Journal of Tropical Biodiversity

Changes in the Home Range of Bornean Orangutans (Pongo pygmaeus wurmbii) Before and After Forest Fires at Tuanan Research Station, Central Kalimantan

Silvia Hasan, Sri Suci Utami Atmoko — Mon, 01 Dec 2025 10:48:57 +0700

The Bornean orangutan (Pongo pygmaeus wurmbii), an endangered species native to the tropical forests of Borneo, plays a crucial role in the ecosystem as a keystone species and seed disperser. However, habitat degradation, particularly from forest fires, poses a significant threat to their survival. This study investigates the impact of forest fires on the home ranges of Bornean orangutans at the Tuanan Orangutan Research Station (TORS), Central Kalimantan, Indonesia. Data were collected before and after the 2019 forest fire, focusing on changes in orangutan movement patterns and their responses to altered fruit availability. The results showed that, following the fire, most observed individuals decreased their home range size, except for the flanged male (Dado) and the adult female (Juni), who expanded their home ranges. The forest fire led to a significant reduction in fruit tree productivity, which was reflected in the fluctuating fruit availability index (FAI). Additionally, smoke from the fire disrupted pollination, further impacting fruit production and orangutan foraging behavior. Kernel Density Estimator (KDE) analysis revealed changes in the movement paths and home-range sizes of the orangutans before and after the fire. These findings highlight the adaptability of orangutans to habitat changes induced by fire, and the importance of understanding how fire-related environmental changes affect orangutan survival and behavior. The study underscores the need for practical conservation efforts to mitigate the effects of habitat degradation and maintain food resources for orangutans in post-fire landscapes.

Condition of Seagrass at Prawean Beach, Jepara, Based on the Seagrass Ecological Quality Index (SEQI)

Endang S. Wahyuni, Edy Yuwono , Sri Handayani — Mon, 01 Dec 2025 11:31:29 +0700

This study aims to investigate the bioecology of seagrass at Prawean Beach, Jepara, through analysis of species composition, the Seagrass Ecological Quality Index (SEQI), environmental water parameters, as well as the connection between environmental variables and seagrass cover. Data collection was carried out in September at two stations using the method transect-quadratic, while the physical-chemical parameters water were measured in situ and analyzed in a way statistically. Research results show that Thalassia hemprichii is the dominant species with the highest coverage in all point observations, while Enhalus acoroides, Cymodocea rotundata, and Halodule uninervis have lower cover more low. The SEQI value is in the range of 45–50% which indicates a quality ecosystem in category medium. Analysis Spearman correlation reveals that brightness influential significant to cover seagrass (r = 0.82; p = 0.048), whereas salinity, temperature, DO, pH, nitrate, and phosphate show no significant connection. Findings This indicates that disturbance of the physical coast potential becomes factor main influencing factor health field of seagrass at Prawean Beach.

Wild Cats Diversity and Activity Patterns in Bukit Baka Bukit Raya National Park, Kalimantan, Indonesia

Mon, 01 Dec 2025 11:58:03 +0700

Kalimantan is home to five species of wild cats, but scientific information about them is still limited. This study aims to examine the biodiversity, spatial distribution, relative abundance, activity patterns, and occupancy rate of wild cats in the Belaban Resort, Bukit Baka Bukit Raya National Park (BBBR NP). Data collection was conducted from March 2024 to August 2025 at 25 camera trap (CT) stations, which were operated for a total 6.756 trap-nights. The analysis includes calculation of the relative abundance index, occupancy, distribution, and activity patterns. A total 45 independent events of wild cats from three species were recorded, namely the sunda clouded leopard, leopard cat and marbled cat. The leopard cat has the highest relative abundance (5,01 events per 100 trap-nights). The sunda clouded leopard showed the highest occupancy probability (ψ = 0,794), while the marbled cat had the lowest abundance and occupancy. The spatial distribution showed that 60% of the camera stations recorded at least one species of wild cat, with two stations at elevation of 520-762 meters above the sea level recording to the highest detections, in line with the high presence of potential prey. There findings underscore the importance of maintaining forest cover, increasing area patrols, and involving the community in controlling hunting and encroachment as part of area management planning. Overall, the results of this study provide a scientific basis for the implementation of adaptive conservation and the strengthening of management strategies to ensure the sustainability of wild cat populations in the Belaban Resort, BBBR NP

External Quality Of Merawangarab Chicken Eggs With Different Genetic Composition

Rafif Nurwansyah, Harini Nurcahya, Ikhsan Matodang, Sri Darwati — Mon, 01 Dec 2025 12:21:21 +0700

Eggs, as a food ingredient, possess complete nutritional value that is beneficial for human health, are readily available, affordable, and popular with the public. Likewise, hatching eggs provide the nutrients needed for the development of chicken embryos. Therefore, eggs for consumption as food and hatching eggs. The external quality of eggs is one indicator of egg quality. Merawang chickens and arab chickens are local Indonesian chickens. Crossbreeding of the two chickens is expected to produce superior offspring in production and egg quality. This study aimed to evaluate the external quality of merawangarab crossbred chicken eggs with different merawangarab genetic compositions (M), namely 25% M, 50% M, 62.5% M, and 75% M with a total of 30 hens. The materials used were eggs from merawangarab crossbred chickens. This study used a randomized block design (RAK) and continued with Tukey's further test. The external quality of eggs observed was shape index, egg weight, shell weight, and shell ratio. Different genetic compositions did not affect the external quality of merawangarab crossbred chicken eggs. Eggs from four crossbred merawangarab chickens were (25% M, 50% M, 62.5% M and 75% M) classified as small

Fish Diversity and Catch Composition of Purse Seine Fisheries Across Multiple Fishing Grounds in Weru Village, Lamongan Regency

M Ainul Labib, Tatang Mitra Setia, Nonon Saribanon — Mon, 01 Dec 2025 12:38:58 +0700

Purse seine fisheries represent an important component of capture fishing activities conducted by local fishers in Weru Village, Lamongan Regency. However, spatial variations in catch composition and fish diversity across different fishing grounds are still poorly documented. This study aims to analyze fish community structure at four purse seine fishing locations through assessments of catch composition and ecological indices. Data were collected during July–August 2025 through direct observations at landing sites by recording the number of individuals for each species. Analytical procedures included the Shannon-Wiener Diversity Index (H’), Pielou’s Evenness Index (E), and Simpson’s Dominance Index (C) to evaluate community differences among locations. The results reveal clear spatial differences in fish community structure. In total, the purse seine fishery recorded 11 fish species with a total of 15,041 individuals across four fishing locations, indicating a marked disparity in catch abundance across the sites. Locations A and B were dominated by Hilsa kelee, with high catch numbers (3,886 and 7,286 individuals), resulting in low diversity (H’ = 0.18 and 0.06) and high dominance (C = 0.94 and 0.98). In contrast, location D demonstrated a more balanced and stable fish community structure, reflected in its notably higher diversity (H’ = 1.29), high evenness (E = 0.66), and low dominance (C = 0.40). These findings offer important baseline insights to support spatially informed management of small pelagic fisheries in the coastal.