Department of Arctic and Marine Biology, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
Department of Natural Resources Science, University of Rhode Island, Kingston, RI, 02881, USA.
Oecologia. 2022 May;199(1):139-152. doi: 10.1007/s00442-022-05165-0. Epub 2022 Apr 26.
Seasonality and long-term environmental variability affect species diversity through their effects on the dynamics of species. To investigate such effects, we fitted a dynamic and heterogeneous species abundance model generating the lognormal species abundance distribution to an assemblage of freshwater zooplankton sampled five times a year (June-October) during the ice-free period over 28 years (1990-2017) in Lake Atnsjøen (Norway). By applying a multivariate stochastic community dynamics model for describing the fluctuations in abundances, we show that the community dynamics was driven by environmental variability in spring (i.e., June). In contrast, community-level ecological heterogeneity is highest in autumn. The autumn months (i.e., September and October) that rearranged the community are most likely crucial months to monitor long-term changes in community structure. Indeed, noises from early summer are filtered away, making it easier to track long-term changes. The community returned faster towards equilibrium when ecological heterogeneity was the highest (i.e., in September and October). This occurred because of stronger density-regulation in months with highest ecological heterogeneity. The community responded to the long-term warming of water temperature with decreasing species diversity and increasing abundance. Unevenness associated with variabilities in abundances might affect species interactions within the community. These can have consequences for the stability and functioning of the ecosystem.
季节性和长期环境变异性通过对物种动态的影响来影响物种多样性。为了研究这些影响，我们拟合了一个动态异质物种丰度模型，该模型产生对数正态物种丰度分布，用于描述 28 年来（1990-2017 年）无冰期内每年五次（6 月至 10 月）在挪威 Atnsjøen 湖采集的淡水浮游动物组合。通过应用多元随机群落动态模型来描述丰度波动，我们表明群落动态是由春季（即 6 月）的环境变异性驱动的。相比之下，群落水平的生态异质性在秋季最高。在秋季（即 9 月和 10 月），群落发生了重新排列，这些月份很可能是监测群落结构长期变化的关键月份。事实上，初夏的噪音被过滤掉了，更容易追踪长期变化。当生态异质性最高时（即 9 月和 10 月），群落更快地回到平衡状态。这是因为在生态异质性最高的月份，密度调节更强。群落对水温的长期变暖做出了反应，表现为物种多样性降低和丰度增加。丰度变化引起的不均匀性可能会影响群落内的物种相互作用。这些可能对生态系统的稳定性和功能产生影响。
