PCK 2

EX-SITU CONSERVATION OF RAFFLESIA

Rafflesia

In-situ conservation means "on-site conservation".

• It is the process of protecting an endangered plant or animal species in its natural habitat, either by protecting or cleaning up the habitat itself, or by defending the species from predators.

• This term refers also to the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of tree species, and is increasingly being applied to conservation of agricultural biodiversity in agroecosystems by farmers, especially those using unconventional farming practices.

Ex-situ conservation means literally, "off-site conservation".

• It is the process of protecting an endangered species of plant or animal outside of its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild area or within the care of humans.

• While ex-situ conservation comprises some of the oldest and best known conservation methods, it also involves newer, sometimes controversial laboratory methods.

Rafflesia Life History

• " a penetrating smell more repulsive than any buffalo carcass in an advanced stage of decomposition" (Mjoberg, 1928) There are approximately 17 Rafflesia species distributed throughout Southeast Asia (Nais, 2000; Meijer, 1997; Mat Salleh, 1991).

• These species are highly specific as to the hosts that they parasitize, preferring only a few species of Tetrastigma (a member of the common grape family) that are distributed in the same geographic area.

• Although technically a member of the plant kingdom, Rafflesia challenges traditional definitions of what a plant is because they lack chlorophyll and are therefore incapable of photosynthesis (as are all members of its family, Rafflesiaceae).

• While many parasites appear like normal plants, Rafflesia lacks any observable leaves, roots, or even stems (Meijer, 1993). Likened to fungi, Rafflesia individuals grow as thread-like strands of tissue completely embedded within and in intimate contact with surrounding host cells from which nutrients and water are obtained (Mat Salleh, 1996).

• Perhaps the only part of Rafflesia that is identifiable as distinctly plant-like are the flowers; however, even these are bizarre because they attain massive proportions (up to 3 ft in diameter) and are usually reddish-brown and stink of rotting flesh.. Although parasitic, Rafflesia species do not typically kill their hosts in spite of the drain on resources that they cause.

• . Pollination in Rafflesia has been studied (Beaman et al., 1988) but is likely a rare event due to the several factors. The flowers are unisexual and single sites usually produce either male or female flowers (see exception below).

• Therefore, in order to have effective pollination (reproduction), male flowers must be in close proximity to, and open at the same time as female flowers so that flies (or any other insect) can transfer pollen.

Challenges to Studying Rafflesia

• First, individuals grow entirely embedded within the body of the host plant that they parasitize (Kuijt, 1969). As such, Rafflesia individuals are only visible when they erupt from within the host body as a flower bud. Although traditional means of studying Rafflesia, like anatomical sectioning, could be performed, this method would likely result in death of both the host and parasite.

• Second, Rafflesia is rare in occurrence and can only be found in relatively remote lowland forests of Southeast Asia. In this region, much of its habitat has been converted to farm land or timber concessions and in some parts of its range, the buds are harvested and sold for their purported medicinal qualities.

• Third, even once Rafflesia individuals become visible as flowers, these only survive a few days before decomposing. All of these factors make it difficult to even find Rafflesia sites and even when they are known, the sites are often not protected so there is no guarantee that they will exist in subsequent years.

Rafflesia arnoldii bud, one day before opening.

• Unlike other parasites that are important to study due to the economic loss they cause to important crops, Rafflesia causes economic benefit through ecotourism: thousands of people go to Sabah (Malaysian, Borneo) annually hoping to see Rafflesia blooms (Nais & Wilcock, 1998).

• For this reason, there is great interest in conserving Rafflesia sites rather than eradicating existing populations (as is the case for noxious parasitic plant weeds).

• Although preserving as much of its habitat as possible would be the simplest and most obvious way to conserve Rafflesia, this is not currently practical throughout its range. Therefore, there is a need to investigate key questions that will establish priorities for ex situ (not natural habitat) propagation, management of currently protected sites and procurement of unprotected sites, and in situ (within natural habitat) breeding programs.

• Rafflesia Arnoldii can only grow in the undisturbed rain forest in Southeast Asia mainly in Borneo and Sumatra Islands. Several species are known to have grown in these areas. In Bengkulu, where the plant was first discovered, the flower can be found in Taba Penanjung, a natural reserve 44 km north of Bengkulu, a city in southern part of Sumatra Island.

• Locally known as “patma raksasa” or giant flower, Rafflesia Arnoldii that grows in Bengkulu has weight up to 11 kilograms and diameter of around one meter. The flower with its five petals let out a disturbing odor just like the smell of dead body in an advanced stage of decomposition. The strong smell is needed to attract flies to transfer pollen from one flower to another. Although categorized as plant, Rafflesia does not have roots, stems, leaves and chlorophyll. The only part that makes it look like plant is its massive reddish brown flower.

Rafflesia arnoldii

Rafflesia manillana and Rafflesia micropylora.

The flower bud

Pollen inside the flower

• Rafflesia is a parasite as it lacks the ability to photosynthesize. They parasitize few species of Tetrastigma (some kind of grape). Rafflesia has roots embedded within the host cell from which it obtains water and other nutrients. However, Rafflesia does not kill its host.

• Pollination is rare because the flower is unisex. Unless there is a male flower in close proximity to a female flower that opens at the same time as the male flower so flies could transfer pollen, no pollination will occur. Once pollination does happen, it takes months for the bud to bloom with mortality rate of 80-90% and the flower will only last for five to seven days only. The best time to see the flower is during the month of September to December.

Recent Status

• In the last decade, the primary forest of Sumatra and Borneo, the main habitat of Rafflesia Arnoldii had been converted to timber concession or farmland. With the forest disappearing at an alarming rate, it can be assumed that the number of surviving Rafflesia Arnoldii is decreasing rapidly as well. In the next few years, it is feared that this plant can become extinct.

• In addition, the sites where Rafflesia flower grows is not protected. Thus there is no guarantee that the flower will grow again on the same sites in the coming years. To make matters worse, local people often harvest the buds to be used as medicine.

Rafflesia arnoldii

Rafflesia site

• Something obviously needs to be done to preserve this unique plant. Conserving the forest is critical although in many situation not always practical.

• Other ways to avoid extinction is by protecting the existing Rafflesia sites to enable an in situ breeding program so the flower could grow over and over again on the same sites.

• In addition to the in-situ program, ex-situ propagation can also be arranged by recreating the species environment outside its natural habitat.

Rafflesia photos from Poring in Kinabalu National Park