Comment: Novak et al. (2021) overestimated the successes of species translocations and minimized their risks

When deciding whether to translocate a species, it is important know likely benefits and risks. Thus, Novak et al.'s (2021) analysis of past species translocations assess their successes unintended consequences welcome. However, conclusion that “The widespread paucity negative impacts stemming from conservation are signal regulators, decision-makers, stakeholders conservationists can be entrusted with the safe timely use translocations” undermined by several problems led them overstate minimize impacts. Their conclusions about overwhelming success (“Translocations have played will play vital necessary role in conserving 70% US endangered species,” “conservation routinely yielded intended benefits”) not supported data. The figure includes 41% listed or recovered for which been performed, 16% planned, 12% possible future implied existing planned captive propagation. For 28% no translocation has yet it's impossible benefit conservation. Including extremely optimistic because unsupported actual successes. In addition, “a role” only fraction were translocated. Table 1 summarizes history sample 20 randomly drawn data set they identified as having Three five these appear translocated into nature at all. Ten twelve failed establish populations, such small numbers up this point must small, and/or so recently long-term success. al. did present any quantitative criteria could judged “vital necessary,” but generous reading suggests perhaps 5 (the Kootenai River population Acipenser transmontanus, Amorpha crenulata, Gila purpurea, Mustela nigripes, Rana sevosa). Consequently, number necessary” probably closer 10% than 70%. also minimized translocations, writing that: “Of 1014 total taxa we found recorded spanning 125 years, one restricted instance caused loss biodiversity”; (referring biocontrol agents United States) “only 3% (21) resulted consequences.” But sources searched (e.g., USFWS recovery plans Schwarzländer [2018]) do typically contain information. None other documents used compile contained on although some known potential cause Gurney al., 2015; Schiffman, 1994). (2018) address nontarget effects biocontrols all, compendium upon based (Winston 2014) mentioned few passing, rather complete list. consulted report impacts, provide reliable estimate severity frequency translocation. further claimed routine monitoring game should detect translocations. This assumes strong enough support analyses someone analyses. ambiguity zebra mussels (a enormous impacts) fish populations (Higgins & Vander Zanden, 2010; Strayer 2004) illustrates how unwise rely detecting using species. Although accurately assessed, I agree most had Rather attributing motivation (conservation), suggest product kinds common: modest augmentations reintroductions specialized whose kept multiple factors. Based literature non-native Ricciardi 2013), may predictable (i) traits, (ii) radical (augmentation an vs. re-establishment occupied site introduction new site), (iii) rigor planning protocols (as emphasized biocontrol). To extent differ efforts traits potentially keystones like woolly mammoth passenger pigeon hybrids narrowly endemic specialists), moving outside recent ranges (assisted migration), protocols, reliably predict al purposes, essential confronting climate change threats biodiversity ecosystem services. often reach goals, diverting resources activities, harmful consequences. If maximize fairly Despite admirable added little our understanding succeed, work was G. Evelyn Hutchinson Chair Cary Institute Ecosystem Studies. None. David L. conceived wrote paper, all All collected study presented paper Supporting Information S1. Appendix S1 information Please note: publisher responsible content functionality supporting supplied authors. Any queries (other missing content) directed corresponding author article.