Diversity stabilizes but does not increase sapling survival in a tree diversity experiment
Diversity stabilizes but does not increase sapling survival in a tree diversity experiment
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DOI：
10.1111/rec.13927
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发表时间：
2023-05
影响因子：
3.2
通讯作者：
R. King;J. Pullen;S. Cook-Patton;J. Parker
中科院分区：
文献类型：
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作者：
R. King;J. Pullen;S. Cook-Patton;J. Parker
植树具有增加物种多样性和固碳的潜力，但种植失败和早期死亡对植树的成功构成了重大障碍。生物多样性-生态系统功能理论表明，不同的树木种植可以通过组合效应或促进效应来改善生存结果，但对这一假说的检验仍然很少。在这里，我们使用了一项大规模的树木多样性实验，对近8,000棵树进行了监测，以测试(1)树种多样性是否提高了存活率，(2)树木多样性是否稳定了种植失败的风险，和(3)相对于其他常见的苗木死亡驱动因素(如草食和土壤水分)，多样性效应是否重要。我们发现，只有物种特性显著影响生存的可能性，而不是植物功能多样性，也不是样地物种丰富度或系统发育多样性。海拔和土壤湿度对存活率的影响很小，但两者都解释了数据中非常小的差异(r2marg≤0.011)。然而，较高的树木多样性确实大大减少了样地间存活率的差异，单一栽培的变异系数(30.4%，28.4-32.6%，95%的自举可信区间)比4-(16.3%，13.8-18.7%)和12种样地(12.8%，10.8-14.7%)高近2倍。最终，我们的结果表明，使用多样化的物种可以降低种植失败的风险(即组合效应)，但物种选择在早期建立中仍然起着很大的作用。
Tree plantings have the potential to increase species diversity and sequester carbon, yet planting failure and early mortality pose significant barriers to their success. Biodiversity‐ecosystem function theory suggests that diverse tree plantings could improve survival outcomes through either the portfolio or facilitation effect, yet there remain few tests of this hypothesis. Here, we use a large‐scale tree‐diversity experiment (BiodiversiTREE), with monitoring of nearly 8,000 individual trees to test whether (1) tree species diversity increases survival rates, (2) tree diversity stabilizes the risk of planting failure, and/or (3) diversity effects are important relative to other common drivers of seedling mortality (e.g. herbivory and soil moisture). We found that only species identity significantly impacted the likelihood of survival, not plant functional diversity nor plot species richness nor phylogenetic diversity. There were minor effects of elevation and soil moisture on survival, but both explained a very small amount of variation in the data (r2marg ≤ 0.011). Higher tree diversity did, however, strongly reduce variation in survival across plots, with nearly 2‐fold higher coefficients of variation in monocultures (30.4%, 28.4–32.6% 95% bootstrapped confidence interval) compared to 4‐ (16.3%, 13.8–18.7%) and 12‐species plots (12.8%, 10.8–14.7%). Ultimately, our results suggest that employing diverse species can lower the risk of planting failure (i.e. the portfolio effect), but that species selection still plays a large role in early establishment.