School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Environ Sci Pollut Res Int. 2022 Nov;29(55):83993-84005. doi: 10.1007/s11356-022-21657-1. Epub 2022 Jul 1.
Disentangling the relative contributions of deterministic and stochastic processes was critical to compressive understanding of underlying mechanism governing geographic pattern and assembly of phytoplankton community, while it was seldom performed in connected lakes under human pressure. Here, we investigated phytoplankton community pattern in relation to environmental and spatial factors over 81 lakes located in the middle and lower reaches of Yangtze River (MLYR) floodplain, where many lakes suffered from eutrophication and cyanobacterial blooms. A majority of MLYR lakes had higher phytoplankton abundance surpassing 10 cells/L and were dominated by common bloom-forming cyanobacterial genera, including Pseudanabaena, Microcystis, Merismopedia, Dolichospermum, Limnothrix, and Raphidiopsis. Phytoplankton community exhibited a striking geographical pattern both for taxonomic and functional compositions, while functional groups were less sensitive, and dissimilarity in communities displayed no significant increases with increasing geographical distance. Further, species richness explained much higher percentage of community variations than species turnover, indicating a reduced effect of environmental filtering of phytoplankton species with tolerance to similar environments in connected MLYR lakes. Both deterministic and stochastic processes governed assembly and biogeographic of phytoplankton community. Variation partition analysis showed that spatial factors exhibited greater influence on phytoplankton community compared to environmental variables. The stronger influence of spatial factors was further demonstrated by Mantel test and neutral community model. These findings indicate that deterministic and stochastic processes exhibited similar biogeographic patterns for phytoplankton community in MLYR lakes, but stochastic process was overwhelmingly dominated. Moreover, a large proportion of unexplained variation implies that complex interactions exist to shape assembly mechanism of phytoplankton community in MLYR lakes.
解析确定性和随机性过程对理解控制浮游植物群落地理格局和组装的潜在机制至关重要，但在人类压力下的连通湖泊中，这很少被执行。在这里，我们研究了与环境和空间因素有关的浮游植物群落模式，涉及位于长江中下游（MLYR）泛滥平原的 81 个湖泊，其中许多湖泊遭受富营养化和蓝藻水华的影响。大多数 MLYR 湖泊的浮游植物丰度较高，超过 10 个细胞/L，并且以常见的形成水华的蓝藻属为主，包括伪鱼腥藻、微囊藻、束丝藻、鱼腥藻、水绵和裂面藻。浮游植物群落的分类和功能组成都表现出明显的地理模式，而功能组则不太敏感，群落的不相似性随着地理距离的增加没有显著增加。此外，物种丰富度解释了群落变化的更高比例，而不是物种周转率，这表明在连通的 MLYR 湖泊中，具有相似环境耐受性的浮游植物物种的环境过滤效应降低。确定性和随机性过程共同控制了浮游植物群落的组装和生物地理学。变异划分分析表明，与环境变量相比，空间因素对浮游植物群落的影响更大。Mantel 检验和中性群落模型进一步证明了空间因素的更强影响。这些发现表明，确定性和随机性过程对 MLYR 湖泊浮游植物群落表现出相似的生物地理学模式，但随机性过程占主导地位。此外，大量未解释的变异表明，在 MLYR 湖泊中，复杂的相互作用存在于浮游植物群落的组装机制中。
