The contribution of intraspecific trait variation to changes in functional community structure along a stress gradient
The contribution of intraspecific trait variation to changes in functional community structure along a stress gradient
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种内性状变异对沿着压力梯度的功能群落结构变化的贡献
DOI：
10.1111/jvs.13112
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发表时间：
2022
影响因子：
2.8
通讯作者：
Mori Akira S.
中科院分区：
文献类型：
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作者：
Kitagawa Ryo;Masumoto Shota;Kaneko Ryo;Uchida Masaki;Mori Akira S.
我们考虑了两种与种内性状变异（ITV）对苔原植被沿应力梯度变化的功能群落结构的贡献有关的可能性。首先，ITV可以通过促进各胁迫条件下的最优性状值来促进植物物种在胁迫梯度上的成功；因此，ITV增强了向最优特征的收敛。第二，只有少数优势种的独立度与最优性状一致，其他物种的独立度促进了群落内性状的多样化。地点：加拿大魁省萨鲁特（北纬62°12′，西经75°39′）。方法在不同的环境胁迫梯度条件下（恶劣、中等和竞争）对植被进行调查。我们对叶片碳(C)和氮(N)含量、比叶面积（SLA）和株高这4个植物功能性状进行了跨梯度的ITV评价。我们评估了四个特征的社区加权平均值（CWMs）和功能离散度（FDis）。这些指数是根据所有生境（mean - CWM和mean - FDis）和每个生境（ITV - CWM和ITV - FDis）中所有个体的平均性状值计算得出的。结果4个性状沿胁迫梯度，平均- CWM（叶片N含量、SLA和株高）呈上升趋势，叶片C含量呈下降趋势。通过对ITV - FDis和平均FDis的比较发现，除了叶片C含量外，ITV在环境胁迫梯度的非生物胁迫端和竞争端分别倾向于降低和增加FDis值。结论沿非生物胁迫-竞争梯度的梯度效应促进了群落向最优性状的变化。特别是，除叶片C含量外，3个性状的ITV可能有助于最优性状值的均衡，并有助于在恶劣生境中“通过环境过滤”。然而，当物种竞争更丰富的资源时，只有一些优势物种可能表现出最优的性状值。因此，ITV可能允许在竞争而不是恶劣的非生物条件下的群落内的性状多样化。
QuestionWe considered two possibilities related to the contribution of intraspecific trait variation (ITV) to changes in functional community structure along a stress gradient in tundra vegetation. First, ITV could contribute to the success of plant species across the stress gradient by promoting optimal trait values for each condition along the gradient; thus, ITV enhances convergence toward optimal traits. Second, ITV of only a few dominant species aligns with the optimal trait, and ITV of other species promotes trait diversification within communities.LocationSalluit, Québec, Canada (62°12′N, 75°39′W).MethodsVegetation was surveyed under three different conditions (harsh, intermediate, and competitive) representing an environmental stress gradient. We assessed ITV across the gradient for four plant functional traits: leaf carbon (C) and nitrogen (N) contents, specific leaf area (SLA), and plant height. We assessed community‐weighted means (CWMs) and functional dispersion (FDis) for each of the four traits. These indices were calculated from mean trait values from all individuals across all habitats (mean‐CWM and mean‐FDis), and from each habitat (ITV‐CWM and ITV‐FDis).ResultsFor the four traits, increasing trends (leaf N content, SLA, and plant height) and decreasing trends (leaf C content) in mean‐CWM along the stress gradient were maintained and pronounced for ITV‐CWM. Comparisons between ITV‐FDis and mean‐FDis suggested that, except for leaf C content, ITV tends to reduce and increase FDis values at the abiotically stressful and competitive ends of the environmental stress gradient, respectively.ConclusionsITV along the abiotic stress–competition gradient appears to promote community‐level changes towards optimal traits. In particular, ITV in three traits (with the exception of leaf C content) may contribute to equalization of optimal trait values, and to “passage through environmental filtering” in harsh habitats. However, when species deal with competition for richer resources, only some dominant species may show optimal trait values. Therefore, ITV may allow for trait diversification within communities under competitive rather than harsh abiotic conditions.