Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
Ecology. 2022 Aug;103(8):e3735. doi: 10.1002/ecy.3735. Epub 2022 Jun 9.
The impact of multitrophic interactions on metacommunity structure, despite extensive theory and modeling/manipulative studies, has remained largely unexplored within naturally occurring metacommunities. We investigated the impacts of mutualistic partners and predators on a butterfly metacommunity, as well as the impacts that local and landscape characteristics have across three trophic levels: flowering plants, butterflies, and butterfly predators. Using data for butterfly diversity/richness, flowering plant diversity/richness, and butterfly predation (on clay butterfly models) across 15 grassland sites, we posed 3 questions. (1) How do mutualist metacommunity structure, predation pressure, and local and regional habitat characteristics affect butterfly metacommunity structure? (2) How do local and regional habitat characteristics affect flowering plant metacommunity structure? (3) How do local and regional habitat characteristics affect predation pressure? Floral diversity and richness had a positive effect on butterfly diversity and richness (Question 1). Site size positively affected floral diversity and richness (Question 2), and through this relationship site size had an indirect positive effect on butterfly diversity and richness (Question 1). In contrast to previous work, no other variables impacted butterfly diversity/richness. This result was particularly surprising for predation pressure: Our results suggest that within our study system, butterfly community diversity and richness are not strongly impacted by predation. Predator attacks occurred more in larger and more isolated sites (Question 3), suggesting that predators respond more strongly to landscape characteristics than abundance or diversity of butterfly prey species. This decoupling of predation pressure and butterfly communities suggests that conserving and restoring healthy predator populations may not negatively impact butterfly communities. If diverse plant communities are maintained, even small and isolated habitat patches can be valuable for butterfly conservation, which may influence reserve design and habitat restoration strategies.
尽管有广泛的理论和模型/操纵研究，但在自然发生的集合群落中，多营养级相互作用对集合群落结构的影响在很大程度上仍未得到探索。我们研究了共生伙伴和捕食者对蝴蝶集合群落的影响，以及本地和景观特征在三个营养级（开花植物、蝴蝶和蝴蝶捕食者）上的影响。使用 15 个草地站点的蝴蝶多样性/丰富度、开花植物多样性/丰富度和蝴蝶捕食（在粘土蝴蝶模型上）的数据，我们提出了 3 个问题。（1）共生集合群落结构、捕食压力以及本地和区域生境特征如何影响蝴蝶集合群落结构？（2）本地和区域生境特征如何影响开花植物集合群落结构？（3）本地和区域生境特征如何影响捕食压力？花卉多样性和丰富度对蝴蝶多样性和丰富度有积极影响（问题 1）。站点大小对花卉多样性和丰富度有积极影响（问题 2），并且通过这种关系，站点大小对蝴蝶多样性和丰富度有间接的积极影响（问题 1）。与以前的工作相反，没有其他变量影响蝴蝶多样性/丰富度。这一结果对于捕食压力尤其令人惊讶：我们的结果表明，在我们的研究系统中，蝴蝶群落的多样性和丰富度不受捕食的强烈影响。捕食者的攻击更多地发生在较大和较孤立的地点（问题 3），这表明捕食者对景观特征的反应比对蝴蝶猎物物种的数量或多样性更为强烈。捕食压力与蝴蝶群落的这种解耦表明，保护和恢复健康的捕食者种群可能不会对蝴蝶群落产生负面影响。如果维持多样化的植物群落，即使是小而孤立的栖息地斑块也对蝴蝶保护具有重要价值，这可能会影响保护区设计和生境恢复策略。
