Abstract. Muhtadi A, Pulungan A, Nurmaiyah, Fadlhin A, Melati P, Sinaga RZ, Uliya R, Rizki M, Rohim N, Ifanda D, Leidonald R, Wahyuningsih H, Hasani Q. 2020. The dynamics of the plankton community on Lake Siombak, a tropical tidal lake in North Sumatra, Indonesia. Biodiversitas 21: 3707-3719. The tidal lake is a very dynamic estuary ecosystem and very vulnerable to environmental stresses and disturbances. Plankton is an aquatic organism that is very easily affected by environmental pressures and disturbances. This study aimed to reveal the phenomenon of plankton dynamics in tropical tidal lakes in Indonesia. The study was conducted at Siombak Lake from September 2018 to August 2019. Data were collected at high and low tides every month during the full month. The data analysis included plankton abundance, diversity index, and the relationship between water quality and plankton with PCA and succession analysis. The results showed that in Siombak Lake was found 66 genera which consisted of 54 phytoplankton genera and 12 zooplankton genera. Plankton abundance is higher in parts of the lake (stations 1-8) than in the river (stations 9-11) at both high and low tide. Temporally it shows that plankton abundance is higher in the rainy season (Feb-Aug, outside May) than in the rainy season (Sep-Jan, and May). Spatially, plankton in Siombak Lake at high tide is more influenced by TSS, phosphate, and salinity, while at low tide, it is influenced by TSS, Water transparency, BOD, silicate, salinity, and dissolved oxygen. Temporally, plankton in Siombak Lake at high tide is more influenced by salinity, conductivity, Debit, TSS, and salinity, while at low tide, it is influenced by salinity, conductivity, turbidity, TSS, TDS, DO, BOD, and COD. Based on the plankton Frontier succession graph, it shows that Siombak Lake is included in stage 1 and stage 2. Stage 1 occurs before the rainy season (August-September) and the peak of the dry season (March-April).

Laut Tawar Lake is located in Aceh Tengah District is the largest lake in Aceh Province. The lake, located at an altitude of 1230 meters above sea level, produces about 13 species of freshwater fish. Fish depik (Rasbora tawarensis), eyas (Rasbora sp.), and relo (Rasbora sp.) are endemic species of Laut Tawar Lake. This study aims to estimate the potential of fish production based on the value of morphoedaphic index. The observation was conducted for one year, from October 2016 until September 2017. The measurement of electric conductivity value of lake waters was conducted on 7 (seven) stations selected purposively in the lake area about 5870 hectares. The results showed that morphoedaphic index value of Laut Tawar Lake ranged from 5.10 to 7.84 with an average of 6.14. Potential of fish production in the lake is 33.47 kg/ha/yr with total potential of fish production of 196.49 ton/yr. The value shows a decrease of 10.93 kg/ha/yr over a period of 22 years. This decrease is caused by changes in morphometry parameters and water quality of Laut Tawar Lake.

Abstract. Sahputra E, Harahap RH, Wahyuningsih H, Utomo B. 2021. Assessing the sustainability status of mangrove forest ecosystem management by coastal community in Jaring Halus Village, North Sumatra, Indonesia. Biodiversitas 22: 1-9. Mangrove forest ecosystems provide various important ecological (physical and protection) and economic services. Mangrove forest needs to be sustainably managed to ensure their functions and benefits are available in perpetuity. Still, issues regarding sustainable management of mangrove forests are rarely discussed, especially in Indonesia. This research aims: (i) to gain the fundamental understanding of the level of sustainable mangrove management by determining indicator attributes that can be categorized as leverage factors; ii) obtain the perceptions of coastal communities in mangrove forest management; and iii) investigate the compliance of coastal communities in mangrove forest management. Data were obtained through a series of interviews, field observation and focused group discussion (FGD) and questionnaires conducted from January 2018 to March 2019 in Jaring Halus Village, Secanggang Subdistrict, Langkat District, North Sumatra, Indonesia. Data were analyzed using multidimensional scaling (MDS). The results showed that the status of mangrove forest management in Jaring Halus Village was categorized as moderately sustainable with a score of 65.83%. The majority of the coastal community (96% of respondents) perceived and understood the value of protecting the mangrove ecosystem, which provided physical (ecological), economic, and social functions. The community's understanding and knowledge of the importance of mangrove forests is due to the high level of dependency on their main livelihood as fishermen. Around 97% of the respondents held strong obedience to the mangrove forest management in Jaring Halus Village, which could be attributed to local wisdom related to natural resource management.

No abstract

No abstract

No abstract

Abstract. Wahyuningsih H, Sinaga SMS, Hartanto A. 2022. Ichthyofauna diversity in Pematang Matik Coastal Waters, Serdang Bedagai District, North Sumatra. Biodiversitas 23: 4992-5000. Pematang Matik Coastal waters are coastal areas that have a major role in the life of various fish species. Research on fish diversity in coastal waters is very important in order to gain a better understanding on the fish diversity in coastal areas such as North Sumatra, including Indonesia. The objective of this study was to initiate an inventory of fish species, their abundance and assessment of its biodiversity based on Shannon's diversity index (H'), and evenness index (E) in Pematang Matik coastal waters. The research was conducted from September to October 2021 at four stations with different human activities by the coastal community. Fish samples were taken using fishing nets that were installed for 12 hr with two replications. In this study, 21 species of fish from 19 families were identified. The highest abundance of fish was obtained from the Mugilidae family, namely Crenimugil crenilabis and Liza macrolepis. The fish diversity index obtained was 2.19-2.95, while the uniformity index obtained was 0.719-0.968. The values ??of H' and E at Station 4 (absent from any human interferences) have higher values ??than the other three stations. The diversity, as expressed in H' value in four research stations, indicates that the coastline has a high diversity of fish species.

ABSTRACKThe purpouse to analyze (1) The influence of policy factors (2) The influence of curriculum factor (3) The influence of factors of participation (4) The influence of facilities management factor .Determination of the number of samples using Slovin technique so as to obtain the number of samples of 92. The results showed it can be concluded that simultaneous effect of environmentally sound policy variable, the implementation of environmentbased curriculum and management of supporting facilities towards the realization of Adiwiyata Mandiri School at SMA Negeri 1 Sunggal Sunggal Subdistrict. (4) SMA Negeri 1 Sunggal does not have Adiwiyata Mandiri standard because the implementation of curriculum and policy has not been consistent and continuous. ABSTRAKTujuan untuk menganalisis (1) Pengaruh faktor kebijakan (2) Pengaruh faktor kurikulum (3) Pengaruh faktor partisipasi (4) Pengaruh faktor manajemen fasilitas. Penentuan jumlah sampel menggunakan teknik Slovin sehingga diperoleh jumlah sampel sebesar 92. Hasil penelitian menunjukkan dapat disimpulkan bahwa secara simultan pengaruh variabel kebijakan berwawasan lingkungan, penerapan kurikulum berbasis lingkungan dan manajemen fasilitas pendukung terhadap realisasi Sekolah Adiwiyata Mandiri di SMA Negeri 1 Sunggal Sunggal. (4) SMA Negeri 1 Sunggal tidak memiliki standar Adiwiyata Mandiri karena penerapan kurikulum dan kebijakan belum konsisten dan berkesinambungan.