Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, USA.
Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois University, DeKalb, Illinois, USA.
Ecology. 2024 Jan;105(1):e4192. doi: 10.1002/ecy.4192. Epub 2023 Nov 27.
In the midst of an ongoing biodiversity crisis, much research has focused on species losses and their impacts on ecosystem functioning. The functional consequences (ecosystem response) of shifts in communities are shaped not only by changes in species richness, but also by compositional shifts that result from species losses and gains. Species differ in their contribution to ecosystem functioning, so species identity underlies the consequences of species losses and gains on ecosystem functions. Such research is critical to better predict the impact of disturbances on communities and ecosystems. We used the "Community Assembly and the Functioning of Ecosystems" (CAFE) approach, a modification of the Price equation to understand the functional consequences and relative effects of richness and composition changes in small nonvolant mammal and dung beetle communities as a result of two common disturbances in North American prairie restorations, prescribed fire and the reintroduction of large grazing mammals. Previous research in this system has shown dung beetles are critically important decomposers, while small mammals modulate much energy in prairie food webs. We found that dung beetle communities were more responsive to bison reintroduction and prescribed fires than small nonvolant mammals. Dung beetle richness increased after bison reintroduction, with higher dung beetle community biomass resulting from changes in remaining species (context-dependent component) rather than species turnover (richness components); prescribed fire caused a minor increase in dung beetle biomass for the same reason. For small mammals, bison reintroduction reduced energy transfer through the loss of species, while prescribed fire had little impact on either small mammal richness or energy transfer. The CAFE approach demonstrates how bison reintroduction controls small nonvolant mammal communities by increasing prairie food web complexity, and increases dung beetle populations with possible benefits for soil health through dung mineralization and soil bioturbation. Prescribed fires, however, have little effect on small mammals and dung beetles, suggesting a resilience to fire. These findings illustrate the key role of re-establishing historical disturbance regimes when restoring endangered prairie ecosystems and their ecological function.
在当前生物多样性危机的背景下，大量研究主要集中在物种损失及其对生态系统功能的影响上。群落组成变化（生态系统响应）不仅受到物种丰富度变化的影响，还受到物种损失和获得导致的组成变化的影响。物种对生态系统功能的贡献存在差异，因此物种的丧失和获得对生态系统功能的后果取决于物种身份。此类研究对于更好地预测干扰对群落和生态系统的影响至关重要。我们使用“群落组装与生态系统功能”（CAFE）方法，对 Price 方程进行了修改，以了解北美草原恢复过程中两种常见干扰（计划火烧和大型食草动物的重新引入）对小型非飞行哺乳动物和蜣螂群落的丰富度和组成变化的功能后果及其相对影响。该系统中的先前研究表明，蜣螂是至关重要的分解者，而小型哺乳动物则调节草原食物网中的大量能量。我们发现，蜣螂群落对野牛的重新引入和计划火烧的响应比小型非飞行哺乳动物更为敏感。野牛重新引入后，蜣螂的丰富度增加，由于剩余物种的变化（依赖于背景的组成部分）而不是物种更替（丰富度组成部分）导致蜣螂群落生物量增加；出于同样的原因，计划火烧导致蜣螂生物量略有增加。对于小型哺乳动物，野牛的重新引入通过物种的丧失减少了能量传递，而计划火烧对小型哺乳动物的丰富度或能量传递几乎没有影响。CAFE 方法表明，野牛的重新引入通过增加草原食物网的复杂性来控制小型非飞行哺乳动物群落，并通过粪便矿化和土壤生物扰动增加蜣螂种群，从而可能有益于土壤健康。然而，计划火烧对小型哺乳动物和蜣螂的影响很小，这表明它们对火灾具有一定的抵抗力。这些发现说明了在恢复濒危草原生态系统及其生态功能时，重新建立历史干扰模式的关键作用。
