Assessment of Corbicula moltkiana Growth by Different Methods on Variation of Substrates in Lake Maninjau, West Sumatera, Indonesia

Corbicula moltkiana is a mussel species in Lake Maninjau and one of the targeted fisheries resources in the lake. This study aimed to determine the feasibility of a controlled growth experiment of mollusk biota in describing their natural growth. The assessment was carried out in areas with different habitats in shore lake, namely sand and gravel-stone substrates. A consecutive 12 month- sampling was carried out from June 2013 to May 2104 using a Surber sampler at a 1-3 m depth were used to assess the wild population growth. Moreover, the growth of the controlled population was observed by rearing various sizes of mussels in artificial substrate namely three small baskets which installed in the shore area with 1-3 m depth at each station for four months. Monthly sampling was carried out to measure the shell length. The growth of C. moltkiana on wild population by VBGF methods show that at the gravel-stone substrate was higher, but the growth a controlled population in artificial substrate seemed in the sand substrate was higher than that in the gravel-stone substrate. The growth of aquatic biota in a controlled system (especially C. moltkiana) does not always reflect similar conditions to their wild growth.

Alpha and beta diversities of Trichoptera (Insecta) assemblages in natural and rural subtropical streams

Aim The aim of this study was to determine the diversity of Trichoptera in subtropical streams and the effects of environmental variables and geographical position on alpha and beta diversity in natural and rural streams. Methods We collected Trichoptera with a Surber sampler in 12 small order subtropical streams (six streams with apparent absence of anthropic disturbance and six streams with rural activity in their drainage areas) and measured limnological variables. We evaluated the effects of environmental variability and geographical distance on the dissimilarity of the assemblage and calculated the contribution of alpha and beta diversity for each stream. Results We collected a total of 1,264 Trichoptera larvae distributed in 17 genera and 11 families. The genera Phylloicus and Smicridea were found in almost all streams. We observed a positive effect of environmental variability on biological variability but not of geographical distance. The environmental variability was basically generated by the influence of higher concentrations of dissolved organic carbon and nutrients. We observed the greatest contribution of the alpha diversity of the Trichoptera assemblages in natural streams and of beta diversity in the rural streams. Conclusions Our results demonstrate that the variability of Trichoptera is affected by environmental characteristics, but not by geographical position.

Effectiveness of protected areas for the conservation of aquatic invertebrates: a study-case in southern Brazil

Aim This work aimed to analyze the effectiveness of protected areas (PA) as maintainers of the fauna of benthic macroinvertebrates and the use of these in the water management of these areas. We tested the hypothesis that in streams located within the PA there will be greater abundance and diversity of organisms. Methods We collected macroinvertebrates in streams located inside and outside two PA in Southern Brazil: (Fritz Plaumann State Park, Santa Catarina, Teixeira Soares Municipal Natural Park, Rio Grande do Sul). In each stream we measured physical and chemical variables of the water. Three sub-samples of macroinvertebrates were collected on stony substrate with a Surber sampler and calculated abundance of organisms, rarefied richness, Shannon diversity and Evenness. Results The streams located in the interior of the PA presented well oxygenated waters and slightly basic pH. The electrical conductivity was higher in the external sections than the UC. We observed that rarefied richness, Shannon diversity and equitability were higher in the streams located inside the PA. PerMANOVA indicates that the composition was different between streams sections (p = 0.03) and PA (p = 0.01). Conclusions The use of organisms as bioindicators showed a potential response to the environmental integrity of streams. Thus, these organisms have potential for use by PA managers for monitoring and decision making on the maintenance of protected areas.

DENSITY AND DIVERSITY OF AQUATIC MITES IN A SPRING FED STREAM OF GARHWAL HIMALAYA, INDIA

Hydrachnidia, commonly called water mites are an important and diverse group of benthic insects which is usually neglected by the aquatic biologists in their routine biodiversity duties. Present study is an attempt to investigate the dynamics and diversity of water mites from a freshwater stream Randi Gad from Pauri Garhwal which is a lower order stream of river Alaknanda. Mites were collected using a square framed Surber Sampler of 1m2 of the stream bed. Samples were preserved and brought to laboratory for further study. A total of fourteen species from five families were observed with a maximum density of 138 mites.m-2 in the month of January. Coefficient of similarity and Shannon wiener diversity index was calculated for diversity and cluster analytical study.

DENSITY AND DIVERSITY OF AQUATIC MITES IN A SPRING FED STREAM OF GARHWAL HIMALAYA, INDIA

Hydrachnidia, commonly called water mites are an important and diverse group of benthic insects which is usually neglected by the aquatic biologists in their routine biodiversity duties. Present study is an attempt to investigate the dynamics and diversity of water mites from a freshwater stream Randi Gad from Pauri Garhwal which is a lower order stream of river Alaknanda. Mites were collected using a square framed Surber Sampler of 1m2 of the stream bed. Samples were preserved and brought to laboratory for further study. A total of fourteen species from five families were observed with a maximum density of 138 mites.m-2 in the month of January. Coefficient of similarity and Shannon wiener diversity index was calculated for diversity and cluster analytical study.

Advances in Understanding Landscape Influences on Freshwater Habitats and Biological Assemblages

<i>Abstract.</i>—The applicability of catchment indicators for predicting aquatic invertebrate responses in both vertical and lateral dimensions of river ecosystems is poorly understood. Therefore, our objective was to determine whether landscape indicators can predict coupled benthic-hyporheic responses in river and riparian environments. To do so, we assessed the relationships between the proportion of crop fields, instream habitat conditions, and abundance of larval and adult Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa in (and from) benthic and hyporheic zones of a 15-km segment of the Satsunai River (catchment area: 725 km2), eastern Hokkaido, northern Japan. Invertebrates were collected using colonization traps (hyporheic taxa), Surber sampler (benthic taxa), and Malaise traps (adults). We first identified insect taxa belonging to each of the benthic dwellers (EPT, excluding chloroperlid Plectoptera) and hyporheic dwellers (chloroperlid Plectoptera) based on the relative unit-volume abundances in benthic zone (7-cm surficial part of riverbed) and hyporheic zone (30 and 50 cm deep). Nitrate concentration and total chlorophyll, the abundance of larval insects in both zones, and adult insects from the benthic zone increased with an increasing proportion of crop fields. In contrast, the abundance of adult invertebrates originating from the hyporheic zone maximized in the area with an intermediate proportion of crop fields. We attributed this disparity to the spatial variability in total availability of functional hyporheic habitat in a vertical dimension, which could not be explained by the abundance estimates on a unit-volume basis. Overall, the proportion of crop fields in a catchment can be used to predict numerically similar (coupled) abundance responses of EPT larvae in river benthic and hyporheic zones. Furthermore, the use of landscape indicators in predicting coupled benthic-hyporheic responses in the riparian zone can be improved with information on the vertical extent of functional hyporheic habitat.

Methods of sampling benthic invertebrates in lotic habitats: a spatial and temporal evaluation

Aim We compared the effectiveness of two sampling devices, the Surber sampler and the D-frame net, commonly used in the analysis of invertebrate fauna structure in biomonitoring programs. These programs use the response of benthic invertebrates to assess changes in aquatic ecosystems because they respond quickly to spatial and temporal variations. However, the lack of consensus on the best method of sampling the fauna may reduce the quality of these studies. Methods We evaluated both devices in four structurally different reaches of streams, two in places with preserved riparian vegetation and two occurring in places with many anthropic disturbances. We repeated the analysis at the dry season of two consecutive years. Results The two samplers were equally effective in analyzing the benthic fauna and sensitive enough to identify spatial and temporal variation in the structure of this fauna, influenced by the presence or absence of riparian vegetation, by the position of the reach with this vegetation (upstream or downstream of the reach without vegetation) and the characteristics of the substrate. Conclusions The analyzed fauna structure was similar for the two samplers, but we consider the use of Surber more advantageous and effective because it collects a smaller number of individuals, reducing the time of processing and identifying in the laboratory, and allows a better definition of the area sampled.

Integrated analysis of water quality from two rivers used for public supply in southern Brazil

Aim This study aimed to evaluate the water quality of streams that are used for public supply, through an integrated analysis using a biotic index, as well as physicochemical and microbiological parameters. Methods The data were obtained monthly, from November 2014 to April 2015, at eight locations in two rivers in the south of Brazil. The landscape is predominantly rural, with the occurrence of small reforested areas, as well as yerba mate and grape cultivations. Macroinvertebrate samples were collected monthly using a Surber sampler. Water temperature and dissolved oxygen concentration were measured in the field using a portable oximeter. The following parameters were measured in the laboratory: pH, Turbidity, BOD, Conductivity and Nitrate. Results The evaluation carried out in the rivers revealed good water quality, but some sample sites presented reduced water quality. The waters of the Leãozinho River were classified as doubtful at site 1 and as good at sites 2, 3 and 4. Ligeirinho River presented an acceptable rating at sites 1 and 4 and was classified as good at sites 2 and 3. The BMWP’ index was significantly correlated with the abundance of macroinvertebrates, EPT richness and BOD. The abundance and richness of macroinvertebrates in Leãozinho and Ligeirinho Rivers were associated with the physical, chemical and microbiological parameters. Conclusion This study reinforces the importance of biomonitoring in the evaluation of water quality for human consumption, considering that environmental management and monitoring practices should integrate physicochemical, microbiological and biological parameters.

RESPON KOMUNITAS BENTHIK INSEKTA EMPAT BULAN PASCA-KEBAKARAN HUTAN 2002 DI HULU KALI BOYONG GUNUNG MERAPI

The purpose of this research is to study the response of benthic insect community in the headwater of BoyongRiver, Mount Merapi, four months post-forest fire in 2002. Energy at the headwater ecosystem was based on thedetritus food-chain. The presence of benthic community indicated forest health. The forest fire caused energy whichentered into the river changed from allochtonous coarse particulat organic matter (CPOM) to fine particulatorganic matter (FPOM). This change would be responded by the functional group of benthic community. Datawere collected with Surber Sampler. The result showed that there were 12 genus constituent of benthic insectsconsisted of functional groups of collector gather, collector filter, predator, dan scrapper. The dominant functionalgroups were collector gather and collector filters, 2256 individual/m3 or 86.02% and the dominant genus of Baetisand Leutcra. Otherwise, scrapper was founded 111 individual/m3 or 4% and predator 256 individual/m3 or 10%.This condition showed that four months post-forest fire indicated dominant allochtonous in Boyong River wasCPOM and FPOM with size of 1 mm. The quality of nutrients in the water was low, otherwise, the sedimentnutrients was high. The dominance of functional group of collectors indicated that ecosystem of headwater forestin Boyong River had not been fully recovered.

Kelimpahan Serangga Air di Sungai Toraut Sulawesi Utara

Serangga air merupakan kelompok Arthropoda yang dapat dijumpai hampir pada jenis perairan misalnya pada habitat lentik atau lotik. Seranggan air dalam suatu ekosistem berperan penting dalam rantai makanan selain itu juga serangga air dapat dijadikan sebagai bioindikator terhadap penentuan kualitas suatu perairan. Penelitian ini bertujuan untuk menganalisis kelimpahan serangga air yang terdapat di Sungai Toraut. Lokai penelitian terletak pada Sub DAS dari DAS Dumoga Kabupaten Bolaang Mongondow, Sulawesi Utara. Sungai ini memiliki luas sekitar 249 km2 dan hulunya terletak di Taman Nasional Bogani Nani Wartabone (TNBNW). Penelitian ini menggunakan metode Purposive Random Sampling dengan menggunakan alat surber sampler. Total individu yang didapatkan dari 3 stasiun sebanyak 1497 individu dengan jumlah famili sebanyak 24 yang terdiri dari 27 spesies. Spesies serangga air yang paling banyak ditemukan pada stasiun satu, sedangkan yang sedikit pada stasiun 3. Kelimpahan spesies yang paling banyak ditemukan adalah Hydropsyche sp.Arthropods is a group of aquatic insects that can be found in almost all types of aquatic habitats for example lentic or lotic habitat. In the field of ecology, aquatic insects plays a role in the food chain, moreover the aquatic insects can be used as bioindicator to determine the quality of water. This study aims to analyze the abundance of aquatic insects found in the Toraut River. This study lies in the sub-watershed from the watershed of Dumoga Bolaang Mongondow, North Sulawesi. This river has an area of ​​approximately 249 km2 and its located in the headwaters of Bogani Nani Wartabone National Park. The method used in this study is purposive random sampling method by using a sampler surber. Total individuals were obtained from 3 stations are 1497 individuals with total 24 families consisting of 27 species. The most commonly species of aquatic insects found at station 1, whereas slightly at station 3. The most commonly species of aquatic insects found is Hydropsyche sp.