47 research outputs found
PREDICTING HABITAT DISTRIBUTION OF ENDEMIC AND CRITICALLY ENDANGERED DIPTEROCARPUS LITTORALIS IN NUSAKAMBANGAN, INDONESIA
No full textROBIANSYAH, I. 2017. Predicting habitat distribution of endemic and critically endangered Dipterocarpus littoralis in Nusakambangan, Indonesia. Reinwardtia 16(1): 11 - 18. - The tree species Dipterocarpus littoralis (Bl.) Kurz. is endemic to Nusakambangan and categorized as critically endangered. In the present study, the habitat suitability of the species in Nusakambangan was predicted using logistic regression analysis and Maxent model. Three topographic variables (elevation, slope, and aspect), distance from river and coastline, and one vegetation index (Normalized Difference Vegetation Index (NDVI)) as well as two water content indexes (Normalized Difference Water Index (NDWI) and Normalized Difference Moisture Index (NDMI)) were used as predictors of the models. Employing initial number of 82 presence and 250 absence data of D. littoralis, both models were able to predict the suitable areas for the species with fairly high success rate. The AUC and Kappa value for logistic regression were 0.77 ± 0.027 and 0.34 ± 0.058, respectively, while the respected values for Maxent were 0.91 ± 0.062 and 0.37 ± 0.025. Logistic regression analysis identified a total area of 26.13 km2 to be suitable for D. littoralis, while a smaller suitable area (7.85 km2) was predicted by Maxent model. Coastal areas in the west part of the island were predicted by both models as areas with high suitability for D. littoralis. Furthermore, distance from coastline and river, elevation, NDVI, NDWI and NDMI were suggested to be very important for the species ecology and distribution. The results of this study may serve as a basis for population reinforcement and reintroduction programs of D. littoralis and guide for ecosystem management of Nusakambangan Island as a whole. </jats:p
Predicting the Impact of Climate Change on the Distribution of Flindersia Pimenteliana F. Muell. in Indonesian Papua and Papua New Guinea
No full textPopulation of Flindersia pimenteliana (Maple Silkwood) in Indonesian Papua and Papua New Guinea is severely fragmented and experiencing a continuing decline due to habitat destruction and illegal logging. This species is very susceptible to environmental changes and at greater risk of extinction due to its small and fragmented geographic ranges and low abundance. Using maximum entropy (MaxEnt) method, the present study predicted the impact of climate change on the distribution of the species across its native distribution area. Elevation and 19 bioclimatic variables commonly used in species distribution modeling were used as predictors. The prediction model of the current potential distribution identified a total area of 156,214 km2 in Indonesian Papua and Papua New Guinea (18% of total land area) as suitable habitat for F. pimenteliana. Elevation and precipitation of the wettest, coldest and warmest quarters contributed most to the model. Based on the average of HadGEM2-ES and MIROC-ESM models, potential distribution projections under RCP8.5 scenario suggested a habitat gain of 16% for 2050 and 8% for 2070 in the species distribution. Whereas under RCP4.5, an average habitat gain of 7% was predicted for both 2050 and 2070. The newly suitable habitats were predicted to be found mainly in Southern and Western Highland of Papua New Guinea. Protection of these areas from habitat destruction and land use change is needed to assist F. pimenteliana find the most suitable climate for its survival
Predicting the impact of climate change on the distribution of flindersia pimenteliana f. Muell. In indonesian papua and papua new guinea
No full textPopulation of Flindersia pimenteliana (Maple Silkwood) in Indonesian Papua and Papua New Guinea is severely fragmented and experiencing a continuing decline due to habitat destruction and illegal logging. This species is very susceptible to environmental changes and at greater risk of extinction due to its small and fragmented geographic ranges and low abundance. Using maximum entropy (MaxEnt) method, the present study predicted the impact of climate change on the distribution of the species across its native distribution area. Elevation and 19 bioclimatic variables commonly used in species distribution modeling were used as predictors. The prediction model of the current potential distribution identified a total area of 156,214 km2 in Indonesian Papua and Papua New Guinea (18% of total land area) as suitable habitat for F. pimenteliana. Elevation and precipitation of the wettest, coldest and warmest quarters contributed most to the model. Based on the average of HadGEM2-ES and MIROC-ESM models, potential distribution projections under RCP8.5 scenario suggested a habitat gain of 16% for 2050 and 8% for 2070 in the species distribution. Whereas under RCP4.5, an average habitat gain of 7% was predicted for both 2050 and 2070. The newly suitable habitats were predicted to be found mainly in Southern and Western Highland of Papua New Guinea. Protection of these areas from habitat destruction and land use change is needed to assist F. pimenteliana find the most suitable climate for its survival
THE USEFULNESS OF ECOLOGICAL NICHE CONCEPTS IN UNDERSTANDING PLANT COMMUNITIES
Get PDFPlant communities have been attracting many scientists due to their complexity and unclear underlying mechanisms that support it. How large numbers of competing plant species manage to coexist, for instance, is one of the major unresolved questions in plant community ecology. Ecological niche concept is a classical theory which tries to address this question. The development of this concept will be presented in this paper. Recent studies, although few in number and incomplete in many ways, do suggest that plants segregate along various environmental niche axes. Although it is unlikely that niche separation along environmental axes is the only mechanism of coexistence in any large community, the evidence now suggests that ecological niche concept plays a more significant role than has been previously appreciated
Characterization Of A New Biotype Moringa Of Saudi Arabia Using Rapd And Issr Markers
No full textMoringa peregrina and M. oleifera are the only Moringa species found in Saudi Arabia. Both species are drought resistant and have very high nutritional and medicinal properties. Detection of genetic diversity is of great value for the improvement of nutritional and medicinal value of these plants. The aim of the present study was to characterize a new biotype Moringa observed in Al Bahah Region, Saudi Arabia. We used 11 RAPD and 15 ISSR primers to characterize and compare the new biotype with M. peregrina and M. oleifera. Level of polymorphism generated by each marker was calculated. We also calculate Nei and Li?s coefficient to measure the genetic distance between the studied species. Level of polymorphism generated by RAPD and ISSR was 46% and 57%, respectively. RAPD and ISSR primers revealed that the new biotype shared 55 amplicons (45.08%) with both M. peregrina and M. oleifera, 28 amplicons with M. peregrina (22.95%), 21 amplicons (17.21%) with M. oleifera, and displayed 18 unshared amplicons (14.75%). Based on RAPD data, genetic distance between M. oleifera and M. peregrina was 0.32, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.21 and 0.29, respectively. For ISSR data, genetic distance between M. oleifera and M. peregrina was 0.5, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.36 and 0.34, respectively. Based on these results we suggested that the new biotype is a hybrid crossbred between M. peregrina and M. oleifera
Assessing the impact of climate change on the distribution of endemic subalpine and alpine plants of New Guinea
No full textPlant species of alpine and subalpine ecosystems in tropical mountains are prone to habitat loss due to future climate
change. In the present study, the impact of climate change on the distribution of five endemic plant species of subalpine and
alpine regions in New Guinea is assessed using Maxent. Models developed for all species had an AUC > 0.9, TSS > 0.7 and
sensitivity, specificity and overall accuracy better than 0.8, indicating high model performance. Current suitable habitats of
the species were predicted to occur mainly along the mountain ranges in the middle of the New Guinea Island, with elevation
and extreme temperature related variables being the most influential factors. Future predictions for these species showed
significant loss of suitable habitats, especially in Papua New Guinea. These results may serve as a basis for planning the
conservation actions needed to conserve the species, especially in addressing potential future climate change
Effect of quadrat shapes on measurement of tree density and basal area: a case study on Scots Pine (Pinus silvestris L.)
Get PDFWhile quadrat shape of 10 x 10m has been commonly used in tree studies, the efficiency of this shape compared to the other shapes of size 100 m2 has not been tested. In this study, effect of various shapes of 100 m2 quadrat on measurement of Scots Pine (Pinus silvestris L.) density and basal area would be assessed. The aim was to assess the effect of quadrat shapes of 10 x 10m, 5 x 20m and 2 x 50m on the estimation of density and basal area of the pine in two woodlands in Norwich and to find the most efficient shape, statistically and with respect to sampling time. The results from all quadrat shapes similarly showed that the density and basal area of the Pines between two woodlands were significantly different. In site with lower pine density, the density and basal area measurement were not affected by variety of quadrat shapes. In site where the density of the Pine was higher, however, mean density and basal area measurement using 2x50m quadrat gave higher value than of the other two shapes. In term of efficiency, all shapes were not significantly different in statistical precision and sampling time. Shape of 5x20m, however, was more preferable as it required fewer samples before the mean of density and basal area always falls inside the 95% confidence interval of whole samples mean
Current Status of the invasive Langkap Palm (Arenga obtusifolia) in Indonesia: Distribution, Impact on Biodiversity and Control Management
Get PDFAs its spread and dominance has negative impacts on diversity, current information on Langkap status in Indonesia is needed in order to control its distribution and protect biodiversity. In the present study, through a comprehensive literature review of published papers and reports, updated information regarding Langkap Palm in Indonesia will be presented. This information includes current distribution of the species, the impact of the species on plant biodiversity, and management approaches used to control the species. The present study found a total of 12 localities in Java and Sumatra Island identified to be the natural habitat distribution of Langkap. The species was known to have dominantly distributed in the half of these localities. To control the distribution of the species, mechanical (trunk cutting) and chemical methods (herbicide application) might be applied.
 
Population status and habitat preferences of critically endangered Dipterocarpus littoralis in West Nusakambangan, Indonesia
Get PDFThe conservation of the endemic tree species Dipterocarpus littoralis (Bl.) Kurz. is hampered by the paucity of information on its population biology and ecology. Consequently, a targeted survey was carried out in the West Nusakambangan Nature Reserve to assess its population size and structure as well as habitat preferences. In total, 676 individuals of D. littoralis were located at 52 locations, with an extent of occurrence of 3.66 km2 and an area of occupancy of 1.71 km2. The population had an inverse-J-shaped distribution of diameter at breast height (DBH), with 63% of individuals in the 0-5 cm class and another 21% in the 5-10 cm class; only 11 (1.6%) mature individuals (DBH≥30) were found. D. littoralis was associated with steep, low, southwest-facing sites and sites that had high litter cover and thickness. Illegal logging and fuel-wood chopping were the main threats to D. littoralis and its habitat. In addition, an invasive shrub, Langkap (Arenga obtusifolia, Arecaceae), was a potential competitor with the seedlings throughout the reserve. In view of its endemism, narrow range and localized distribution, small population, environmental preferences, and the severe threats from anthropogenic activities and invasive species, D. littoralis appears to more than justify its conservation status of Critically Endangered
Morphological Characterization of a New Biotype Moringa of Saudi Arabia
Get PDFDari total 13 spesies Moringa, di Saudi Arabia hanya terdapat dua spesies, yaitu M. peregrina dan M. oleifera. Kedua spesies ini memiliki kandungan nutrisi dan bahan obat yang tinggi serta mampu bertahan pada iklim kering. Biotipe Moringa baru yang berbeda dengan kedua spesies ini telah teramati di daerah Al Bahah, Saudi Arabia. Pada penelitian ini, karakterisasi dari biotipe baru ini telah dilakukan dengan mengamati 22 karakter kualitatif dan kuantitatif dari daun, biji dan bunga. Semua karakter ini kemudian dibandingkan dengan M. peregrina dan M. oleifera untuk mengetahui hubungan biotipe baru dengan kedua spesies. Hasil pengamatan pada karakter kualitatif menunjukan bahwa biotipe baru ini memiliki 8 karakter (tepi anak daun, warna bunga, bentuk kelopak dan mahkota bunga, perlekatan kelopak bunga, warna dan orientasi kepala sari, dan bentuk dasar  bunga) yang sama dengan kedua spesies, satu karakter (distribusi warna merah pada perhiasan bunga) dengan M. peregrina  saja, tiga karakter (tipe susunan anak daun, kulit biji dan sayap biji) dengan M. oleifera saja. Untuk karakter-karakter kuantitatif, hasil pengukuran menunjukan semua karakter pada biotipe baru berada pada posisi antara M. peregrina and M. oleifera. Berdasarkan hasil ini, kami menyimpulkan bahwa biotipe baru dari Moringa ini adalah hibrid hasil persilangan M. peregrina dan M. oleifera.Kata kunci: biotipe, bunga, Moringa peregrina; Moringa oleifera, daun, biji
