Impact of climate and land use change on the distribution of orchids in Estonia

Habitat loss and climate change are driving global declines in terrestrial orchid populations. In Europe, predicted north- ward range shifts suggest that northern regions may serve as future refugia. Estonia— one of northern Europe’s most orchid-rich countries—offers a valuable case study for assessing climate change impact on orchids. Using species distri- bution models (SDMs), we projected range changes for 31 orchid species under moderate (SSP245) and high-emission (SSP585) scenarios, integrating land use change projections through the 21st century. Currently, the western islands and coastal areas host the highest orchid diversity, forming a hotspot for calcicole tuberous species that grow preferentially in open and semi-open habitats. Under both scenarios, many of these species are expected to shift eastward. However, significant losses in orchid richness are predicted as early as 2040, severely impacting these western orchid hotspots and large parts of central and eastern Estonia, with non-calcicole rhizomatous species inhabiting forest and wet forest habitats emerging as the most vulnerable taxa. Projected changes intensify under SSP585, where 2040–2060 conditions resemble those expected under SSP245 by 2080–2100. The period up to 2040 emerges as a critical bottleneck, especially for rare and threatened species. While some recovery is projected after 2060 under high-emission scenarios, earlier population declines may lead to irreversible losses. Estonia holds promise as a northern refuge for orchids under climate change, but proactive conservation efforts are urgently needed before 2040 to avert future biodiversity loss.