Wood traits explain microbial but not termite‐driven decay in Australian tropical rainforest and savanna
Wood traits explain microbial but not termite‐driven decay in Australian tropical rainforest and savanna
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DOI：
10.1111/1365-2745.14090
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发表时间：
2023-03
影响因子：
5.5
通讯作者：
S. Law;Habacuc Flores‐Moreno;A. Cheesman;R. Clement;M. Rosenfield;Abbey R. Yatsko;L. Cernusak;J. Dalling;T. Canam;Isra Abo Iqsaysa;Elizabeth S. Duan;S. Allison;P. Eggleton;A. Zanne
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作者：
S. Law;Habacuc Flores‐Moreno;A. Cheesman;R. Clement;M. Rosenfield;Abbey R. Yatsko;L. Cernusak;J. Dalling;T. Canam;Isra Abo Iqsaysa;Elizabeth S. Duan;S. Allison;P. Eggleton;A. Zanne
木本物种腐烂率的变化是预测枯木中碳储存命运的一个关键不确定性，特别是在热带地区。量化生物腐烂剂（特别是微生物和白蚁）在不同气候下和具有不同木材特性的物种之间的相对贡献可能有助于解释这种变化。为了填补这一知识空白，我们使用了来自澳大利亚东北部雨林 (n = 10) 或稀树草原 (n = 6) 的 16 种植物的木质茎，有或没有白蚁进入。为了进行比较，我们还在两个地点部署了标准化的非本地松木块。我们假设，在限制微生物活动的条件下，白蚁会增加枯木腐烂的速度。具体来说，在干燥条件下和具有限制微生物分解者特征的木材品种中，白蚁对木材腐烂的贡献应该更大。白蚁对茎的发现率出人意料地低，在雨林和稀树草原中分别仅发现了 17.6% 和 22.6% 的可接触原生茎。与我们的假设相反，白蚁发现的茎只在雨林中分解得更快。在雨林和稀树草原上，白蚁发现并腐烂松木块的速度比本地松木的茎要高。我们发现同一地点内不同本地木材品种的白蚁发现率和微生物腐烂率存在显着差异。尽管木材特征解释了 85% 的微生物腐烂变化，但它们并不能解释白蚁驱动的腐烂。对于未被白蚁发现的茎，木材养分浓度和紫丁香基：愈创木基木质素比率较高但碳浓度和木材密度较低的物种的腐烂率较高。合成。死木周转和碳储存的生态系统规模预测应考虑木材性状对分解者群落的影响。在澳大利亚热带地区，白蚁导致的地面原生木材的腐烂程度低于预期。即使存在白蚁，它们也不一定会增加热带森林中倒下的原生木材的分解速度。我们的研究揭示了澳大利亚热带雨林和稀树草原之间木材腐烂的驱动因素有何不同；进一步的研究应该测试这种差异是否适用于全世界。
Variation in decay rates across woody species is a key uncertainty in predicting the fate of carbon stored in deadwood, especially in the tropics. Quantifying the relative contributions of biotic decay agents, particularly microbes and termites, under different climates and across species with diverse wood traits could help explain this variation. To fill this knowledge gap, we deployed woody stems from 16 plant species native to either rainforest (n = 10) or savanna (n = 6) in northeast Australia, with and without termite access. For comparison, we also deployed standardized, non‐native pine blocks at both sites. We hypothesized that termites would increase rates of deadwood decay under conditions that limit microbial activity. Specifically, termite contributions to wood decay should be greater under dry conditions and in wood species with traits that constrain microbial decomposers. Termite discovery of stems was surprisingly low with only 17.6% and 22.6% of accessible native stems discovered in the rainforest and savanna respectively. Contrary to our hypothesis, stems discovered by termites decomposed faster only in the rainforest. Termites discovered and decayed pine blocks at higher rates than native stems in both the rainforest and savanna. We found significant variation in termite discovery and microbial decay rates across native wood species within the same site. Although wood traits explained 85% of the variation in microbial decay, they did not explain termite‐driven decay. For stems undiscovered by termites, decay rates were greater in species with higher wood nutrient concentrations and syringyl:guiacyl lignin ratios but lower carbon concentrations and wood densities. Synthesis. Ecosystem‐scale predictions of deadwood turnover and carbon storage should account for the impact of wood traits on decomposer communities. In tropical Australia, termite‐driven decay was lower than expected for native wood on the ground. Even if termites are present, they may not always increase decomposition rates of fallen native wood in tropical forests. Our study shows how the drivers of wood decay differ between Australian tropical rainforest and savanna; further research should test whether such differences apply world‐wide.