Invasive plant mats promoted the decomposition of native leaf litter by micro-, meio-, and macroinvertebrates in an eutrophic freshwater lake in the Three Gorges Reservoir area, China

Abstract

To investigate the effect of invasive Alternanthera philoxeroides mats on native leaf litter decomposition, we allocated two native leaf species of contrasting recalcitrance (Neosinocalamus affinis and Ficus virens) in litterbags with four different mesh sizes (0.025, 0.042, 0.5, and 5 mm) and the bags were either incubated under floating A. philoxeroides mats (Vegetated site) or under floating plastic foam boards without A. philoxeroides mats (Unvegetated site) for 65 days in Jianhu Lake, China, in July 2020. The average decomposition rates increased with pore size of litterbags. The interaction intensity of the site effect in leaf mass loss was negative in 0.025 mesh and positive in other meshes, while no significance existed between two native species in the same mesh sizes and sites. The contribution of microbes to decomposition was more than 50% in both sites. The contribution in the vegetation site was as follows: microbes [ mi-croinvertebrates [ meioinvertebrates [ macroinvertebrates, compared with microbes [ macroinvertebrates [ meioinvertebrates [ microinvertebrates in the unvegetated site. The results suggest that A. philoxeroides mats can promote the decomposition of native leaf litter, and that the roles of micro-, meio-, and macroinvertebrates in decomposition are important but underestimated.

Effect of litter decomposition on mowing and plant composition change during Solidago stand restoration

“…In coarse mesh bags, decomposition is the result of three main processes such as microbial breakdown, macroinvertebrate consumption, and physical abrasion, in which microbial breakdown accounts for the majority of decomposition in fine mesh bags (Fugère et al, 2020;Bärlocher et al, 2020). Decomposition rates increased as the size increased in litterbags (Chen et al, 2022b). This was similar to the case when comparing coarse to fine mesh litter bags; decomposition rates were higher in coarse mesh litter bags in our experiment.…”

“…Because the litter decomposition process depends directly and indirectly on many environmental, biological, and anthropogenic factors, it can be used as an indicator of soil health (Fugère et al, 2020;Bärlocher et al, 2020;Wang et al 2020a,b). Organisms such as microbes and soil invertebrates lead to decomposition, so population variations will change this process (Chen et al, 2022b). In coarse mesh bags, decomposition is the result of three main processes such as microbial breakdown, macroinvertebrate consumption, and physical abrasion, in which microbial breakdown accounts for the majority of decomposition in fine mesh bags (Fugère et al, 2020;Bärlocher et al, 2020).…”

“…litter C, N, phosphorus (P), C: N ratios, and lignin) and the rate of litter decomposition rate (Gong et al, 2015). The decomposition is mainly processed by microbes and invertebrates (Chen et al, 2022b). Regardless of the type of land exploited, elevated temperatures and reduced precipitation patterns constantly slow the decomposition of litter through microbial and faunal impacts (Yin et al, 2019).…”

How Eutrophication Promotes Exotic Aquatic Plant Invasion in the Lake Littoral Zone?

“…Meanwhile, eutrophication caused an increase in plant SOD activity and a reduction of plant phenolics and starch contents in both native species, which reduced the ability of native species to resist invasion. Previous studies have shown that plant-invaded habitats have increased water turbidity and nitrogen and organic matter concentrations, which is associated with the ability of invaders to modify habitats and increase eutrophication. , Moreover, invasive plant-habitat interactions, resulting in reduced habitat heterogeneity, may have a negative impact on plant community dynamics, which may then promote continued invasion. ,, Therefore, eutrophication in the littoral zone has a suppressive effect on the morphology and physiology of native plants, causing habitat degradation, which may be followed by continued plant invasion, i.e., a vicious cycle that exacerbates the degradation of littoral habitats.…”

“…12,92 Moreover, invasive plant-habitat interactions, resulting in reduced habitat heterogeneity, may have a negative impact on plant community dynamics, which may then promote continued invasion. 90,93,94 Therefore, eutrophication in the littoral zone has a suppressive effect on the morphology and physiology of native plants, causing habitat degradation, which may be followed by continued plant invasion, i.e., a vicious cycle that exacerbates the degradation of littoral habitats.…”