title: Non-target effects of herbicides on soil nematode assemblages.
abstract: BACKGROUND
  Herbicides are used extensively to control weeds. However, little is known about the non-target effects of herbicides on soil nematode assemblages. The objective of this study was to determine whether herbicides affect the abundance of nematodes in specific trophic groups. Meta-analysis was performed, and the calculated effect size, lr, quantified the impact of herbicides on the abundance of total nematodes and five trophic groups (bacterivores, fungivores, plant parasites, omnivores and predators).
  
  
  RESULTS
  Measurements of lr indicated that herbicides decreased abundance of both fungivores and predators; however, abundance of bacterivores, plant parasites and omnivores increased. Overall, total nematode abundance tended to increase in response to herbicide application.
  
  
  CONCLUSIONS
  The decrease in predator abundance suggests that herbicide application disturbs soil food webs. The increase in bacterivore and decrease in fungivore abundance suggest that bacterivores are more tolerant and both fungivores and predators more sensitive to herbicide applications. Herbicides also have non-target effects on omnivores, which may be due to the increased amount of food resources for omnivores after weed control. Additionally, the use of herbicides may result in a risk of an increase in plant-parasitic nematode abundance.
authors.affiliation: Key Laboratory for Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan 410125, China. jzhao@isa.ac.cn
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Neher
authors.forename: Shenglei
authors.initials: S
authors.lastname: Fu
authors.forename: Zhi'an
authors.initials: Z
authors.lastname: Li
authors.forename: Kelin
authors.initials: K
authors.lastname: Wang
mesh_terms: D000818:Animals; D017753:Ecosystem; D006540:Herbicides / Q000494:pharmacology*; D009348:Nematoda / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D012987:Soil / Q000469:parasitology
chemical_list: D006540:Herbicides; D012987:Soil