Home range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before. The first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km² in a non-fragmented forest and 600 km² in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another. Home range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans.

Total aboveground carbon (TAC) and total soil carbon stock in the agroforestry system at the Balung River Plantation, Sabah, Malaysia were investigated to scientifically support the sustaining of natural forest for mitigating global warming via reducing carbon in the atmosphere. Agroforestry, monoculture, and natural tropical forests were investigated to calculate the carbon stock and sequestration based on three different combinations of oil palm and agarwood in agroforestry systems from 2014 to 2018. These combinations were oil palm (27 years) and agarwood (seven years), oil palm (20 years) and agarwood (seven years), and oil palm (17 years) and agarwood (five years). Monoculture oil palm (16 years), oil palm (six years), and natural tropical forest were set as the control. Three randomly selected plots for agroforestry and monoculture plantation were 0.25 ha (50 × 50 m), respectively, whereas for the natural tropical forest it was 0.09 ha (30 × 30 m). A nondestructive sampling method followed by the allometric equation determined the standing biomass. Organic and shrub layers collected in a square frame (1 × 1 m) were analyzed using the CHN628 series (LECO Corp., MI, USA) for carbon content. Soil bulk density of randomly selected points within the three different layers, that is, 0 to 5, 5 to 10, and 10 to 30 cm were used to determine the total ecosystem carbon (TEC) stock in each agroforestry system which was 79.13, 85.40, and 78.28 Mg C ha⁻¹, respectively. The TEC in the monoculture oil palm was 76.44 and 60.30 Mg C ha⁻¹, whereas natural tropical forest had the highest TEC of 287.29 Mg C ha⁻¹. The forest stand had the highest TEC capacity as compared with the agroforestry and monoculture systems. The impact of planting systems on the TEC showed a statistically significant difference at a 95% confidence interval for the various carbon pools among the agroforestry, monoculture, and natural tropical forests. Therefore, the forest must be sustained because of its higher capacity to store carbon in mitigating global warming.

Estimation of biomass of a mountainous tropical forest using satellite data is an alternative approach to extensive field surveys. However, sampling of the biomass can be expensive, time-consuming, and difficult depending on the nature of field conditions. Instead of directly estimating the biomass from the satellite data when the sample size is small, it is intended to estimate the biomass of the mountainous tropical forest in Kinabalu Park, Sabah, Malaysia, using the well-established biophysical relationship between crown diameter and biomass. Landsat thematic mapper (TM) data are corrected for geometric distortion and are georeferenced to facilitate satellite data extraction. Path radiance for atmospheric correction is derived using the histogram method, and the Minnaert correction approach is employed to correct for topographic effects. Correlation and regression analyses are carried out with the six original bands and several derived satellite variables (several vegetation indices, tasseled cap trans... L'estimation de la biomasse d'une forêt tropicale montagneuse à l'aide de données satellitaires constitue une approche alternative à l'approche basée sur des campagnes intensives de relevés de terrain. Toutefois, l'échantillonnage de la biomasse peut être handicapé par des contraintes de coûts et de temps et en raison des difficultés imposées par les conditions de terrain. Au lieu d'estimer directement la biomasse à partir des données satellitaires lorsque l'échantillon est petit, l'étude consiste à estimer la biomasse de la forêt tropicale montagneuse située dans la région de Kinabalu Park, Sabah, en Malaysie, en se basant sur la relation biophysique bien établie entre le diamètre de la couronne et la biomasse. Les données Landsat TM sont corrigées pour les distorsions géométriques et géo-référencées pour faciliter l'extraction des données satellitaires. La radiance de parcours utilisée pour la correction atmosphérique est dérivée à l'aide de la méthode par histogramme. L'approche de correction Minnaert ...