Public choice of species for the ‘Ark’: Phylogenetic similarity and preferred wildlife species for survival

Summary

Humans play a role in deciding the fate of species in the current extinction wave. Because of the Similarity Principle, physical attractiveness and likeability, it has been argued that public choice favours the survival of species that satisfy these criteria at the expense of other species. This paper empirically tests this argument by considering a hypothetical ‘Ark’ situation. Surveys of 204 members of the Australian public inquired whether they are in favour of the survival of each of 24 native mammal, bird and reptile species (prior to and after information provision about each species). The species were ranked by percentage of ‘yes’ votes received. Species composition by taxon in various fractions of the ranking was determined. If the Similarity Principle holds, mammals should rank highly and dominate the top fractions of animals saved in the hierarchical list. We find that although mammals would be over-represented in the ‘Ark’, birds and reptiles are unlikely to be excluded when social choice is based on numbers ‘voting’ for the survival of each species. Support for the Similarity Principle is apparent particularly after information provision. Public policy implications of this are noted and recommendations are given.

Introduction

Prioritising efforts to preserve biodiversity is a critical aspect of conservation biology. Resources available to protect wildlife species from extinction are often limited, and choices have to be made about which species to concentrate conservation efforts on (Tisdell, 1990). Public preference for selecting species, therefore, becomes an important component in preservation decisions. It is claimed that humans prefer animals that are similar to themselves (the Similarity Principle) and that these are considered to be physically attractive or more likeable (Gunnthorsdottir, 2001; Kellert, 1980; Plous, 1993). Survey-based studies have shown that while people were willing to pay more to conserve animals that are threatened or have important ecological roles, preservation bids are nevertheless high for species that are similar to humans or are attractive to them (e.g., mammals>birds>reptiles) (DeKay & McClelland, 1996; Gunnthorsdottir, 2001; Samples, Dixon, & Gowen, 1986; Tkac, 1998). In fact, Metrick & Weitzman (1996), Metrick & Weitzman (1998) found that government spending decisions for conserving endangered species in the United States were most influenced by ‘visceral’ characteristics such as physical size and whether the animals were higher life forms than by scientific characteristics such as the degree of species endangerment or taxonomic distinctiveness.

The Similarity Principle implies that where only a limited number of species can be saved, mammals may dominate the group of animals chosen to join the ‘Ark’ while animals from other taxonomic groups such as reptiles may be poorly represented or not represented at all. According to Gunnthorsdottir (2001), if the support of citizens for wildlife conservation policies is guided by such “superficial characteristics” of an animal, then an “animal's external characteristics may seal its fate”.

This study aims to test the Similarity Principle by using a simulated public choice experiment involving 24 native Australian tropical mammal, bird and reptile species, and the stated preferences of a sample of the Australian public for the survival of each of the species. Using the plurality voting system, the species can be ranked by the percentage of survey respondents who responded ‘yes’ to the question of whether to preserve a species or not. These rankings were examined on two different occasions: prior to participants being given information about the species and afterwards. This was done in order to take into account the effect of information provision in altering choice. Although widely used in democracies, voting systems are just one possible means for determining social choices. For example, aggregate willingness to pay for a policy change is sometimes used as an alternative method, particularly by economists. However, it should be noted that ‘popularity’ is likely to be only one of the factors that determines actual support for the survival of particular species.

Our approach is different from the willingness-to-pay approach and those involving the measurement of parameters such as degree of concern or attractiveness employed in previous studies (e.g., DeKay & McClelland, 1996; Gunnthorsdottir, 2001; Samples et al., 1986) in that it attempts to eliminate the confounding effect of species endangerment from the survey participants’ decision-making process. In studies involving willingness-to-pay, the urgency of the needed action to preserve a species from extinction can influence the amount of resources (funds) allocated by participants to saving it. Here, we only enquire of participants whether or not they favoured the survival of the species in the surveys and endeavour to identify the factors that could have influenced participants’ decisions. This form of inquiry has not been previously done.

The aim of this paper is to discuss the possible factors that could have influenced the rankings of the species (does the Similarity Principle hold strongly? How did the provision of information about the species alter participants’ choices? What other factors could have influenced the rankings?) and policy implications.