Reisch Christoph, Schmid Christoph
Institute of Plant Sciences University of Regensburg Regensburg Germany.
Research Unit Comparative Microbiome Analysis German Research Center for Environmental Health Neuherberg Germany.
Ecol Evol. 2018 Dec 12;9(1):664-671. doi: 10.1002/ece3.4791. eCollection 2019 Jan.
Biological diversity comprises both species diversity (SD) and genetic diversity (GD), and it has been postulated that both levels of diversity depend on similar mechanisms. Species-genetic diversity correlations (SGDC) are therefore supposed to be generally positive. However, in contrast to theory, empirical data are contradictory. Furthermore, there is a pronounced lack of multispecies studies including also the ecological factors potentially driving species and genetic diversity. We analyzed the relationship between the species diversity of dry grasslands and the genetic diversity of several dry grassland plant species, therefore, in the context of habitat fragmentation and habitat conditions. Our study revealed a lack of correlation between species and genetic diversity. We demonstrated previously that SD mainly depends on habitat conditions (vegetation height and cover of litter), whereas GD is significantly affected by habitat fragmentation (distance to the nearest dry grassland in 1830 and connectivity in 2013). This seems to be the main reason why SD and GD are not congruent in fragmented grasslands. Our results support, hence, the observation that positive SGDCs can mainly be found in natural, island-like study systems in equilibrium and at similar levels of heterogeneity. In fragmented dry grassland ecosystems, which differ in heterogeneity, this state of equilibrium may not have been reached mitigating the positive relationship between SD and GD. From our study, it can be concluded that in fragmented dry grasslands, the protection of SD does not necessarily ensure the conservation of GD.
生物多样性包括物种多样性（SD）和遗传多样性（GD），并且据推测这两个多样性水平依赖于相似的机制。因此，物种 - 遗传多样性相关性（SGDC）通常被认为是正相关的。然而，与理论相反，实证数据相互矛盾。此外，明显缺乏包括可能驱动物种和遗传多样性的生态因素的多物种研究。因此，我们在栖息地破碎化和栖息地条件的背景下，分析了干旱草原的物种多样性与几种干旱草原植物物种的遗传多样性之间的关系。我们的研究揭示了物种多样性与遗传多样性之间缺乏相关性。我们先前证明，物种多样性主要取决于栖息地条件（植被高度和凋落物覆盖度），而遗传多样性受栖息地破碎化显著影响（1830年到最近干旱草原的距离以及2013年的连通性）。这似乎是破碎化草原中物种多样性和遗传多样性不一致的主要原因。因此，我们的结果支持这样的观察结果，即正的物种 - 遗传多样性相关性主要可以在处于平衡状态且异质性水平相似的自然、岛屿状研究系统中找到。在异质性不同的破碎化干旱草原生态系统中，可能尚未达到这种平衡状态，从而减弱了物种多样性和遗传多样性之间的正相关关系。从我们的研究可以得出结论，在破碎化的干旱草原中，保护物种多样性不一定能确保遗传多样性的保护。
