于衰退和替代物种的身份，而物种特异性模型可以帮助阐明这种变化。未来的预测将需要考虑到树种的变化，以产生对碳和氮储存和损失的有意义的估计。
Invasive insects and pathogens can cause long-term changes in forest ecosystems by altering tree species composition, which can radically alter forest biogeochemistry. To examine how tree species change may alter long-term carbon (C) and nitrogen (N) cycling in northeastern U.S. forests, we developed a new forest ecosystem model, called Spe-CN, that allows species composition to shift over time. We simulated the effects of species change due to three invaders—beech bark disease (BBD), hemlock woolly adelgid (HWA), and sudden oak death (SOD)—on forest productivity, C storage, and N retention and loss over a 300-year period. The model predicted changes in C and N cycling rates and distribution between vegetation and soils after stands were invaded, with the magnitude, direction, and timing dependent on tree species identity. For a stand in which sugar maple (Acer saccharumMarsh.) replaced American beech (Fagus grandifoliaEhrh.) due to BBD, the model predicted a change from net C loss (−13% after 100 years) to net C storage (+10% after 300 years), as plant C gain (+36%) overtook C loss from soils (−11%) and downed wood (−24%). Following replacement of eastern hemlock (Tsuga canadensis(L.) Carr.) by yellow birch (Betula alleghaniensisBritt.) due to HWA, early loss of forest floor C (−28% after 100 years) was exceeded by gain of plant and downed wood C after 145 years; by 300 years, total C differed little between invaded and un-invaded stands. Where red maple (Acer rubrumL.) replaced red oak (Quercus rubraL.) due to SOD, loss of plant and soil C generated net C loss (−29%) after 100 years that continued thereafter. In contrast to C, for which patterns of storage and loss differed considerably among invasion scenarios, total N was ultimately lower following invasion across all three scenarios. Predicted nitrate leaching was also correspondingly higher in invaded vs. un-invaded stands (+0.3 g m−2year−1of N from nitrate), but the leaching increase lagged by nearly 100 years following HWA invasion. Together, these results demonstrate that the effects of pest-induced tree species change on forest C and N cycling vary in magnitude, direction of effect, and timing of response following invasion, depending on the identity of the declining and replacing species, and that species-specific modeling can help elucidate this variation. Future predictions will need to account for tree species change to generate meaningful estimates of C and N storage and loss.