Data from: How do similarities in spatial distributions and interspecific associations affect the coexistence of Quercus species in the Baotianman National Nature Reserve, Henan, China

Congeneric species often have similar ecological characteristics and use similar resources. These similarities may make it easier for them to co-occur in a similar habitat but may also lead to strong competitions that limit their coexistence. Hence, how do similarities in congeneric species affect their coexistence exactly? This study mainly used spatial point pattern analysis in two 1 hm2 plots in the Baotianman National Nature Reserve, Henan, China, to compare the similarities in spatial distributions and interspecific associations of Quercus species. Results revealed that Quercus species were all aggregated under the complete spatial randomness null model, and aggregations were weaker under the heterogeneous Poisson process null model in each plot. The interspecific associations of Quercus species to non-Quercus species were very similar in Plot 1. However, they can be either positive or negative in different plots between the co-occurring Quercus species. The spatial distributions of congeneric species, interspecific associations with non-Quercus species, neighborhood richness around species, and species diversity were all different between the two plots. We found that congeneric species did have some similarities, and the closely related congeneric species can positive or negative associate with each other in different plots. The co-occurring congeneric species may have different survival strategies in different habitats. On one hand, competition among congenerics may lead to differentiation in resource utilization. On the other hand, their similar interspecific associations can strengthen their competitive ability and promote local exclusion to non-congeneric species to obtain more living space. Our results provide new knowledge for us to better understand the coexistence mechanisms of species.

同属物种通常具有相似的生态特征与资源利用策略。此类相似性既可能推动它们在相似生境中共存，也可能引发激烈种间竞争，进而限制其共存能力。那么，同属物种间的相似性究竟如何影响它们的共存过程？本研究以中国河南宝天曼国家级自然保护区内的两块1公顷（hm²）样地为研究载体，主要采用空间点格局分析（spatial point pattern analysis）方法，对比栎属（Quercus）物种的空间分布相似性及其种间关联（interspecific associations）特征。研究结果表明，在完全空间随机零模型（complete spatial randomness null model）下，所有栎属物种均呈聚集分布；而在异质泊松过程零模型（heterogeneous Poisson process null model）下，两块样地内的物种聚集强度均有所降低。在样地1中，栎属物种与非栎属物种的种间关联模式高度相似。但对于共存的栎属物种而言，其种间关联在不同样地中可表现为正关联或负关联。两块样地的同属物种空间分布、与非栎属物种的种间关联、物种邻域丰富度以及物种多样性均存在显著差异。本研究发现，同属物种确实存在一定共性，且亲缘关系较近的同属物种在不同样地中可呈现正或负的种间关联。共存的同属物种在不同生境中可能采取差异化的生存策略：一方面，同属物种间的竞争可能促使其发生资源利用的生态位分化；另一方面，它们相似的种间关联特征可强化自身竞争能力，推动对非同类物种的局部排斥，以获取更多生存空间。本研究结果为我们深入理解物种共存机制提供了全新的认知视角。