Subordinate plants sustain the complexity and stability of soil micro‐food webs in natural bamboo forest ecosystems

Abstract

Summary Subordinate plants have a significant impact on soil organisms in primary successional floodplains and grassland ecosystems, but their role in subtropical forest ecosystems remains unclear. An experiment was conducted in a subtropical forest to test the hypothesis that removal of shrubs or subordinate arbour tree species would reduce the complexity and stability of the soil micro‐food web. Principal response curves (PRCs) were performed to assess the responses of soil microbial and nematode communities to plant removal compared with a control through time. The effect of plant removal on complexity and stability in the soil micro‐food web was assessed using a suite of indices including ratio of omnivorous‐predatory to herbivorous nematode abundance (OP : H ratio), nematode diversity, resistance and resilience. Furthermore, increments of bamboo productivity among treatments were estimated. Soil microbial community structure changed in response to plant removal in 2009, but recovered in 2010, and the only change observed was increased soil fungal biomass. In contrast, plant removal had greater impact on soil nematode community composition in 2010 than 2009. Subordinate arbour tree species removal (with or without shrubs) decreased the values of nematode richness, evenness, diversity, ratio of microbial‐feeding to herbivorous nematode abundance (M : H ratios), OP : H ratios and resistance indices in 2010, but only decreased OP : H ratios in 2009 and increased the values of nematode dominance in 2010. Although increments in bamboo productivity were statistically similar among treatments, there was a trend decreasing progressively from control to shrub removal + selective‐cutting of subordinate arbour tree species, shrub removal, and selective‐cutting of subordinate arbour tree species treatments. Synthesis and applications. Subordinate plants help sustain the complexity and stability of soil micro‐food webs in subtropical bamboo forest ecosystems. Therefore, protection of subordinate plants and maintaining high plant diversity are important parts of a responsible management strategy in subtropical bamboo forests.

The response of the soil microbial food web to extreme rainfall under different plant systems

“…Given their ability to fixed N, legumes are the most common species that consistently influence soil nematodes27. Although a recent study argues that neighboring plant diversity increases nematode diversity, abundance and resistance17, the role of legumes as a key species in plant communities is well established. Likewise, our study provides evidence that legume addition significantly enhanced bacterivores in the G. max mixed culture and tended to increase omnivore-predator nematodes in the M. sativa mixed culture (p = 0.064) when compared to the monoculture (Fig.…”

“…Few studies have examined the effects of the composition of plant species in increasing the uptake of nutrients for the focal species via soil food-web stability15. In theory, the presence of different plant species (especially the presence of legumes) with different above-and belowground functional traits could potentially increase soil food-web complexity and stability1617. However, stronger competition among different species may also decrease the stability of the soil food web under extreme rainfall, even in the presence of a legume10.…”

“…Recent investigations showed that subordinate plant diversity increases nematode diversity, abundance and stability17. However, many researchers have revealed that the species identity has a stronger influence on the nematode community than the species richness1920.…”

Grazing simplifies soil micro‐food webs and decouples their relationships with ecosystem functions in grasslands

“…Many previous studies have documented how livestock grazing changes plant communities (Bai et al, 2012;Milchunas & Lauenroth, 1993) and soil physicochemical properties (Semmartin, Bella, & Salamone, 2009;Zhou et al, 2017). As part of soil detrital food webs, soil micro-food webs mainly include soil microorganisms (e.g., bacteria and fungi), microbivores (e.g., bacterial-feeding (BF) and fungal-feeding (FF) nematodes), and micropredators (e.g., omnivorous and carnivorous nematodes; Lavelle, 1997); these organisms contribute to the decomposition of soil organic matter and soil C and N mineralization (Lavelle, 1997;Shao et al, 2016). Several recent studies have reported that livestock grazing can greatly affect soil micro-food webs in grassland ecosystems (Veen, Olff, Duyts, & Putten, 2010;Yang, Nolte, & Wu, 2017).…”

Long-term nitrogen addition alters the community and energy channel but not diversity of soil nematodes in a subtropical forest

“…Abundance and diversity of nematodes are correlated with many geochemical processes such as ecosystem succession, litter decomposition and N cycling (Fu et al 2000;Neher et al2012;Zhao et al 2012). Several related studies have shown that the development and characteristics of nematode communities were greatly affected by plant community characteristics (Li et al 2007;de la Peña et al 2016;Shao et al 2016;Zhao et al 2019). Because nematodes are sensitive to external disturbances (e.g., land-use change and environmental pollution) and nematode communities are generally regarded as effective indicators of the health and stability of soil food webs (Bongers 1990;Powell 2007;Zhao et al 2013).…”