REINWARDTIA REINWARDTIA Vol. 15. No. 2. 2016 A JOURNAL ON TAXONOMIC BOTANY, PLANT SOCIOLOGY AND ECOLOGY REINWARDCOTNIATE NTS Vol. 15. No. 2. 2016 Page CONTENTS Page ISSN 0034 – 365 X | E-ISSN 2337 − 8824 | Accredited 792/AU3/P2MI-LIPI/04/2016 ASIH PERWITA DEWI, NUNIK SRI ARIYANTI & EKO BAROTO WALUJO. Diversity of plants used for plaited crafts by the Dayak Iban-Désa in Kabupaten Sintang, Kalimantan Barat, Indonesia ................................................... 67 DIAN LATIFAH, ROBERT A. CONGDON & JOSEPH A. HOLTUM. Growth responses of palm seedlings to different light intensities manipulating canopy gaps with an ecophysiological approach ............................................... 81 ROSIE PRITCHETT, AURORA PHILLIPS, ANI MARDIASTUTI & ANDREW POWLING. Rattan diversity and broad edaphic niches in a tropical rainforest of Buton, Sulawesi, Indonesia ................................................................... 99 R E INGGIT PUJI ASTUTI & RUGAYAH. A new species of Murraya from Cyclops Mountain, Papua, Indonesia ......... 111 I N W DEDEN GIRMANSYAH. A new species of Begonia (Begoniaceae) from Sumbawa, Lesser Sunda Islands, A Indonesia .........................................................................................................................................................................115 R D T I PUTU GEDE P. DAMAYANTO & ELIZABETH A. WIDJAJA. A new species of Schizostachyum (Poaceae- IA Bambusoideae) from Sumba Island, Indonesia .............................................................................................................. 119 J. F. VELDKAMP. A revision of Iseilema (Gramineae) in Malesia ............................................................................. 123 MIRAADILA M. I., SHABDIN Z. & MEEKIONG K. Two new species and one new geographical record for Sarawak, Malaysia (Cyperaceae: Mapanioideae) .......................................................................................................................... 129 Reinw ardtia is a LIPI accredited Journal (792/AU3/P2MI-LIPI/04/2016) http://e -journal.biologi.lipi.go.id/index.php/reinwardtia Herbarium Bogoriense Botany Division Resear ch Center for Biology – Indonesian Institute of Sciences Reinwardtia is a LIPI accredited Journal (792/AU3/P2MI-LIPI/04/2016) Cibinong Science Center http://e-journal.biologi.lipi.go.id/index.php/reinwardtia Jln. Raya Jakarta − Bogor, Km 46 CibinoHnegr b1a6r9iu1m1 ,B Po.Ogo.r Bieonsxe 2 5 Cibinong IndoneBsoiatany Division Research Center for Biology – Indonesian Institute of Sciences Cibinong Science Center Jln. Raya Jakarta − Bogor, Km 46 Cibinong 16911, P.O. Box 25 Cibinong Indonesia D e c e m b e r 2 0 1 6 1 5 (2 ) : 6 7 – 1 3 5 2016 15 (2) REINWARDTIA A JOURNAL ON TAXONOMIC BOTANY, PLANT SOCIOLOGY AND ECOLOGY Vol. 15 (2): 67 – 135, December 22, 2016 Chief Editor Kartini Kramadibrata (Mycologist, Herbarium Bogoriense, Indonesia) Editors Dedy Darnaedi (Taxonomist, Herbarium Bogoriense, Indonesia) Tukirin Partomihardjo (Ecologist, Herbarium Bogoriense, Indonesia) Joeni Setijo Rahajoe (Ecologist, Herbarium Bogoriense, Indonesia) Marlina Ardiyani (Taxonomist, Herbarium Bogoriense, Indonesia) Himmah Rustiami (Taxonomist, Herbarium Bogoriense, Indonesia) Lulut Dwi Sulistyaningsih (Taxonomist, Herbarium Bogoriense, Indonesia) Topik Hidayat (Taxonomist, Indonesia University of Education, Indonesia) Eizi Suzuki (Ecologist, Kagoshima University, Japan) Jun Wen (Taxonomist, Smithsonian Natural History Museum, USA) Barry J Conn (Taxonomist, School of Life and Environmental Sciences, The University of Sydney, Australia) David G. Frodin (Taxonomist, Royal Botanic Gardens, Kew, United Kingdom) Secretary Rina Munazar Layout Dede Aryanto Illustrators Subari Wahyudi Santoso Anne Kusumawaty Correspondence on editorial matters and subscriptions for Reinwardtia should be addressed to: HERBARIUM BOGORIENSE, BOTANY DIVISION, RESEARCH CENTER FOR BIOLOGY– INDONESIAN INSTITUTE OF SCIENCES CIBINONG SCIENCE CENTER, JLN. RAYA JAKARTA – BOGOR KM 46, CIBINONG 16911, P.O. Box 25 CIBINONG INDONESIA PHONE (+62) 21 8765066; Fax (+62) 21 8765062 E-MAIL: [email protected] http://e-journal.biologi.lipi.go.id/index.php/reinwardtia Cover images: Mapania sembilingensis Miraadila, Shabdin & Meekiong. A. Habit; B. Leaf apex details; C. Sheath margin details; D. Capitate inflorescence; E. Spike; F. Spicoid bract [Drawing by Meekiong, K.]. The Editors would like to thank all reviewers of volume 15(2): David Simpson, Herbarium Kewense, Royal Botanic Gardens, Kew, UK Herwasono Soedjito, Research Center for Biology, Indonesian Institute of Sciences, Bogor, Indonesia Jay H. Bernstein, Robert J. Kibbee Library, Kingsborough Community College, New York, USA Kuswata Kartawinata - Integrative Research Center, The Field Museum, 1400 Lake Shore Drive, Chicago, USA Mark Hughes - Royal Botanic Garden Edinburgh, Edinburgh, Scotland, UK Mien A. Rifai - Akademi Ilmu Pengetahuan Indonesia (AIPI), Ind onesia Siti Nur Hidayati - Middle Tennessee State University, Tennessee, U SA Soejatmi Dransfield - Herbarium Kewense, Royal Botanic Gardens, Kew, UK Wong Khoon Meng - Singapore Botanic Garden, Singapore REINWARDTIA Vol 15, No 2, pp: 99 − 110 RATTAN DIVERSITY AND BROAD EDAPHIC NICHES IN A TROPICAL RAINFOREST OF BUTON, SULAWESI, INDONESIA Received 09 July, 2016; accepted 01 September, 2016 ROSIE PRITCHETT Centre for Biological Sciences, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK AURORA PHILLIPS School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, BN2 4GJ, UK ANI MARDIASTUTI Department of Forest Resources, Conservation and Ecotourism, Faculty of Forestry, Bogor Agricultural University, Bogor, Indonesia ANDREW POWLING School of Biological Sciences, University of Portsmouth, King Henry I Street, Portsmouth, PO1 2DY, UK. Email:[email protected] ABSTRACT PRITCHETT, R., PHILLIPS, A., MARDIASTUTI, A. & POWLING, A. 2016. Rattan diversity and broad edaphic niches in a tropical rainforest of Buton, Sulawesi, Indonesia. Reinwardtia 15(2): 99 – 110. — This paper attempts to answer the question: how can at least 20 species of rattan palms in the genus Calamus (family Palmae (Arecaceae)) co -exist in a rainforest? A survey of rattans was made in Lambusango Forest on Buton, an island close to south east Su- lawesi, in Indonesia. Rattan species and numbers were recorded in 87 quadrats of 30 × 10 m, laid out along linear tran- sects in habitats with a variety of soils. Evidence for edaphic (soil) niches was sought. Different rattan species were found to be adapted to soils with different conductivity and pH values. Standardised mean difference (d) scores were calculated for pairs of species based on their response to soil pH. Of the 66 pairs tested, 61 were found to be signifi- cantly different statistically. Such differences suggest, but do not prove, that many species occupy different edaph- ic niches. It was found that species which show a preference for soils with intermediate pH values (5.0 to 6.5) can grow in soils with a wide range of pH values, implying broad edaphic niches and that competition between these spe- cies is weak. Correspondence analysis shows that many species do not distinguish greatly between many soils with intermediate pH values. It is concluded that rattan species show evidence for having different edaphic niches, although the niches for many species are broad. It is speculated that many rattan species may be ecologically equivalent and that a weak version of ecological neutrality theory may apply. Key words: Neutrality, niches, rattan, soil, Sulawesi. ABSTRAK PRITCHETT, R., PHILLIPS, A., MARDIASTUTI, A. & POWLING, A. 2016. Keanekaragaman rotan dan relung edafis yang luas di hutan hujan tropis Buton, Sulawesi, Indonesia. Reinwardtia 15(2) 99 – 110. — Tulisan ini mencoba untuk menjawab pertanyaan: bagaimana setidaknya 20 jenis rotan marga Calamus (suku Palmae (Arecaceae)) hidup berdampingan di hutan hujan? Sebuah survei rotan telah dilakukan di hutan Lambusango di Buton, sebuah pulau yang dekat dengan Sulawesi Tenggara, Indonesia. Jumlah jenis individu rotan yang direkam dari 87 petak 30 × 10 m, diletakkan di sepanjang garis transek pada habitat dari berbagai jenis tanah. Pengaruh terhadap relung edafis (tanah) dicari. Jenis rotan yang berbeda diduga ditemukan sesuai dengan tanah dengan konduktivitas dan pH yang berbeda nilainya. Nilai rata-rata perbedaan standarisasi (d) dihitung untuk jenis-jenis yang berpasangan berdasarkan respon mereka terhadap pH tanah. Dari 66 pasang diuji, 61 ditemukan secara signifikan berbeda secara statistik. Perbedaan tersebut menyarankan, tapi tidak membuktikan, bahwa banyak jenis menempati relung edafis berbeda. Ditemukan bahwa jenis yang menunjukkan preferensi untuk tanah dengan pH menengah (5.0-6.5) dapat tumbuh di tanah dengan berbagai nilai pH, menyiratkan relung edafis yang luas dan bahwa persaingan antar jenis ini lemah. Analisis kores- pondensi menunjukkan bahwa banyak jenis rotan tidak terlalu berbeda diantara jenis tanah dengan nilai pH menengah Disimpulkan bahwa jenis rotan menunjukkan bahwa mereka memiliki relung edafis yang berbeda, meskipun banyak jenis memiliki relung yang luas. Hal ini menimbulkan spekulasi bahwa banyak jenis rotan mungkin secara ekologi setara dan bahwa teori netralitas ekologi mungkin berlaku walaupun masih belum terlalu kuat. Kata kunci: Netralitas, relung, rotan, Sulawesi, tanah. 99 100 REIN WARD TIA [VOL.15 INTRODUCTION Powling et al., 2015). The rocks include lime- stones, sandstones, chert and peridotite, the last of A central question of ecology is how can so these giving rise to ultrabasic (ultramafic) soils. many species of the same trophic level co-exist in Thus the forest has very diverse topography and a habitat without one species out-competing the soils, and many different forest types exist others and causing their local extinction? This (Powling et al., 2015). The heteroge-neity of the problem is of particular relevance to plants, where habitats suggests that much ‘niche space’ is different species compete for a very limited range available to plants, so many different ecological of environmental resources, namely light, water niches should be available for different species to and a few mineral nutrients (Silvertown, 2004). occupy (Colwell & Rangel, 2009). This could One explanation is that each species is adapted to account for why so many rattan species can co- an ecological niche: a set of environmental and exist. biotic resources which allows it to persist; even in The expectation would be that niche-dependent the presence of other species, each of which is rattan species should be found only in distinct adapted to a different set of resources (Hutchinson, habitats, where soil type, soil moisture, slope 1978; Colwell & Rangel, 2009). Such adaptation exposure, surrounding vegetation and other factors involves ‘trade-offs’ (Grime, 2001). would offer the niche space required by the If species do exploit niches there should be species. This would suggest that the community of distinct differences between species and a rattans and other plant species has formed by the consequence would be that individuals within process of ‘niche assembly’ (Hubbell, 2001), species should increase in number when rare, since whereby all available niches are taken, so all niche the resources on which they depend would be space is occupied. under-exploited (Levine & HilleRisLambers, Alternatively, if rattan species are neutral and 2009; Wilson, 2011). This frequency dependence not niche-dependent, they can co-exist within would be due to intraspecific competition being habitats due to ecological equivalence of all greater than interspecific competition. individuals. Therefore a community could have An alternative explanation for the co-existence arisen by the arrival of various species that co- of species has been offered by Hubbell (2001). exist due to lack of mutual competition. The term This explanation assumes that all individuals of all Hubbell (2001) uses for this process is ‘dispersal- species present are ecologically equivalent; hence assembly’. Such a process may be important in the species are ‘neutral’, in that no species is assumed assembly of rattan species in the Lambusango to be competitively superior to others. Such a Forest, since the ideas of island biogeography theory is offered as useful in ecological research theory may apply (MacArthur & Wilson, 1967). for its descriptive and predictive powers, even Following these ideas, Sulawesi can be considered though it is understood that the world is not strictly the meta community, providing the primary source neutral. Rather it assumes that differences are not of palm species for Buton (Powling, 2009), while functionally significant (Hubbell, 2001; Rosindell Lambusango Forest can be considered the local et al., 2012; Matthews & Whittaker, 2014). The community, receiving species by dispersal from theory of neutrality suggests that replacement of Sulawesi. one species by another can be a very slow process, Field observations (Powling et al., 2015) have occurring on the same time scale as speciation suggested that some rattans of Lambusango differ (Hubbell, 2001). in their adaptation to soil pH. Both soil pH and The problem of co-existence of similar and conductivity are quantitative measures of soil possibly competing species applies to the rattans, differences, likely to be related since both are which are climbing palms (family Palmae influenced by the base status of soils. In some (Arecaceae), sub-family Calamoideae) requiring situations these parameters can vary over very forest trees for support (Dransfield et al., 2008). small distances, for instance when water draining Since many are congeneric and have the same from limestone areas runs over sandstone soils general way of life they might be expected to (Powling et al., 2015). compete ecologically with each other. Evidence shows that small-scale variability in At least 20 species of rattans, all classified in soil conditions, particularly soil fertility, the genus Calamus, have been found in i n fluences the distribution of neotropical palms in Lambusango Forest on the island of Buton, forests (Svenning, 2001). Soil type can be situated close to (10 km at nearest) the coast of regarded as a niche parameter and it has been south east Sulawesi, in Indonesia (Widayati & shown that soil nutrient availability influences the Carlisle, 2012; Powling et al., 2015). The forest, composition of understorey palm communities in part of which is a wildlife reserve, has a wide Panama (Andersen et al., 2012). Transplantation variety of habitats. In altitude it runs from 0 to 700 experiments have shown that species which occur m, with rainfall over 2000 mm per year, and a naturally in low-nutrient sites grow better in such variety of underlying rocks (Milsom, 2000; sites, compared with species which occur naturally 2016] PRIT CHET T et al . : Ratta n dive rsity in a tropi cal fore st 101 in high-nutrient sites. To some extent the relative took place during July and August 2010. This performances of the species were reversed in high- period would normally be the dry season, which nutrient sites (Andersen et al., 2014). lasts from July to October. However, due to La The work to be described concerns an Niña weather conditions, arising from inter-annual investigation of soil parameters and their influence sea surface temperature variations of the tropical on the diversity and distribution of rattan species Pacific (NOAA, 2016), heavy rainfall was at various sites, with differing geology, in experienced throughout the study period. Lambusango Forest. The sites were separated by The survey of rattan abundances was conducted distances of up to 12 kilometres and were at sites in the forest, named Anoa, Bala, deliberately chosen for their variety of rock and Kakenauwe and Lapago, which are shown on the soil types. Thus the survey took place over a wider map of the forest in Powling et al. (2015). An area and in a wider variety of habitats than most, if additional site, Jalan Kodok, lying between not all, published surveys designed to test the Kakenauwe and Lapago, was also used. Sites were neutral theory of biodiversity (Chase, 2014). Soil chosen which showed little evidence of rattan pH and conductivity, together with canopy cover, collection in the years before the survey. They tree number and tree trunk area, were measured in differed in underlying geology (Milsom, 2000) and quadrats at the sites. This paper describes only the therefore topographies and soils. Topographies influence of soils on rattans, since soil type was varied from shallow to steep slopes and included found to be the primary factor controlling rattan ridges and river valleys. The altitudes of the species diversity. However, other factors can survey sites varied from approximately 250 m to influence rattan growth and diversity and soil 500 m above sea level. Sites were selected to characteristics are not the sole influence. include soils derived from the following rock It can be assumed that conductivity is an types: limestone, sandstone, chert and peridotite; approximate measure of soil fertility, with alluvial soils were also included. increasing conductivity indicating increasing fertility. However, the possibility of toxic or non- Rattan abundance survey nutrient ions being present in some soils, Rattans were investigated along linear transects particularly ultrabasic soils, means that such a which ran through areas of forest with uniform soil relationship might not hold. Soil pH, rather than types. Six 30 × 10 m quadrats were recorded on conductivity, is therefore used in some of the each transect, with 30 m gaps between quadrats so following analyses as a better single measure of that vegetation in each quadrat was independent of general soil conditions. Plants vary in their ability that in its neighbours. As a result, the length of a to grow on soils with different pH values, with typical transect was 330 m. Between 12 and 24 requirements for either alkaline or acid soils quadrats were recorded at each forest site, on shown by some plants (Grime et al., 2007). Such either two or four transects. There was one plants occupy at least two different edaphic niches exceptional transect, on chert soil at the Bala site, when soil pH is taken as a niche axis. where nine quadrats were recorded over a length The object of this investigation was to of 510 m. An overall total of 87 quadrats on 14 determine whether the congeneric rattans require transects were recorded. just one or two distinct soil types or whether they Within each quadrat individual plants, and show spaced distributions along axes of soil pH number of stems of multi-stemmed species, of all and conductivity, suggesting each species occupies rattan species were counted. The rattan species had a distinct edaphic niche. Edaphic niches might been identified previously by comparison with then explain why at least 20 rattan species co- named specimens in the herbaria at Kew, U.K., exist. and Bogor, Indonesia (Powling, 2009). MATERIALS AND METHODS Soil measurements Soil samples were taken from the centre (15 m) Description of forest sites of each quadrat from a depth of 1–5 cm. Soil (15 The study was carried out in the Lambusango ml) was mixed with 10 ml of demineralised water Forest on the island of Buton, within both the and measurements made using a Hanna Combo pH reserve and the surrounding area, which is official- and EC meter (Hanna Instruments, Rhode Island, ly designated as ‘limited production forest’. USA). Together these areas cover 95,000 ha (Widayati & Soil moisture at a depth between 1.0 and 6.5 Carlisle, 2012). Outline maps of Buton and the cm was determined in situ as a percentage of the forest are presented in Powling et al. (2015). The maximum moisture capacity of the soil in ‘limited production forest’ is set aside for low- question, using a Kelway soil tester (Kel intensity timber extraction; steep slopes in this Instruments, New Jersey, USA). The measure- area make intensive logging and rattan collection ments reported were taken on a single day, 8th difficult. The main survey of rattan abundances August 2009. 102 REIN WARD TIA [VOL.15 Data analysis Competition between rattans Data were analysed using Microsoft Excel 2007 If rattan species segregate into niches on soils and Minitab 16. Standardized mean difference of different types it would be expected that they effect size (d) scores were calculated using the compete for soil resources, i.e. show root Practical Meta-Analysis Effect Size Calculator competition. Fig. 1 shows that quadrats contained program (Wilson, 2013). Other calculations were between one and eight species, with a modal performed according to Magurran (2004). number of four. The number of individual rattan plants and stems averaged 30.1 per quadrat, with a RESULTS range between 3 and 102. The 102 individuals occurred in one of the quadrats with eight species. Species investigated In view of the density of species and individuals in The rattan species found, their total numbers at least some of the quadrats it seems probable that and the number of quadrats in which each species root competition does occur between rattan occurred are shown in Table 1. The Table shows species. 12 named species, with two entries for the species It was noted that within disturbed habitats there Calamus zollingeri, indicated by the local names were frequently one or two common or dominant for the two varieties ‘batang’ and species. These were often C. zollingeri (one or ‘mombi’ (Powling, 2009). Results to be presented other variety) and/or C. ornatus, with in one case show that these two varieties differ significantly in Calamus sp. 2 being most common. These species their response to soils of differing pH values, so are multi-stemmed and able to form clumps of the two varieties are treated separately, except for stems derived from one original plant, so able to the rank-abundance plot and species abundance hold their position and spread. The commonness distribution. Three unidentified species are of these species in disturbed areas suggests this included in Table 1 since they were also found in characteristic gives them a competitive advantage the survey. Five other species known to exist in above ground over other rattans in high light the forest (Powling, 2009) were not found during environments. the survey. Table 1. Species of rattan found in survey quadrats Rattan species found in survey Species no. No. of Individuals No. of quadrats (as listed in Powling, 2009) Calamus koordersianus Becc. 1 149 21 Calamus leptostachys Becc. ex K. Heyne 2 132 22 Calamus minahassae Warb. ex Becc. 3 167 47 Calamus mindorensis Becc. 4 28 9 Calamus ornatus Blume 5 561 60 Calamus pedicellatus Becc. ex Heyne 6 47 10 Calamus siphonospathus Mart. 7 158 25 Calamus suaveolens W. J. Baker & J. Dransf. 8 157 9 Calamus subinermis H. Wendl. ex Becc. 9 18 10 Calamus symphysipus Mart. 10 102 25 Calamus validus† W. J. Baker 11 4 3 Calamus zollingeri Becc. ‘batang’ 12 96 20 Calamus zollingeri Becc. ‘mombi’ 13 440 36 Calamus sp. 1 14 354 26 Calamus sp. 2 15 193 14 Calamus sp. 3‡ 16 11 3 †Previously Daemonorops robusta (Baker, 2015). ‡ A species not listed in Powling, 2009. 2016] PRIT CHET T et al . : Ratta n dive rsity in a tropi cal fore st 103 Rank-Abundance and Species Abundance Dis- rattan species. tribution A rank-abundance (Whittaker) plot (Magurran, Responses of rattan species to soils 2004) of all species is shown in Fig. 2. The species The mean values for pH and conductivity of the show an acceptable fit to a linear (geometric) soils in quadrats in which the rattan species grew distribution (Kolmogorov-Smirnov test statistic = are plotted in Fig. 5. It can be seen that the species 0.162 with a 5% critical value = 0.224), which are distributed in the same general pattern as the indicates an order of dominance among the soil samples (Fig. 4). This indicates that most, if species. However, the species curve is noticeably not all, soil types are exploited by at least one sigmoid. Such a curve shape often results when rattan species. plotting species found in communities and Fig. 6 shows a plot of the mean pH values and indicates that the geometric model of species ranges of the soils on which the rattan species dominance might not apply. were found growing (C. validus is omitted due to The sigmoid shape suggests the overall species only four plants being recorded in the survey). The abundance distribution may be lognormal plot shows that the species with the broadest (Magurran, 2004). This distribution results when ranges have soil pH means between approximately some species are common and some rare but a 5.0 and 6.5. Species that are better adapted to soils larger number are of intermediate occurrence. with higher and lower pH values have narrower When logarithms of species numbers are plotted as ranges. It is noticeable that three species adapted a histogram a normal distribution results (Preston, to low pH soils have very small ranges. This 1962). The result for the rattan species is shown in indicates that some species are specialised to Fig. 3, where logarithms to the base 4 are used tolerate acidic soils but cannot grow on soils with (black columns). The distribution expected if the higher pH values. To a lesser extent this also rattans followed an exact lognormal distribution is applies to species adapted to grow on soils with also plotted (white columns). The observed high pH values. The general relationship is not an distribution does not differ significantly from the artefact caused by small sample size resulting in expected lognormal distribution (Kolmogorov- the appearance of limited range, since there is no Smirnov test statistic = 0.143 with a 5% critical significant correlation between sample size and value = 0.230). range (r = 0.389, p = 0.152). However, the three The veil line (Preston, 1962) is on the extreme species referred to above are exceptions since they left of the distribution, with 0.0015 (in effect, zero) have small ranges even when allowing for their species predicted to be beyond (to the left of) the sample size, suggesting that they are specialised veil line. This position is to be expected given that for growth only on very acidic soils. the rarest species (C. validus and Calamus sp. 3) Comparison of species on soils with different each occurred in three quadrats, when in most pH values could be made by performing a one- lognormal distributions the rarest species occurs in way analysis of variance. However, such an only one quadrat. The position of the veil line analysis would require homogeneity of variances would appear to indicate that all the rattan species for the species and this was not the case. Even in the forest were found during the survey. when using only the 12 species and varieties with However, this is known not to be the case the largest sample sizes, Bartlett’s test statistic was (Powling, 2009). 652.04, p<0.001, and Levene’s test statistic was 39.08, p<0.001. Therefore, to compare the species’ Relationship of soil pH and soil conductivity abilities to grow on different soils a matrix of d Measurements made on soil samples during values (Nakagawa & Cuthill, 2007) is presented July and August in 2010 are plotted in Fig. 4. This (Table 2). A d value is a standardised measure of includes measurements additional to those made the size of difference and can have 95% on the soils in the 87 quadrats. The Figure shows a confidence limits calculated to show whether the d U-shaped curve with conductivity initially value indicates a statistically significant difference declining as pH rises, but then increasing to high between two species being compared. The matrix values as pH increases further. It is presumed that in Table 2 arranges the rattan species in order of at the lowest pH values certain substances, such as their mean soil pH values (four species with low manganese, aluminium, possibly iron and soil numbers of individuals found in the survey are organic acids, become ionised and soluble (Grime, excluded from the matrix). The results show that 2001), thus contributing to conductivity. Some of most pairs of species show significant differences these ions, particularly aluminium, may be toxic to from each other, indicating that, generally, they many plants, including rattans. Most of the soil grow in soils with differing pH values. The samples with the lowest pH values were from the calculation of d values requires the calculation of area with chert bedrock and low rattan diversity, multiple t values (one for each pair of species); where acidity and drought during the dry season also the distributions of the soil pH values on may together make conditions impossible for most which each species was growing were not always 104 REIN WARD TIA [VOL.15 Fig. 1. Distribution of the number of rattan species per Fig. 2. Rank-Abundance plot for rattan species quadrat, obtained in the 2010 survey. (triangles) with the fitted line for a geometric distribution (diamonds). The rattan species are ordered on the baseline from most common to least common. Fig. 3. Species abundance distribution for the rattans. Fig. 4. The relationship between soil pH and soil The bars show logarithms (to base 4) of the number of conductivity. Soil types – black circles: calcareous; red individuals of each rattan species (black columns) and squares: from sandstone; green diamonds: ultrabasic; the expected number of species, based on a lognormal blue triangles: from chert; orange arrow heads: alluvial. distribution, in each category (white columns).