The Status Of Floristic Inventory Of The Tropics Biology Essay

Published: Last Edited:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

The study on which this section is based (Campbell and Hammond, 1988 ) was derived from consultation with regional experts in floristic and forest inventory throughout the tropics. It sough to define the status of tropical inventory, and to highlight areas in most need of further collecting activity. The need is based primarily on three categories; 1, areas that are poorly collected that are includes disciplines which are still neglected in the basic survey of the fascinating vegetation of the tropics and, therefore, form obvious gaps on he distribution maps of species, 2, areas that are imminently threatened by deforestation, and 3, centers of endemism. In this study, we systematically explore the degree to which floristic patterns are habitat driven on the local and landscape scales.

The tropical flora consists of some 155,000 species of flowering plants, 11,000 fern and fern allies, 16,000 bryophytes, and at least 90,000 fungi. The tropical flora is by far the richest in species diversity, yet it is also the most poorly collected. This diversity is being reduced before we have made an adequate basic inventory let alone conducted modern biosystematic and population biology studies in the area. Even to understand the origin and dynamics of temperate flora, it is essential to have adequate knowledge of the tropical flora from which the temperate flora was derived.

In any discussion of inventory of the tropical flora it is important to consider habitat diversity and species diversity. Its tend to ignore the habitat diversity of the tropics which contributes to its species richness, and to think of it as one large uniform rain forest. In fact, the tropics contain many arid regions with deserts or scrubland, such as caatingas of northern Brazil, a large temperate element in the flora of the high mountains, and a unique alpine flora such as that of the Paramos in South America and the Afro- alpine region described by Hedberg (1964), besides many different types of forest and savanna. The second edition of the UNESCO [1] vegetation map of Africa is the result of the written material of habitats types of Malesia that are the summed up by Jacobs (1974), those of South America by Hueck (1966) and those of Africa by White (in press).

There are no time here to summarize the fascinating diversity of habitats in the tropics, but it is important to collect from and to plan conservation of this habitats diversity. Until now, collecting has given rather uneven coverage to the different habitats. The location of different habitats has been overlooked frequently in biogeographic analyses of the neotropical vegetation, although the inventory of habitats distribution is vital to biogeographic studies.

For what purpose that the floristic inventory should be given priority?

The floristic inventory should be given priority because of several factors that influence the recent status of the tropics forest. The tragedy of the biological inventory of the tropics is that destruction of the vegetation is proceeding more rapidly than the inventory. The tropical flora occurs mostly within the territory of developing countries where technological advance is urgent. Such advance traditionally includes the destruction of large areas of natural vegetation for replacement by farms. In addition there is population pressure in many tropical countries where the annual net population increase is often over 3%, (The Environment Fund, 1976).

Many authors have drawn attention to the destruction of the natural vegetation in the tropics, for example, Gomez- Pompa et al. (1972), Richards (1973), Janzen (1974), Holdridge (1976), Raven (1976), Gentry (1978), and any of the authors in Prance & Elias (1976). It is not the purpose of this to review in detail the destruction of the tropical vegetation, but as the tropical areas are vital for the understanding of the biology and evolution of all plants, it is important to draw attention to the urgent need to accelerate all biological inventory and conservation work in the tropics. According to recent estimated 49.2 acres of tropical rain forest are being removed each minute or a total of 11,000,000 hectares a year (Lucas, 1977: Sommer, 1976). Inventory work daily becomes a more important task to perform, as destruction of natural of natural habitats encroaches. Since there is not separate treatment of conservation, that it must logically be stressed as a part of inventory. It is not possible or profitable to list examples of tropical destruction from each area discussed below, but it should draw attention to this race between inventory and destruction in the tropics and hope that can also focus on the efforts more towards conservation. None of the other subjects treated at this symposium can be completed without the conservation of large areas, and without a comprehensive basic inventory.

The regional status of inventory

Its can be divide by three main region that are includes the tropical Africa, tropical Asia and the neotropics. These three region is where the floristic inventory are estimating conducted well by the numbers of researcher.

Africa regions

These systematic work of the region are readily accessible through the symposia and publications of "Association pour I'etude taxononique de la flore de I'Afrique Tropicale" (AETFAT ). All about the taxonomic features includes the bibliography and list of new taxa and nomenclatural changes for all tropical African plants are published annually. Progress reports on collections, the regional floras, mapping, ets given in the proceeding of their symposia which take place every fourth year. AETFAT plays a similar role of Africa as Flora Malesiana does for Asia in making available much information and bibliographic data invaluable for research in the area. A review of the current status of collecting in Tropical Africa was given by Hepper (in press)

The evidence by Leonard (1975 ) prepared for AETFAT a map of the extent of the floristic exploration in Africa south of the Sahara up to 1963. This map divides the region into 3 categories; poorly- known, moderately known, and well- known areas. Any additional formation of changes to this map and the revised edition were presented at AETFAT congress 1978. (Hepper, in press ). The another example of inventory of Africa region is enshrined in The Flora of Tropical Africa, but its only attempt at a general flora of the regions (Oliver, 1868- 1937 ). Then,it has largely been replaced by the modern regional floras, especially The Flora of West Tropical Africa (recently revised ), Flora of Tropical East Africa, and Flora Zambesiaca.

There are the statistical evidence that are new taxa in Africa from 1953- 1965 (Leonard, 1968 ) and showed a gradual decline from 1177 new names (577 new species ) in 1953 to 723 new names (287 new species ) in 1965. The rate of description of new species continued at approximately the same rate in 1975 (figure 1 ). The fact that 270 new species were describes in 1975 show that the basic species inventory of the African flora has not yet ended. The amount of synonym proposed in the years 1971- 1975 (AETFAT data ) are shown in the figure 1. It shows that there is apparently a gradual drop in the net gain in species because of increasing synonymy, 218 net gain in 1971 as compared with 119 in 1975. Nevertheless, the total number of new descriptions in Africa south of the Sahara for the 21 year period, 1953- 1975 are impressive; 319 new genera, 7478 new species, and 2538 infraspecific taxa. That is a new genus every 3 week and a new species for every day of the 21 years (Hepper). A flora in this active state of description that is need of further collecting. There are the reports on progress of various African floras given in Kubitzki (1971) include emphasis on the need for further collecting as mentioned in Boulos (1971 ) for Libya, Ake' Assi (1971 ) for the Ivory Coast, and Le Thomas (1971 ) for Gabon, etc.

Distribution maps of African taxa such as those published by Bamps (1969 ), in the very useful series "Distribution Plantarum Africanarum" that show of the African flora is really well explored in comparison with the neotropic. For this reason more analytical phytogeographic papers have come from taxonomists working on the African flora. The better known plant distributions have enabled much better phytogeographic analysis of the flora. (White, 1962, 1965, 1971 ) in the introduction chapters in Chapman & White (1970 ).

But, Hepper mentioned that the collecting situation in the Africa regions is still having large gaps. It is because, by think that the general collections are now required only from lesser known regions, and stressed the need for specialist collections and for resident botanists to carry out the long- term investigations. The idea is some particular gaps in collecting such as the tendency to collect mountain tops and ignore the forested slopes.

The native African flora has been disappearing rapidly under human population pressure for longer than that of Malesia or the neotropics [2] . The shrinkage of the tropical forest of Africa are mentioned by Shantz (1948 ), and than work together with Turner's (1985 ) for the photographic account of the destruction of the forest that is frightening report for any biologist. Hepper also stressed that the collecting are should be done well in the poorly known areas because of the rate at which the natural vegetation is disappearing.

In Madagascar, where the largest contributions have been made by H. Perrier de la Bathie and H. Humbert, the original species-rich forests have been almost totally disturbed and the race to collect this exciting flora before it is obliterated is lost. Koechlin (1972 ) summarized the situation in Madagascar; "Many problems still have to be solved in the field : although the exploration of the flora is well advanced, much remains to be done in the areas of plant biology and phytosociology.

Tropical Asia

The Asian tropic are probably not well collected as Africa, but are much more better than the neotropics. The information of the Asian tropical areas compiled and published in The Flora Malesiana and its become the useful bulletin. The Flora Malesiana is the project that cover the Indonesia, Malaysia, Brunei, the Philippines, Singapore, eastern New Guinea, and the Solomon Island.

According Dr. Jacobs, he list out the following places in Malesia as undercollected and need further basic inventory. Includes in his list are The Andaman Island, Southern Sumatra, Central Borneo, Celebes, Kabaena, Ceram, West New Guinae (Meerilakte and the Star Mountains in West Irian, the Kikari area in the south of Papua, the Philippines (especially the Sierra Madre on the east coast of Luzon ), and the Cape York peninsular of Australia which has in recents times yielded several genera that were known only from Malesia. The northwest Australian coast is still poorly known. Perhaps Celebes is the least collected area and is now less known than New Guinea, especially the eastern and southeastern area of the island. Celebes also illustrates the race against development, since the International Nickel Company in cooperation with Bechtel has billion dollar nickel mining concern in Celebes.

Jacobs (1977 ), has summarized the progress in the publication of Flora Malesiana. By the end of 1976, 116 families, 453 genera, and 3288 species of angiosperms had been monographed out of an estimated total of 25000 species. The fact that only 13.15% of the flora has thus far been published together with the figures for Flora Neotropica given below, show the magnitude of the task in tropical areas and the shortage of botanists to work up the result of inventory. The slow production of monographs is a serious problems and lags behind the progress of development. However, a basic collecting inventory is more important before forest are destroyed. For examples, Pteridophytes, the Flora Malesiana has published 5 families, 14 genera, and 350 species or 14% of the estimated 2500 species.

Tables 3 from Flora Malesiana reprudeces their synthesis of the collecting situation in the larger units of Malesia. It points to the need for further collection from Sumatra and Celebes.

A comparison of three major continental areas of the tropics in terms of statistics of species descriptions is not as straightforward as it may seem since the different status of knowladge in each flora has tended to result in ather different species concept in each area. Although the tendency is toward much new synonymy in all three areas, the Malesian botanists seem to have a more conservative altitude to the species concept. For example, Leenhouts (1967 ) reduced all 255 species of Allophylus (Sapindaceae ) to the single species A. cobbe Raeusch. Whitmore (1976 ) cites other examples, the concept of the reticulately polymorphic ochlospesies came from work on the African flora (White, 1962 ). The species concept of Africa lies somewhere between that of Malesia and the narrower concept that has predominated in the neotropic until recently. It is not the purpose of this paper to evaluate the merits of these different concepts, but an acknowledgement of their existence is necessary for the comparison of data between the different areas. The different kinds of species that exist in the tropics, accepting three kinds ; the discrete isolated and morphologically invariable species, the species with distinct infraspecific taxa, and the reticulately variable ochlospecies.

There are numerous local floristic works within the Flora Malesiana region the best known of which is Backer & Bakhnizen van den Brink's (1963- 1968 ) Flora of Java.

In the Asian tropics outside Malesia the situation is similar with a reasonable basic inventory but still some neglected areas.

Table show that collecting status of some Pasific Island: (1) only casual collecting, (2) poorly collected (not professional collected ), (3) moderately well collected, (4 ) rather wel collected but some gaps, (5) quite well collected. More than one number means different island in group collected to different degrees. (F. R. Fosberg, per. comm. )

Thailand had intensified general collection since 1960 with a wide coverage of habitats and areas but little specialist collection. Collection has been stimulated by the joint Thai- Danish project on the Flora of Thailand under the leadership of Kai Larsen and Tem Smitinand and their collaboratiors.

Sri Lanka has been extremely well collected and worked up under the Flora of Ceylon project directed by F. Raymond Fosberg. This project has included much specialist collecting and the result of this are obvious in the resultant monograph.

Indo- China had little collection since World War II except for few vegetational studies in Laos and South Viet Nam. The political upheaval in that region has not been conducive to botanical inventory. The use of chemical defoliants in the war has truly devastated large areas of the forest of Indo- China.

The Flora Malesiana Bulletin serves a very fine role of reporting on progress in tropical Asian Botany, even in countries outside the range of the flora itself, and is commendable for the amount of useful information generated. The annual columns on progress in Malesian Botany, exploration, and on recent publications serve to keep us up to date on the state of Asian botany: There is a need for such a bulletin attached to Flora Neotropica.

For the tropical Pasific island data that show by Dr. F. R. Fosberg, it show that there are island which remain poorly collected. Exact statistic on collecting are not available, but there is obviously much still to be done in this area that is do fascinating from the point of view of island biogeography. Dr. A. C. Smith has worked extensively in Fiji so that the archipelago can now be considered well collected, and he is following up with a flora of the island.

The Neoropics

The New World tropics are certainly much less known than Africa or Asia and are still in the process of the first basic inventory. New species are still being collected in large numbers form many places, as, for example, the large number of new species from recent collections in the upland of Panama, from coastal Ecuador, from the forests of the state of Bahia, Brazil, and from many other localities.

The collecting density throughout the neotropics is much less than for the Malesia, but added to this, the greater numbers of species in the neotropics flora and the unevenness pf collection throughout the area mean that the basic comprehensive species inventory is still most inadequate and by no means nearing its completion.

Unfortunately, there are no equivalent The Flora Malesiana Bulletin or the AETFAT publications in the neotropics. Thus, calculations of botanical activity are harder to make and are less accurate. A comparison of many aspects of the ecosystems of Africa and South America is given in Meggers et al (1973), but it does not cover the subject of inventory in any details. The last comprehensive review of the state of neotropical botany was that Verdhoorn (1945 ). Much collecting has taken place since 1945 and some aspects, particularly from the conservation point of view, were surveyed in Prance & Elias (1977 ). In Prance (press ) the country- by- country review of the status of Botanical exploration in South America are given, and Gentry (1978a ) reviewed the floristic need of Central America and the Pacific coastal region of northern South America. There is no space to give such as a detailed review here, but few examples will serve to show the situation in the neotropics.

For the example, Peru also offer a wide range of plant habitats, from arid desert regions to the humid tropical forest of Amazonian territory. Despite the long history of collection in Peru, it is still poorly known botanically. The Flora of Peru initiated by Macbride in 1936 has recently been reactivated as a cooperative Field Museum- Missouri Botanical Garden project. This has stimulated more collection in recent years, particularly from the poorly collected Amazonian region.

Brazil, the largest country of South America, has a long history of botany, and a great diversity of vegetation. With an area of 8511965 km2 , the collecting density of the country is certainly well under 1 specimen per square kilometer. National herbaria have about 2 million specimen. Some of the poorly collected area of Brazil includes the state of Acre, Serra Paca'as Novas in Amazonia. Besides the Amazonian region, there are many other neglected areas of Brazil such as the coastal forest of Bahia and Espirito Santo some parts of the arid caatinga region. In January 1976, Brazil initiated an ambitious program called Programa Flora. This program plans to make a detailed inventory of Brazil's vegetation by collecting programs and by the preparation of a computerized label data bank of Brazilian berbaria. The program is devided into five regional project. Arrangement for North American participation in collecting program have been made and collecting will start in the fall of 1977.

Another example is the Caribbean island of the Antilles that have o flora of 12000- 15000 species (Howard, 1977 ). The island, which stretch over 1700 miles east to west and 1200 miles northto south, have many local endemics. For example Leo'n amd Alain estimated that almost 50% of the 6000 species of Cuba are endemic, and Hispaniola has 33% endemism in its flora of 5000 species. The history of floristic work has been a one- island approach which has led to many species being described from several islands, and more island "endemics" are being reduced than new species described. One of the needs of Caribbean botany is a monographic approach to compare elements of its flora with South and Central America ad to calculate the true percentage of endemism. As mentioned by Howard (1977 ), the plant life of Caribbean cannot be regarded as unknown or needing immediate study or a massive collecting program. The area has been well collected in comparison to Latin America.

There is, however, a need for any of the experimental type collections listed in the next section. Howard (1977 ) list many examples of environmental destruction in the Caribbean, and, elsewhere further collecting data is needed for conservation information.

Recent monographic work has shown the words of Standley to be true, and most neotropical monographs include a considerable amount of synonymy, but at the same time also include a large number of new species.

Another stimulus to collecting in the neotropics is the Flora Neotropica monograph series initiated in 1964. The table above gives a list of the monographs published to date: 2466 species or 2.74% of estimated total of 90000 flowering plants has been treated, and 819 species or 1.64% of the 50000 fungi have been treated. Since the series also includes ferns, bryophytes, and algae, the task to be completed is enormous.

The future of floristic inventory

In summary, Africa is the best collected continent of the tropics. It than closely followed by Asia and Malesia. In these areas, a basic floristic inventory is includes the species exists, but the sample size of the collecting species is not enough for the purpose of understanding of their biology and ecology. In the neotropic, the basic inventory are still underway, and there are many new species are still be found. However, it is not the cause to slowed down the collecting anywhere in the tropics. Its need the different emphasis that provide an adequate experimental sample. Some of the focus of the future collecting and these correspond with the needs of a more experimental approach to tropical taxanomy.

Throughout the tropics many species are known from incomplete material. Future collecting should be focusing on previously inadequately collected material such as the fruits of many tall trees, and collections should be accompanied by the good field data and note on dispersal where possible. For the example, that are poorly lianas collecting that are stated by Jacob (1976 ). It also the collecting problem of the large fleshy, monocotyledons such as Zingiberaceae (Burtt, 1976 ), Musaceae, and Araceae in their way to pickled flowers are essential for adequate study. The collected specimen that need liquid preserved materials should be collected and distributed to specialists. Other group that also poorly collected included tropical macrophytes, bamboos, palms, and Utricularia.

The future collector also need to put label data on colour, scent, size, texture, structure, and habit of the specimens, for liquid material, and for black- and- white photographs of habit and habitat. As studies on floral biology, phytogeography and evolution in the tropics increase these are needed. It is often better to collect fewer numbers but to documented them well. It is should be done well to avoid the collected specimen become a waste collecting.

The economic plants also need to be collect in the ways to provide an adequate sampling of many of most important economic plants and even their wild relatives. The country has occurred in some tropical areas where the local herbarium is a Forestry Herbarium. The concentrated collecting on the forest tress and non- economic plant like forest herbs and lianas have been neglected, for example, on north of the Borneo, Surinam and French Guiana where forest herbaria are the most botanical institutes.

The plants of secondary forest also must includes in the program of collecting specimen. These plants are neglected as 'inferior cousins' of the primary forest. But, in several cases, there are extremely rich and interesting flora, and should also be further collected. For example, many hard- to- collect forest lianas In Bignoniaceae, Malpighiaceae and Menispermaceae occur abundantlyin the secondary forest areas of the neotropics. A survey by Rodrigues found that 374 species in 63 families on an area of 35000m2 of secondary forest near Manaus. Many author mentioned that the secondary forest also played a important role in the evolution of tropical flora (Go'mez Pompa, 1972 ). It is, therefore, most important that we make a better inventory of secondary areas in the tropics.

General collecting is important and has really provides the basic inventory of the tropical vegetation. However, a specialist in any family finds far more interesting things about his group than the general collector. The specialist soon learn to recognize his group from the diversity of the forest, and field studies by specialist have contributed many interesting results from the tropical forest. There is much in favor of taxonomy focusing in collection. A general collector who concentrates on certain group will also produce interesting collections.

Another important aspect for tropical forest areas is the concentration on the small areas over an extended period. This is best done by resident botanist and small areas can be highly rewarding, from both a taxonomic and ecological point of view. For example, the selection of one hectare of forest for study in the relatively well known area near Manaus, Brazil yielded many interesting results, including at least two new species from the 236 tree species on the hectare (Prance et al, 1976 ). When it is inventoried well, its then followed by entomologists, soil zoologists and mycorrhiza specialist who could link their wok to an accurate botanical inventory. These completely inventory then become important as general collecting and often yields data of great used for conservation, as well as ecology and other disciplines. It is one of the best ways to encourage interdisciplinary research.

Next, the inventory must not be isolated from the other subject under discussion in the symposium. It is significant to present about animal- plant interaction, tropical ecosystem, and integrative approaches to the study of plant structure. Future collectors need to be more aware of the research being carried on in these and other field, and to be ready to contribute data. The lack of pollinator data in the tropics is enormous, and both the general collector and the specialist collector can contribute much to pollination ecology by making a few observations on flower visitors, scent, etc. In the other ways, inventory is not about the collection of herbarium, but also includes inventori of pollination mechanisms, other insect- plant relationship, phenology, mycorrhiza, types of photosynthesis, nitrogen fixing bacteria, chromosome numbers and morphology as mentioned by Raven in 1975.

One of the most striking facts about the tropics is that the vast majority of specimens are deposited in herbaria in temperate region. The history of settlement and development has dictated the distribution of specimens, and this is now a major problem for the development of systematic and conservation the tropic. There are two types of the herbaria in the tropic that can easily be enumerated on two hand. The Bogor and Singapore in Malesia, Calcutta in India, The East African Herbarium in Nairobi, the Forest Herbarium in Ibadan, Nigeria, and the Jardim Botanico and Museu Nacional in Rio de Janeiro. There are of course fortunately a large number of smaller tropical herbaria that plays an important local role; for example there are at least 49 herbaria in Brazil, 16 in Colombia that both are hampered by the lack of type specimen and literature.

The lack resources has also been accompanied by a lack of trained personnel in tropical countries which has also hampered the progress of inventory. These facts, coupled with the increase of nationalism, have led to the implementation of strict rules to govern collecting activity by foreigners with the result that there are some tropical areas where it is impossible for foreigner to collect at present.

In order to complete the inventory of the tropics, it is necessary to stimulates more training of local resident botanist (Prance, 1975 ) to deposit properly identified material in all tropical herbaria equipped to house them, and to publish in local journal in the countries where we working. This will not only have an effect on the standard of botany and ecology students in our training program in Manaus, Brazil, is an unforgettable experience. By the time, these young biologist then become more seriously in force for conservation in few years time.

In order to progress in the future inventory and conservation of the plant resources of the tropics, botanist must adhere more strictly to the excellent guidelines agreed upon by many major United States Research Institutions (Hairston, 1970 ).

A summary of South America herbaria and areas covered

Recently floristic inventory of Malaysia

Previous studies have attracted the researcher from botanical field to continue their study on the status of floristic inventory in tropical region , especially in Malaysia. The government and the sector under the government's advice were still do their work on these field on the basis of awareness and responsibility on the diversity and density of species of it. For the examples, Forest Research Institute of Malaysia (FRIM ) and forest department of each states are the organization that responsible to some kind of forestry inventory of Malaysia.

Floristic composition of Pasoh forest reserve, a lowland rain forest in peninsular Malaysia

There are several research that have been done for these purpose and recorded as the new inventory record of these region. For example, between 1985 and 1988, FRIM established a large scale forest plot at Pasoh Forest Reserve, Negeri Sembilan, to monitor long term changes in a primary forest. Pasoh Forest Reserve was chosen as the site for the large scale forest plot because it was far from centres of population and yet still easily accessible by car, and also because its ecology and flora had been studied during the International Biological Program (Ashton 1976, Soepadmo & Kira 1977). The reserve is located at 2° 59'N latitude and 102° 18'W longitude, or about 140 km southeast of Kuala Lumpur, in the interior portion of Negeri Sembilan amidst a broad expanse of flat lands and gently rolling ridges that about the westward side of the Main Range. Prior to 1900, this south-central portion of the Malay Peninsula comprised nearly 100,000 ha of relatively unbroken forest.

The plot is situated in the last remnant of that forest. Pasoh Forest Reserve was much larger before the early 1970s when many of the southern compartments were converted to plantations of oil palm, so that today, the reserve is only about 6000 ha in size. The southernmost 2000 ha are administered by FRIM as a Research Centre, and are divided into three portions: a core of 650 ha of primary lowland forest that lies between 80 and 120 m above sea level; a buffer zone of 30-y-old selectively logged forest on three sides of the core; and primary hill forest on the western side of the core rising to an elevation of about 500 m.

The plot is a 50-ha rectangle 1 km long and 500 m wide. The enumeration included all free standing trees and shrubs > 1 cm dbh. Climbers were excluded. The methods by which the plot was surveyed, the trees measured and species identified are recounted in Manokaran et al (1990). Here we can note that all trees over 10 cm dbh were identified in the field by the senior author, who also identified leaf specimens from saplings of the more difficult taxa. The more common taxa were identified by the staff of FRIM under the the training and supervision by the senior author. As the result, the new inventory of the species there are recorded.

The result show that there are comparisons with many other forests can be made if we restrict the calculation of diversity to trees above 10 cm dbh. For 50-ha at Pasoh, they found trees above 10 cm representing 660 species in 244 genera and 67 families. Mean density was 530 trees per ha representing about 210 species. This is about as high or higher than the diversities reported for other rich primary lowland forests in Malaysia and Indonesia. At Sungei Menyala Forest Reserve, also in Negeri Sembilan but west of the Main Range, Wyatt-Smith (1949) found about 150 species per ha, which is about 25% lower diversity than at Pasoh. Ashton (1964) described a lowland forest in Andulau, Brunei, that had about 140 species per ha; a lowland forest in East Kalimantan had about 540 trees and 180 species per ha according to Kartawinata et al. (1981); while at Gunung Mulu National Park in Sarawak Proctor et al. (1983) described two rather dense l-ha samples: 615 trees and 225 species in alluvial forest and 778 trees and 210 species in dipterocarp forest on a hillside. They indicated that their sample sites may not have been representative of median conditions.

Familial composition of the tree flora

In the same way that individual species did not constitute conspicuous dominants, we found that taxonomic families were represented in regularly diminishing proportions. The relative importance of different families with regard to number of species, number of stems and basal. It was based on all stems > 1 cm dbh for 50 ha, except for the values of basal area, which are based on 20 ha.

The Euphorbiaceae was ranked first in species diversity, first in abundance of trees, and third in basal area. The significance of this family in the Malayan lowland forest was noted by early students of the forest, but its importance may often be overlooked because many of the species are smaller trees of the understorey and lower canopy.

The Myrtaceae and Lauraceae may be considered together for they ranked second and third in species diversity, but twelfth and sixteenth in tree density, and eighth and twenty-first in basal area. The attributes of high diversity and low density were not unexpected for these families in the lowland forest; it was, to the contrary, entirely in keeping with what little is

known of these two poorly understood families. They included species of all five stature classes, but in neither family that find a particular species to be very common. In diversity of genera, the two families were very different from one another. Nearly all of the species of Myrtaceae at Pasoh belong to the genus Eugenia, whereas the Lauraceae was represented by many more or less equally diverse genera.

The Rubiaceae is the most diverse of all families of trees when the flora of the entire Malay Peninsula is tallied, but at Pasoh it ranked only fourth in species diversity and fourth in tree density. Its relatively lower ranking at Pasoh may be explained by the isolated and restricted geographic distribution of many of its species. Most of the species of Rubiaceae at Pasoh were shrubs and treelets, but nonetheless, the family was represented by two of the most frequent species for trees over 10 cm dbh, Aidia wallichiana Tirving, and Porterandia anisophylla (Roxb.) Ridl. Among the many species of smaller trees, several were very numerous.

The Dipterocarpaceae ranked only tenth in species diversity, with 30 species, but it constituted more than 9% of the trees and 25% of the basal area, which ranked the family second and first in those respective categories. This is the family that best characterizes the upper canopy and emergent layers of the Malaysian forest, and the family by which most lowland rain

forests are classified to type.

The Annonaceae ranked third in density, and fifth and sixth in number of species and basal area respectively. The uniformly high rankings indicate the importance of this family, especially among the smaller trees and lower canopy. We might note that if woody climbers were included in the study, then Annonaceae would likely become the most diverse and most abundant family.

The penultimate family to consider is the Burseraceae, which ranked only thirteenth in diversity, with 22 species, but ranked fifth in density and fourth in basal area. We can here note that three of the most frequent canopy tree species are members of the Burseraceae (Table 2). The family isimportant in all lowland and lower hill forests of Peninsular Malaysia, and very often it includes the most frequent species at a site, as it does in Sungei Menyala. Finally, the family Fagaceae because of the sharp discordance of its rankings. With only 15 species it ranked sixteenth in diversity, and seventeen in density, but it ranked fifth in basal area, contributing 4.57% of the total. The Fagaceae is well known for its importance in the upper hill and montane forest of Peninsular Malaysia, but it is also conspicuous in the lowlands.

The Dipterocarpaceae was the most abundant family for trees larger than 10 cm dbh, and accounted for four of the 25 most abundant species. The Euphorbiaceae was the second most abundant family, and the most diverse family, but only two of the 25 most abundant species are euphorbs, indicating the extent to which the family dominated the minor components of the forest. The 19 other most abundant species represent 11 different families. For trees over 30 cm dbh, family representation was much less mixed. Seventeen of the most abundant species in this class were in three families, Dipterocarpaceae, Leguminosae, and Fagaceae. The composition of minor families at Pasoh, such as the diversity and frequency of Ebenaceae, and the scarcity of palm trees, was also entirely consistent with other lowland Dipterocarp forests of Peninsular Malaysia.

By the data preserve, it is quite an effectively research result of floristic inventory status of the research area. By separate the data recorded by the family and their habit, there are more systematic research and easy source for the next researcher to abreast on it in the next further study.

A floristic analysis of the lowland dipterocarp forests of Borneo

Floristic analyses are very useful for identifying spatial patterns in plant diversity and composition, and when combined with environmental, geological and historical variables, can provide important information on the processes that maintain the high levels of tree species diversity in tropical forests.In these field study, there are several research have been done especially in the Borneo region.

Borneo is the second largest tropical island in the world after New Guinea and is floristically very rich, possibly harbouring up to 15,000 different plant species including c. 3000 species of trees. [3] The majority of these tree species is found in the lowland rain forests, which in Borneo are usually dominated by species of the Dipterocarpaceae (Whitmore, 1984). Although the geological history of Borneo is rather complicated (Ridder- Numan, 1998; Morley, 2000), it is likely that the recent glacial periods during the Pleistocene have had a profound influence on the present-day tree flora of the island. During these periods Borneo was connected by land bridges to the south-east Asian mainland and present-day islands such as Java and Sumatra (Morley, 2000). Evidence also suggests that during these glacial periods south-western Borneo consisted mainly of savanna vegetation with some scattered rain forest fragments along major rivers and on mountain slopes, while northern and eastern Borneo remained covered with rain forest (Heaney, 1991; Verstappen, 1992; Thomas, 2000; Gathorne-Hardy et al., 2002). This means that the current situation, in which the whole island is covered with rain forest must have developed relatively recently, after the last glacial period (c. 10,000 years ago). If so, this recolonization of south-western Borneo by rain forest trees since the last ice-age might still be visible in the present-day tree flora.

The tree species inventory data from 28 locations of tropical lowland (below 500 m altitude) dipterocarp rain forest from Borneo to investigate the floristic patterns on this island. The main aims are to:

(1) identify floristic regions for Borneo within this forest type,

(2) determine the characteristic taxa of these regions,

(3) study tree diversity patterns within Borneo and

(4) relate the floristic and diversity patterns to abiotic factors.

In the research, for the better sample of the total genera composition ofthe locations, the random draws of 640 trees were repeated six times for each location (with replacement of all individualsafter each draw of 640 trees). This means that in all further analyses each location was represented by six random samples of 640 trees. A drawback of this method is that six random draws from locations with few trees inventoried will be more similar in generic composition than those of locations with a large number of trees inventoried. However, the floristic similarity between the six draws from each location were, in all cases, much smaller than between locations.Figure 1 Map of Borneo with the 28 locations used in this study (see also Table 1).Montane areas (altitude above 500 m) are indicated in grey. [4] 

Figure 1 Map of Borneo with the 28 locations used in the study

The result show that, it is a quite efficient research on the flora of Borneo. Below are the result of the research.

The data set used for the floristic analysis contained 77 families and 363 genera. On average, a random sample of 640 trees consisted of 41.6 ± 3.8 families and 103.0 ± 12.7 genera. Variation in diversity between locations, even when they were close together, was high. Lambir (Sarawak) stood out as the most diverse forest in Borneo, with both the highest family (49.0) and genera diversity (139.8). However, on a regional scale, both family and genera diversity were highest in south-east Borneo, while diversity decreased towards the north-west (West Kalimantan and western Sarawak) and north-east of Borneo (northern East Kalimantan and Sabah).

These diversity patterns were more pronounced for genera than for families. No relation was found between mean annual rainfall and family, nor genera diversity. The Dipterocarpaceae and Euphorbiaceae were by far the most dominant tree families in the lowland dipterocarp forests of Borneo with 21.9% and 12.2% of all trees, respectively (Table 2). Shorea (Dipterocarpaceae), Syzygium (Myrtaceae), Diospyros (Ebenaceae), Madhuca (Sapotaceae) and Dipterocarpus (Dipterocarpaceae) were the most common tree genera in Borneo with 12.3%, 5.0%, 3.4%, 3.2% and 3.1% of trees, respectively.

As expected the Dipterocarpaceae, which consists mainly of upper canopy and emergent tree species, was the most dominant tree family in Borneo with 21.9% of all trees. The Euphorbiaceae, which mainly consists of understorey and low to upper canopy tree species, ranked second with 12.2% of all trees. This is a pattern typical for most evergreen rain forests in the Sunda region which encompasses the mainland of southeast Asia, Sumatra, Java and Borneo . [5] The floristic composition of these forests differs markedly from those of tropical Africa and America where the legume family dominates. [6] Among Borneo's lowland families the legumes only rank 12th, and no legume genus even occurs among the 25 most common genera. This difference is probably related to the fact that the flora of the Sunda Region, due to its isolation from other tropical regions since the Middle Cretaceous, followed its own evolutionary pathway (Morley, 2000). However, it still remains to be explained why the dipterocarps became the dominating tree family in south-east Asia, especially as they only form an inconspicuous element in the tropical tree floras of Africa and America.

Since the situation of Borneo floristic are diverse in species diversity, the result also show that the rate of extinction are relatively low. The research can be a recorded proof for the argue of the lowland forest in Borneo are low in species diversity and high in species extinction. In the other hand, the research are can be categorized as a better field study of the floristic inventory especially in this region.

Inventory of the tropics is not nearly complete, yet destruction of their natural ecosystems continues not only unabated, but at a faster rate than inventory. There is an urgent need to accelerate the process of inventory and at the same time to encourage alternatives that will buy time for us by delaying the destruction of the world's richest biome. The more knowledge we gather about the ecosystem the better the possibility that we can use it on a sustained- yield basis. In the meantime we should do all we can do to encourage some of the alternatives; the exploitation of seasonal forest (Budowski, 1976; Goodland & Irwin, 1977 ), floodplain forest (Goodland & Irwin, 1975; Prance, in press ), of secondary forest ( Budowski. 1975; Farnworth & Golley, 1974 ), and better distribution of food produced in temperate regions. Clearly there is still an enormous challenge ahead of us in the task of a complete tropical inventory.