Plant reproductive phenology along an elevation gradient in the extreme environment of the Canadian High Arctic

ABSTRACT Background The extreme environment of the Canadian High-Arctic is experiencing unprecedented climate change with temperatures rising at three times the global average. There is a compelling need to understand how the phenology of Arctic plants will respond. However, long-term High-Arctic phenology monitoring is challenging due to the region’s remoteness. Aim To predict phenological responses of Arctic plants to climate change using an elevation gradient with associated temperature gradient as a proxy for climate change. Methods Flowering and seed dispersal times of seven Arctic species were recorded along an elevation gradient on Ellesmere Island, Nunavut, Canada in 2015 and related to air temperature measured at plant height and growing day degree (GDD). Results Flowering and seed dispersal times were earliest at the warmest site. A significant relationship with temperature was observed in flowering times of five species and seed dispersal times of one species. Conspecifics experienced fewer GDD at peak flowering at the coldest site than at warmer sites. Conclusions Temperature gradient observations provide insights into phenology–temperature relationships that complement long-term monitoring and enhance our ability to understand the impacts of climate change in remote regions. However, potential species adaptation along the temperature gradient should be taken into account. This single summer of results should be viewed with caution.