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CONSERVATION STRATEGIES OF SHOREA LUMUTENSIS (DIPTEROCARPACEAE) IN PENINSULAR MALAYSIA
In situ conservation areas should be intensively managed to support the natural regeneration of
target species and prevent them from competition with other species that may become dominant
following the rules of natural succession. The demographic study conducted in Sungai Pinang
showed that the population consisted of a low number of medium-sized trees and had high
mortality of seedlings. Thus, silviculture treatments should be designed to encourage seedling
regeneration and enhance sapling growth by selectively eliminating the two prominent associated
palm species (E. tristis and C. castaneus), so as to minimize the space competition and maximize
the sunlight exposure. Nevertheless, as the two island populations were entirely isolated from
mainland populations and the three mainland populations were isolated from each other either
due to geographical barrier or fragmentation, restricted gene flow and contemporary demographic
independence are anticipated. Therefore, the five populations should be considered as distinct
management units, which will require specific management prescriptions. Like monitoring,
management prescription activities are often expensive in time and resources. Hence, active
management should be carried out with decreasing intensity and eventually stops when
monitoring indicates that survival and reproduction, especially the quality of the offspring,
have achieved acceptable levels.
Ex situ Conservation
Ex situ conservation can be divided into several specific techniques, such as seed storage, in
vitro storage, DNA storage, field gene bank and botanical garden. As the species produces
recalcitrant seeds which are extremely short-lived in nature, ex situ conservation based on seed
storage and periodic regeneration appears to be more in principle than in practice. Although in
vitro conservation is seldom useful or economically viable for the conservation of forest trees,
it may be more relevant to S. lumutensis with seed storage problems. The use of DNA storage
method is rapidly increasing in importance. It is now routinely possible to amplify specific
oligonucleotides or genes from the entire mixture of genomic DNA. The advantage of this
technique is that it is efficient, simple and takes up little space but the obvious problem is that
it does not allow the regeneration of entire plants (Maxted et al. 1997b). A better assurance
against possible extinction in its natural habitat is the establishment of the species in ex situ
conservation areas, such as botanical gardens and arboreta. Realistically, however, botanical
gardens and arboreta collections are always limited to a small number of individuals.
Although the establishment of new populations to areas outside their historic range might not
be successful due to genetic and ecological adaptation problems, increased use of S. lumutensis
in terms of planting in forest areas, watersheds and degraded lands or as field gene bank should
be encouraged. The idea is that the cultivation of a valuable but rare tree species can result in
multiplication and distribution of its germplasm. Moreover, when a rare species becomes
common as a result of planting, and its products have economic value, the harvesting pressures
on its natural populations will decrease.
As the species is outcrossed and the majority of its genetic diversity was partitioned within the
population, a minimum of 10 unrelated mother trees per population should be used to establish
a field gene bank. In addition, as the species exhibited significant spatial genetic structure up
to the scale of about 20 m, the selected mother trees for seed collections should be more than 20
m apart. Chances for success are greatest if seeds are drawn from a composite cross among the
available populations so that natural selection will weed out unsuccessful genotypes from among
the segregating progeny of such hybrid populations (Barrett & Kohn 1991). Larger seeds have
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