Trophy hunting: Insufficient evidence.

Abstract

In their Letter “Trophy hunting bans imperil biodiversity” (30 August, p. [874][1]), A. Dickman et al. argue that banning trophy hunting would be detrimental to conservation. We agree that evidence for effectiveness is important before actions are taken. However, Dickman et al. do not provide evidence that bans to trophy hunting harm biodiversity ([ 1 ][2]). Dickman et al. claim that trophy hunting indirectly benefits biodiversity because populations (and their habitats) are better protected in places or times where trophy hunting has occurred. However, no comprehensive research has tested that hypothesis. Even previous work by Letter authors Dickman and Johnson (led by Macdonald) concludes that we know too little to infer whether trophy hunting (selective hunting for recreation) contributes to the conservation of wild lions ([ 2 ][3])—one of the best-studied trophy-hunted species. Dickman et al. overstate their case. For example, the claim that “more land has been conserved under trophy hunting than under national parks” seems based on the statement from Lindsey et al. ([ 3 ][4]) that “[o]ver 1,394,000 km2 is used for hunting in sub-Saharan Africa, exceeding the area encompassed by national parks by 22% in the countries where hunting is permitted” ([ 3 ][4]). However, this interpretation is misleading because those lands include private lands, protected areas that allowed subsistence hunting, and various other classes of protected areas, not exclusively trophy hunting concessions. In addition, the authors' prediction that a ban on trophy imports or hunts would indirectly harm biodiversity could be just the converse: Perhaps hunting concessions would be upgraded in protection by catalyzing a governmental rethinking of carnivore management systems. An evidentiary basis for informing controversial policy interventions, such as trophy hunting, demands strong inference with full disclosure of uncertainties and disentangled value judgments from observations or inferences. Stronger evidence might be gleaned through adequate tests of the effectiveness of trophy hunting for protecting the hunted population, including broad-scale experiments using multiple replicated land parcels subject either to hunting or another putative form of biodiversity protection under similar socioeconomic systems, or tracking of populations before and after trophy hunting (accounting for other threats). Rigorous examinations would likely reveal outcomes that vary by population, geography, other threats to biodiversity, and socioeconomic and governance contexts. Finally, the addition of a long list of signatories implies a call to authority that should play little or no role in what should ultimately be an evidence-based scientific debate. By contrast, clear evidence, transparently conveyed and clearly demarcated from the ingrained values of those involved (whether they support or reject trophy hunting), could help elucidate environmental, ethical, social, and economic dimensions of this controversial activity whose ultimate conservation effects remain poorly understood. Dickman et al. respond: “…[A]ction should not be taken without evidence for its effectiveness…[but] we believe the burden of proof clearly lies with those who support [the removal of trophy hunting]…” See the [full response][5]. 1. [↵][6]1. A. Treves et al ., Conserv. Biol. 33, 472 (2018). [OpenUrl][7] 2. [↵][8]1. D. W. Macdonald et al ., Mamm. Rev. 47, 247 (2017). [OpenUrl][9] 3. [↵][10]1. P. A. Lindsey et al ., Biol. Conserv. 134, 455 (2007). [OpenUrl][11] Correction (16 March 2020): Competing interest declarations for F.J.S.-A. and P.C.P. have been added. A.T. is President of the Board of Directors of Future Wildlife, a tax-exempt organization with the mission to preserve nature, especially wild animals, and an unpaid science adviser for Project Coyote. F.J.S.-A. is on the Science Advisory Board of Project Coyote. P.C.P. is on the Science Advisory Board for Project Coyote and is associated with the IUCN species survival commission and four specialist groups. [1]: http://www.sciencemag.org/content/365/6456/874 [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: http://science.sciencemag.org/content/366/6464/435.1/tab-e-letters [6]: #xref-ref-1-1 View reference 1 in text [7]: {openurl}?query=rft.jtitle%253DConserv.%2BBiol.%26rft.volume%253D33%26rft.spage%253D472%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: #xref-ref-2-1 View reference 2 in text [9]: {openurl}?query=rft.jtitle%253DMamm.%2BRev.%26rft.volume%253D47%26rft.spage%253D247%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [10]: #xref-ref-3-1 View reference 3 in text [11]: {openurl}?query=rft.jtitle%253DBiol.%2BConserv.%26rft.volume%253D134%26rft.spage%253D455%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx