Subterranean ecosystems - Universidade de Évora

IAH 2007 XXXV Congress - Groundwater and Ecosystems Lisbon, Portugal
how. Why is the issue of understanding and convincing of the beneficial functions and usefulness of ecosystems,
often expressed in terms of “ecological services” in an effort to reach decision makers and the general public.
What to protect is a quite difficult question to answer. It tends to refer to either an appreciated landscape
component such as an iconic site, a certain forest, a beautiful lake, a certain wetland, etc. that should be protected
already for its social value. But it may also be interpreted as the catchment as a whole, referring to certain crucial
functions, such as groundwater recharge, to be protected for their ecological value.
Also, how to protect an ecosystem is a demanding question to answer. Water’s many parallel functions
(Fig. 2), its integrating capacity and role in linking land and water, upstream and downstream, humans and
ecosystems, invites the possibility to make use of this capacity within integrated water resources management
(IWRM). This makes water an interesting entry point for ecosystem protection and IWRM an interesting tool.
Fig. 2. Water’s many parallel functions.
Focus on ecosystem water determinants
Attention has then to be directed to the water determinants of the particular ecosystem in focus: what water
supports the particular ecosystem, where it comes from, how it might be protected, and what response time one
should expect. Terrestrial ecosystems are often linked to the rainwater partitioning process which directs focus to
land use and its management. Other such systems may be groundwater-fed, directing focus to where that
groundwater was recharged and how far and for how long time it has travelled. Aquatic ecosystems on the other
hand dwell in a habitat formed by streamflow, representing a mix of water components with different history.
Groundwater is generally a component of that mix and may have travelled short distance or long distance,
quickly or slowly. Wetlands, finally, represent a highly diffuse type of ecosystem, which can be anything from a
highland bog to a sea shore. Its water determinants – what water keeps the wetland wet – can therefore have very
different origin.
As a consequence of water’s deep-going involvement in ecosystem life, ecosystem management can, as
already indicated, make use of water’s potential role as an entry point and be entered into an integrated water
resources management (IWRM). For this purpose, however, IWRM would have to be developed into ILWRM
where L stands for land use, and water incorporates both blue and green water.
In order to proceed along this path it will be essential to develop a joint understanding between ecologists
and hydrologists, both those with focus on water behaviour in a river basin and those with focus on groundwater
transported in deep aquifers. Core questions will include issues such as where does the water come from and
where does it go? How long has it been on route before arriving at the surroundings of the particular ecosystem.
And what can be done in terms of management?
It will be quite important to develop a meta-language that can be used for all the discussions required to
enter protection of vital ecosystems into integrated water resources management. Since the ILWRM process will
involve a lot of trade off striking in terms of balancing humans and nature in efforts to be moving towards
sustainable ecosystem management, such meta-language will have to be understandable also by all the
stakeholder groups involved in the trade offs.
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