Bridging the Gap Between Theory and Practice: Assessing Two Decades of Methodological Procedures and Reporting Omissions in Roadkill Studies of The Brazilian Cerrado

Abstract

This review assesses two decades (2000–2024) of Road Ecology research in the Brazilian Cerrado, a global biodiversity hotspot. We analyzed 63 studies on four major vertebrate groups to quantify trends, methodological procedures, omissions, and road mortality, drivers that could compromise the evidence base for environmental management. While research output has expanded temporally, it remains geographically concentrated in established states (Goiás, Minas Gerais, and São Paulo), leaving high-deforestation frontiers like the Matopiba region (Tocantins, Maranhão, Piauí, and Bahia) severely under-represented. Methodologically, the prevailing reliance on high-speed vehicle surveys (48% of studies; mean 53 km/h) and the scarcity of foot-based monitoring lead to a systematic underestimation of small-bodied taxa. Furthermore, 90% of the studies failed to report at least one key methodological procedure; specifically, 51% omitted the number of observers, 49% failed to report traffic volume, and even the total distance monitored and monitoring frequency were not specified in 11% and 16% of the studies, respectively. While methodological reporting has improved over time, omissions remain influenced by bibliometric drivers; specifically, larger authorship scales and articles often constrain methodological disclosure. Observed roadkill rates (ranging from 0.008 to 0.030 ind/km/day) reflect detection and carcass persistence biases rather than ecological reality, with highly detectable mammals and birds dominating records. To bridge the gap between theory and applied science, we propose a Minimum Reporting Checklist. It ensures data reporting and comparability, providing a universal standard to enhance the technical rigor of academic research, environmental licensing, and wildlife mitigation policy globally.