This article came out last month, but it’s taken me this long to find time to read it, and to do the necessary background reading to write up a post about it. This article in PLoS ONE describes a study done in 2006 by French scientists to determine whether or not people actually value rare things more than common things. The study was intended as a follow-up to an earlier article in PLoS Biology about the anthropogenic Allee effect, which accepted the theory that humans do value rare things, and as a result participate in various activities based on perceived rarity that contribute to population declines.

Over on the Guilty Planet blog, two of these “do people value rare things” studies, including the PLoS One study, are described. In one study, people at upscale hotels and suburban grocery stores chose between “rare” and “common” sturgeon caviar, which were actually identical species of farmed sturgeon. The “rare” sample was overwhelmingly preferred. The other study measured clicks on a website for slide shows of rare species and common species, the duration of time people were willing to wait for the slide shows to load, and the number of times they tried to re-load them. The study found that people attempted to access the rare species slide show by a significant majority, and were willing to wait longer for it to load.

Personally, I don’t find this terribly interesting. It’s nice to have an empirical basis for the assumption that people value rare things, I suppose, but it seems obvious enough that empirical study wasn’t actually necessary. However, I did find the initial study defining the anthropogenic Allee effect to be fascinating.

The Allee effect is an established effect important to ecology and applied conservation biology which describes the relationship between reproduction capability and population sustainability as population density of species declines. The authors of the PLoS Biology study coined the term “anthropogenic Allee effect” (AAE) to describe a purely artificial Allee effect generated by human activity relating to the “paradox of value” of supposedly rare species of plants and animals. As rarity increases, so does the price people are willing to pay for access to these rare species.

Human activities that can cause an AAE are:

  • Collections, where naturalists, collectors, scientists all work harder and pay more for specimens of increasingly rare species in an attempt to find them before they become extinct;
  • Trophy hunting, as hunters will pay more for the prestige of trophies of rare and restricted species, which may in turn drive up illegal poaching;
  • Luxury items, such as caviar and abalone, which have inflated prices for rare species;
  • Exotic pets, which includes both illegal trading and smuggling, as well as the extreme, exponential increase in prices for some species when endangered species protection is under consideration, before such protections are actually in place — one striking example is that of the turtle Chelodina mccordi , which gained recognition in the pet trade after being described in scientific literature and is now nearly extinct in the wild;
  • Traditional medicine, which prefers rare species over common ones, and is a driving force behind poaching of many species such as tigers and rhinos, and;
  • Ecotourism, when the influx of tourists to an area of significance for species can exert enough stress to cause declines in populations, thus increasing scarcity and driving still more tourism, in a feedback loop sure to spell disaster unless tourism is curbed or capped (such as tourist limitations imposed in the Galapagos).
24 hour armed guard over rhinos in a Zambian park

24 hour armed guard over rhinos in a Zambian park

Such human activities can have extensive impacts on rare and endangered species, even when they’re driven by concern and compassion for biodiversity, as in the case of ecotourism. Decisions to list species as endangered and to supply them with legal protection need to be carefully weighed against our ability to enforce these protections and suppress illegal trade driven by a renewed awareness of their rarity outside the conservation community. While conservationists can play to humans’ love of rare things as a way to generate interest in their plight, that must be carefully weighed against the possibility of creating an AAE and risking further exploitation.

Humans Love Rare Things; Albinos Safe, Endangered Species Screwed : Guilty Planet.

PLoS ONE: Rare Species Are Valued Big Time.

PLoS Biology: Rarity Value and Species Extinction: The Anthropogenic Allee Effect.