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All Journal Vivabio : Jurnal Pengabdian Multidisiplin Journal of Comprehensive Science Indonesian Biodiversity Journal Quagga: Jurnal Pendidikan dan Biologi Indonesian Biodiversity Journal Bioeksperimen Advances in Tropical Biodiversity and Environmental Sciences
Djarang, Rievo H
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Waterbirds as bioindicators of ecosystem health: seasonal dynamics in Tondano Lake, Indonesia Djarang, Rievo; Harindah, Gerry; Suriani, Ni Wayan; Taulu, Marthy Lingkan Stella
Bioeksperimen: Jurnal Penelitian Biologi March 2026
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/bioeksperimen.v12i1.15450

Abstract

Waterbird diversity in Tondano Lake reflects ecological degradation caused by water-hyacinth invasion and sedimentation. This study analyzed the diversity and abundance of waterbirds in Tondano Lake, Indonesia, across wet (February-May) and dry (June-October) seasons in 2025 to assess their role as bioindicators of ecosystem health. Multi-season observations were carried out monthly along a 6.5 km transect at ten strategic points. Eight waterbird species from three families were recorded, with Egretta garzetta being the most abundant (29.1%) and Alcedo atthis the least (4.8%). The Shannon-Wiener diversity index (H' = 1.92) indicates a moderate level of species diversity, which reflects a pattern of ecological simplification when compared to pristine tropical lakes such as Lake Sentarum (H' = 2.5). Waterbird abundance showed significant negative correlations with water hyacinth density (r = -0.68, p = 0.032) and water depth (r = -0.72, p = 0.019), revealing that invasive vegetation and shoaling are primary drivers of habitat loss. These findings demonstrate that waterbirds function as sensitive bioindicators of ecological stress, highlighting the urgent need for integrated watershed management to prevent further community collapse.
The Role of Riparian Vegetation in Pollutant Filtration and Sediment Stabilization in Lake Tondano, Indonesia Wiesye Nangoy; Gerry Harindah; Rievo Djarang; Utari Satiman
Quagga: Jurnal Pendidikan dan Biologi Vol 18 No 2 (2026): QUAGGA : Jurnal Pendidikan dan Biologi
Publisher : Program Studi Pendidikan Biologi, Fakultas Keguruan dan Ilmu Pendidikan, Universitas Kuningan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25134/quagga.v18i2.527

Abstract

Riparian vegetation plays a crucial role in maintaining aquatic ecosystem stability by acting as a natural buffer against anthropogenic pollution and erosion. This study analyzed the composition, structure, and ecological functions of riparian vegetation in Lake Tondano, North Sulawesi, Indonesia, with emphasis on pollutant filtration and sediment stabilization. Field surveys were conducted from May to August 2025 at ten riparian stations surrounding Lake Tondano (4,638 ha). Vegetation sampling used a stratified line transect method with fifty plots of varying sizes according to vegetation strata. Quantitative analysis included relative abundance, frequency, dominance, Importance Value Index (IVI), and the Shannon–Wiener diversity index (H’). Ecological functions were assessed through correlations between vegetation structure and reported nutrient and sediment reduction efficiencies from tropical riparian studies. A total of fifteen dominant riparian species were identified, mainly from the families Poaceae and Cyperaceae. Cyperus papyrus (IVI = 21.81%) and Metroxylon sagu (IVI = 29.65%) functioned as key ecological species, while Ficus septica showed the highest IVI (90.83%), indicating strong structural dominance. The Shannon–Wiener diversity index (H’ = 2.65) reflects moderate to high diversity. Riparian vegetation was estimated to reduce nutrient loads by 40–60% and erosion by 30–50%, highlighting its importance for ecosystem-based lake management.
The Effect of Glycerol on the Production of Environmentally Friendly Bioplastics From Cassava Peel (Manihot Esculenta) and Corn Cobs (Zea Mays) Merliana Christmas Turangan; Helen Joan Lawalata; Utari Satiman; Rievo Handry Djarang
Journal of Comprehensive Science Vol. 5 No. 2 (2026): Journal of Comprehensive Science
Publisher : Green Publisher Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59188/jcs.v5i2.4009

Abstract

Conventional plastics made from synthetic polymers have a low biodegradation rate, which contributes greatly to environmental pollution. The use of agricultural waste such as cassava husks (Manihot esculenta) and corn cobs (Zea mays) as bioplastic raw materials is one of the alternatives for the development of environmentally friendly materials. This study aims to determine the effect of variations in the amount of glycerol and the length of decomposition time on the biodegradability of bioplastics made from cassava husks and corn cobs. The study used an experimental method with a Two-Way Factorial Design, covering three concentrations of glycerol (0 mL, 15 mL, and 30 mL) and three decomposition times (3, 6, and 9 days). The results showed that the treatment without glycerol (0 mL) did not form bioplastics so it could not be analyzed. The data was tested using Two Way ANOVA. The results of the biodegradability test showed that the glycerol concentration had a significant effect, and the 30 mL formulation resulted in the highest degradation rate of 91.026% on day 9.
Co-Authors Anita Costanci Christine Tengker Christny Ferdina Evie Rompas Debby Jacqualine Jochebed Rayer Desire Atna Sridanty Rumondor Emma M Moko Gerry Harindah Harindah, Gerry Helen Joan Lawalata IRIANI SETYAWATI Jacklin Stella Salome Manoppo Jantje Ngangi Latip, Irwan Livana Dethris Rawung Marthy L S Taulu Meity Nelltje Tanor Merliana Christmas Turangan Michellia Pamela Sanggor Mokosuli Yermia Samuel Ni Wayan Suriani Nofia Poluan Nonny Manampiring Nova L.I.M Ogi Patandean, Selvrining Patricia Mardiana Silangen Rampengan, Mercy Maggy Franky Rosenta Sipayung Sakul, Ernest Hanny Sakul, Zefanya Escriva Rafael Stanny Sicilia Rawung Utari Satiman Wiesye Nangoy YOSUA LINU