Bornean tropical forests recovering from logging at risk of regeneration failure
Bornean tropical forests recovering from logging at risk of regeneration failure
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DOI：
10.1111/gcb.17209
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发表时间：
2024-03-01
影响因子：
11.6
通讯作者：
Dent，Daisy
中科院分区：
文献类型：
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作者：
Bartholomew，David C.;Hayward，Robin;Dent，Daisy
通过营林处理(丰富种植、砍伐攀缘植物和解放间伐)积极恢复被认为是对伐木森林的重要干预措施。然而，它加强更新的能力是伐木森林长期恢复的关键，这一点仍然知之甚少，特别是对于后代苗木的生产和生存。为了了解采伐和恢复的长期影响，我们跟踪了北婆罗洲未采伐和采伐后30-35 年未采伐和已采伐森林中桅杆结实后立即萌发的幼苗的多样性、存活率和特性。在恢复后15-27 年，我们监测了5119株苗木在未采伐林(UL)、自然更新采伐林(NR)和通过恢复造林处理(AR)积极恢复的采伐林的混合景观中的萌发情况，持续了约1.5 年。测定了15个树种399株苗木的14个叶、根和生物量分配性状。结果后不久，UL和AR林的苗木密度高于NR林，但在前6个 月内，AR林的成活率最低。群落组成因林型不同而不同，树冠后5~6个月，AR和NR林的物种丰富度和均匀度均低于UL林，但差异不显著；在 后5~6个月，AR和NR林的物种丰富度和均匀度均低于UL林，但差异不显著。群落组成的差异改变了不同森林类型的群落加权平均性状值，与UL林相比，NR林的根生物量分配更高。树冠后3 个月左右的死亡率受性状的影响，相对UL林，AR林具有更多的获得性性状和相对的地上投资。我们对幼苗存活率和多样性降低的研究结果表明，伐木后更新的时间很长，特别是对一些分类群来说。主动恢复伐木森林可以恢复最初的苗木生产，但AR森林死亡率的上升降低了主动恢复以加强苗木群落的补充或多样性的效力。这表明，目前积极的恢复做法可能无法克服伐木森林更新的障碍，这可能会推动未来森林植物群落的长期变化。
Active restoration through silvicultural treatments (enrichment planting, cutting climbers and liberation thinning) is considered an important intervention in logged forests. However, its ability to enhance regeneration is key for long‐term recovery of logged forests, which remains poorly understood, particularly for the production and survival of seedlings in subsequent generations. To understand the long‐term impacts of logging and restoration we tracked the diversity, survival and traits of seedlings that germinated immediately after a mast fruiting in North Borneo in unlogged and logged forests 30–35 years after logging. We monitored 5119 seedlings from germination for ~1.5 years across a mixed landscape of unlogged forests (ULs), naturally regenerating logged forests (NR) and actively restored logged forests via rehabilitative silvicultural treatments (AR), 15–27 years after restoration. We measured 14 leaf, root and biomass allocation traits on 399 seedlings from 15 species. Soon after fruiting, UL and AR forests had higher seedling densities than NR forest, but survival was the lowest in AR forests in the first 6 months. Community composition differed among forest types; AR and NR forests had lower species richness and lower evenness than UL forests by 5–6 months post‐mast but did not differ between them. Differences in community composition altered community‐weighted mean trait values across forest types, with higher root biomass allocation in NR relative to UL forest. Traits influenced mortality ~3 months post‐mast, with more acquisitive traits and relative aboveground investment favoured in AR forests relative to UL forests. Our findings of reduced seedling survival and diversity suggest long time lags in post‐logging recruitment, particularly for some taxa. Active restoration of logged forests recovers initial seedling production, but elevated mortality in AR forests lowers the efficacy of active restoration to enhance recruitment or diversity of seedling communities. This suggests current active restoration practices may fail to overcome barriers to regeneration in logged forests, which may drive long‐term changes in future forest plant communities.