Saar Liina, de Bello Francesco, Pärtel Meelis, Helm Aveliina
Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005, Tartu, Estonia.
Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic.
Oecologia. 2017 May;184(1):1-12. doi: 10.1007/s00442-017-3812-9. Epub 2017 Jan 19.
During the past century, grasslands in Europe have undergone marked changes in land-use, leading to a decline in plant diversity both at local and regional scales, thus possibly also affecting the mechanisms of species sorting into local communities. We studied plant species assembly in grasslands with differing habitat history and hypothesised that trait divergence prevails in historical grasslands due to niche differentiation and trait convergence prevails in more dynamic grasslands due to competitive exclusion and dispersal limitation. We tested these hypotheses in 35 grassland complexes in Estonia, containing neighbouring grassland habitats with different land-use histories: continuously managed open historical grassland, currently overgrown former grassland and young developing grassland. We assessed species assembly patterns in each grassland type for finer scale-a 2 × 2 m plot scale from a local community pool and for broader scale-a local community from the habitat species pool for that grassland stage and observed changes in trait means at finer scale. We found that grasslands with long management history are assembled differently from former grasslands or young developing grasslands. In historical grasslands, divergence or random patterns prevailed at finer scale species assembly while in former or developing grasslands, mostly convergence patterns prevailed. With increasing scale convergence patterns become more prevalent in all grassland types. We conclude that land-use history is an important factor to consider when assessing grassland functional trait assembly, particularly at small scales. Understanding the mechanisms behind species assembly and their relationship with land-use history is vital for habitat conservation and restoration.
在过去的一个世纪里，欧洲的草原在土地利用方面发生了显著变化，导致当地和区域尺度上的植物多样性下降，进而可能也影响了物种进入当地群落的分选机制。我们研究了具有不同栖息地历史的草原中的植物物种组装情况，并假设由于生态位分化，性状发散在历史悠久的草原中占主导地位，而由于竞争排斥和扩散限制，性状趋同在更具动态性的草原中占主导地位。我们在爱沙尼亚的35个草原复合体中检验了这些假设，这些复合体包含具有不同土地利用历史的相邻草原栖息地：持续管理的开阔历史草原、目前已长满植被的 former 草原和年轻的正在发育的草原。我们评估了每种草原类型在更精细尺度（从当地群落库中选取的2×2米样方尺度）和更广泛尺度（该草原阶段栖息地物种库中的当地群落）下的物种组装模式，并观察了更精细尺度下性状均值的变化。我们发现，管理历史悠久的草原与 former 草原或年轻的正在发育的草原在组装方式上有所不同。在历史悠久的草原中，在更精细尺度的物种组装中发散或随机模式占主导地位，而在 former 或正在发育的草原中，大多是趋同模式占主导地位。随着尺度的增加，趋同模式在所有草原类型中变得更加普遍。我们得出结论，在评估草原功能性状组装时，土地利用历史是一个重要的考虑因素，特别是在小尺度上。了解物种组装背后的机制及其与土地利用历史的关系对于栖息地保护和恢复至关重要。
