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Khảo sát về cây thuốc trong Vườn Quốc gia Ba Vì, Việt Nam. Tác động của các phương pháp đối với bảo tồn và sử dụng bền vững Conservation of medicinal plant resources is a critical ecologic, cultural and economic issue in Vietnam, as with other parts of South-east Asia, and the tropics and sub-tropics generally. The paper describes the development and application of a survey methodology, using standard phytosociological techniques, for the quantitative inventory of medicinal plants in BaVi National Park, northern Vietnam. One hundred and twenty-six permanently marked transects, each 50 10 m, were established over the ranges of altitudes and characteristic vegetation structural types present in the Park. Over 200 medicinal plant species used by Dao people were sampled (of a documented total of about 300 species including introduced species grown in home gardens), in vegetation types ranging from closed evergreen forest at high altitude (>1000 m), through secondary forest formations, bamboo thicket, open grassland and plantation, distributed generally along a declining altitude gradient. Forty-one of 44 economically important medicinal species were sampled also. Important medicinal plant species, half being vines, were concentrated particularly in more-orless intact, late secondary closed forest habitats at higher elevations. The status of most important medicinal plant species was found to be rare or uncommon, and to exhibit scattered (as opposed to clumped) distributions. The paper discusses implications of the applied methodology and the assembled data for the inventory, conservation, and sustainable use of medicinal plants at local and broader regional scales. # 2001 Elsevier Science Ltd. All rights reserved.
A survey of medicinal plants in BaVi National Park, Vietnam: methodology and implications for conservation and sustainable use Tran Van On a , Do Quyen a , Le Dinh Bich a , Bill Jones b , Josette Wunder b , Jeremy Russell-Smith c, * a Hanoi College of Pharmacy, Viet Nam b Association for Research and Environmental Aid, Sydney, Australia c Parks Australia (now included within Environment Australia), Jabiru, Australia Received 10 November 1999; received in revised form 20 June 2000; accepted 7 July 2000 Abstract Conservation of medicinal plant resources is a critical ecologic, cultural and economic issue in Vietnam, as with other parts of South-east Asia, and the tropics and sub-tropics generally. The paper describes the development and application of a survey methodology, using standard phytosociological techniques, for the quantitative inventory of medicinal plants in BaVi National Park, northern Vietnam. One hundred and twenty-six permanently marked transects, each 50  10 m, were established over the ranges of altitudes and characteristic vegetation structural types present in the Park. Over 200 medicinal plant species used by Dao people were sampled (of a documented total of about 300 species including introduced species grown in home gardens), in vegeta- tion types ranging from closed evergreen forest at high altitude (>1000 m), through secondary forest formations, bamboo thicket, open grassland and plantation, distributed generally along a declining altitude gradient. Forty-one of 44 economically important medicinal species were sampled also. Important medicinal plant species, half being vines, were concentrated particularly in more-or- less intact, late secondary closed forest habitats at higher elevations. The status of most important medicinal plant species was found to be rare or uncommon, and to exhibit scattered (as opposed to clumped) distributions. The paper discusses implications of the applied methodology and the assembled data for the inventory, conservation, and sustainable use of medicinal plants at local and broader regional scales. # 2001 Elsevier Science Ltd. All rights reserved. Keywords: Medicinal plants; Ethnobotany; Conservation; Inventory; Vietnam; South-east Asia; East Asia 1. Introduction Considerable and growing attention has been given in recent years to issues surrounding the in situ conserva- tion, and ecologically- and economically-based sustain- able use, of wild (i.e. undomesticated) populations of medicinal plants (MPs) (e.g. Akerele et al., 1991; Plotkin and Famolare, 1992; Balick et al., 1996). Most con- servation focus has been given to individual, inter- nationally and regionally economically signi®cant, over- exploited MP species (Anon., 1995±1997). Nowhere are these issues more acute as in tropical and sub-tropical regions (e.g. Africa, the Americas, Asia), where still today most people rely on medicinal, timber, and an array of other non-timber vegetable/animal products, derived principally from increasingly degraded, frag- mented, species-diverse forest and savanna biomes (e.g. Farnsworth and Soejarto, 1991; Toledo et al., 1992; Iwu, 1996; Voeks, 1996; Caniago and Siebert, 1998). Medicinal plant conservation has an extensive con- temporary literature covering a range of subject areas. Schippmann (1997) provides 590 references for the per- iod 1990±1996, derived from over 50 relevant journals, newsletters, and databases. This work covers, in ranked thematic order, mostly: economic and trade aspects (181 entries); status and threat issues pertaining typically to individual taxa (166); cultivation and harvesting issues (120); regional/culturally focused ethnobota ny studies (110 entries); species descriptions and identi®cation (100); and policy and legislation issues, including intel- lectual property rights (71). Most listed regional studies 0006-3207/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(00)00125-7 Biological Conservation 97 (2001) 295±304 www.elsevier.com/locate/biocon * Corresponding author at Centre for Indigenous Natural and Cultural Resource Management, Northern Territory University, Darwin, Northern Territory 0909, Australia. E-mail address: jeremy.russell-smith@nt.gov.au (J. Russell-Smith). have focused on the Indian subcontinent, followed by the Americas then China, with relatively few concerning Africa and South-east Asia (Schippmann, 1997). Few studies address, or provide regional empirical examples of, quantitative ecologi cal survey (i.e. resource inventory), sustainability, and associated database designs. As noted by Hall and Bawa (1993), however, the undertaking of ecological surveys focusing on the distribution, abundance and population structures of MPs is fundamental to the assessment of the conserva- tion status of wild populations, and prerequisite for addressing harvesting sustainability of key or target species. Principles and guidelines concerning MP con- servation database design, networking and main- tenance, are outlined in Synge and Heywood (1991). Toledo et al. (1992) provide a rare example of a national MP database then under development for tropical forest regions in Mexico, combining data from regional ethno- botanical studies with plant species inventories undertaken at a range of scales (e.g. sites, 4 1ha;localities, 1±10 ha; regions, up to ca. 1000 ha). In this paper, we describe the application of a standard quantitative ecological survey design for assessment of the distribution, abundance and status of MPs, as used by the Dao ethnic group, in BaVi National Park, northern Vietnam. The design has potential also for various inventory, conservation, and sustainability assessment applications at broader regional scales. As discussed below, the assessment and conservation of MPs in Viet- nam is a critical ecologic, cultural and economic issue in that country; Schippmann (1997) lists just two Vietna- mese references, and single references for neighbouring Kampuchea and Laos. The project was undertaken col- laboratively between the Vietnam National University (Centre for Resource and Environmental Studies), Hanoi College of Pharmacy, the Association for Research and Environmental Aid (an Australian Non-Government Organisation aid agency), and the Australian Nature Conservation Agency (now included within Environ- ment Australia). 2. Regional context and study area Spanning the tropical, monsoon climatic zone, Viet- nam has a high biodiversity with more than 10,000 described species of higher plants (Pham, 1999), of which 3200 species have been recorded as having med- icinal properties (Vo, 1997). However, with a high population density and increasing demands for eco- nomic development, Vietnam has lost more than 50% of its forest cover over the past ®ve decades (Vietnam Ministry of Science, Technology and Development, 1995). Current rates of deforestation of remnant dense (>40% canopy cover) broad-leaved forests in Vietnam are estimated to be >1% p.a. (Blasco et al., 1996). Vietnam now faces over-exploitation of its plant resources, including MPs. Given the importance of native MPs in the domestic economy (Nguyen, 1996), investigation of the conservation and sustainable use of MPs in Vietnam is an urgent matter. BaVi National Park is located generally between 21 01 H ±21 H 07 H N and 105 18 H ±105 0 25 H E in the BaVi Dis- trict, Ha Tay Province, northern Vietnam, approxi- mately 50 km north-west of Hanoi (Fig. 1). BaVi was established as a National Park in 1992. The Park covers an area of 7377 ha, including a Strictly Protected Area (i.e. core area) above 400 m elevation of 3000 ha sur- rounding three mountain peaks where there is still rela- tively pristine tropical montane and semi-evergreen forest (sensu Blasco et al., 1996) at higher elevations. The Park is surrounded by a Particular Use Zone (i.e. buer zone) of approximately 15,000 ha, previously under the control of Park authorities but now falling under District jurisdiction, but where a range of non-Park activities (e.g. growing of crops, cattle grazing) is permitted. Alti- tude ranges from 100 to 1296 m above sea level. Average rainfall is 1660 mm, 90% of which is received during the wet season months, June to October. Geology comprises mostly ®ne-textured sedimentary rocks (AREA, 1993). Towards the end of the nineteenth century, the French botanist, Balansa, collected 5000 plant speci- mens from the BaVi region. Recent investigations have revealed more than 800 plant species, occurring in 427 genera and 98 families. At present the Park's ¯ora is estimated to comprise 1500±2000 higher plant species (Nguyen, 1990). Amongst the describ ed species are 13 local endemics (AREA, 1993), and 10 species recorded in the Vietnamese Red Data Book for rare and endan- gered plants (Tran and Tran, 1998). More than 30 0 local plant species ha ve been recorded as having medic- inal value; a preliminary listing of these species is pro- vided in AREA (1993). There is a population of some 45,000 people, belong- ing to Kinh, Muon g and Dao groups living in the Par- ticular Use Zone (PUZ) of the Park. Outside the PUZ population densities are high, with an estimated popu- lation of around 15 million living in the Red River delta lowlands, comprising 14,700 km 2 (Le and Tran, 1993). Of the three ethnic groups, the Dao constitute the major users of MPs in the Park, and this paper focuses on MPs as de®ned and used solely by this ethnic group. Shifting cultivation commenced in the mountainous BaVi region as late as the 1920s when Dao people migrated to the area. Since 1965, Dao people have been resettled in the PUZ where they now reside in two main communes consisting of about 2000 people. Transition to a settled agricu ltural lifestyle has been dicult, how- ever, and most Dao families continue to depend on harvesting of natural resources to some extent at least. Controlled harvesting of some natural products (fuel- wood, fodder, medicinal plants and other vegetative 296 T. Van On et al. /Biological Conservation 97 (2001) 295±304 resources) is permitted in rehabilitation plantation areas; regardless, illegal removal of both plant and ani- mal resources continues throughout the Park. Dao people daily collect and process substantial quantities of MPs from the Park and its surrounds, both for domestic and commercial purposes. Along with the cultivation of cassava and other agricultural crops, the exploitation of MPs constitutes a major economic acti vity. MP pro- ducts are sold extensively by the Dao in surrounding towns and communities (including the capital Hanoi), for both wholesale and retail markets. 3. Methods 3.1. Medicinal plants MPs used by Dao people were recorded in interviews and participatory ®eld surveys, particularly with herb- alists and collectors, over 2 years. Specimens of all MPs were co llected during ®eld trips. One complete set of reference specimens is lodged with the Herbarium of the Hanoi College of Pharmacy (HNP). Throughout the paper, reference is made to a subset of MPs, the Important Medicinal Plant (IMP) species. IMPs were identi®ed using standard Participatory Rural Appraisal (PRA) techniques where herbalists were asked to rank a list of regularly used local MPs com- piled on the basis of extensive participatory ®eld obser- vations. IMPs were determined on three criteria: (1) proportion of herbalists using each listed species; (2) frequency of use; and (3) market value. Details (and results) of the applied PRA methodology, along with information concerning the medicinal properties ascri- bed to MPs by Dao herbalists, pro cessing techniques, and other ancillary data, are not presented here but form part of continuing studies being undertaken by the ®rst author as part of a PhD research program. 2.2. Vegetation habitats and medicinal plant survey As a means for developing a habitat framework for describing the distributions and ecologi cal relations of MPs in BaVi National Park, 126 permanent transects, each 50  10 m, were established over the ranges of altitudes and characteristic vegetation structural types (primary and secondary forest, bamboo thicket, grass- land, and plantation) present in the Park. Based on advice provided by Dao informants, four of the above transects were established speci®cally in areas known to contain certain rare IMPs. Vegetation data recorded at each transect included the identi®cations and densities of all tree species (55cm DBH), canopy height of the three tallest stems, bamboo cover (%), other grass cover (%), and indices for canopy cover [1=closed canopy (5 75%); 2=partial canopy; 3=open canopy (< 10%], and disturbance (1= primary/ intact forest; 2=secondary forest/thicket vegetation; 3=mostly cleared/replanted). Recorded environmental data included altitude, slope, aspect, geology, water Fig. 1. Location of BaVi National Park, Vietnam. T. Van On et al. /Biological Conservation 97 (2001) 295±304 297 availability (0=a bsent; 1=seasonal; 2=permanent), and slope position (1=valley bottom; 2=footslope; 3=mid- slope; 4=topslope; 5=crest). At each transect, the abundance of individual MP species was recorded using the following scale: 1=1 individual present; 2=2±6 indivi duals; 3=7±20 indivi- duals; 4=21±50 individuals; 5=51±100 individuals; 6=101±200 individuals; 7=201±500 individuals; 8= >500 individuals. An estimate of the total abundance of MP individuals occurring at an individual transect was calculated by summing the maximum values possi- ble for respective classes (e.g. 20 individuals for abun- dance class 3) for all MP species sampled on the transect. 3.2.1. Analysis Preliminary analysis of the survey data was under- taken using standard numerical pattern analysis techni- ques incorporating classi®cation (i.e. grouping of transects based on ¯oristic similarity) and ordination (i.e. relative ordering along one to few dimensions, or vectors, of transects based on ¯oristic similarity). While a wide variety of classi®cation and ordination proce- dures are available (e.g. see Gauch, 1982; Causton, 1988; Legendre and Legendre, 1998), we employed widely used, complementary classi®cation (TWIN- SPAN; Hill, 1979a) and ordination (Detrended Corre- spondence Analysis (DCA); Hill and Gauch, 1980) procedures based on reciprocal averaging (Hi ll, 1973), contained in the simple-to-use, computationally e- cient, DECORANA package (Hill, 1979b). While both procedures have limitations (e.g. Knox and Peet, 1989; Van Groenewoud, 1992), they aord generally eective solutions especially where (as in this study Ð see Results) vegetation patterning is under the in¯uence of one dominant vegetation gradient and species' respon- ses are predominantly unimodal (Peet et al., 1988; Mucina and van der Maarel, 1989). As a means for developing a habitat framework, polythetic divisive classi®cation was undertaken with TWINSPAN on a data matrix comprising 126 transects  94 tree species (presence/absence) occurring in at least ®ve transects. Classi®cation was truncated at the third division level, and yielded six readily interpreted trans- ect groups (see Results). Complementary Detrended Correspondence Analysis (DCA) ordination was undertaken to derive transect scores for the ®rst two vectors. Using the six groups as a framework, subsequent analyses involved: (1) calculation of group frequencies for nominal (e.g. species occurrence) and ordinal (e.g. slope position) variables; and (2) calculation of group means and standard errors for measurement variables (e.g. no. IMPs, stem density, altitude). To assist inter- pretation of major trends in these data, a range of environmental, vegetation structure, and MP data were correlated (Pearson's r) with the ®rst two DCA vectors derived from ordination of the matrix of 126 transects  94 tree species. Correlations were also undertaken between MP variables and other environm ental and structural variables, over all transects. All data manip- ulation was performed with the DECODA package (Minchin, 1990). 4. Results 4.1. Medicinal plants A total of 207 MPs, of about 300 recorded in the BaVi area (AREA 1993), were sampled in the 126 transects. Many of those unrecorded, however, occur as exotics grown only in home gardens. Forty one IMP species, of a total of 44 determined through the PRA process, were sampled in transects; the three unrecorded species are all considered to be very rare in the local area by Dao herbalists. Of the 44 IMPs, three are grown already in home gardens (Alstonia scholaris, Cinnamo- mum zeylanicum, Tradescantia zebrina), and at least two others could readily be grown (Piper retrofractum, Tra- vesia palmata) from layered cuttings and seed, respec- tively. A listing of IMPs is provided in the Appendix A, along with information concerning their lifeforms, abundance in transects, and frequency of occurrence in each of the six habitat groups derived through classi®- cation (see below). Using these data we have classi®ed the current occurrence of IMPs in BaVi National Park as follows: (1) status, where occurrence in 1±2 transects= rare, 3±9 transects=uncommon , and 10+ transects= common; and (2) dispersion, where modal abundance in transects of 1±6 individuals=scattered, and 7+ indivi- duals=clumped. These data are summarised in Fig. 2. Of note in Fig. 2 is that the status of over half the IMPs is either rare or uncommon, and dispersion of the great majority is scattered. Half the IMPs, including three species not sampled in transects, are vines (see Appen- dix). 4.2. Habitat framework TWINSPAN classi®cation of a data matrix, compris- ing 126 transects  94 tree species occurring in ®ve or more transects, yielded six readily interpreted habitat types (groups). The ®rst dichotomy separated 38 highly disturbed and plantation transects all occurring at low altitude, from other secondary and primary forest trans- ects occurring up the mountainside. Plantation transects (with very low tree species diversity Ð Group 6) were distinguished from other open low altitude transects (Group 5) in the se cond dichotomy. For the 88 transects occurring at higher altitudes, two further divisions yielded 298 T. Van On et al. /Biological Conservation 97 (2001) 295±304 four site groups more-or-less neatly partitioned along the altitudinal gradient as follows: a group of nine transects comprising mostly undisturbed (primary) montane forest vegeta tion atop the mountain peaks, at a mean elevation of 1200 m (Group 1); 24 transects comprising mostly disturbed, closed canopy, late sec- ondary forest at a mean of 1000 m (Group 2); the majority of transects (43) representative of partly canopied, early secondary forest on midslopes, at a mean of 650 m (Gr oup 3); and 12 transects representa- tive of closed canopy, late secondary forest, associated particularly with creeklines, at a mean elevation of 450 m (Group 4). The frequency of occurrence of common tree species (i.e. occurring at 10 or more transects) in each of these six groups is presented as a sorted table in Table 1. Means and modal values for a range of environmental, vegetation structure, and MP variables, are given for each of these groups in Table 2. Given that all transects were found to be located on similar sedimentary parent materials, substrate (geology) data are not included in Table 2. The predominant in¯uence of the altitudinal gradient on the ¯oristic and structural patterning of vegetation habitats in BaVi National Park is indicated by the highly signi®cant negative correlation between altitude and DCA scores for the ®rst vector (Table 3). This interpretation is reinforced by: highly signi®cant nega- tive correlati ons between DCA vector 1 scores and tree species diversity per transect, and canopy height; and corresponding highly signi®cant positive correlations with disturbance, canopy cover, and grass cover indices (Table 3). The second major axis of variation in these data is evidently related to moisture availability (Table 3). 4.3. Distribution and abundance of medicinal plants Whereas the complement of useful MP species occur- red under all habitat conditions in BaVi National Park, including in plantations and highly disturbed open- canopy situations, IMP specie s were mostly restricted to secondary growth and primary fores t conditions on the mountainside and peaks, particularly between 600 and 1000 m elevation (Table 2). Overall, non-important MP species were found mostly at lower elevations in typi- cally disturbed habitats, and IMPs were found mostly in relatively species diverse, undisturbed forest conditions at higher elevations (Table 4). MPs were most abundant in association with creek- lines in late secondary forest vegetation at lower eleva- tions (Group 4), then early secondary forests at intermediate elevations (Group 3) and plantations (Group 6), and least abundant at high elevations (Groups 1 and 2; Table 2). Overall, MP abundance was shown to be strongly negatively correlated with altitude and better structurally developed forest habitat condi- tions, and strongly positively correlated with relatively disturbed, open-canopied, grassy situations (Table 4). 5. Discussion 5.1. Status of medicinal plant species in BaVi National Park Data presented here were derived from 126 transects sampling just 6.3 ha, or 0.09% of the total area of BaVi National Park. The sampling eort was not randomly distributed; rather, plots were located mostly with respect to a strati®ed design focusing on sampling major habitats across the full altitudinal range. This resulted in uneven sampling intensity over the Park area; for example, 80 transects were used to sample vegetation in the core area of the Park above 400 m, at a sampling density approaching 0.13% . As well, some sampling eort was intentionally focused on areas high on the mountainside known to contain certain rare IMP spe- cies. Despite these design limitations, it is evident that assembled data aord useful insights into the distribu- tions and `natural' habitat conditions of many indivi- dual MP species, but especially the sub-set of naturally occurring, culturally and economically IMP species. The data indicate that while there was a substantial MP resource base for Dao people occurring in BaVi National Park, much of this was associated with species occupying modi®ed, open-canopy habitats and planta- tions, typically at lower elevations. Such disturbance- adapted species, furthermore, presumably will continue to be advantaged (in the short term at least) by ongoing degradation of remaining forested areas. Prior to the establishment of the Park in 1992, it was estimated that Fig. 2. Relationship between status and dispersion of 44 important medicinal plant species in BaVi National Park (refer to text for details). T. Van On et al. /Biological Conservation 97 (2001) 295±304 299 as much as 150 ha of forest habitat was being cleared annually (Vietnam Ministry of Forestry, 1989) with the result that probably as little as 1,500 ha of intac t forest habitat remained by the early 1990s (AREA, 1993). In modi®ed tropical settings many studies have noted the singular importance of degraded secondary, and culti- vated vegetation types as repositories of regional phar- macopeia (e.g. Kohn, 1992; Toledo et al., 1992; Voeks, 1996). Species and structural diversity in tropical and sub-tropical forests declines nevertheless with increasing modi®cation (e.g. Whitmore, 1984). In contrast, the great majority of IMP species were found to be associated mostly with remnant, relatively intact secondary forest formations at higher elevations; however, at least 10 IMP species were recorded at least once in substantially modi®ed habitats (Groups 5 and 6; see Appendix), or were already being grown in home gardens. Most remaining IMP species were found to be rare or uncommon, occurring typically in dispersed populations, and comprising a disproportionately large number of vines. Given their domestic and economic value, such species evidently are most at risk from ongoing local exploitation. In the absence of remedial attention, howeve r, the fate of IMPs may be likened to that of vertebrates in the Park where, following surveys conducted in 1962 and 1991±1992, it was concluded that ``mammal species richness in BaVi is poor, large mam- mals have become locally extinct, small-medium size mammals remain, but in small numbers'' (AREA, 1993, p. 19). Table 1 Sorted table of frequency of common tree and tall shrub species (occurring in 10 or more plots) in each of six classi®cation groups a Species code Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 (n=9) (n=24) (n=43) (n=12) (n=9) (n=29) Manglietia conifera 721 Eberhardtia aurata 75 Cryptocarya impressa 661 Litsea baviensis 7132 Meliosma longifolia 483 Antidesma fordii 4611 Tabernaemontana sp1 594 Syzygium sp5 113 Beilschmidtia balansae 281 Acer oblonga 284 Litsea balansae 21012 Ficus glandulifera 317202 Mischocarpus fuscescens 355 1 Tabernaemontana kwangsiensis 4511 Cylindrokelupha balansae 168 Knema corticosa 88 Adinandra integerrima 311 Claoxylon longifolia 1321 Helicia hainanensis 28112 1 Caryodaphnopsis baviensis 2796 1 Ostodes katherinae 720 1 1 Wrightia balansae 381 Saurauia tristyla 417 72 Trevesia palmata 153053 Scheera octophylla 1 2 15 1 3 4 Macaranga adenantha 210 1 Helicia sp362 10 Evodia meliaefolia 1522 Ficus fulva 110 22 1 Bischoa javanica 110 26 1 Saraca indica 210 Ficus hispida 637 6 Evodia lepta 11 1 1 21 Randia tomentosa 21 312 Rhus chinensis 111214 Mallotus philippensis 235 Breynia fruticosa 4318 Liquidamber formosana 1410 Ficus heterophylla 28 Acacia mangium 10 a n=no. transects per group. Where given, voucher specimens as lodged at Hanoi College of Pharmacy (HNIP). 300 T. Van On et al. /Biological Conservation 97 (2001) 295±304 A critical issue facing conservation of the Park's remaining biodiversity thus is to assist local commu- nities develop alternative means for deriving or growing natural products outside the Park. Such an approach has been taken with the establishment of fast growing timber species, albeit mostly exotic Acacia and Eucalyptus spp., on land formerly cleared and in need of rehabilitation. These endeavours have reduced the extent of ®rewood removal from the Park, as well as providing income for the local community through the sale of thinnings, poles, etc.; further, as supply has increased, the value of these products has decreased markedly (AREA, 1993). IMPs likewise are signi®cant in this regard. Challenges have included developing eective, simple propagating techniques, developing successful establishment regimes in home garden situations (presumably requiring at least wind-protection and semi-shade), appropriate training, cultural acceptance, and ultimately, raising awareness of the need for sustainable harvesting of medicinal plant species in the wild. To these ends an integrated program, involving over 200 herbalists and farmers, was initiated in the PUZ of the Park in 1993 and completed recently. One of its priorities was to encourage the cultivation of MPs as an agricultural crop in home gardens, and to replant threatened species in degraded areas of the Park as a regenerative strategy. To date, 23 IMP species have been collected, propa- gated (using simple, culturally appropriate techniques), and successfully planted in trials under suitable habitat conditions (e.g. initial protective shade) at several loca- tions in the PUZ area. 5.2. Inventory, sustainab ility and regional MP conservation Both in Vietnam and in broader regional contexts, there is an evident requirement for addressing the conservation status of MPs and associated sustainability issues, as there is for conserving biodiversity generally. The Vietnamese population comprises at least 54 ethnic groupings, most of whom depend heavily still on native Table 3 Correlations between independent environmental, vegetation and medicinal plant variables with vectors 1 and 2 from DCA ordination of 126 transects  94 common tree species Variable Vector 1 Vector 2 rP rP Altitude À0.91 <0.0001 0.02 NS No. tree species À0.85 <0.0001 À0.05 NS Grass cover 0.81 <0.0001 À0.06 NS Canopy height À0.80 <0.0001 À0.09 NS Disturbance 0.74 <0.0001 À0.16 NS Canopy cover 0.64 <0.0001 À0.12 NS Slope À0.56 <0.0001 0.12 NS No. important medicinal species À0.51 <0.0001 0.09 NS No. other medicinal species 0.58 <0.0001 À0.19 NS Abundance of medicinal plants (all species) 0.54 <0.0001 À0.01 NS Geology 0.14 NS 0.04 NS Aspect 0.08 NS À0.13 NS Stem density À0.56 <0.0001 À0.18 0.04 Slope position À0.33 <0.0001 À0.26 0.003 Water availability À0.10 NS 0.46 <0.0001 Table 2 Mean (Æ S.E.M.) and modal values of environmental, vegetation structure, and medicinal species variables, for six ¯oristic groups de®ned by classi®cation of 126 transects  94 tree species occurring at ®ve or more transects a Variable Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 (n=9) (n=24) (n=43) (n=12) (n=9) (n=29) Environmental Altitude (m) 1203Æ25 998Æ32 654Æ30 443Æ31 293Æ26 214Æ15 Slope ( ) 36.4Æ4.7 38Æ3.3 32.5Æ2.3 21.6Æ3.5 18.5Æ4.6 18Æ1.6 Modal water availability Absent Absent Absent Present Absent Absent Modal aspect North South/west North North East East Modal disturbance class Primary Secondary Secondary Secondary Secondary Plantation Modal canopy cover Closed Closed Half Closed Open Open Modal slope position Topslope Midslope Midslope Creekline Lowerslope Lowerslope Vegetation structure No. tree species 20.6Æ1.8 20.7Æ1.2 13.9Æ0.8 6.5Æ14Æ0.5 1.7Æ0.4 Stem density (no./ha) 828Æ56 628Æ45 543Æ38 261Æ48 144Æ20 325Æ92 Canopy height (m) 27.8Æ2.7 23.1Æ0.7 18.9Æ1 11.6Æ1.2 8.3Æ1.4 6.1Æ0.7 Bamboo cover (%) 8.3Æ2.3 10.8Æ4.4 13.7Æ3 16.6Æ8.3 17.8Æ9.7 3.1Æ1.8 Grass cover (%) 0 0 8.2Æ2.4 22.5Æ8.9 35Æ8.6 60Æ5.5 Medicinal species No. important medicinal species 3.4Æ0.6 5.6Æ0.9 5.4Æ0.4 3.6Æ0.8 0.8Æ0.3 0.4Æ0.1 Total no. medicinal species 8.1Æ1.0 11.3Æ1.3 14.9Æ0.9 9.3Æ1.1 13.9Æ2.6 13.3 1.0 Modal medicinal species abundance per transect 26±50 51±100 201±500 >500 101±200 201±500 a n, No. transects per group. T. Van On et al. /Biological Conservation 97 (2001) 295±304 301 MPs for domestic purposes. However, despite the undertaking of qualitative inventories of MPs in various parts of Vietnam over the past few decades (Le, 1997), the development of quantitative, systematic approaches remains, as elsewhere, elusive. An objective of the present study has been the regio- nal application of a standard numerical methodology for assessing the distribution, abundance and status of MPs. Such assessment is an essential ®rst step for addressing the ecological sustainability of harvesting Non-timber Tropical Forest Products (NTFPs), includ- ing MPs (Hall and Bawa, 1993). For example, data assembled here may be used in spatial an alyses [e.g. using Geographic Information Systems (GIS)] to pre- dict, hence map the probable distributions of MP taxa, and ultimately derive baseline population estimat es of target species. The statistical con®dence with which spatial analyses are undertaken, however, obviously depends especially on sampling intensity, and repre- sentativeness/strati®c ation of plot locations. Further, being digital, the database assembled for BaVi National Park may be readily extended with inventory data from other sampled locations (e.g. within the Par k itself, other reserves, regions), including surveys undertaken at dierent sampling times for ongoing monitoring and sustainability assessment pur- poses. Additionally, such digital data may be incorpo- rated into other databases, thereby informing local through to broader regional contexts. Once assembled, such data sets are amenable for quantitative analyses using a broad range of numerical tools and approaches (e.g. Margules and Austin, 1991; Legendre and Legendre, 1998). While the compilation of numerical NTFP and MP databases is evidently still in its infancy in south-east and east Asi an contexts (Schippmann, 1997), quantita- tive MP sampling approaches are evident, for example, in the work of Toledo et al. (1992) for Mexico, Voeks (1996) for disturbed Brazilian Atlantic forests, and Caniago and Siebert (1998) for a localised study in rapidly deforesting Kalimantan, Indonesia. A useful regional model is provided also by a current, major integrated MP conservation and resource development project in Sri Lanka, which includes quantitative assessment of the in situ conservation status and har- vesting sustainability of MPs in four key national loca- tions (World Bank, 1997). Such approaches have broader regional potential. Acknowledgements We are extremely grateful to Professor Vo Qui and Dr. Peter Bridgewater, and contributing organisations, for the support and foresight to undertake this project. Mr. Le Van Lanh and Mr. Phung Tien Huy assisted with organising the initial ®eld program. Tracey May produced Fig. 1. William Milliken and two anonymous referees are thanked for their constructive comments on the manuscript. Table 4 Correlations between medicinal plant variables and other independent environmental and vegetation structure variables from 126 transects a Variable No. important medicinal species No. other medicinal species Abundance of medicinal species rP rPrP Grass cover À0.54 <0.0001 0.23 0.01 0.36 <0.0001 No. tree species 0.52 <0.0001 À0.32 0.0003 À0.39 <0.0001 Canopy height 0.49 <0.0001 À0.32 0.0002 À0.38 <0.0001 Disturbance À0.48 <0.0001 0.48 <0.0001 0.34 <0.0001 Altitude 0.37 <0.0001 À0.52 <0.0001 À0.55 <0.0001 Slope 0.35 <0.0001 À0.34 <0.0001 À0.27 0.002 Canopy cover À0.33 <0.0001 0.34 <0.0001 0.36 <0.0001 Stem density 0.22 0.01 À0.09 NS À0.28 0.002 Slope position 0.03 NS 0.03 NS À0.16 NS Aspect 0.07 NS À0.03 NS 0.18 0.05 Geology 0.02 NS À0.03 NS 0.16 NS Water availability 0.07 NS À0.29 0.0008 À0.05 NS a NS, not signi®cant, where =0.05. 302 T. Van On et al. /Biological Conservation 97 (2001) 295±304 Appendix References Akerele, O., Heywood, V., Synge, H. (Eds.), 1991. 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World Bank (1997) Sri Lanka Conservation and Sustainable Use of Medicinal Plants Project: Detailed Project Description. Unpub- lished Sta Appraisal Report of the World Bank, Colombo. 304 T. Van On et al. /Biological Conservation 97 (2001) 295±304 . A survey of medicinal plants in BaVi National Park, Vietnam: methodology and implications for conservation and sustainable use Tran Van On a , Do Quyen a , Le Dinh Bich a , Bill Jones b ,. and application of a survey methodology, using standard phytosociological techniques, for the quantitative inventory of medicinal plants in BaVi National Park, northern Vietnam. One hundred and. having medic- inal value; a preliminary listing of these species is pro- vided in AREA (1993). There is a population of some 45,000 people, belong- ing to Kinh, Muon g and Dao groups living in