Geoscience Reference
In-Depth Information
Table 8.1
Summary of ecological attributes and benefits derived from undisturbed peat swamp (
after
Silvius and Giesen, 1996).
Attributes
Benefits
Regulation of
hydrology
Prevents or mitigates flooding in adjacent populated or agricultural areas;
provides fresh water supply for drinking, washing, irrigation etc.; prevents
saline water intrusion to agricultural lands, freshwater aquifers and up-river
segments of short coastal peat land rivers
Maintenance of
biodiversity
Serves as gene bank of unique, representative biota and haven for some
species of other nearby ecosystems (e.g. mangrove and mixed dipterocarp
forest) whose home ranges extend into the peat swamp or whose habitats
have disappeared or been dramatically altered by human activity; provides
wildlife, fish, plant and microbial habitats and niches for many endemic taxa
Source of renewable
bioresources
Provides variety of commercially valuable timber, latex, resins, traditional
culture foods, dyes, medicinal plants, fungi and microbes (many
pharmacological taxa have been used effectively by indigenous cultures yet
are unknown to modern medical science; other taxa of potential
pharmaceutical value remain undiscovered)
Regulation of
climate
Stores carbon in accumulating peat thus mitigating build-up of atmospheric
CO
2
contributing to global warning; regulates local climate via forest cover
evapotranspiration, heat absorption and shading, oxygen generation,
wind break, etc.
Source of natural
history
Stores palynological record of ecosystem's natural history via pollen and
seed rain, and may have archaeological deposits of interest; based on the
peat swamp ecosystem's unique attributes and its continued existence due
primarily to its previous inaccessibility as one of the few remaining pristine
wildernesses, it is a valuable repository of ecological materials about
which little is known and from which we can learn and enjoy via research,
educational and wilderness recreational activities
table level depends strongly on the water table level of the previous year. On an annual
basis, runoff is the main element of the peat water balance reacting to the variation
in influx. Evapotranspiration, which depends mainly on radiation, is quite stable year
on year. Over short periods, such as a single rain shower, the effect of precipitation on
the water table level depends mainly on the capillary and osmotic moisture content of
the unsaturated peat layer and on the water table before the rain.
The runoff from the peat dome depends markedly on the slope of the dome and
the hydraulic conductivity of the underlying peat. Water movement in the central part
of the peat is slower due to its flatter topography than at the slope of the peat dome
(see Chapter 2). Therefore, because of the slower water movement in the central part
of the peat dome, the impact of precipitation on the annual water table is greater in the
central part than on the slope. The mean annual water table and the effect of yearly
precipitation differ over the whole peat complex. Thus, the impact of precipitation
on the water level also depends on the peat complex in the short term during rainfall.
The water level will start to rise sooner in the part of complex in the central part of
the dome, where the distance from the peat surface to the water level is shorter in
comparison with the periphery. The amount of water needed to moisten the upper
peat layer during rainfall is also related to the pre-rainfall water level. In addition, the
