Rapid and widespread biodiversity losses around the world make it important to survey and monitor endangered species, especially in biodiversity hotspots. Bukit Barisan Selatan National Park (BBSNP) is one of the largest conserved areas on the island of Sumatra, and is important for the conservation of many threatened species. Sumatran tigers (Panthera tigris sumatrae) are critically endangered and serve as an umbrella species for conservation, but may also affect the activity and distribution of other carnivores. We deployed camera traps for 8 years in an area of Bukit Barisan Selatan National Park (BBSNP) with little human activity to document the local terrestrial mammal community and investigate tiger spatial and temporal overlap with other carnivore species. We detected 39 mammal species including Sumatran tiger and several other threatened mammals. Annual species richness averaged 21.5 (range 19–24) mammals, and remained stable over time. The mammal order significantly affected annual detection of species and the number of cameras where a species was detected, while species conservation status did not. Tigers exhibited a diurnal activity pattern, and had the highest temporal overlap with marbled cats (Pardofelis marmorata), dholes (Cuon alpinus), and Malayan sun bears (Helarctos malayanus), but little overlap with other carnivores. These findings suggest that some smaller carnivores might be adjusting temporal activity to avoid tigers or mesocarnivores. The stable trends in richness of terrestrial mammal species show that BBSNP remains an important hotspot for the conservation of biodiversity.

Birds have an important role in controlling natural ecosystems. The presence of hunting traces every year indicates hunting at the Way Canguk Research Station. If this happens continuously, it can cause a decrease in the diversity and population of chirping birds. Therefore, this research needs to be carried out to determine the diversity, evenness, richness, relative density, as well as environmental factors that affect the chirping bird community, and the intensity of bird hunting in SPWC. The research was conducted at the Way Canguk Research Station, Bukit Barisan Selatan National Park, using the point count method.

In Southeast Asian dipterocarp forests, a general flowering (GF) occurs at the multiannual interval. At this phenomenon, at least 40% of the trees in the stands flower in synchrony, dominated by the flowering of the Dipterocarpaceae family that hypothesized to be caused by changes in climate factors, especially ENSO. This study aimed to determine the pattern of flowering trees in Bukit Barisan Selatan National Park (BBSNP) and to determine a model for predicting flowering patterns associated with climatic factors in 2021-2050. Flowers and fruits were observed every month from February 1998 to September 2020 at Way Canguk Research Station, BBSNP. The climatic factors used were temperature, rainfall, humidity, wind speed, and the ENSO index. We used a generalized linear model to link climatic factors and flowering and model future flowering. The results showed no GF in BBSNP because the highest flower synchronization only reached 37.8%. The climatic factor with the highest coefficient was ENSO, but flowering was mostly influenced by fluctuations in climate factors, not its absolute value. The model estimated that the flowering in 2021 - 2050 will peak to 34.4% in December 2044 and further ensure good forest regeneration. Thus, BBSNP can still be suitable for conservation purposes.

Abstract. Adyn MF, Sibarani MC, Utoyo L, Surya RA, Sedayu A. 2022. Role of siamang (Symphalangus syndactylus) as seed dispersal agent in a Sumatran lowland tropical forest. Biodiversitas 23: 2101-2110. Seed dispersal is mutualistic interaction between angiosperms and dispersal agents. One of the important dispersers for lowland tropical forests, including in Bukit Barisan Selatan National Park (BBSNP), is siamang (Symphalangus syndactylus Raffles, 1821). This study aimed to determine the seed dispersal pattern, composition of dispersed seeds, and the seed fate dispersed by siamangs at Way Canguk Research Station, BBSNP, Lampung, Indonesia, from February-April 2021. We used the continuous focal sampling method to observe siamang behavior, while the purposive sampling method collected feces and seeds. Siamangs dispersed endozoochory dominantly, all fecal contained seeds, deposited more in the morning, and more scattered than clumped. With a gut passage time of 22.5 ± 3 hours, the seed dispersal distance was 223.9 ± 142 meters from the parents. Seeds < 3 mm were more numerous, but seeds > 3 mm were dispersed more often. Siamang was recorded to disperse a mean of 3.3 ± 1.4 species/feces, and 22 species were dispersed. The germination test showed that only 28% of total planted seeds successfully germinated. Based on in situ monitoring, the remaining deposit sites only accounted for 12% of total records, while the germination rate of dispersed seeds from these deposit sites varied. Further studies are needed with a larger sample to test the consistency of these findings.

Abstract. Fitriansyah RA, Setiawan A, Rustiati EL, Utoyo L, Sibarani MC. 2022. Spatial distribution and temporal patterns of food tree availability of hornbills (Bucerotidae) at Way Canguk Research Station, Bukit Barisan Selatan National Park, Indonesia. Biodiversitas 23: 1990-1997. The presence of hornbills in an area is associated with food availability. As more food sources become available, the hornbill population in the area may increase. The purpose of this research was to determine the spatial distribution of hornbill food trees and to determine the long-term temporal fruiting pattern of hornbill food trees at Way Canguk Research Station (WCRS), Bukit Barisan Selatan National Park, Indonesia. We surveyed vegetation plots across the research station to assess the spatial distribution and analyzed long-term phenology survey data of the research station that have been collected from February 1998 to December 2020. We recorded 64 species of hornbill food trees with a total of 911 individuals in 197 of 200 survey plots. The temporal fruiting pattern of hornbill food trees during the last 22 years was relatively stable, with an average of fruiting tree percentage of 10.4% (SD: 3.2%, N: 260 months). The highest percentage of fruiting food trees occurred in September 2008, which amounted to 18.3% and the lowest percentage occurred in September 1998 with a percentage of 2.2%.