Journal of Tropical Biodiversity

The Effect of Food Tree Abudance in the Home Range of Adolescent Sumatran Orangutans (Pongo abelii) in Suaq Balimbing, Gunung Leuser, National Park, South Aceh

2026-03-30T20:32:11+07:00

Ranging behavior plays a key role in the spatial and social strategies of Sumatran orangutans (Pongo abelii), a species characterized by fission-fusion dynamics and female philopatry. This study aims to analyze the relatedness between home range size and overlap levels with the utilization of food tree abundance in adolescent orangutans with differences in maternal relatedness and sex. This study uses long-term data from 2021–2024 at the Suaq Balimbing Research Station, Gunung Leuser National Park, South Aceh. Home range data were obtained using GPS, while food tree abundance was analyzed using Kriging interpolation. Home ranges were estimated using Kernel Density Estimator with a dyadic overlap approach. Statistical analysis was conducted using Generalized Linear Models to test the influence of home range size on overlap levels with related and unrelated individuals and food tree abundance. The results showed that home range overlap levels were influenced relatedness, with higher overlap is mother-offspring compared to other individuals. Adolescent orangutans will broader their space utilization in areas with low to moderate abundance of food trees. Sex and relatedness factors were more dominant in shaping adolescent ranging patterns compared to food trees. These findings indicate that the space use strategy of adolescent orangutans is not only determined by ecological factors, but also by sex and relatedness, which are more dominant in shaping adolescent ranging patterns.

Effect of Nano Biofertilizer with Spirulina platensis on Vegetative Growth and Nutrient Solution Stability in Floating Raft Hydroponic System of Vegetable Crops

2026-03-30T21:05:02+07:00

This study aimed to evaluate the effect of nano biofertilizer derived from Spirulina platensis on the vegetative growth of mustard greens (Brassica juncea) and the stability of nutrient solution in a floating raft hydroponic system. The treatments included 100% AB mix solution as control, 100% Spirulina nano solution, and a combination of AB mix + Spirulina nano. The nano biofertilizer was formulated in two particle sizes, namely F1 (±165 nm) and F5 (±380 nm), each tested in combination with nutrient solutions to assess their effectiveness on plant growth and solution stability. Vegetative growth parameters observed were plant height, leaf number, leaf width, leaf length, and chlorophyll content. Solution stability was evaluated through measurements of pH, Electrical Conductivity (EC), and Total Dissolved Solids (TDS/PPM). The experiment was arranged in a randomized block design (RBD) with five treatments and four replications, he results showed that the combination treatment of 50% AB mix + 50% Spirulina nano (particle size F5) produced the best vegetative growth, with plant height reaching ±31 cm at the 6th week, greater leaf number, and higher chlorophyll content compared to other treatments. The 100% Spirulina nano treatment supported plant growth, but the results were still below those of AB mix. Analysis of pH, EC, and PPM indicated that Spirulina nano contributed to maintaining solution stability within the optimal range for hydroponics (pH 5.5–6.5; EC 500–1000 µS/cm). Spirulina nano has potential as an environmentally friendly alternative biofertilizer, either as a partial substitute or as a supplement to hydroponic nutrients, particularly when formulated in appropriate nano particle sizes (F1 and F5) to enhance nutrient absorption efficiency and stability of the floating raft hydroponic system

Density Figure of Aedes aegypti Larvae in the Laboratory Center of Universitas Nasional and Its Surrounding Residences

2026-03-30T21:28:29+07:00

Dengue remains a public health problem in Indonesia, caused by dengue virus with Aedes aegypti as the primary vector. Vector control requires data on larval density as an indicator of transmission risk. This study aimed to calculate the larval density of Ae. aegypti at the Laboratory Center of Universitas Nasional (UNAS) and its surrounding residences, and to describe the location and types of water-holding containers that potentially serve as mosquito breeding sites. The study was conducted from May to August 2025 using a descriptive observational approach. A total of 100 houses (premises) and 287 water-holding containers were inspected to calculate the House Index (HI), Container Index (CI), Breteau Index (BI), Density Figure (DF), and Larvae-Free Index (ABJ). The results showed HI = 38%, CI = 21%, BI = 59, DF = 6, and ABJ = 62%, indicating high larval density and a potential risk of dengue transmission. Most positive water-holding containers were found outdoors, and the most common container type identified was bucket. These findings suggest that environmental conditions still support mosquito breeding. It is recommended that the community routinely implement mosquito breeding site eradication activities based on the 3M-Plus principle (Menguras: draining and scrubbing containers; Menutup: tightly covering containers; Mendaur ulang: reusing or recycling discarded items; plus: additional preventive measures), that larval monitoring cadres (JUMANTIK) expand the coverage of larval surveillance, and that future research broaden its scope and methodology to obtain a more comprehensive understanding

Tree Stand Structure of Surili (Presbytis comata) Habitat in the Abi-Karna Forest Block, Tea and Cinchona Research Center, Gambung, Bandung Regency, West Java

2026-03-30T21:54:16+07:00

Primates play a crucial role in forest conservation through seed dispersal from the fruits they consume. Factors influencing primate presence in their habitat include food availability, the presence of predators, and human activity. This study aimed to analyses the tree stand structure of the surili habitat in the Abi-Karna Forest Block, PPTK-Gambung, Pasir Jambu, West Java. The study was conducted over three days, from May 2-4, 2024, using the line transect method. Parameters measured included the number of trees, tree height (h), stem diameter (cm), crown thickness, crown curvature, and crown width diameter. Data analysis included relative density index, dominance, and tree species diversity. The results showed differences in tree stand structure between the western and eastern zones of the Abi-Karna Forest. The western zone had a higher tree species diversity than the eastern zone, with 2,022 and 1,612, respectively. The dominant tree species in both zones were Rasamala and Puspa. Tree heights in the western and eastern zones were 16-20 m, while tree DBH was 10-30 cm. The dense forest canopy plays acrucial role in providing primary food sources and maintaining ecosystem health. The dense canopy cover in the western zone is more conducive to surili activity than in the eastern zone. The tree stands in the Abi-Karna Forest provide food sources, shelter, and movement routes for surili (Presbytis comata) and other primates, such as the Javan langur (Trachypithecus mauritius), found in the area

Javan Primates’ Abundance and Distribution In The Mekarbuana and Sukasari, Mount Sanggabuana, West Java

2026-03-30T22:15:38+07:00

Mount Sanggabuana is a limited production forest area with potential primate diversity in West Java. This study aims to determine the distribution and abundance of primates in the Mekarbuana area, Karawang, and Sukasari area, Purwakarta. The study was conducted in October-November 2024 in Mekarbuana and September 2025 in Sukasari using the Recce method, with a total of eight observation routes. Data collected included the number of individuals, groups, coordinate positions, and primate activity. The encounter rate was calculated as the number of individuals or groups per kilometer of route. The results showed that in Mekarbuana, 4 primate species were recorded, namely Trachypithecus mauritius with an abundance of 7.47 ind/km and a relative abundance of 67%, Presbytis comata with an abundance of 2.36 ind/km and a relative abundance of 21%, Hylobates moloch with an abundance of 0.98 ind/km and a relative abundance of 9%, and nocturnal primate Nycticebus javanicus with an abundance of 0.39 ind/km and a relative abundance of 4%. In Sukasari area, 3 species were recorded, namely Trachypithecus mauritius with an abundance of 2.75 ind/km and a relative abundance of 89%, Hylobates moloch with an abundance of 0.23 ind/km and a relative abundance of 5%, and Nycticebus javanicus with an abundance of 0.23 ind/km and a relative abundance of 6%. Trachypithecus mauritius was the dominant species in both locations. Differences in primate abundance in both locations were influenced by food availability, vegetation structure, and the level of habitat disturbance. This research provides baseline data for primate conservation management on Mount Sanggabuana.