No abstract

Urban lakes are important environmental assets that contribute significant ecosystem services in urbanised areas around the world. Consequently, urban lakes are more exposed to anthropogenic pressures. Zooplankton communities play a central role in lake processes and, as such, are very sensitive to the impacts of human activities both through in-lake and catchment processes. Understanding their ecological function in urban lakes and how they respond to urbanisation is essential for environmental sustainability. In this study, we investigated the reliability of zooplankton size structure as indicators of anthropogenic stressors in urban lakes. We examined the relationship between environmental variables and zooplankton community size spectra derived as mean body size, density, and biomass. Our study showed that the overall mean body size was within the small size group ranged from 416 to 735 µm equivalent spherical diameter (ESD). Despite no significant difference in total zooplankton density between lakes, there was variability in the total density of the five different size classes. Total biomass was characterised by a significant proportion of size >750 µm. As the specific parameter of normalised biomass size spectra (NBSS), the slopes of the NBSS varied from moderate (−0.83 to −1.04) for a community with higher biomass of the larger size zooplankton to steeper slopes (from −1.15 to −1.49) for a community with higher biomass of smaller size. The environmental variables, represented by total phosphorus (TP) and chlorophyll a (chl-a), had a strong effect on zooplankton biomass and NBSS, where TP and chl-a were significantly correlated with the increase of total biomass and corresponded well with a less negative slope. Our results indicated that the community metric was sensitive to nutrient input and that size-based metrics have the potential to serve as key indicators for the management of urban lakes.

Situ Cibuntu, is one of urban ponds located in Bogor Regency, West Java. With a maximum surface area of 11 ha and maximum depth of 1,20 m, the pond serves as irrigation for nearby agricultural fields and recreational fishing. Located in relatively high urban pressure, the pond is highly affected by domestic, agricultural and industrial inflow which can influence the biotic community such as benthic macroinvertebrate. We studied benthic invertebrate community structure in Situ Cibuntu from October to November 2018 to determine the role of environmental factors on benthic macroinvertebrates. Samples were collected biweekly from five sampling points using an Ekman sediment grab with three replicates. Our study revealed 16 species of benthic macroinvertebrates belonging to four classes including Gastropoda, Bivalvia, Clitellata, and Insecta. Melanoides tuberculata species was found to have the highest abundance with an average abundance of 858 individuals/m2. Shanon-Wiener Diversity Index shows a relatively low diversity ranged from 0.61 to 1.26, while evenness index ranged from 0.36 to 0,66. Simpson Dominance Index ranged from 0.24 to 0.93.Keywords:DominanceCommunityAbundanceDiversityBenthic MacroinvertebratePond CibuntuABSTRAKSitu Cibuntu merupakan salah satu situ urban (urban pond) yang terletak di Kabupaten Bogor, Provinsi Jawa Barat. Situ Cibuntu yang memiliki luas permukaan 2,11 ha dengan kedalaman maksimum 1,20 m dimanfaatkan sebagai sumber irigasi pertanian dan sarana pemancingan ikan. Situ di kawasan perkotaan dapat mengalami tekanan karena pengaruh limbah domestik, pertanian, dan industri yang dapat mempengaruhi komunitas biotik seperti makroinvertebrata bentik. Penelitian ini bertujuan untuk mengetahui komunitas makroinvertebrata bentik di perairan Situ Cibuntu. Penelitian dilakukan pada bulan Oktober hingga November 2018 di lima stasiun pengamatan. Pengambilan sampel dilakukan sebanyak tiga kali dengan interval waktu dua minggu. Sampel makroinvertebrata bentik diambil dari sedimen pada setiap stasiun dengan menggunakan Ekman grab sebanyak tiga kali ulangan. Secara keseluruhan ditemukan 16 spesies makroinvertebrata bentik yang tergolong ke dalam empat kelas meliputi Gastropoda, Bivalvia, Clitellata, dan Insekta. Spesies Melanoides tuberculata memiliki kelimpahan tertinggi dengan nilai rata-rata sebesar 858 individu/m2. Keanekaragaman makroinvertebrata bentik tergolong rendah hingga sedang dengan nilai indeks Shanon Wiener (H’) berkisar 0,61-1,26. Nilai indeks kemerataan Pielou (E) berkisar 0,36-0,66, sedangkan indeks dominansi Simpson (D) berkisar 0,24-0,93.Katakunci:DominansiKomunitasKelimpahanKeanekaragamanMakroinvertebrata bentikSitu Cibuntu

Study on freshwater ecology have been long focused on subtropical habitats with few references to tropical regions including Indonesia. Zooplankton, in particular, is an important component of aquatic ecosystem as they are key player of aquatic food webs, thus a solid understanding of their community structure can be of direct benefit to freshwater ecosystem management. The spatial patterns of zooplankton diversity in Lake Tondano, Celebes Island – Indonesia were studies in 2013, with the main aim was to understand how local environmental and habitat heterogeneity driving the zooplankton community structure. We performed field samplings to collect zooplankton using a vertical tow with a 156 μm mesh plankton net from 1 meter above sediment to the surface and to measure environmental parameters using portable multi probes water quality checker from three different water columns. The sampling sites were selected to include different habitats within the lake to look at diversity of the entire zooplankton communities including Rotifers, Cladocerans, and Copepods in Lake Tondano, Indonesia. A total of 21 species of cladocerans, 31 copepods, and 60 rotifers were identified from Lake Tondano. Our result indicates a relatively low number of cladocerans which is may be associated with high predatory pressure from planktivorous fish, especially within the open pelagic zone.