Geoscience Reference
In-Depth Information
CHAPTER 12
The Use of Bryophytes for Fluvial
Assessment of Mountain Streams
in Portugal
Cristiana Vieira
1
,AnaSeneca
1
, Maria Teresa Ferreira
2
and Cecılia Sergio
3
1
Centro de Investiga¸ ao em Biodiversidade e Recursos Gen eticos (CIBIO), Porto, Portugal
2
Forest Research Centre, Technical University of Lisbon, Portugal
3
Centre for Environmental Biology (CBA), Lisbon University, Portugal
Introduction
availability of dissolved carbon dioxide is not
limited (Bain and Proctor, 1980; Vitt and Glime,
1984; Grime
et al.,
1990).
Nevertheless, the use of bryophyte information
for aquatic plant monitoring purposes has been
inconsistent. This is despite advice that recording
the presence and extent of bryophyte taxa is
needed as part of aquatic macrophyte inventories
(Environment Agency, 2003), or that bryophyte
species can be used for assessing the trophic status
of rivers (Holmes
et al.,
1999; Haury
et al.,
2006).
In Portugal, bryophyte surveys are included in the
national biological assessment work programme for
the European Water Framework Directive (WFD;
Council of the European Communities, 2000).
However, the use of bryophyte information is
limited by problems in identifying certain difficult
taxa, remaining uncertainties about ecological
requirements and incomplete species distribution
data.
This chapter describes work to improve existing
knowledge about bryophyte communities and the
environmental factors affecting their distribution in
the mountain streams of north-west and central-
western Portugal. In so doing we explore the
Bryophytes have been used extensively as
indicators of fluvial and ecological conditions in
watercourses (Vanderpoorten, 2002; Zechmeister
et al.,
2003; Fritz
et al.,
2009). They are nutritionally
independent from their growing substrata, many
have perennial life strategies enabling them
to survive in harsh conditions and most are
directly influenced by the physico-chemical
properties of the water they inhabit (Proctor, 1982;
Glime and Vitt, 1984). Furthermore, bryophyte
communities are influenced by lithological and
climatic gradients and also by different types and
extent of physical disturbance to river ecosystems
(Muotka and Virtanen, 1995; Suren, 1996; Scarlett
and O'Hare, 2006). In some places, bryophyte
information has been used to establish near-
natural 'reference' conditions for conservation
and water quality purposes and also to assess the
hydrological character of watercourses (Slater
et al.,
1987; Vanderpoorten, 2002). This approach is
particularly relevant for shallow mountain streams
where bryophytes are adapted to live with little
competition from higher plants and where the
