We analized the character of distributional pattern of Dryobalanops lanceolata by calculating the correlation dimension. We counted points reflected at the boundary as well as at the corner to correct the lack of points near the boundary. Its cerrelation dimension is about 1,33 with small scale and it has some remarkable decreases and increases in dimension, suggesting the change of the character of the distribution, Comparing the correlation dimension with the box dimension and I-delta index, correlation dimension is sensitive to the scale where the distributional character changes, Therefore the correlation dimension can be a new index that shows the change of the characters of distribution in scale.

View full abstract

The survival and germination of buried seeds in a tropical rain forest were examined for 45 spp. of woody plants at Pasoh Forest Reserve, West Malaysia, The fresh viable seeds were packed in bags made of aluminum mesh and were burried in soil at 5 cm depth under closed canopy. The seed bags were successively sarnpled at three months to three years after burial and the fate of seeds was checked. Germination tests under the open site conditions in a greenhouse were also conducted for fresh seeds and the exhumed seeds. Survival curves of bur{ed seeds were fitted by the Weibul distribution model and the mean life span of ungerminated viable seed was estimated. Although most primary forest species had short-lived seeds, 16% of primary forest specie$ had a mean life span exceeding one year, The mean life span of secondary forest species varied between shorter than 1,5 months and longer than ten years and 77% of secondary species had a mean life span exceeding one year. Furthermore, the mean life span of seed significantly depended on the germination type, fruit morphology, and seed weight. The long-lived seeds of secondary forest species germinated rapidly under open-site conditions, while few germinations were recorded for the seed population buried in the forest so{l, The long-lived seeds of primary forest species germinated slowly even in the forest soil, and their delayed germination in the forest soil may result from their woody endocarp surrounding seeds.

View full abstract

Dryobalanops aromatica and D. Ianceolata (hereafter denoted as Lin and Dl, respectively) are major Dipterocarp species constituting an emergent layer in the Bornean Rain Forest, and their distributions are in proximity, but never overlap. Thus, we examined the relationship between the distribution of these species and soils with reference to the soil physico-chemical, morphological, and microbiological properties,
Based on the topographical investigation, was located only on the upper slope, whereas Dl occupied on both upper and lower slopes. The soil solums examined around these two species were always deeper than 1,3 meter. Soil texture was always sandy for the soils around Da, on the other hand, ranging from sandy te clayey for these around Dl. Furthermore, the following differences were found; 1) organic layer was thicker {n the Da soils, 2) soil color of subsurface horizons was duller in the Dl soils, and 3) only the Dl soils contained coarse fragments. 4) the amounts of exchangeable cations such as Ca and/or Mg and total oxides’ content of K₂O, MgO, and P₂O₅ were higher for the Dl soils, 5) the amounts of exchangeable At and H were higher in the Da soils, 6} proportion of air phase and volume of macropore, and the value of sand content were higher for the Da soils, showing that the Da soils easily attain to drier soil moisture condition after rainfall, which was proved by monitoring soil water potential, 7) ten times as much fungal colonies were detected in the Da soils as compared to the Dl soils.
These result$ suggest that Da emerges on a sandy soil with a dominance of drier soil moisture condition for some period and a low nutrient status with high acidity on the reflection of stable pedogenetic processes, while Dl stands on either clayey or sandy soil with a dominance of reductive condition for a certain period and relatively high nutrient status with low acidity, reflecting weak pedogenctic processes. It was well-known that shifting cultivators utilize a land where Dl dominates as a productive crop field, Their traditional way of land selection proves to be rational from the standpoint of soil science.

View full abstract

West Katimantan has about 10 species of Shorea cal]ed as tengkawang whose fruits are economically useful as source of fat. The fruits were collected from natural and semi-natural forests and plantations. We made eight plots in tengkawang forests in 1991 to study the change of forests by the human activity. In Ngabang which had been the capital city of old Landak Kingdom, the king made two plantations of ca. 1 krn² about 100 year ago. In tengkawang species, S. stenoptera was mainly planted on flat bank near river, and S, amptexicautis, and S. pinanga was on upper slope. They reached 125 cm in DBH and 49m in height. The average diameter increment of tengkawang from 1991 to 1994 was 0.28 (± 0.32 SD) cm/yr. Two rubber tree species, Hevea brasiliensis and Palaquium gutta were p:anted under the canopy of tengkawangs of fiat bank and slope, respective]y. The plot had 123 species of wild and cultivated trees (DBH > 4.8cm) in 1 ha, and the diversity was similar to the natural tengkawang forest.
On river banks of small stream near a village Muarailai, semi-natural tengkawang forests were found. Large trees reached 186 cm in DBH. People had cut useless trees and planted useful trees such as Hevea and Durio under the canopy of tengkawang. Along the Daid River, tengkawang forest remained nearly natural condition. The forest structure was similar to semi-natural forest but no p]anted trees except one escaped shrub Bullucia pentamera introduced from Latin America. The common tengkawang, S stenoptera dominated exclusively on flat river banks of sandy soil and the diversity was not so high. Thwe ether dipterocarp forest on slope had higher diversity,

View full abstract

The spatial distribution of sympatric Scaphium species (Sterculiaceae), Scaphium borneense, S. Iongipetiolatum, and S. macropodum was analyzed with reference to topography in a permanent plot of 52 ha in Lambir, Sarawak, East Malaysia. These are large, deciduous trees. The total numbers of S. borneense, S. Iongipetiolatum, and S macropodum larger than 1 cm DBH in the plot were 1135, 63, and 122, respectively. All Scaphium species showed clear clump distribution in the plot, and their distribution was associated with topography. The index of spatial association supports the existence of strong habitat segregation among the three Scaphium species in a small spatial scale (smaller than ca. 1250 m²), and between S. borneense and S. Iongipetielatzam in a large spatial scale larger than 2.5 ha). S. borneense and S macropodum mainly occurred in sites higher than and lower than 180 m in altitude in the plot, respectively. S. longipetiolatum was completely restricted to sites lower than 140 m in altitude. The differences in height within plot correlated with soil texture and water conditions. The lower part of the plot had clayish and wet soil. The higher part was covered by sandy and dry soil, We can thus conclude that the sympatric Scaphium species have divergent habitats and coexisted by segregating their habitats with respect to topography and/or soil.

View full abstract

The tree height growth of individual trees of Engkabang jantong (Shorea macrephylla) was monitored in a plantation forest, which was established at the Semengoh forest reserve, Kuching district. Sarawak, Malaysia in 1973, The assessment of tree height growth was repeated fifteen times during 21 observation years. Mean height was 19.3 m at the stand age of 21 years old, The growth trajectories with respect to time after planting were approximated by the simple logistic equation, of which three coefficients were determined by the non-linear least squares method. The coefficients were the intrinsic growth rate r, carrying capacity K, and coefficient k₀ determined by initial conditions, The mean estimated r of 0.2983/year represented very rapid initial growth of E, jantong compared with Cryptomeria japonica commonly used in Japanese plantation forestry. The repulsive relationship was observed between r and K and framed the r-K continuum, which could visualize a position of an individual along it and suggested a resource limit in partitioning mass and energy into two contrasting biological functions, r and K. Furthermore, unusually large r values for dead trees might be an adaptation against damages caused by planting trees and animal herbivores. All these results were strongly linked with promising properties of E, jantong as a species potentially available in the plantation forestry in the tropics.

View full abstract

An equatorial rain forest in West Sumatra suffered defoliation and severe stem damages from two storms in early 199S, Intensity of litter production at a storm generated gap site was 225 ton ha^-1, and big woody debris over 10 cm in diameter accounted for 78%. A mass of fine litter promptly lost its weight of dry matter in Ao layer directly after the event, and the Tate tended to have a positive correlation to the initial amount of accumulation. An impact of these mass litter production on a material cycling of an equatorial rain forest ecosystem was simulated basing on these field data and monitoring data of a forest since 1981. The simulation showed that fine litter would supply nutrients enough for revegetation at an initial stage in particular, and a great amount of woody debris would contribute to the process at later stages because of their low decomposition rate. The time needed for 95% loss of initial litter amount by decomposition at a gap site was estimated at 11 years in this forest i[respective of amount, when the composition of litter is same. This average decay rate overcomes a net primary productivity. From a carbon balance between both potential rates of decay and growth for initial 11 years after a damage, it shows that about 100(organic matter) ton ha^-1 of litter production is a boundary value between its sink and source for this stand.

View full abstract

There are many ccological studies of ants. occupying the myrmecophytes. in relation to the infractions between hosts and symbionts. However, the other occupants of myrmecophytes have been scarcely studicd. It is very important to investigate all the occupants and arboreal fauna to clarify their symbiotic relationships. Wc surveyed the complete occupant fauna inhabiting the epiphytic myrmecophytes, Hydnophytum moseleyanum in mangrove forests in Papua New Guinea. A diverse fauna was revealed, that was composed of 11 ant species and 39 spceies of other animal groups. Almost all the occupant species would be comrnensals facultatively utilizing the space inside the myrmecophytcs for their inhabitation. The existence of the epiphytic myrmecophyteg. should play a significant role for the maintenance of arboreal biodiversity because myrmecophytes provide the shelters and moisture for arboreal animals and markedly increase potential sites for their dwelling.

View full abstract

The influence of sheep grazing on species composition and coverage by vegetation in arid and serniarid grasslands was observed along a gradient of sheep grazing intensities during one growing season in the Thar Desert, India. In both types of grassland, four plots were separated by fences and eight, six, three or zero sheep per ha introduced. Total coverage was higher and more stable under grazing pressure in the semiarid than in the arid grassland. The impact of grazing on vegetation coverage in the arid grasslands was remarkable. The large variation in coverage in the arid grassland was due to three dominant annual legumes, Indigofera species, which accounted for 93% of total variance in coverage. In the semiarid grassland, however, no dominant species was found and the changes in coverage caused by grazing were small.

View full abstract

Body size. host preference, mate preference and the effects of inter-strain mating on fertility were compared between two syrnpatric “strains” of Indonesian Epilachna vigintioctopunctata, one on selanaeeeus plants and the other on the leguminous weed Centrosema pubescens. The two strains were different in body size and host preference, but seemed to lack effective reproductive barriers except host fidelity.

View full abstract

On Mt. Kinabalu, the altitudinal distribution of dung beetles (Scarabaeoidea) was studied in a lowland forest at Poring (550-950 m in altitude), a montane forest at Park Headquarters (PHQ) (1350-1950 m), and a transitional lowland-montane forest at Sayap (950-1350 m), by using carrion or dung baited traps. Among 61 collected species (12 genera, four families), dominant species were Onthophagus obscurior, O, cervicapra, Catharsius molossus and Synapsis cambeforti in the lowland forest; Onthophagus sp. 16, O. sp. 17 and Phaeochroops silphoides in the transitional forest; and Onthaphagzas sp. 19 and O. sp. 14 in the montane forest. Onthophagus sp, 15, O. pacificus, Copris sp. and Phaeochroops gigas were widely distributed from lowland to highland. Along with the increase of altitude, the species diversity and it$ evenness decreased in the carrion-visiting beetles but showed little change in dung-visiting beetles. The species exclusively visiting carrion were absent above 1350 m. Some generalist beetles, which were collected from both carrion and dung traps, tended to be collected more frequently from dung traps at higher altitudes. This is probably at least because the proportion of beetles captured on dung increased competition for carcasses with the burying beetle Nicrophorus podagricus (Silphidae) which was dominant above 1350 m in altitude.

View full abstract

One hundred baited traps, based on small mineral water bottles, were used to trap Hymenoptera in the crown- and field-layers of 50 tree specimens, during the dry season in the region of Madang, Papua New Guinea in August and September, 1995. A total of 12 baits from plant and animal oils and orange juice-based solutions were used. Both the numbers of species and individuals of non-formicld Hyrnenoptera and abundance of both ants and all insects trapped were very low. There was no significant difference in abundance between field- and crown-layers for non-formicid Hymenoptera, ants or all insects. However. there was a significant effect of trap bait, after summing both ‘up’ and ‘down’ catches, using patchouli and tea oils and all the orange juice-based baits. The possible effects of an alteration of trapping protocol and changing climate are discussed, Brief comparisons are made with similar studies. Species of several families of Hymenoptera were noted flying regularly in the trapping area, but were not trapped themselves. From this, and the low diversities of all members of non-formicid Hymenoptera, it is concluded that baited traps are not an effective method of mass-sampling this group and are unlikely to become a component of sampling packages for hymenopteran diversity, It is suggested that the cempromise between large numbers of replicatesandnon-specific,inexpensive, baits is so great that the trapping effectiveness is virtually nullified.

View full abstract

Twenty-four sorts of insect and mite galls were collected from Peucang Island, Panaitan Island, and the Krakatau Islands, Indopnesia in 1982 almost 100 years after the world-famous eruption of Krakatau Island. The collection consisted of 1 Thysanopteran, 2 Psyllid, 1 Aphid, 11 Cecidomyiid, 1 Lepidopteran, and 8 Eriophyid galls.All the galls collected are illustrated and their collection data are recorded together with host plant information. Shape and other characteristics are briefly described particularly for the newly-found galls. Faunistic differences between the Krakatau Islands and Peucang-Panaitan are also commented upon.

View full abstract

Pharus virescens Doell is a monocarpic herbaceous bamboo dominantly thrived in the understory of Neotropical rain forest of La Macarena and Tinigua National Parks of Colombia. During October 1990 and January 1991, we encountered a monocarpic mass flowering of a local population of P. virescens. Since then, we have investigated the recovery process to find out the next synchronous mass flowering occurred between October 1995 and January 1996 which showed the monocarpic life span was five years, The propagule was epizoochory, thus 6 mammalian orders including 26 speces and 12 avian species were confirmed attaching many of the caryopses. The distribution area of flowered population was estimated as 718 km² alongside the Duda and Guayabero Rivers.

View full abstract