Kristjánsson Bjarni K, Combot Doriane, Reilent Anett, Phillips Joseph S, Leblanc Camille A-L
Department of Aquaculture and Fish Biology Hólar University Sauðárkrókur Iceland.
Department of Biology Creighton University Omaha Nebraska USA.
Ecol Evol. 2024 Jun 25;14(6):e11560. doi: 10.1002/ece3.11560. eCollection 2024 Jun.
Understanding which factors shape and maintain biodiversity is essential to understand how ecosystems respond to crises. Biodiversity observed in ecological communities is a result of the interaction of various factors which can be classified as either neutral- or niche-based. The importance of these processes has been debated, but many scientists believe that both processes are important. Here, we use unique ecosystems in groundwater-filled lava caves near Lake Mývatn, to examine the importance of neutral- versus niche-based factors for shaping invertebrate communities. We studied diversity in benthic and epibenthic invertebrate communities and related them to ecological variables. We hypothesized that if neutral processes are the main drivers of community structure we would not see any clear relationship between the structure of community within caves and ecological factors. If niche-based processes are important we should see clear relationships between community structure and variation in ecological variables across caves. Both communities were species poor, with low densities of invertebrates, showing the resource limited and oligotrophic nature of these systems. Unusually for Icelandic freshwater ecosystems, the benthic communities were not dominated by Chironomidae (Diptera) larvae, but rather by crustaceans, mainly Cladocera. The epibenthic communities were not shaped by environmental variables, suggesting that they may have been structured primarily by neutral processes. The benthic communities were shaped by the availability of energy, and to some extent pH, suggesting that niche-based processes were important drivers of community structure, although neutral processes may still be relevant. The results suggest that both processes are important for invertebrate communities in freshwater, and research should focus on understanding both of these processes. The ponds we studied are representative of a number of freshwater ecosystems that are extremely vulnerable for human disturbance, making it even more important to understand how their biodiversity is shaped and maintained.
了解哪些因素塑造并维持生物多样性对于理解生态系统如何应对危机至关重要。在生态群落中观察到的生物多样性是各种因素相互作用的结果，这些因素可分为基于中性或基于生态位的因素。这些过程的重要性一直存在争议，但许多科学家认为这两个过程都很重要。在这里，我们利用米湖附近充满地下水的熔岩洞穴中的独特生态系统，来研究基于中性与基于生态位的因素对塑造无脊椎动物群落的重要性。我们研究了底栖和表栖无脊椎动物群落的多样性，并将其与生态变量相关联。我们假设，如果中性过程是群落结构的主要驱动因素，那么我们将不会看到洞穴内群落结构与生态因素之间有任何明显的关系。如果基于生态位的过程很重要，我们应该会看到群落结构与不同洞穴间生态变量变化之间存在明显的关系。这两个群落的物种都很贫乏，无脊椎动物密度低，表明这些系统资源有限且营养贫瘠。与冰岛淡水生态系统不同的是，底栖群落并不以摇蚊科（双翅目）幼虫为主，而是以甲壳类动物为主，主要是枝角类。表栖群落不受环境变量的影响，这表明它们可能主要是由中性过程构建的。底栖群落受到能量可用性以及在一定程度上pH值的影响，这表明基于生态位的过程是群落结构的重要驱动因素，尽管中性过程可能仍然相关。结果表明，这两个过程对淡水无脊椎动物群落都很重要，研究应侧重于理解这两个过程。我们研究的池塘代表了许多极易受到人类干扰的淡水生态系统，因此了解它们的生物多样性是如何形成和维持的就显得尤为重要。
