Spatial patterns of biodiversity are inextricably linked to their
collection methods, yet no synthesis of these patterns or their
consequences exists. As such, our view of ecosystems may be incorrect,
undermining countless ecological and evolutionary studies. Using 742
million records of 374,900 species, we explore the global patterns and
impacts of accessibility in terrestrial and marine Systems. Pervasive
sampling and observation biases exist across animals, with only 6.74%
of the globe sampled, and disproportionately poor tropical sampling.
High-elevations and deep-seas are comparably unknown. Over 50% of
records in most groups account for under 2% of species. Citizen-science
exacerbates biases, and normalizing the practice of valuing data
publication is essential to bridge this gap and better represent species
distributions from more distant and inaccessible areas, and provide the
necessary basis for conservation and management.