Cloud
forest hydrology and effects of global change
Theme
leader: Prof. Sampurno
Bruijnzeel
Hydrologically speaking, cloud-affected
ecosystems such as tropical montane cloud forests (TMCF) are amongst
the least explored terrestrial vegetation types. The frequent presence
of wind-driven fog and drizzle (occult precipitation) not only
constitutes an additional input of water but also affects TMCF
physiological functioning - mostly through the suppression of
transpiration. Thus, for a given amount of rainfall, TMCF are likely
to produce more streamflow than do 'regular' forests. TMCF are subject
to rapid conversion to other forms of land use (notably pasture), the
hydrological consequences of which are as yet poorly known. At the
same time, the specific climatic conditions prevailing in TMCF render
them particularly vulnerable to climatic drying.
The VU University Amsterdam had a long tradition of collaborative
hydrological research in various TMCF environments, with studies
completed to date (2015) in Puerto
Rico, LaGomera, Costa Rica, Mexico, and SE
Brazil and with new collaborative research underway in Tanzania and Kenya. Earlier work focused mostly on
quantifying hydrological processes whereas the more recent research
rather focuses on the impacts of cloud forest conversion and climate
change.
Key research questions addressed by the programme
include:
- What is the hydrological significance of fog interception in
various types of TMCF; and how does this vary along rainfall (wet-dry)
and temperature (warm-cool) gradients?
- How does the presence of fog affect plant physiological
functioning?
- How do catchment water balance and water yield change after
converting TMCF to pasture, cropping or coffee plantation under
contrasting climatic conditions?
- How efficient is the capturing of fog water by secondary
vegetation or planted trees compared to old-growth cloud forest and
how does this change with vegetation age and structure? What is the
precise role of epiphytes and mosses in this regard?
- What causes the much reduced stature of the more fog-ridden types
of TMCF?
- How is TMCF hydrology affected by regional climate change induced
by land-cover change downslope?
Key cloud forest hydrology review publications
- Bruijnzeel, L.A., Mulligan, M. and Scatena,
F.N. (2011). Hydrometeorology of tropical montane cloud forests:
emerging patterns. Hydrological Processes 25, 465-498. DOI:10.1002/hyp.7974.
- Bruijnzeel, L.A., Scatena, F.N. and Hamilton, L.S. (Editors)
(2010). Tropical Montane Cloud
Forests. Science for Conservation and
Management. Cambridge University Press,
Cambridge, 740
pp.
- Bruijnzeel, L.A., Eugster, W. and Burkard, R. (2005). Fog as a hydrological input. Chapter 38 in Anderson, M.G. (Editor), Encyclopedia of Hydrological Sciences. John Wiley, Chichester, pp. 559-582.
- Bruijnzeel, L.A. (2005). Tropical montane cloud forests: a unique hydrological case. pp. 462-483 in M. Bonell and L.A. Bruijnzeel (Editors), Forests, Water and People in the Humid Tropics. Cambridge University Press, Cambridge.
- Bruijnzeel, L.A. (2001). Hydrology of tropical montane cloud forests: a reassessment. Land Use and Water Resources Research 1, 1-18.
- Bruijnzeel, L.A., Hamilton,
L.S. (2000). Decision time for cloud
forests. IHP Humid Tropics Programme
Series no. 13, UNESCO, Paris, 41
pp.
- Bruijnzeel, L.A., Veneklaas,
E.J. (1998). Climatic conditions and tropical
montane forest productivity: the fog has not
lifted yet. Ecology 78, 3-9.
- Bruijnzeel, L.A., Proctor,
J. (1995). Hydrology and biogeochemistry of
tropical montane "cloud forests": what do we
really know? pp. 38-78
in L.S. Hamilton, J.O. Juvik & F.N. Scatena
(Editors), Tropical Montane Cloud
Forests. Ecological Studies
no. 110. Springer, New York.
Documentary DVD
- Wohlgroth, A. (direction), Kunz,
D. (camera), Schmid, S. (script) & Bruijnzeel,
L.A. (production) (2004). Mountains in the
Mist. DVD documentary film (47 min) on
the biodiversity and hydrological values of
tropical montane cloud forest. Halsundbeinbruch
Films, Zurich, Switzerland, and Vrije
Universiteit, Amsterdam.
Last modified: Wed Dec 30 12:23:02 CET 2015