2025/12/08 by Ditte Marie Christiansen, Hans Henrik Bruun, Matilda Arnell +2 · 1 voice
Agricultural and Biological Sciences · Earth and Planetary Sciences · Environmental Science · #Archaeological Research and Protection #Mediterranean and Iberian flora and fauna #Species Distribution and Climate Change
paper · pdf · doi:10.21203/rs.3.rs-8277973/v1
crossref issued 2025/12/08 · crossref published 2025/12/08 · openalex publication_date 2025/12/08 · openalex created_date 2025/12/08 · crossref created 2025/12/08 · crossref deposited 2025/12/12 · crossref indexed 2026/02/28 · openalex updated_date 2026/07/15
Abstract Historic data are essential for quantifying changes in biodiversity and their drivers. Much legacy data remains undigitized in archives such as natural history museums, representing untapped resources for assessing past biodiversity patterns. In 1904, the first systematic survey of species distributions of the entire Danish flora was initiated. Most field surveys were conducted in the early 20th century. Results were published as black and white printed maps (1931–1976). We used automated georeferencing and image classification to extract data from all published maps. We present 1340 historic distribution maps of vascular plant species, subspecies and varieties in Denmark at 10 × 10 km resolution. These maps represent the Danish flora of native and archaeophyte species known at the time, except some of the most common native species. By comparison with modern distribution data, long-term increases and declines can be accurately quantified, contributing to large-scale analysis of national, European or global plant diversity changes in the modern era.