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Invasive plants are a major problem for land managers and have widespread and lasting environmental impacts. The invasive shrub Amur honeysuckle (Lonicera maackii) is a pervasive and noxious plant in the Midwest region of the United States.

Despite this, many land managers may be uncomfortable with herbicide control of this and other invasive plants due to unknown impacts on ecosystem components including soils.

To examine if herbicide control of Amur honeysuckle impacts soil enzyme activity and soil communities, we treated Amur honeysuckle with Garlon^®4 (triclopyr) suspended in Basal Bark Oil, Basal Bark Oil alone and untreated controls, then assessed soil community, soil enzyme activity and arbuscular mycorrhizal density changes among treatments and across the subsequent growing season.

We found that basal bark herbicide treatments of Amur honeysuckle do not negatively impact soil enzyme activity, nor do they impact fungal, prokaryotic or oomycotan diversity or community structure. There was a slight but likely ecologically unimportant effect on community structure associated with basal bark oil applications, but not with herbicide applications. Arbuscular mycorrhizal colonization was negatively affected by herbicide use but this is likely due to reduction in host health and/or mortality.

Taken together, this suggests that herbicide control of Amur honeysuckle does not impact soils and land managers can treat these invasive plants without concern for negative soil outcomes.

 

Precipitation changes among years and locations along gradients of mean annual precipitation (MAP). The way those changes interact and affect populations of soil organisms from arid to moist environments remains unknown. Temporal and spatial changes in precipitation could lead to shifts in functional composition of soil communities that are involved in key aspects of ecosystem functioning such as ecosystem primary production and carbon cycling. We experimentally reduced and increased growing-season precipitation for 2 y in field plots at arid, semiarid, and mesic grasslands to investigate temporal and spatial precipitation controls on the abundance and community functional composition of soil nematodes, a hyper-abundant and functionally diverse metazoan in terrestrial ecosystems. We found that total nematode abundance decreased with greater growing-season precipitation following increases in the abundance of predaceous nematodes that consumed and limited the abundance of nematodes lower in the trophic structure, including root feeders. The magnitude of these nematode responses to temporal changes in precipitation increased along the spatial gradient of long-term MAP, and significant effects only occurred at the mesic site. Contrary to the temporal pattern, nematode abundance increased with greater long-term MAP along the spatial gradient from arid to mesic grasslands. The projected increase in the frequency of extreme dry years in mesic grasslands will therefore weaken predation pressure belowground and increase populations of root-feeding nematodes, potentially leading to higher levels of plant infestation and plant damage that would exacerbate the negative effect of drought on ecosystem primary production and C cycling. 

Abstract Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.