Search Results (4)

Soil, which exhibits difference in nutrient contents and aggregate sizes, provides spatially distinct habitats for biota. Cover crops influence the compositions of soil organism communities, playing an indispensable role in regulation of underground food webs and ecosystem functions. However, the effect of cover crops on soil microbes and nematodes distribution within different aggregate sizes remains unknown. Thus, a field experiment in a kiwifruit orchard with cover crops was conducted to estimate the distribution of soil nematodes and bacteria with different soil aggregate sizes (mega-aggregate (>2 mm, LMA), macro-aggregate (0.25–2 mm, SMA), and micro-aggregate (<0.25 mm, MA)) and cover crop treatments (four cover crop species (CC) and no cover crop as control (CK)). The results showed that bacterial compositions varied with both aggregate sizes and cover crop treatments. The composition of bacterial community was significantly different between mega-aggregate and micro-aggregate, and bacterial community diversity was significantly higher in micro-aggregate compared with mega-aggregate. Moreover, cover crop treatment dramatically changed the compositions of bacterial communities. However, the nematode communities were mainly impacted by soil aggregate sizes. Larger aggregates (mega- and macro-aggregates) contained higher abundance of omnivores/predators and lower abundance of fungivores. In contrast to bacterial community, the richness of nematode community was lower in micro-aggregates compared with larger aggregates (mega- and macro-aggregates). Redundancy analysis (RDA) and structural equation model (SEM) showed soil organic carbon (SOC) was the main soil factor that directly and indirectly affected both bacterial and nematode communities. The investigations of both bacterial and nematode communities could provide a better understanding on carbon and nutrient cycling across aggregate size fractions. Full article

Serious soil degradation due to human intervention in subtropical China has resulted in a series of ecological problems. Soil fauna is an important part of forest soil ecosystems and plays a vital role in the maintenance of soil quality and can sensitively reflect the soil disturbances caused by human activities. This study assessed the long-term effects of reforestation on the soil fauna community and underground food web. Soil fauna was sampled from plots in a 30-year reforestation positioning test site. Six reforestation models (the pure Schima superba (Ss) forest, pure Liquidambar formosana (Lf) forest, pure Pinus massoniana (Pm) forest, mixed forest of Lf & Ss, mixed forest of Pm & Ss, and the mixed forest of Lf & Pm) were chosen in Taihe County, southern China. The results found that the mixed vegetation restoration of Lf & Pm significantly improved the soil fauna abundance and biomass when compared with other reforestation models in the degraded red soil region. Acari and Collembola accounted for 65.8% and 23.3%, respectively, of the total soil fauna abundance in the region. The mixed forest of Lf & Pm had a positive effect on the abundance of secondary decomposers and micro predators in Acari. Moreover, a significant increase in the abundance of Collembola was found in the Lf & Pm stand type. The stand type with the highest soil faunal population also had a higher soil fauna biomass. Therefore, reforestation in a degraded red soil area had positive effects on the soil fauna community. Full article

Both global warming and alien plant invasion can affect the biotic communities in the soil. Most studies are focused on the soil microbial community, but little is known about how global warming, along with alien plant invasion, affects the diversity and function of the soil nematode community. In this study, the individual and interactive effects of experimental warming and Canada goldenrod (Solidago canadensis L.) invasion on soil nematode communities were measured. Experimental air warming, in combination with different levels of S. canadensis invasion, were applied. The results showed that S. canadensis invasion significantly increased chao1, maturity, and structure indexes of the nematode community by 31.44%, 25.57%, and 329.3%, respectively, and decreased the basal index by 48.70% (all p < 0.05). Only the Simpson index was affected by the interaction between warming and S. canadensis invasion. Warming enhanced the S. canadensis invasion effect on the soil nematode community. The changes in nematode community were correlated with shifts in nutrient availability and resource stoichiometry, as well as microbes in the soil. These findings demonstrated that global warming and S. canadensis invasion may, directly and indirectly, alter the soil nematode community, which may considerably affect the functioning of underground food webs. Full article

Underground waters are still one of the most important sources of drinking water for the planet. Moreover, the fauna that inhabits these waters is still little known, even if it could be used as an effective bioindicator. Among cave invertebrates, planarians are strongly suited to be used as a study model to understand adaptations and trophic web features. Here, we show a systematic literature review that aims to investigate the studies done so far on groundwater-dwelling planarians. The research was done using Google Scholar and Web of Science databases. Using the key words “Planarian cave” and “Flatworm Cave” we found 2273 papers that our selection reduced to only 48, providing 113 usable observations on 107 different species of planarians from both groundwaters and springs. Among the most interesting results, it emerged that planarians are at the top of the food chain in two thirds of the reported caves, and in both groundwaters and springs they show a high variability of morphological adaptations to subterranean environments. This is a first attempt to review the phylogeny of the groundwater-dwelling planarias, focusing on the online literature. The paucity of information underlines that scarce attention has been dedicated to these animals. Further revisions, including old papers and books, not available online will be necessary. Full article