sentences:  An editorial published in the same edition found the possible link between neonicotinoid pesticide use and a decline in bird numbers “worrying”, saying that the persistence of the compounds (half-life of 1000 days) and the low direct toxicity to birds themselves implies that the depletion of the birds' food source (insects) is likely responsible for the decline and that the compounds are distributed widely in the environment.The editors write that while correlation is not the same as causation, “the authors of the study also rule out confounding effects from other land-use changes or pre-existing trends in bird declines”.From June to October 2014 a comprehensive Worldwide Integrated Assessment of the impact of systemic pesticides on biodiversity and ecosystems (WIA) was published in the journal "Environmental Science and Pollution Research".