McMahon Kathryn M, Evans Richard D, van Dijk Kor-Jent, Hernawan Udhi, Kendrick Gary A, Lavery Paul S, Lowe Ryan, Puotinen Marji, Waycott Michelle
School of Science and Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, WA, Australia.
Western Australian Marine Science Institution, Crawley, WA, Australia.
Front Plant Sci. 2017 Dec 5;8:2026. doi: 10.3389/fpls.2017.02026. eCollection 2017.
Clonality is common in many aquatic plant species, including seagrasses, where populations are maintained through a combination of asexual and sexual reproduction. One common measure used to describe the clonal structure of populations is clonal richness. Clonal richness is strongly dependent on the biological characteristics of the species, and how these interact with the environment but can also reflect evolutionary scale processes especially at the edge of species ranges. However, little is known about the spatial patterns and drivers of clonal richness in tropical seagrasses. This study assessed the spatial patterns of clonal richness in meadows of three tropical seagrass species, , and , spanning a range of life-history strategies and spatial scales (2.5-4,711 km) in Indonesia and NW Australia. We further investigated the drivers of clonal richness using general additive mixed models for two of the species, and , over 8° latitude. No significant patterns were observed in clonal richness with latitude, yet disturbance combined with sea surface temperature strongly predicted spatial patterns of clonal richness. Sites with a high probability of cyclone disturbance had low clonal richness, whereas an intermediate probability of cyclone disturbance and the presence of dugong grazing combined with higher sea surface temperatures resulted in higher levels of clonal richness. We propose potential mechanisms for these patterns related to the recruitment and mortality rates of individuals as well as reproductive effort. Under a changing climate, increased severity of tropical cyclones and the decline in populations of mega-grazers have the potential to reduce clonal richness leading to less genetically diverse populations.
克隆性在许多水生植物物种中很常见，包括海草，其种群通过无性繁殖和有性繁殖相结合来维持。一种常用的描述种群克隆结构的方法是克隆丰富度。克隆丰富度强烈依赖于物种的生物学特性，以及这些特性如何与环境相互作用，但它也能反映进化尺度上的过程，特别是在物种分布范围的边缘。然而，对于热带海草中克隆丰富度的空间格局和驱动因素知之甚少。本研究评估了印度尼西亚和澳大利亚西北部三种热带海草物种（[此处原文缺失物种名]、[此处原文缺失物种名]和[此处原文缺失物种名]）草甸中克隆丰富度的空间格局，这些物种跨越了一系列生活史策略和空间尺度（2.5 - 4711公里）。我们还使用广义相加混合模型，对其中两个物种（[此处原文缺失物种名]和[此处原文缺失物种名]）在8°纬度范围内进一步研究了克隆丰富度的驱动因素。未观察到克隆丰富度随纬度有显著格局，但干扰与海表面温度相结合能有力地预测克隆丰富度的空间格局。遭受气旋干扰概率高的地点克隆丰富度低，而气旋干扰概率中等且儒艮啃食与较高海表面温度同时存在的地点，克隆丰富度水平较高。我们提出了与个体的补充和死亡率以及繁殖努力相关的这些格局的潜在机制。在气候变化的情况下，热带气旋强度增加和大型食草动物种群数量下降有可能降低克隆丰富度，导致种群遗传多样性降低。
