4 - Implications of global warming and rising sea-levels for macrofungi in UK dune systems

Summary

Introduction

The effects of environmental change on the sand-dune ecosystem do not have to be considered hypothetically; they can be observed. Sand dunes are, by definition, dynamic systems, being created, shaped, modified, sustained or eroded by continual changes in a wide range of abiotic and biotic environmental factors. The fungi which inhabit this coastal ecosystem are subject to, and are part of, those same changes. Frankland (1981) stated that ‘community life for a fungus is dynamic’. This is nowhere more true than in sand-dune habitats where the combination of a dynamic biological organism functioning in a dynamic resource system constitutes a veritable dynamic duo, capable of long-term survival and viability.

Climatic background

Sea levels along the British coastline have been fluctuating for thousands of years. Around 12000 B.P. they were 50 m lower on the Welsh coast (Savidge, 1983). Some 5000 years ago it would have been possible to cross the Straits of Dover from England to France on dry land (Zuckerman, 1986). Mean global sea-level has risen by about 10–15cm during the twentieth century (Robin, 1986). Yet sand dunes in various stages of development still occupy 9% of the coastline of mainland Britain (Ranwell & Boor, 1986), in the form of spit dunes, bay dunes, hindshore dunes, prograding dunes or offshore island dunes. They provide all the classic dune habitats for fungi: yellow and grey dune, dune slack, dune grassland, dune scrub and dune heath (Fig. 4.1).