Upper range limit establishment after wildfire of an obligateseeding montane forest tree fails to keep pace with 20th century warming

Aims How species respond to climate change at local scales will depend on how edaphic and biological characteristics interact with species physiological limits and traits such as dispersal.Obligate seeders,those species that depend on fire for recruitment,have few and epi-sodic opportunities to track a changing climate envelope.in such cases,long-distance seed dispersal will be necessary to take advan-tage of rare recruitment opportunities.We examine recruitment patterns and seedling growth below,at and above the timberline of an obligate-seeding Australian montane forest tree(Eucalyptus delegatensis)after stand-replacing fire,and place these changes in the context of regional warming.Methods We use two methods to detect whether E.delegatensis can estab-lish and persist above the timberline after stand-replacing wildfire in montane forests in south-east Australia.First,we examine estab-lishment patterns by using belt transects at six sites to quantify how changes in post-fire recruit density with increasing distance above the timberline seven years post-fire.Second,to determine whether dispersal or physiological constraints determine post-fire establish-ment patterns,we transplanted seedlings and saplings into bare ground above(100 m elevation),at,and below(50 m elevation)timberline 18-months after fire.We monitored seedling growth and survival for one growing season.Important Findings There was minimal upslope migration of the species after fire with most saplings observed near seed-bearing timberline trees,with only occasional outpost saplings.Transplanted seedlings and saplings sur-vived equally well across one growing season when planted above existing timberlines,relative to saplings at or below the timberline.Seedling and sapling growth rates also did not differ across these location,although seedlings grew at much faster rates than saplings.These findings suggest that upslope growing season conditions are unlikely to limit initial range expansion of trees after fire.instead,it is more likely that seed traits governing dispersal modulate responses to environmental gradients,and global change more generally.