A phylogeographic analysis of Achillea maritima (cottonweed), with an assessment of the impacts of future climate change on distributions across the species range

Abstract

Coastal ecosystems and the flora which characterize these ecosystems are experiencing mounting pressure from the impacts of climate change and anthropogenic activities. Achillea maritima is an obligate species of coastal sand dunes, which is experiencing declines in numerous regions throughout its range. The Irish population which represents the northern limit of the species is critically endangered, and in need of decisive conservation action to prevent local extinction. In this study we have used a combined approach of phylogeography and species distribution modelling to determine the genetic diversity of the species across its range and the potential impacts of climate change on the species. The results show that A. maritima has a low level of genetic diversity across its distribution with no diversity within any of the populations fringing the Atlantic Ocean. Species distributions models display an increasing suitability in northern latitudes, with Ireland becoming more climatically suitable in the future. There was a clear decline in distributional suitability in the Eastern Mediterranean, this finding outlining a need for conservation efforts in this region before the loss of populations. Due to the low level of genetic diversity found within the species for the studied markers more research will be required before any re-introduction programme can be undertaken.

Date of Award	Jul 2024
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Lorraine Scott (Supervisor) & Neil Reid (Supervisor)