Models Supporting Decision-Making and Policy Evaluation - Environmental Modelling: Finding Simplicity in Complexity - page 332

land-cover change and land-management interventions
applied singularly but, in reality, they will occur con-
currently and may need to be applied concurrently in
complex spatial patterns. This complexity leads to diffi-
culties in building simple interfaces for the application
of such scenario/policy option combinations and also
difficulties in interpreting the complex impacts of such
combinations on the system under study. Aside from
issues of model complexity, communication, validation
and trust, which develop incrementally with use in sys-
tems like WaterWorld, the key remaining barriers to use
are (e) willingness to adopt PSS in the policy process and
(f) who will use these systems and what is their role in
decision-making organizations.
Willingness to adopt depends upon finding an
appropriate place for PSS in decision-making processes.
Projects such as the current CGIAR COMPANDES
project 17 are working with a variety of stakeholders in
the Andes (and also the Ganges, Nile, Limpopo, Volta,
Mekong) to build confidence and competence in the use
of WaterWorld. Greatest willingness seems to be within
the NGO and advocacy group communities - as well
as consultants for whom systems like this can provide
scientific support and potentially lend some scientific
legitimacy to policy stances or proposed interventions.
Uptake of WaterWorld is thus greatest (though not
exclusively) outside of policymaking organizations but
rather in those groups advocating support for or against
particular policies or interventions that may be made by
those with power and influence.

and effectiveness of these tools. It is for both modellers
and policy analysts to ensure that such open and usable
tools are used jointly and with care such that they improve
decision-making and policy-testing process rather than
misdirect or impede it.

20.5 Acknowledgements

The development of FIESTA and AguAAndes (the pre-
cursors to WaterWorld) were funded by projects: Hydro-
logical impacts of converting tropical montane cloud
forest to pasture, with initial reference to northern
Costa Rica (UK DfID R7991 with the Free University
of Amsterdam), DESURVEY A Surveillance System for
Assessing and Monitoring of Desertification (EC FP6) and
CGIAR Challenge Programme on Water and Food Basin
focal project for the Andes system of basins (CGIAR).
Parts of this paper are reproduced from Mulligan, M.
(2011) Geobrowser-based simulation models for land
degradation policy support, in Monitoring and Modelling
Dynamic Environments (eds A.P. Dykes, M. Mulligan,
J. Wainwright), John Wiley & Sons, Ltd, Chichester.
Thanks to Arnout van Soesbergen and John Wainwright
for editorial contributions to this chapter.

References

Aylward, B., Bandyopadhyay, J. and Belausteguigotia, J.C. (2005)
Freshwater ecosystem services. In Ecosystems and Human Well-
being: Policy Responses , Volume 3. Findings of the Responses
Working Group of the Millennium Ecosystem Assessment (eds
K. Chopra, R. Leemans, P. Kumar and H. Simons), Washington
DC,Island Press.
Balmford, A., Green, R.E. and Scharlemann, J.P.W. (2005) Sparing
land for nature: exploring the potential impact of changes in
agricultural yield on the area needed for crop production. Global
Change Biology 11 , 1594.
Bruijnzeel, L.A., Mulligan, M. and Scatena, F.N. (2010) Hydrome-
teorology of tropical montane cloud forests: emerging patterns.
Hydrological Processes, 25 (3), 465-98.
Buytaert, W., Celleri, R., De Bievre, B. et al . (2006) Human impact
on the hydrology of the Andean p aramos. Earth-Science Reviews ,
79 , 53-72.
Cook, S., Fisher, M., Tiemann, T. and Vidal, A. (2011) Water,
food and poverty: global- and basin-scale analysis. Water Inter-
national , 36 (1), 1-16.
Daily, G.C. (1997) Nature's Services: Societal Dependence onNatural
Ecosystems , Island Press, Washington.
Daily, G.C., Soderqvist, T., Aniyar, S. et al . (2000) The value of
nature and the nature of value. Science , 289 , 395-6.
Epstein R. (1984) In defense of the contract at will. University of
Chicago Law Review , 51 (4), 947-75.

20.4 Conclusions

Environmental science needs to better link to real-
world policy application and simulation-based policy-
support systems are an appropriate way to do so. It
is clear that most policy problems applied to heteroge-
neous landscapes are far too complex to keep track of
with conceptual and analytical approaches, so numerical,
computer-based approaches are the only option. How-
ever, these approaches need to be better communicated
by scientists and better understood and valued by the
donor and policy communities so that their development
is championed and supported, and especially so that they
are used in policy support. The two-way feedback between
decision maker and modeller that dynamic, interactive
PSS use can bring will be critical to improving the value

17 See www.benefitsharing.org (accessed 6 April 2012).