Geoscience Reference
In-Depth Information
species, some of which, such as signal crayfish and
Japanese knotweed, occur in or near rivers.
An awareness of the serious threat that invasive
alien species pose to biodiversity and to ecosystem
services now extends across Europe and beyond.
For example, the European Commission is
developing an invasive non-native species
strategy (http://ec.europa.eu/environment/nature/
invasivealien/index en.htm) as part of its goal
of halting the decline of biodiversity by 2020.
This initiative is supported by a range of
European and global databases (e.g. DAISIE -
http://www.europe-aliens.org/index.jsp) which
have been compiled to show the distribution of
alien species, provide information on their biology,
and suggest methods of prevention and control.
The lack of scientific data on rivers and climate
change 20 years ago is well illustrated in a recent
editorial in
Aquatic Conservation
(Ormerod, 2009)
where 43 of the 44 references cited were published
in the year 2000 or later. However, sufficient
evidence on the effects of climate change on
river temperature (Langan
et al.
, 2001; Webb and
Nobilis, 2007), and on flow regimes (Barnett
et al
.,
2006) has now been accumulated to show that in
many parts of the world rivers will be profoundly
affected during this century. Ecological impacts
(compounded by increasing human demand) are
likely to be many and varied, including direct
effects on life cycles and growth rates from rising
temperatures or displacement of animals and plants
through higher flows; and indirect effects such as
the flow-related dilution of pollutants or transport
of sediments (Ormerod, 2009, Cosgrove
et al
.,
this volume, Ormerod and Durance, this volume).
The influence of climate change on rivers will
undoubtedly be near the top of the list of threats
over the next few decades (Strayer and Dudgeon,
2010).
Global climate change
Potential threats from climate change were
certainly being discussed in 1990, but interest and
concern — by scientists, politicians and the general
public — has grown substantially since then. By
coincidence, the issue of
New Scientist
that was
published the week before the 1990 conference
contained a leading article on the subject, where
the tenor of the text was strikingly similar to
articles written 20 years later: 'It was a sight to
behold. There were the Americans, in Sweden last
week for the Intergovernmental Panel on Climate
Change, repeating their government's well-worn
homilies about global warming: how uncertain all
this science is, how expensive it would be to do
anything, how silly to get excited until we are
absolutely sure the world is in peril.' (
New Scientist
no. 1733, 8 September 1990).
Yet the impact of climate change on river
conservation and management was rarely
mentioned 20 years ago. In
River Conservation
and Management
, derived from the 1990 conference
(Boon
et al
., 1992) there is just one passing
reference to climate change. In his chapter on river
conservation and catchment management, Newson
(1992) said: 'There remains a deficit of knowledge
in relation to the predictive ability to manage long-
term; sustainability requires predictability, and
climate change is making predictability particularly
difficult for river systems'.
The place of nature conservation
within a wider framework
Nature conservation (including the conservation
of river habitats and species) is increasingly
considered as part of a much wider framework of
environmental policy and practice. The last two
decades have experienced significant changes
around the world in environmental regulation,
and in the organizational structures and legislation
needed to carry it out.
In 1990, the York rivers conference was
arranged by the Nature Conservancy Council
(NCC) - the statutory body responsible for Nature
Conservation in England, Wales and Scotland. In
1991 the British government abolished the NCC
and replaced it with separate, statutory 'country
agencies' - English Nature (now Natural England),
the Countryside Council for Wales, and Scottish
Natural Heritage - and set up the Joint Nature
Conservation Committee to provide an overview
for Great Britain as a whole. The roles and
responsibilities have changed to some extent over
the years; all three now have broader remits than
