Evaluating conservation biology texts for bias in biodiversity representation

Balancing the Needs of People and Nature, 2nd edition [17]; and Essentials of Conservation Biol- ogy, 6th edition [18]. These seven books were published by both US (n = 2) and UK (n = 5) publishers. Collectively, these seven books are commonly used for introductory undergraduate courses in conservation biology around the world. Within each textbook, we evaluated the figures, tables, and boxes as examples of the type of diversity presented. To avoid any differences in interpretation, the lead author conducted all the data entry. Specifically, from each figure, table, and box, we recorded taxonomic group (if a specific species or group was described or shown in an image), if the species or taxonomic group was an aquatic or terrestrial organism, the continent where data were gathered, ecosys- tem type (if specifically stated in the example or if it could be identified), and if the example mentioned genetic diversity (if specifically stated in the example or if it could be inferred). Because there is not a singular source for classifying ecosystems, we grouped them into 15 broad classes that are representative of ecosystem descriptions in the literature and from Bailey [19]. Upon compiling data across the seven texts, we then tabulated overall totals and propor- tions and textbook specific totals and proportions for analysis. To determine if the representa- tion of taxonomic groups in textbooks was similar to the group’s relative abundance on Earth (according to [3]), we conducted a chi-square analysis. For human influence and genetic diver-

sity, we simply calculated the percentage of examples presenting such information as a com- parative dataset for which analysis does not exist. Finally, for ecosystems, we compared frequency of use among classes to determine how often each ecosystem type was used in exam- ples (Table 1). All analyses were conducted in Microsoft Excel with a p � 0.05 considered significant. Results We found that textbooks were significantly biased in their taxonomic coverage of Earth’s bio- diversity relative to its actual biodiversity, (χ2 = 109.118; df = 8; p < 0.001). Of all taxa cited in the textbooks, mammals were used most frequently, accounting for 31% of all examples refer- ring to a specific species or group (Fig 1). Amphibians were the least used example of all main taxonomic groups. Terrestrial organisms were used more frequently as examples than aquatic organisms, but mirrored Earth’s actual aquatic and terrestrial species diversity and hence pre- sented a relatively accurate example of representativeness (Fig 2). In examples where data col- lection location was mentioned, North America was the most frequently mentioned continent, while Antarctica was the least mentioned site (Fig 3). Only 2.5% of all examples mentioned genetic diversity. Forest ecosystems were the most frequently cited terrestrial ecosystems, while coral reef ecosystems were the most frequently cited aquatic ecosystems (Fig 4). Terres- trial ecosystems were used in more examples (75%) than aquatic ecosystems (25%). In exam- ples mentioning ecoregions, tropical regions were the most frequently mentioned (43%),

followed by Arctic (29%) and temperate (14%), while the Indo-Malay (7%) and Australasia (7%) regions were least mentioned. However, only 3 textbooks (A Primer of Conservation Biol- ogy, 5th edition; An Introduction to Conservation Biology; and Conservation Biology for All) mentioned ecoregions. Within textbooks, Fundamentals of Conservation Biology, 3rd edition was the most repre- sentative of Earth’s actual biodiversity across taxa, while Key Topics in Conservation Biology 2 was least representative (Fig 5). Fundamentals of Conservation Biology, 3rd edition most fre- quently mentioned genetic diversity, while Key Topics in Conservation Biology 2 and Conserva- tion Biology for All mentioned genetic diversity the least. Only two textbooks cited an ecosystem other than forest most frequently. Fundamentals of Conservation Biology, 3rd edi- tion, mentioned reef ecosystems more than any other type, while Key Topics in Conservation PLOS ONE Bias in conservation biology textbooks PLOS ONE | https://doi.org/10.1371/journal.pone.0234877 July 10, 2020 3 / 11