Geoscience Reference
In-Depth Information
CHAPTER 10
Scotland's Freshwater Pearl Mussels:
The Challenge of Climate Change
Peter Cosgrove 1 , Lee Hastie 2 , Jon Watt 3 ,IainSime 4 and Philip J. Boon 5
1 Alba Ecology Ltd, Grantown on Spey, UK
2 Department of Zoology, University of Aberdeen, UK
3 Waterside Ecology, Druimindarroch, UK
4 Scottish Natural Heritage, Inverness, UK
5 Scottish Natural Heritage, Edinburgh, UK
Introduction
et al., 2001) and impacts related to climate change
have been identified as a potential threat to this
species (Hastie et al., 2003a). Combining over
two decades of research, this chapter reviews the
evidence of this threat, presents new data on
the status of the species in Scotland and suggests
management responses needed to help conserve
the freshwater pearl mussel over the next 20 years
and beyond.
Climate change is one of the greatest threats
facing biodiversity. Its effects on species and
ecosystems will vary depending upon the
nature and magnitude of the changes and the
management challenges these pose (Ormerod and
Durance, this volume). Of particular concern are
the impacts on threatened or endangered species,
already stressed by an existing range of pressures.
Scotland is a global stronghold for the freshwater
pearl mussel ( Margaritifera margaritifera ), a fully
protected species which has declined throughout
its range to such an extent that it is now listed
by the IUCN as endangered. The primary causes
of this decline include industrial and agricultural
pollution, over-exploitation by pearl fishermen,
decline in host fish stocks and physical habitat
degradation caused by hydro-electric operations
and small-scale river engineering works (Cosgrove
et al ., 2000a).
Pearl mussels were formerly widely distributed
from the arctic and temperate regions of north-
western Russia, through Fennoscandia and
Europe to the north-eastern seaboard of North
America/Canada. The decline of the pearl mussel
throughout every part of its Holarctic range has
been well documented (Bauer, 1986, 1988; Young
Ecology
The freshwater pearl mussel is one of the longest-
lived invertebrates, capable of living well over 100
years (Bauer, 1988). It has a complex life cycle,
which makes this bivalve particularly vulnerable to
a wide range of factors that can change its aquatic
habitat, as well as directly affecting the species
itself.
Freshwater pearl mussels live buried or partly
buried in the beds of clean, fast-flowing unpolluted
streams and rivers (Plate 14) and subsist by inhaling
and filtering the minute organic particles on which
they feed (Cosgrove et al. , 2000a). Pearl mussels
prefer stable cobble/boulder dominated substrate
habitats with some fine substrate that allows
the mussels to burrow (Cosgrove et al. , 2000b).
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