Wood‐inhabiting fungal communities are a diverse and ecologically critical part of forest ecosystems, yet the spatial structure of fungal biodiversity in these ecosystems is largely unknown. Legislation allowed harvesting of deadwood from temperate rainforests on conservation lands in New Zealand following Cyclone Ita in 2014. Harvesting guidelines specified widely spread harvesting, on the assumption that rare fungal species may be highly spatially restricted, but were not based on quantitative assessment. We sampled fungi in and on logs of Dacrydium cupressinum (Podocarpaceae) a long‐lived, common, canopy tree in lowland New Zealand forests. DNA was extracted from 81 logs varying in decay state across a 40 km long region of West Coast (South Island) forests, and sequenced using general fungal primers for metabarcoding to identify OTUs (operational taxonomic units). We examined three axes of rarity: occupancy, dominance when present, and niche breadth (as spatial extent and decay state specialization). Low‐occupancy fungi were common, including a group of infrequently occurring but dominant when present fungi, the majority of which were Ascomycota. Despite this, there was an overall positive relationship between occupancy and dominance. Widespread, dominant fungi were most commonly Basidiomycota. Testing all fungal OTUs, there were no more fungi with maximum range sizes < 4 km than would be expected at random. Of the 351 low‐occupancy OTUs found two to four times, only 12 had maximum range sizes < 900 m, and there was no more spatial restriction at scales < 900 m than would be expected by random chance, although there was some evidence of niche breadth restriction based on decay state similarity. The results show that fungal communities in deadwood are highly diverse, and include many rare taxa. Nonetheless, the lack of fungal OTUs with spatial restriction at scales < 900 m suggests that spatially dispersed timber harvesting will not mitigate risks of harvesting to rare fungal biodiversity.

中文翻译：

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稀有的木栖真菌不在当地。

居住在木材上的真菌群落是森林生态系统中多样化的且对生态至关重要的部分，但是在这些生态系统中真菌生物多样性的空间结构在很大程度上是未知的。立法允许在2014年飓风伊塔之后在新西兰的保护地上从温带雨林中采伐沉木。采伐准则规定了广泛分布的采伐，其前提是稀有真菌物种可能受到高度的空间限制，但并非基于定量评估。我们在Dacrydium cupressinum的原木中和原木上采样了真菌（罗汉果）新西兰低地森林中的一种长寿，常见的树冠树。从西海岸（南岛）森林40公里长的区域中，以衰减状态变化的81个原木提取DNA，并使用通用真菌引物进行测序，以进行metabarcoding识别OTU（操作分类单位）。我们研究了稀有度的三个轴：占有率，存在时的优势和利基宽度（作为空间范围和衰变状态的特化）。低占用率的真菌很常见，包括一组不经常发生但在现存真菌中占主导地位的真菌，其中大多数是子囊菌。尽管如此，在入住率和支配地位之间总体上存在积极的关系。广泛存在的优势真菌是最常见的担子菌。测试所有真菌OTU，最大范围< 比随机预期的高4公里。在351次发现的2到4次低空OTU中，只有12个的最大射程小于900 m，并且在小于900 m的尺度上没有比随机机会所预期的更多空间限制，尽管有一些利基的证据。基于衰减状态相似性的广度限制。结果表明，枯木中的真菌群落高度多样，并包括许多稀有的分类单元。然而，缺乏真菌OTUs，其在<900 m的尺度上受到空间限制，这表明在空间上分散的木材采伐将不会减轻针对稀有真菌生物多样性的采伐风险。尽管有一些证据表明基于衰变状态相似性的利基宽度限制。结果表明，枯木中的真菌群落高度多样，并包括许多稀有的分类单元。但是，缺乏真菌OTUs，其规模小于900 m的空间受到限制，这表明在空间上分散的木材采伐将不会减轻针对稀有真菌生物多样性的采伐风险。尽管有一些证据表明基于衰变状态相似性的利基宽度限制。结果表明，枯木中的真菌群落高度多样，并包括许多稀有的分类单元。但是，缺乏真菌OTUs，其规模小于900 m的空间受到限制，这表明在空间上分散的木材采伐将不会减轻针对稀有真菌生物多样性的采伐风险。