Geoscience Reference
In-Depth Information
CHAPTER 22
Key Factors in the Management and
Conservation of Temporary
Mediterranean Streams: A Case
Study of the Pardiela River,
Southern Portugal
Joana Rosado
1
, Manuela Morais
1
,Antonio Serafim
1
, Ana Pedro
1
, Helena Silva
1
,
Miguel Potes
1
, David Brito
2
, Rui Salgado
1
, Ramiro Neves
2
, Ana Lillebø
3
,
Antonio Chambel
1
, Vanda Pires
4
, Carlos Pinto Gomes
5
and Paulo Pinto
1
1
Centro de Geofısica, Universidade de Evora, Portugal
2
Instituto do Mar, Departamento de Zoologia, Coimbra, Portugal
3
Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, Portugal
4
Instituto de Meteorologia, I.P., Lisbon, Portugal
5
Instituto de Ci encias Agr arias e Ambientais Mediterr anicas, Universidade de Evora, Portugal
Introduction
Most Mediterranean streams are temporary,
characterized by seasonal events of flood and
drought and inhabited by aquatic communities
that are adapted to this pattern and uncertainty.
As the demand for water increases, especially for
agricultural use, availability is becoming a major
problem, especially during the dry Mediterranean
summers. This has led to extensive physical
modification of rivers to provide more reliable
access to water both for human consumption
and agricultural irrigation (Kondolf and Batalla,
2005). Extreme water shortages and crop failures
during the droughts of the early 1990s exposed the
vulnerability of Mediterranean areas to climatic
extremes
Rivers are complex systems and are strongly
influenced by the landscapes through which they
flow (Hynes, 1975; Vannote
et al
., 1980). Actions
taken well away from the river can sometimes
have adverse effects on channel morphology, river
flow, water quality and biological communities,
with consequent environmental, economic and
social implications and costs. These landscape-scale
factors are particularly relevant in Mediterranean
regions of the world because they amplify the
effects of the annual seasonal wet and dry periods
and the unpredictable variability of precipitation
between years (Boulton, 2003). The impacts on
aquatic ecosystems can be particularly severe
during the dry season (Fisher
et al
., 1998; Stanley
et al
., 1997).
(Weiß
et
al
.,
2007).
An
important
conclusion
from
these
events
was
that
future
climate
change
could
hinder
substantially
efforts
for
a
truly
sustainable
approach
to
