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Erb W.M.,State University of New York at Stony Brook | Borries C.,State University of New York at Stony Brook | Lestari N.S.,Forestry Research and Development Agency | Ziegler T.,German Primate Center
American Journal of Primatology | Year: 2012

Asian colobines typically live in small one-male groups (OMGs) averaging five adult females, but Simias concolor (simakobu or pig-tailed langur) is considered an exception because mostly adult male-female pairs have been reported. However, based on their phylogenetic position and marked sexual dimorphism, simakobu are also expected to form OMGs with multiple females. The preponderance of small groups could be the result of human disturbance (hunting or habitat disturbance) reducing group size in the recent past. To investigate this possibility, we documented the demography of ten wild simakobu groups from January 2007 until December 2008 at an undisturbed site, the Peleonan Forest, Siberut Island, Indonesia. We assessed the population-specific size and composition of groups and documented demographic changes due to births, disappearances, and dispersals throughout our 2-year study. We found OMGs with 3.0 adult females on average in addition to all-male groups, but no adult male-female pairs. The ratio of 0.5 infants per adult female (and 0.64 births per female-year in focal groups) suggested that birth rates were similar to those of other Asian colobines. In 5.1 group-years, we observed six dispersal events and six temporary presences (i.e., less than 3 months' residency). Both males and females dispersed, and juveniles seemed to disperse more frequently than adults. To assess the impact of human disturbance on simakobu demography, we compiled data for seven additional populations from the literature and compared them using multiple regressions. Adult sex ratio and the number of immatures per group were influenced negatively by hunting and positively by habitat disturbance while reproductive rates were not significantly affected by either variable. These findings suggest that adult male-female pairs may result from hunting pressure reducing group size, and that conservation action to reduce hunting in the Mentawai Islands is needed to ensure the survival of this critically endangered species. © 2012 Wiley Periodicals, Inc. Source

Erb W.M.,State University of New York at Stony Brook | Borries C.,State University of New York at Stony Brook | Lestari N.S.,Forestry Research and Development Agency | Hodges J.K.,Reproductive Biology Unit
International Journal of Primatology | Year: 2012

Seasonal breeding in primates is related to the degree of environmental seasonality, particularly the availability and predictability of food. Southeast Asian species in general show moderate birth seasonality due to either low environmental seasonality or unpredictable fluctuations of mast-fruiting food resources. One Southeast Asian primate, the simakobu (Simias concolor), however, has been reported to be a strict seasonal breeder with births occurring in June and July only. It is unclear whether these observations are characteristic of the species or result from a sampling bias. To address this question, we documented the annual distribution of 11 births in eight groups of simakobu over two consecutive years at Pungut, an undisturbed site on Siberut Island, Indonesia. We assessed annual variation in ecology and reproduction via rainfall, temperature, food availability, feeding time, physical condition, conceptions, and births. Mean monthly temperature was nearly constant (26. 3-27. 1 °C), and monthly precipitation always high (219-432 mm). Although simakobu foods were abundant year-round, there were two fruit-feeding peaks in June and September. In contrast to previous reports, we documented births in 7 mo. Most births occurred in October (45 %), the wettest month of the year, and most conceptions in March and April, following a peak in unripe fruit availability. Although sample sizes are very small, females seemed to conceive when their physical condition was best, suggesting that simakobu time conceptions flexibly to the recovery of energy reserves. Across study sites, births occurred in 10 calendar months, indicating that simakobu reproduction is not strictly seasonal. © 2012 Springer Science+Business Media, LLC. Source

Sudrajat D.J.,Forestry Research and Development Agency
Forest Science and Technology | Year: 2015

Genetic variation patterns of white jabon (Anthocephalus cadamba [Roxb.] Miq.), were evaluated at the population level. Eleven natural populations were examined for variations in fruit, seed, and seedling morphophysiological characteristics. Analysis of variance revealed significant differences among populations for all the characteristics studied, except the radicle length. Genotypic variance and genotypic coefficient of variance for all fruit, seed, and seedling characteristics were found to be higher than corresponding environment variance and environment coefficient of variance, indicating that the genotype explained most of the variance for these characteristics. In particular, high heritability values coupled with high genetic gain were found for fruit weight, seedling height, root collar diameter, sturdiness index, leaf number, leaf length, and leaf width. Principal component analysis and hierarchical clustering of various characteristics of fruit, seed, and seedling revealed that most of the geographically distant populations are genetically close. Since these characteristics appear to be under strong genetic control, considerable scope exists for exploitation of heritable additive genetic components for future breeding and improvement in white jabon. © 2015 Korean Forest Society Source

Basri E.,Forestry Research and Development Agency | Yuniarti K.,Forestry Research and Development Agency | Yuniarti K.,University of Melbourne | Wahyudi I.,Bogor Agricultural University | And 3 more authors.
Journal of Tropical Forest Science | Year: 2015

Basic properties and drying quality of 9-year-old Acacia mangium wood from plantation of the Forest Research and Development Agency in Bogor, Indonesia were studied in order to evaluate effects of girdling periods (0, 4 and 8 months) applied before cutting the trees. Results showed that 8 months of girdling resulted in 50.8% reduction in initial (green) moisture content of wood i.e. from 122 to 60% with no occurrence of end splitting in logs during felling. In general, wood quality of girdled tree is better than that of non-girdled tree. Wood density and holocellulose content increased, while tangential and radial shrinkage ratio, ash, silica, lignin, wood pentose and extractive contents decreased. Based on drying characteristics, basic drying schedule for 8-month-girdled wood was at temperature of 50-80 °C and relative humidity of 80-28%, while that for 4-month-girdled wood and control, temperature of 40-65 °C and relative humidity of 83-38%. The longer girdling period also decreased the percentage of honeycombing and degree of deformation during drying. © Forest Research Institute Malaysia. Source

Irawanti S.,Forestry Research and Development Agency | Ginoga K.L.,Forestry Research and Development Agency | Prawestisuka A.,Forestry Research and Development Agency | Race D.,Australian National University
Small-scale Forestry | Year: 2014

The integration of agriculture and forestry is commonly viewed as a foundation for sustainable livelihoods for small-scale farmers. In many tropical countries, traditional farming practices by smallholders include some trees or forest management for multiple purposes. This article reports on research that explores the experiences of smallholders in Central Java, Indonesia, who are increasingly blending aspects of their traditional farming practices with cultivation of commercial timber trees. Smallholders manage complex farming systems that are responding to the demands of commercial markets. Smallholders in Central Java typically manage a wide range of species that yield short-, medium- and long-term products that are used by households and sold into commercial markets. However, the authors’ research indicates that smallholders may not be optimising their forest management in relation to the potential financial returns, leading to a lower expectation of the value of forestry to their livelihoods. Support for community forestry could address several knowledge gaps amongst smallholders, so that community-based commercial forestry achieves its potential. © 2014, Steve Harrison, John Herbohn. Source

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