With a partial government shutdown now in its 3rd week, many Americans are learning the hard way about the wide range of functions their federal government normally serves. One of those little-known functions is preventing the spread of invasive plants, insects, and other species that threaten native ecosystems and valuable natural resources, costing the United States an estimated $120 billion every year. Just last week, the shutdown forced conference organizers at the US Department of Agriculture (USDA) to cancel an annual meeting of 300 scientists working to coordinate research and find solutions. Even before the shutdown, however, USDA regulators had failed to fully live up to their obligations—designated by law—to protect US resources from invasive species.
Science-based regulation is essential to control invasive species
Efforts to control one invasive species sometimes involve introducing another non-native species to serve as “biocontrol” agents. Biocontrol uses natural enemies like predators or parasitoids to control weeds and pests, but this can lead to new problems. And so it was when, in 2010, the USDA permitted release of the biocontrol agent Laricobius osakensis, a beetle native to Japan, for control of the hemlock woolly adelgid—an insect pest that is killing hemlock trees, an important forest species in eastern North America. Colonies of the biocontrol beetle were subsequently found to contain another undescribed beetle species, also a Japan native later named Laricobius naganoensis. The discovery prompted research investigating possible hybridization between L. naganoensis and other species that could become a problem, for example, if varying behavior of hybrids might harm native ecosystems.
However, before scientists could fully understand what L. naganoensis eats, or its other interactions or natural history, its release was also permitted. In December of 2017, the USDA approved unlimited “…field release of L. naganoensis for the control of HWA” as a contaminant because it “cannot be reasonably eliminated from L. osakensis cultures” despite efforts by researchers to help prevent its release.
Harmful impacts of poorly regulated biocontrol go back decades. For example, the cane toad introduced to Australia in 1935 to control sugar cane pests instead caused declines in native predators; the small Indian mongoose wiped out native Fijian birds after its introduction for rat control; and the multicolored Asian lady beetle, introduced for aphid control, has become a serious pest to humans and ecosystems in North America and Europe.
Like many of my colleagues in the field of conservation biology, I believed such uninformed releases were a thing of the past. Biocontrol practitioners now agree that agents should be released only after an informed evaluation of potential risks and this consensus dominates the scientific literature, for example, in Bigler et al. 2006, Barratt et al. 2010, Van Driesche & Simberloff 2016, Heimpel & Cock 2017, and Heimpel & Mills 2017. Information about the agent—how it behaves and interacts with other species in its native range—is needed to predict impacts in places it will be introduced. The importance of accurate identification of agents and avoidance of contamination, even with related species, has long been recognized. Legal safeguards now exist, for example in Australia, New Zealand, South Africa, and the United States to ensure that regulatory officials and the public aren’t caught unaware.
A failure of science and public transparency
Unfortunately, in the case of the Japanese beetle L. naganoensis, the safeguards failed. The Plant Protection Act of 2000 (7 U.S.C. § § 7701-7786) requires the USDA’s Animal and Plant Health Inspection Service to conduct biocontrol agent permitting and tasks the agency with ensuring the process is transparent, accessible, and based on scientific evidence. This usually happens through public review and comment on a USDA-prepared Environmental Assessment (EA) that presents risks and, if necessary, a subsequent and more thorough Environmental Impact Statement. These documents are supposed to be prepared and made public before permitting decisions happen.
Instead, the first mention of L. naganoensis’ release came via a two-page “final decision” document issued by the USDA in December 2017. That document references an EA associated with L. osakensis that was written before L. naganoensis was known to exist. And it gives this groundless rationale for the permitting decision: because L. naganoensis’ diet is assumed similar to that of other Laricobius species, because L. naganoensis makes up a minor component of L. osakensis colonies, and because L. naganoensis is unlikely to persist owing to difficulty finding mates.
All these assumptions are questionable because scientists simply do not understand L. naganoensis well enough to confirm them. Moreover, the referenced EA was never provided for public review and comment. If it had been, the public would have seen that USDA acknowledges “there are no biological studies on L. naganoensis” and “the feeding rate of adult and larvae of L. naganoensis is unknown”. In short, the USDA’s finding of “no evidence…[of] adverse environmental effects” is misleading because such a conclusion must be based on review of a substantial amount of evidence, and little is known about L. naganoensis.
The seriousness of circumventing policy meant to inform and involve the US public and ensure informed decisions is compounded by the irony of allowing introduction of a little-understood species to control a previously introduced invasive species. What could go wrong?
Christy Leppanen is a Research Assistant Professor at the University of Tennessee’s Department of Ecology and Evolutionary Biology. She is interested in progressive and collaborative resource and pest management, particularly prevention and practices that minimize non-target impacts. For more information visit her webpage.
Science Network Voices gives Equation readers access to the depth of expertise and broad perspective on current issues that our Science Network members bring to UCS. The views expressed in Science Network posts are those of the author alone.
USDA (2017) Approval of Laricobius naganoensis (Coleoptera: Derodontidae), a Predatory Beetle for Biological Control of Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), in the Continental United States, Draft Environmental Assessment 2017. Plant Protection and Quarantine, Animal and Plant Health Inspection Service, United States Department of Agriculture, Riverdale, MD. Publication forthcoming
Support from UCS members make work like this possible. Will you join us? Help UCS advance independent science for a healthy environment and a safer world.