Testing theories of mire development using multiple successions at Crymlyn Bog, West Glamorgan, South Wales, UK

Abstract

1 Direct observations of long-term plant succession can be made using quantified plant macrofossil records from peat bogs, providing a means to re-evaluate theories of succession previously based on time-space substitution studies or field stratigraphic surveys. 2 Multiple successions from fen towards raised mire recorded at Crymlyn Bog demonstrate that divergent pathways exist, even when initial conditions are similar within a single bog. 3 Over time-scales relevant to the later stages of mire succession, allogenic forcing factors are significant and may be responsible for driving the direction and rate of species turnover in both forward and reversed hydroseral successions. 4 Differences in the local climatic regime may be responsible for the contrasting character of the mid- and late-Holocene transitional mire communities represented in Core CRB93 at Crymlyn Bog. 5 Plant macrofossil analyses show that Sphagnum is not always a dominant part of the mire community before the establishment of raised peats. Other species including Eriophorum vaginatum, may be equally important ‘ecosystem engineers’ at the fen–bog transition.