Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.
Department of Biology, Lund University, Lund, SE-223 62, Sweden.
Ecology. 2020 Dec;101(12):e03186. doi: 10.1002/ecy.3186. Epub 2020 Oct 7.
The dynamics of ecological communities depend partly on species interactions within and among trophic levels. Experimental work has demonstrated the impact of species interactions on the species involved, but it remains unclear whether these effects can also be detected in long-term time series across heterogeneous landscapes. We analyzed a 19-yr time series of patch occupancy by the Glanville fritillary butterfly Melitaea cinxia, its specialist parasitoid wasp Cotesia melitaearum, and the specialist fungal pathogen Podosphaera plantaginis infecting Plantago lanceolata, a host plant of the Glanville fritillary. These species share a network of more than 4,000 habitat patches in the Åland islands, providing a metacommunity data set of unique spatial and temporal resolution. To assess the influence of interactions among the butterfly, parasitoid, and mildew on metacommunity dynamics, we modeled local colonization and extinction rates of each species while including or excluding the presence of potentially interacting species in the previous year as predictors. The metapopulation dynamics of all focal species varied both along a gradient in host plant abundance, and spatially as indicated by strong effects of local connectivity. Colonization and to a lesser extent extinction rates depended also on the presence of interacting species within patches. However, the directions of most effects differed from expectations based on previous experimental and modeling work, and the inferred influence of species interactions on observed metacommunity dynamics was limited. These results suggest that although local interactions among the butterfly, parasitoid, and mildew occur, their roles in metacommunity spatiotemporal dynamics are relatively weak. Instead, all species respond to variation in plant abundance, which may in turn fluctuate in response to variation in climate, land use, or other environmental factors.
生态群落的动态部分取决于营养级内和之间的物种相互作用。实验工作已经证明了物种相互作用对所涉及物种的影响，但目前尚不清楚这些影响是否也可以在异质景观的长期时间序列中检测到。我们分析了 19 年的 Glanville fritillary 蝴蝶 Melitaea cinxia、其专性寄生蜂 Cotesia melitaearum 以及感染 Plantago lanceolata 的专性真菌病原体 Podosphaera plantaginis 在斑块中的占据情况的时间序列。这些物种在Åland 群岛的 4000 多个栖息地斑块中共享一个网络，为 metacommunity 数据集提供了独特的空间和时间分辨率。为了评估蝴蝶、寄生蜂和霉菌之间的相互作用对 metacommunity 动态的影响，我们在模型中包括或排除了前一年中潜在相互作用物种的存在，以此来评估每个物种的局部定居和灭绝率。所有焦点物种的 metapopulation 动态都沿着宿主植物丰度梯度发生变化，并且由于局部连接性的强烈影响而在空间上发生变化。定居和更不明显的灭绝率也取决于斑块内相互作用物种的存在。然而，大多数影响的方向与基于先前的实验和建模工作的预期不同，并且物种相互作用对观察到的 metacommunity 动态的推断影响是有限的。这些结果表明，尽管蝴蝶、寄生蜂和霉菌之间存在局部相互作用，但它们在 metacommunity 时空动态中的作用相对较弱。相反，所有物种都对植物丰度的变化做出反应，而植物丰度的变化又可能会响应气候、土地利用或其他环境因素的变化而波动。
