The research, led by Pietro Pollo and Michael Kasumovic of the University of New South Wales, represents the most comprehensive assessment of taxonomic bias ever conducted in the field. Previous studies relied on small samples of journals and manual classification of papers, leaving open the question of whether the patterns documented in the early 2000s had persisted. To overcome these limitations, the team analyzed 1,383,803 papers from 612 journals, spanning literature published as far back as 1877, and tracked how the representation of different animal groups changed between 2001 and 2025.

Classifying papers by hand at this scale would have been impossible, so the researchers built a keyword-based algorithm trained on nearly 5,000 manually classified papers. The algorithm drew on the GBIF Backbone Taxonomy and a customized vocabulary of taxonomic terms to identify the animal focus of each paper from its title, abstract, and keywords. When tested against 1,815 papers the researchers had classified independently, the algorithm achieved at least 97.2 percent accuracy for every animal group, with an F1-score of 91.2 percent. The team also verified that the algorithm rarely produced impossible labels, such as identifying a paper in a mammalogy journal as being about something other than mammals.

The scale of the bias is striking. Of the 991,894 papers involving animals, 46.1 percent focused exclusively on invertebrates and 45.1 percent exclusively on vertebrates, figures that appear roughly balanced until one considers that invertebrates account for approximately 95 percent of animal species. When the researchers compared the observed proportion of papers on each group with what would be expected if research effort were distributed in proportion to species richness, insects emerged as the most underrepresented group relative to their diversity, while mammals and fish were the most overrepresented.

The study also documented how bias is embedded in the structure of the field itself. Nearly 40 percent of the 612 journals analyzed had explicit taxonomic restrictions, and a striking 42 percent of these specialized journals focused on arthropods. The researchers found that species-rich invertebrate groups such as insects and arachnids are often relegated to these specialized outlets, which likely reach narrower audiences than general ecology and evolution journals. This means the true extent of vertebrate favoritism may be even more pronounced from the perspective of an average researcher scanning the broader literature.

Perhaps most disappointingly, the overall pattern has shown no improvement since taxonomic bias was first formally discussed in 2002. The proportion of papers on vertebrates across the literature as a whole remained stable over the 25-year study period, and in some subfields it actually increased. In aquatic journals, for example, fish rose from 35.8 percent of papers in 2001 to 49.7 percent in 2025. In behaviour, conservation, and general ecology and evolution journals, mammals and birds remained particularly dominant. The only subfield where invertebrate research increased was zoology journals, likely because these outlets publish much of the work describing new species, the vast majority of which are invertebrates.

The researchers also examined whether journal prestige metrics were linked to taxonomic focus. Papers published between 2021 and 2025 in journals with higher impact factors and citation indicators were more likely to focus on vertebrates, although the relationship was not uniform across subfields. Interestingly, birds were equally likely to appear in high-impact and lower-impact journals, suggesting that the prestige advantage accrues to vertebrates as a broad category rather than to any single charismatic group.

The attention gap proved even more consequential than the publication gap. Compared with papers on invertebrates in the same journal, papers on vertebrates received on average 10.2 percent more citations, 43.1 percent more mentions in online documents such as news outlets and social media, 24.2 percent more readers on the reference manager Mendeley, and 45.1 percent higher Altmetric scores, a weighted measure of overall online attention. These findings align with previous research showing that vertebrates attract more attention on platforms like Instagram and Wikipedia, and even on government-curated imagery such as postage stamps. Within the attention metrics, birds often attracted the greatest online buzz but received the fewest citations, revealing that public appeal and academic influence do not always coincide.

The authors caution that their within-journal attention analyses are correlational and cannot fully rule out confounding factors such as paper topic. Still, they argue that the patterns likely reflect deeper societal biases, since surveys consistently show that people value vertebrates more than invertebrates, a perception that editors, reviewers, and funding committees may unconsciously apply when judging research appeal. The consequences extend beyond academic vanity: taxonomic bias can stifle medical and engineering innovation by limiting biomimetic inspiration from understudied organisms, and it undermines the theoretical generality that ecology and evolution depend upon.

To break the cycle, the researchers propose concrete interventions within academia. They urge journals and funding bodies to systematically collect and publicly report the taxa studied in submitted manuscripts and funded projects, to incorporate taxonomic diversity into guidelines for awards, hiring, and publication decisions, and to establish targeted financial and publishing incentives for research on neglected organisms. They also emphasize the need to revive descriptive disciplines such as taxonomy and natural history, since hypotheses cannot be tested about organisms that have never been described. While such measures may seem ambitious, the authors note that similar skepticism once greeted diversity initiatives that are now widely accepted, and they hope their findings will prompt institutions to extend their commitments to equity to the tree of life itself.

Subject of Research: Taxonomic bias in ecology and evolution research literature

Article Title: Taxonomic Bias Persists in Ecology and Evolution Research Despite Decades of Concern

Article References: Pollo, P., & Kasumovic, M. M. (2026). Taxonomic Bias Persists in Ecology and Evolution Research Despite Decades of Concern. Ecology and Evolution, 16(10), Article e74450. https://doi.org/10.1002/ece3.74450

Image Credits: AI Generated

DOI: 10.1002/ece3.74450

Keywords: taxonomic bias, ecology, evolutionary biology, vertebrates, invertebrates, journal impact factor, Altmetric, biodiversity, conservation, entomology, scientific publishing, citation bias

The study, published in the journal Ambio, represents the first attempt to quantify the magnitude of taxonomic bias globally using consistent statistical methods. Previous work had documented bias in piecemeal fashion: entomologists describing ‘institutional vertebratism’ in funding decisions, botanists diagnosing ‘plant blindness’ in public perception, and conservation scientists coining ‘taxonomic chauvinism’ to explain why amphibians and reptiles attracted so little research. At the microbial scale, the problem is most extreme of all—one recent analysis found that half of all bacteriology papers focus on just ten species. But no one had systematically converted these scattered findings into a common currency to answer the fundamental question: how large is the distortion, really?

To build the dataset, the researchers searched the Web of Science database using an elaborate string of terms targeting studies of research bias, awareness disparity, and favoritism across all branches of life. An initial search in November 2023 returned 1,541 articles, which the team screened against strict eligibility criteria requiring quantitative measures of bias at the species level. Following the PRISMA framework for systematic reviews, they whittled the list down to 78 studies published between 1998 and 2025 across 54 journals, supplemented by a further 11 papers captured through automated alerts through the end of 2025. Two authors independently scored a sample of 100 studies, achieving near-perfect agreement—Cohen’s kappa of 0.89—a standard test of reproducibility in evidence synthesis.

The methodological challenge was formidable. Because the source studies used wildly different approaches—public surveys, bibliometric counts, Wikipedia page views, funding databases—the team converted every reported result into Pearson’s correlation coefficient, a universal metric of association ranging from −1 to 1. Chi-square statistics without standardized effect sizes were transformed using the phi coefficient or Cramér’s V, allowing every comparison to be placed on the same scale. The analysis then employed multilevel meta-analytic mixed-effects models in the R statistical environment, with publication identity included as a random effect to account for the non-independence of multiple estimates drawn from the same study. The researchers grouped the drivers of bias into five conceptually distinct categories: appearance, commonness, conservation priority, utilitarian value, and general taxonomic contrasts.

The headline finding is that positive biases—greater research attention, knowledge, funding, or interest toward particular species—were widespread across every study design, geographic region, and taxonomic scope examined. Yet their magnitude was generally small, with most effect sizes falling below r = 0.5. General taxonomic contrasts produced the strongest average effect (r = 0.40), confirming that plants and invertebrates systematically receive less attention than vertebrates. Aesthetic appearance (r = 0.18), commonness (r = 0.17), and utilitarian value (r = 0.15) all showed smaller but significant positive effects. Notably, the strongest single contrasts emerged precisely where neglect is most commonly alleged: studies comparing plants (r = 0.55) and invertebrates (r = 0.42) against animal controls reported the largest disparities.

Then came the result the authors describe as the most concerning of all. Conservation priority—whether a species is threatened, endangered, or data-deficient—was the only dimension of bias not consistently associated with positive effects across study designs, yielding an effect size indistinguishable from zero (r = 0.02). In plain terms, research effort, funding, and public interest are not reliably directed toward the species that need them most. Charisma, visibility, and familiarity continue to shape the allocation of attention more powerfully than vulnerability. Curiously, Oceania was the lone exception, but across the rest of the world the misalignment held firm. The implication is stark: emotional resonance and symbolism, not extinction risk, determine which organisms enter the political arena and which are left to disappear unnoticed.

The analysis also turned its statistical lens on the literature about bias itself, and found it wanting in familiar ways. Funnel plot asymmetry and a multilevel Egger regression revealed strong evidence of small-study effects: smaller investigations, often based on online surveys or classroom experiments, reported systematically larger effect sizes than their data-intensive counterparts (β = 1.88 ± 0.09, p < 0.001). Crucially, however, effect sizes showed no temporal trend over nearly three decades, and extrapolations for larger studies remained positive—suggesting the underlying signal is robust even if its magnitude is inflated in portions of the literature. There was, tellingly, a further irony: the meta-literature itself is taxonomically biased, with 72 percent of all estimates concerning animals, 68 percent involving vertebrates, and studies focused exclusively on fungi or microorganisms exceedingly rare. The same groups neglected by primary research are neglected by the research that studies neglect.

Geography offered one of the study’s few genuinely surprising insights. Despite enormous differences in regional biodiversity, research traditions, and conservation priorities, the magnitude of detected bias was remarkably uniform across continents—the same groups are overlooked everywhere. The authors note, however, that the Global South remains largely underrepresented in studies of taxonomic bias itself, meaning the current picture may still be incomplete. Within vertebrates, the team found that disparities tied to appearance were particularly pronounced: the gap between a resplendent quetzal and a drab sparrow appears wider than comparable divides among invertebrates or plants, hinting that charisma concentrates attention even within already-favored lineages.

The findings come with candid limitations. Effect sizes are distributed unevenly across taxa and regions—a classic example of the ‘streetlight effect,’ where researchers search where it is easiest to look—and birds and mammals benefit from richer distribution, genetic, and trait data that make studying their biases far more tractable. Categorizing heterogeneous studies into broad predictor groups required interpretive judgment despite explicit coding criteria, and the standard toolkit for detecting publication bias cannot capture the ‘file drawer problem,’ in which null results simply go unpublished. The authors also flag a recent large-scale analysis of roughly 14,600 conservation projects over 25 years, which reported stronger funding biases than the meta-analysis could capture but was too descriptive to yield standardized effect sizes—a reminder that the true picture for money may be darker than the statistics suggest.

So what should change? The authors argue that because the system is skewed rather than broken, no systemic revolution is needed—but deliberate, targeted action is. They propose redirecting conservation focus from individual species toward habitats and species assemblages, adopting positive discrimination mechanisms or dedicated funding schemes for neglected taxa, and encouraging journals to adopt ‘taxonomic inclusivity statements’ akin to existing diversity commitments. Above all, they contend, structural change depends on communication: mild but persistent distortions will remain socially inert if documented only in specialist journals. Just as research teams employ statisticians and data managers, they argue, institutions and funders should support trained science communicators as integral members of the research enterprise—because a biodiversity crisis we cannot see, in the species we ignore, is a crisis we are unlikely to solve.

Subject of Research: Global meta-analysis of taxonomic bias in biodiversity research, funding, and public attention across the tree of life

Article Title: The biodiversity we ignore: A global meta-analysis on taxonomic bias

Article References: Mammola, S., Fontaneto, D., Bellvert, A., Chialva, M., & Adamo, M. (2026). The biodiversity we ignore: A global meta-analysis on taxonomic bias. Ambio. https://doi.org/10.1007/s13280-026-02479-8

Image Credits: AI Generated

DOI: 10.1007/s13280-026-02479-8

Keywords: taxonomic bias, biodiversity, conservation, meta-analysis, charismatic species, plant blindness, institutional vertebratism, speciesism, extinction risk, research funding, invertebrates, fungi