Summed Dominance Ratio Research Articles

The Effect of Shrimp Waste Fertilizer Application on Spinach (Amaranthus tricolor L.) with the Presence of Weeds

The presence of weeds in spinach cultivation land is strongly influenced by the application of fertilizer. Fertilizer has a different content so that it will have an impact on the weed species growth. Identification in this study aims to determine the types of weed species that grow and the dominant types of weed species that grow on spinach cultivation land before and after the application of shrimp waste fertilizer. This research was conducted from June to August 2021, on horticultural crop cultivation in the Sinar Harapan Farmers Group, Tarakan City. The sampling method was a random method using a square plot method with a size of 1 x 1 m as many as 30 samples before and after the application of shrimp waste fertilizer. Observation parameters are counting the number of weed species and the name of the weed species. The data obtained in the field is then processed to determine the level of density, frequency, significant value index (INP), Summed Dominance Ratio (SDR), Margalef Index, Shanon-Wiener Index, Evennes Index and Sorensen Index. The results showed that the weed species before the application of shrimp waste fertilizer on spinach plants were 27 species with the dominant weed species being Cyperus compressus with a Summed Dominance Ratio value of 22.72%. Weed species before the application of shrimp waste fertilizer on spinach plants were 25 species with the dominant weed species namely Cyperus compressus with a Summed Dominance Ratio value of 20.51%. The Margalef index before the application of shrimp waste fertilizer was 3.20 and after the application of shrimp waste fertilizer was 3.05. The Shanon-Wiener index before the application of shrimp waste fertilizer was 2.60 and after the application of shrimp waste fertilizer was 2.40. Evennes index before the application of shrimp waste fertilizer is 0.79 and after the application of shrimp waste fertilizer is 0.74 and the Sorensen index is 85%

The Diversity and Dominance of Weeds in Various Population Proportions of Intercropping Soybeans With Corn

Soybean is an important food crop for Indonesia after rice and corn. Soybean productivity in Indonesia is still low because most farmers use monoculture cropping patterns which has many weaknesses. Intercropping is an alternative to increase soybean productivity because it has many advantages. Soybeans can be intercropped with corn because the two plants have different physical characteristics, physiology and growth patterns. This research aimed to obtain information about the diversity and abundance of weeds in soybean and corn intercropping. The study was conducted using a single factor treatment design which will be arranged in a single plot field design, using Grobogan variety soybean and Bisma variety corn. The treatment was the proportion of soybean and corn populations which consisted of 4 proportions, i.e. 2:1, 3:1, 4:1, and 5:1, and monoculture soybeans were also planted as a control. Observations on weeds were carried out at the age of 2, 8, and 12 weeks after planting (before harvest) with vegetation analysis. The size of each sample is 0.5 m x 0.5 m with 15 sample plots/plots. The results showed that based on the summed dominance ratio (SDR) in the research area, 16 species of weeds were dominated by broadleaf weeds, with the dominant types of weeds being Phyllanthus urinaria L., Eleusine indica L., and Oryza sativa L. The results showed that based on the Summed Dominance Ratio (SDR) in soybean there were 16 species of weeds that were dominated by broadleaf weeds, with the dominant types of weeds being Phyllanthus urinaria L., Eleusine indica L., and Oryza. sativa L. Weeds growing on soybean intercropping with corn and soybean monoculture have a medium diversity index (H').

Study on Weeds Abundance on Rice Fields in Mycorrhizal Inoculation and Different Planting Methods

<span lang="EN-US">The increasing demand for rice and the increasing population growth rate require sustainable rice production. Direct seeding of rice (DSR) combined with the use of arbuscular mycorrhizal fungi (AMF) is needed to achieve sustainable food production. This study aims to determine the effect of the planting method and mycorrhizal inoculation on the diversity, composition and dominance of weeds in a rice field for the sustainability of agricultural production. The research used a split-plot design with three replications. The main plot was the planting method consisting of on row, drum seeder and transplanting, while the subplot was mycorrhizal inoculation divided into with mycorrhizal inoculation and without mycorrhizal inoculation. The observed variables were <span>light</span><span> penetration, weeds population, weeds composition, weeds biomass, </span>summed dominance ratio<em> </em>and community coefficient. The results showed that there were 34 kinds of weeds consisting of 13 families and the dominant weed was annual weeds, most of which were broadleaf weeds. The dominant weed was <em>Alternanthera sessilis</em> (L.) R. Br. ex DC. (sessile joyweed). The planting methods affected the weed population in 24 days after sowing (DAS) and the composition of broadleaf weeds in 24 DAS but did not affect weed biomass. The AMF inoculation did not affect weed population, composition, or biomass. It is necessary to find mycorrhizal species that can affect weed growth.</span>

IDENTIFIKASI JENIS DAN NILAI SUMMED DOMINANCE RATIO (SDR) GULMA DI LAHAN KERING

ABSTRACT
 
 Weeds are unwanted plants and can harm plants so that they can reduce production. The study, entitled identification of species and the value of the summed dominance ratio, was conducted in Limau Manih, Padang, North Sumatra for four months. This study aims to identify the type and value of the summed dominance ratio. The tools used are gembor, meter, machete, cart, knife, hoe, dipper, blender and caliper. While the materials used were fresh Sembung Rambat leaves, seeds, drum fertilizer, raffia rope, polybags, plastic, compost, NPK-Mg. The method used in this research is Completely Randomized Design by making five plots where the five plots will be observed and searched for absolute density values, relative density, absolute frequency, relative dominance, significant value index and SDR. This research is an experiment conducted using several types of weeds, namely; Ageratum conyzoides L, Axonopus compresus, Bidens pilosa L, Boreria alata, Borreria leavis, Brachiaria reptans , Calopogonium mucunoides, Chromolaena odorata L, Cleome rutidosperma DC, Crotalaria mucronate, Cynodon dactylon L, Cyperus kyllingenecha, Digitaschyllingera incha , Melastoma affine, Mimosa pudica, Phillanthus amarus, Uraria lagopodioides L. The results showed that the weed with the highest land tenure value in dry land was Brachiaria reptans. Because it has many seeds and strong rhizomes, it belongs to the C4 species.
 
 Keyword: weed, summed dominance ratio, weed identification

Diversity and Distribution of Traditional Home Gardens Along Different Disturbances in a Dry Tropical Region, India

Home gardening is an indigenous practice of cultivation that has effectively adapted to local ecological conditions over generations. This study examined the effects of disturbance and garden size on biodiversity to develop a better understanding of vegetation cover and its role in livelihood and provision of forest management in the Vindhyan highlands. Data were collected from 60 gardens which were classified into large (> 650 m2), medium (400–650 m2), and small (< 400 m2), based on size and disturbance gradients viz., high, medium, and low. A total of 133 species from 50 families were recorded, in which trees (47.4%) were dominant followed by shrubs (18%) and herbs (16.5%). With respect to disturbance, the highest number of tree species (39) were found at low disturbance (LD) followed by 33 species in medium disturbance (MD) and 32 species in high disturbhance (HD). The total mean richness of species was greater at LD (20.3 ± 2.3) and lowest at HD (18.5 ± 2.2). Tree density was significantly (P≤ 0.05) higher at LD (293.75 ± 16.1 individual ha–1) as compared to MD (221 ± 11.5 individual ha–1) and HD (210 ± 10.3 individual ha–1). However, the results for shrubs and herbs density were considerably different, where shrubs density was highest at HD (70 ± 6.9 individual per 1,000 m2) and lowest at LD (62.5 ± 5.8 individual per 1,000 m2), while the maximum density of herbs was recorded at MD (466.25 ± 29.8 individual per 100 m2) and minimum at LD (370 ± 21.4 individual per 100 m2). The summed dominance ratio indicated frequent use of garden plants in bio-fencing, vegetables, ornamental, and ethnomedicine. Diversity (P< 0.01) and species richness (P< 0.05) showed a significant positive correlation with garden size. The Principal Component Analysis (PCA) showed that the first component (PC1) accounted for 28.6% of variance, whereas the second explained 21.9% of variance in both disturbance and garden size with a cumulative variance of 50.5%. These components depicted the positive association with HD (14.34), SDiv (13.91), TCD (12.47), and HDiv (12.09). We concluded that the diversity of home gardens changed with disturbance, which crucially served as a refuge for native tree species in a degraded landscape. This pattern highlighted the importance of home gardens for plant biodiversity conservation and local livelihood, which must be a viable option for regeneration of deforested dry tropics, while also reducing the burden on dry tropical forest regions.

Occurrence and distribution of Alternanthera bettzickiana (Regel) Voss., an invasive weed in the uplands of Kerala

A survey was conducted in the uplands (or garden lands) along roadsides, uncultivated areas and in wastelands in seven agro-ecological units (AEUs) representing the central zone of Kerala during 2020 and 2021 to assess the occurrence and invasiveness of Alternanthera bettzickiana (Regel) Voss. The weed exhibited highest summed dominance ratio and importance value index in all but one of the AEUs. Diversity indices like Shannon-Wiener index, Simpson’s diversity index and Evenness index were lower for a particular region (AEU 9), showing the dominance of this weed species there. The density of A. bettzickiana was positively correlated with nitrogen content, and dry matter production was influenced by both organic carbon and nitrogen content of the soil. The study concluded that A. bettzickiana is gaining the status of problematic weed in the central parts of Kerala, dominating mostly in uncultivated areas with occational occurrence observed in cropped lands also. Hence, efforts to prevent its spread need to be taken up by concerned authorities.

Ecological and ethnobotanical values of weeds found in the spring rice fields in Chitwan, Nepal

Background: The reliance of human beings on plants for different purposes such as medicine, fodder, fuel, and shelter is fading away, primarily, due to increasing dominance of market economy globally in the recent decades. Ethnobotanical study, especially that of weeds, is playing a crucial role in establishing the relationship between weeds and people, thereby documenting important uses of such weeds. Chitwan, located in the central part of Terai, is considered the grain basket of Nepal. The district is relatively advanced in agriculture, with higher agricultural productivity than that in most of the country. Spring rice cultivation is prevalent in the area. Weed infestation is one of the severe problems adversely affecting rice cultivation. These weeds have different ethnobotanical values for indigenous ethnic groups as well as residents. Methods: Ecological survey was carried out in four distinct sites: the rice fields of the Institute of Agriculture and Animal Science, Gitanagar, Champanagar, and Ujjalnagar of Chitwan, Nepal. Weeds were collected from three randomly placed one-square-meter quadrats in each rice field. The ethnobotanical uses of the weeds were explored via key informant surveys with traditional healers from Tharu and Darai ethnic groups and the Brahmin caste in Mangalpur, Gitanagar, Champanagar, and Ujjalnagar. Results: Weed flora of 53 species belonging to 43 genera and 22 families were reported in the spring rice fields. Cyperaceae (twelve species), Compositae (five species), Fabaceae (four species), Linderniaceae (four species), Plantaginaceae (four species), Poaceae (four species), and Amaranthaceae (three species) were the families with the largest representation, accounting for approximately 68% of all weeds. The most common weeds were Spirodela polyrrhiza (L.) Schleid., Cyperus difformis L., Azolla Lam., Lindernia procumbens (Krock.) Philcox, Mecardonia procumbens (Mill.) Small, and Fimbristylis quinquangularis (Vahl) Kunth. These weeds also possess different ethnobotanical values, the most common being medicinal and fodder values. Conclusions: This study reveals the significance of weeds as medicine along with their medicinal values. People still rely on such plants as a primary healing resource. In addition, weeds can be used as fodder for livestock and have other important uses in local daily life. Hence, there is a dire need to spread awareness regarding ethnobotanical uses of weeds found in spring rice fields in Chitwan. This can possibly contribute to the sustainable uses of weeds, rather than grossly eliminating them from the field, which poses a threat to their extinction. Keywords: Fodder, Important Value Index, Medicine, Summed Dominance Ratio, Tharu

PERBANDINGAN VEGETASI GULMA PADA PERKEBUNAN KELAPA SAWIT (Elaeis guineensis Jacq.) MENGHASILKAN DAN BELUM MENGHASILKAN DI LAHAN GAMBUT

Weed vegetation analysis is important to do in order to know the composition and structure of the vegetation to determine the appropriate weed control measures. This study aims to compare the composition and structure of weeds on peatland immature oil palm plantations and mature palm. This research was conducted from October to December 2020. Vegetation analysis was carried out using a survei method with purposive sampling technique. The parameters observed were density, frequency, dominance, important value index (INP), summed dominance ratio (SDR) and species diversity index (H'). The results showed that the composition of weeds on immature oil palm plantations was found 12 species with number of individual 847, while on mature palm found 9 species with number of individuals 980. The dominant weed structure on immature oil palm plantations is Lempuyangan with SDR values 29,9 % and mature palm is Bandotan with SDR value 23,4%. Weed diversity index on immature oil palm plantations and mature palm is categorized as high with a value of 1.50 for immature oil palm plantations and 1.65 for mature palm.

Yard Biodiversity to Support Local Economic Development in Skouw Mabo Village, Muara Tami Sub District, Jayapura City, Papua Province, Indonesia

The biodiversity of plants in the tropical forests of Papua is the time to be conserved using the yard approach. These plants have ecological benefits for environmental sustainability but also as wildlife habitat. The plants that are planted around community homes now also have an economic impact on the family to improve the family's economy. This study aims to obtain the value of yard biodiversity based on vertical diversity (strata) and functional diversity (horizontal) and to determine its benefits. Data collection using vegetation analysis methods and calculation of biodiversity values using the Shanon and Wiener indices. The results of the study are that there are 2 very dominant types of plants in the yard, namely areca nut (Areca catechu L.) with a summed dominance ratio (SDR) of 58.4-66.2. For other types there are Moringa (Moringa oleifera) with (SDR) 10.8. The conclusion of the dominant areca nut and moringa is closely related to culture and the two plants currently support economically for increasing the income of families in the village.

Diversity Of Weeds Species Around Mango Tree (Mangifera indica L.) On Critical Land In Jombang Regency

Weeds are unwanted wild plants because they can interfere with the main crop cultivation. This study aims to identify and analyze the diversity of weed vegetation that grows around mango trees. This study uses the quadratic method with diagonal observation points and direct exploration techniques. Observation parameters include the type of weed and its population. Then the results of the observations were analyzed using the formula of Important Value Index (INP), Summed Dominance Ratio (SDR), Diversity Index (H'), Index of Similarity (IS), and Dominance Index (C). After doing the research, found 24 species of weeds consisting of broadleaf weeds, puzzles and grasses. The highest SDR value in Tondowulan Village was Cynodon dactylon L. at 13.82%, while in Darurejo Village it was Oplismenus hirtellus (L.) P. Beauv. by 26.53%. Weed diversity was classified as moderate because the weed diversity index value in Darurejo Village was 1.92% while in Tondowulan Village it was 2.31%. The two research locations did not have the same composition of weeds because the similarity value was only 33.33%. There is no weed species that dominates the mango garden because the index value of the weed dominance in Tondowulan and Darurejo Villages in the order of the 3rd largest is less than one.

Hasil Padi dan Kelimpahan Gulma dengan Aplikasi Jenis Pupuk Berbeda di Lahan Kering Tadah Hujan pada Musim Kemarau

Rice yield and proper weed control need to be increased through an environmentally friendly agricultural system approach in rainfed land during the dry season by reducing the dosage of synthetic fertilizers. This study aims to determine the effect of different fertilizer applications on rice yield and weed abundance in rainfed land during the dry season. The study used a split-plot design, with the main plot of rice variety, i.e., Situ Bagendit and IR-64, and subplots of fertilizer, namely synthetic fertilizers (N, P, K), organic fertilizers + P60 + ½ dose of synthetic fertilizers, organic fertilizers + PGPR + ½ dose of synthetic fertilizer and organic fertilizer + P60 + PGPR + ½ dose of synthetic fertilizer with three replications. The variables observed were rice yield components, namely panicle length, total empty grain and content per panicle, grain weights per hill, effective plot and hectare, 1000 grain weight, harvest index, and weeds summed dominance ratio (SDR). The synthetic fertilizers and three various organic fertilizers, biological fertilizers, and synthetic fertilizers gave different results on the SDR of weeds. The weeds of Sphenoclea zeynalica and Cyperus difformis showed consistent dominance with higher SDR than other weeds, i.e.,> 15 and > 10, respectively. The application of organic and biological fertilizers with half the recommended dosage of the synthetic fertilizers is equivalent to applying the recommended dosage of synthetic fertilizers on rice yield during the dry season on the rainfed dryland with low rainfall intensity and a low yield of 1.3–1.7 t/ha.
 Keywords: biological fertilizer, inorganic fertilizer, organic fertilizers, rice, weeds

Pengaruh Herbisida Metil Metsulfuron dan Kombinasinya pada Pengendalian Gulma Tanaman Tebu (Saccharum officinarum L.)

Weed control must use the right dose of herbicide so as not to leave a residual effect on cultivated plants and soil. This study ains to obtain the most appropriate dose of herbicide. Herbicide used in this study were methyl methulfuron and acetic acid combined. This study used a randomized block design (RCBD) witch 2 factors, factor A was asetic acid and factor B was methyl methulfuron and there were 12 treatment combinations with 3 replications. This research was conducted in the practicum of the Departement of Plantation Plant Cultivation, Lampung State Polytechnic. The total research plot was 36 experimentals units. The dosage levels levels of methyl methulfuron tested in this study were: 0%, 55%, 75%, and 105%. While the dose of acetic acid is: 0%, 50%, and 70%. Observations made in this study were weed vegetation analysis, weed cover percent, weed dry weight, Summed Dominance Ratio (SDR), and Community Coefficient Value (C). SDR values indicate that Panicum dicotomyflorum weed, Ricardia brasiliensis, Euphorbia heterophyla, and Cyperus rotundus are the dominant weeds. The results of this study indicate that there is no effect on the dose of methyl methulfuron herbicide, acetic acid, and interactions on methyl methulfuron herbicide and acetic acid on weed control in sugarcane fields (Saccharum officinarum L.).

Keragaman dan Potensi Pemanfaatan Vegetasi Gulma Pasca Pertanaman Padi di Desa Penggaron Kecamatan Mojowarno Kabupaten Jombang

A field study aims to determine the diversity and potential utilization of weed vegetation that grows after rice planting. This research was carried out in paddy fields after monoculture rice planting in Penggaron Village, Mojowarno District, Jombang Regency in July - September 2020. Sampling was based on the quadratic sampling method with sample plots arranged randomly. In each plot the data taken is the name, number and canopy (area of ​​cover) of each plant species to determine density, dominance and frequency. Data analysis includes vegetation analysis to determine Summed Dominance Ratio (SDR) and biodiversity analysis calculated using the Shannon - Wienner diversity index. The results of this study were 26 types of weed vegetation were found in post-rice planting land. The dominant vegetation types include Oryza sativa L .; Limnocharis flava (L.) Buchenav; Phyllanthus urinaria L .; Monochoria vaginalis (Burm.f.) pressl; and Cleome viscosa L with an SDR value of ≥ 5.30%. A total of 15 types of weeds have the potential to be used as a source of food, animal feed, and traditional medicine.

植物功能群去除对高寒草甸群落结构、多样性及生产力的影响

群落中物种的丧失在干扰下普遍存在，但对生态系统过程和功能的影响仍存在较大不确定性。选取青藏高原东缘典型高寒草甸为对象，开展优势植物功能群的梯度去除试验，以模拟长期过牧干扰下物种的损失。经过连续两个生长季的功能群去除，我们对群落的物种组成、结构、多样性和生物量等特征进行了分析，探讨了上述指标的响应过程和机制。研究结果表明：（1）功能群的去除降低了群落高度，增加了物种均匀度，并显著影响了禾草、杂草优势比以及功能群多样性和优势度；（2）同时，去除操作显著减小了凋落物量与禾草生物量，并显著影响了群落地上生物量；（3）进一步分析还发现，禾草、莎草和杂草功能群之间存在显著的竞争关系，群落生产力主要取决于禾草功能群并随物种均匀度的增大而显著减小。上述结果表明，禾草在高寒草甸群落中占据竞争优势地位，植物功能群的损失主要通过改变种间竞争关系、引起有机物质丢失影响群落过程和功能。;Impacts of biodiversity loss on ecosystem dynamics and functioning have aroused considerable attention and controversies. Loss of plant species is common in natural assembled community, whereas the response of ecosystem process remains unclearly. The continuous overgrazing of livestock has resulted significant plant species loss, like palatable grass and sedge species in alpine meadow on the Qinghai-Tibet plateau. In this study, we conducted a plant removal experiment to simulate the species loss along retrogressive succession gradient of alpine meadow resulting from long term overgrazing. A typical alpine meadow located on the eastern edge of the plateau was selected as the object to conduct the removal manipulation. The study site was fenced in April 2014 after the long term moderate winter grazing of yaks to exclude grazing of herbivores. Six removal treatments including: remove no plant species, remove Grass, remove Grass and Sedge, remove all species, randomly remove 25% of community aboveground biomass, and randomly remove 50% of community aboveground biomass. In middle July 2014 and 2015, we removed aboveground part of specific plant species individuals in 1 m×1 m plots. In late July 2016, the community coverage, height, species composition, diversity indices and biomass were investigated based on 0.5 m×0.5 m quadrats to detect response of alpine meadow to the removal experiment. The results showed that (1) removal of plant functional group (PFG) decreased the weighted-average height of community, but had no significant effect on the cumulative coverage of community. (2) Removal manipulation significantly influenced the summed dominance ratio (SDR) of Grass and Forb group, while no significant for Sedge group. (3) Removal of PFG increased the species evenness, and significantly influenced PFG diversity and dominance, whereas showed no significant effects for other diversity indices. (4) Removal of PFG reduced the litter biomass and Grass biomass. Only the removal of all plant reduced the community aboveground biomass. (5) In addition, further analysis showed that the community aboveground biomass was mainly depending on the Grass group, and decreased significantly with the increase of species evenness. And significantly competitive relationships were found among Grass, Sedge and Forb groups. The results showed that Grass species in the alpine meadow community have the greatest competitive advantage, the loss of plant species could change the community properties by means of influencing the inter-specific competitive relationships and significant plant biomass loss. The successive long-term monitoring on the response of community functioning to plant species loss should be strengthened.

IDENTIFICATION OF LOCAL SEEDS BANK WEED AND THE EFFECT OF WEEDING FREQUENCY ON GROWTH AND RESULTS OF CAYENNE (Capsicum frutescens)

Weed is a plant pest organism whose existence is very detrimental to the production of cultivated plants. Weeds and major plants compete to obtain nutrients, sunlight, and water so that their availability is limited to the main plants. Weed abundance in a cultivated land is inseparable from the presence of weed seed banks in the soil. This study aims to identify weed bank seeds in chili cultivation in Tandon Hamlet, Selogiri Subdistrict, Wonogiri Regency and find out the right weeding frequency to get the highest productivity of cayenne pepper. Identification of local weed bank seed by taking soil samples at four different depths, a) 0-5 cm depth; b) 5-10 cm depth; c) 10-15 cm depth; and d) a depth of 15-20 cm. The variables observed included weed frequency, weed density, and summed dominance ratio (SDR). The frequency of weeding of cayenne plants, using a randomized completely block design (RCBD) with one treatment factor, namely weeding frequency (without weeding; 1 weeding at 2 weeks after planting (MST); 2 times weeding at 2 MST and 4 MST; 3 times weeding at 2 MST, 4 MST, and 6 MST; 4 times weeding at 2 MST, 4 MST, 6 MST, and 8 MST). The results showed that the highest weed seed bank density was found in the depth of soil 0-5 cm and 5-10 cm. While the frequency of weeding shows the frequency of 3 times weeding gives the best results on the growth and production of cayenne

The structure and composition of macrozoobenthos community in varying water qualities in Kalibaru Waters, Bengkulu, Indonesia

Abstract. Lilisti, Zamdial, Hartono D, Brata B, Simarmata M. 2021. The structure and composition of macrozoobenthos community in varying water qualities in Kalibaru Waters, Bengkulu, Indonesia. Biodiversitas 22: 106-112. Various human activities affect the quality of the aquatic ecosystem that can be assessed by measuring the physical, chemical, and biological parameters of the waters and sediments. This is the case of Kalibaru Waters, Bengkulu, Indonesia which shows changes in the estuary and marine ecosystems due to the cut-off of the main river around the area for the development of roads and bridges. The objective of this study was to analyze the quality of the waters and substrate, and the structure of the macrozoobenthos community as a bioindicator at the Kalibaru Waters. A survey was carried out in four stations, which was purposively selected based on human activities around the waters. Data collected included the physical and chemical parameters, and the diversity and density of macrozoobenthos species. The density of macrozoobenthos species was analyzed for summed dominance ratio (SDR), diversity (H'), homogeneity (E), and dominance (D) indices. The results showed that the physical and chemical parameters of Kalibaru Waters were acceptable for aquatic life, however, the oil contents at two stations exceeded the ecological threshold. Analysis of the macrozoobenthos community as a bioindicator for water quality found that the diversity and homogeneity indices were at a medium level indicating an unstable community, while the dominant index remained low indicating that none of the species was dominant in the Kalibaru Waters. This information is needed as a reference for the government of Bengkulu Province to make appropriate policies and management decisions to maintain the quality of the aquatic ecosystem in Kalibaru Waters.

Respon Komunitas Burung terhadap Beberapa Tipe Habitat pada Ekosistem Artifisial di Wilayah PT. PJB UP Paiton

Individu burung yang terkumpul dari beberapa spesies dalam satu waktu di dalam ruang tertentu yang membentuk kelompok disebut komunitas burung. Komposisi vegetasi dan spesies tumbuhan merupakan faktor yang mempengaruhi kehadiran burung pada suatu habitat. Komposisi vegetasi yang terjadi akibat campur tangan manusia membentuk ekosistem artifisial atau ekosistem buatan. PT PJB UP Paiton merupakan objek vital nasional berupa area pembangkit listrik untuk Jawa dan Bali. Kehadiran PT PJB UP Paiton membentuk ekosistem artifisial pada kawasan tersebut. Indeks komunitas burung (IKB) adalah Teknik dalam menentukan kualitas suatu kawasan dengan menggunakan daftar spesies burung dan guild sebagai indikatornya. Pengambilan data burung dilakukan dengan metode point transects sampling dan data flora dilakukan dengan teknik sensus, yaitu menghitung dan mengukur setiap individu pada setiap spesies yang dijumpai di dalam lokasi pengamatan. Keanekaragaman spesies burung dihitung dengan indeks keanekaragaman Shannon-Wiener, dan indeks kemerataan. Keanekaragaman spesies tumbuhan diukur dengan menghitung jumlah spesies, dominansi, indeks keanekaragaman dan indeks kemerataan tumbuhan sedangkan komposisi vegetasi diukur dengan nilai persentase summed dominance rasio (SDR). Hasil penelitian mendapatkan keragaman spesies tertinggi (H’= 3,05; E=0,62) di lokasi Perumahan dan keragaman spesies terendah (H’=2,12; E=0,29) di lokasi Pareho. Spesies M. indica menjadi spesies pohon paling dominan pada lokasi perumahan (29.31%) dan kelontong & benduman (42.79%) sedangkan lokasi kantor didominasi oleh pohon A. indica (26.35%) dan pareho oleh A. saman (26.89%). Hasil analisa hubungan vegetasi terhadap burung mendapatkan nilai r2 direntang -0,8 hingga 0,9 dengan nilai uji signifikan Pvalue>0,05. Hasil hitung IKB mendapatkan kategori rendah hingga menengah. Nilai tertinggi (64.4) diperoleh pada lokasi perumahan, dan nilai terendah (42,8) pada lokasi perkantoran.

KERAGAMAN GULMA PADA TANAMAN KELAPA SAWIT (Elaies guineensis Jacq.) BELUM MENGHASILKAN DAN SUDAH MENGHASILKAN DI KEBUN RAMBUTAN PT. PERKEBUNAN NUSANTARA III

Weeds are undesirable plants because they can compete with the oil palm. Weed growth can reduce the production of bunches by 20%. Weeds are not only due to competition against nutrients but also produce allelopathic substances that are toxic to oil palm. Inventory and find out the dominance of weed species is needed in the management of effective weed control. The study aims to determine the diversity of weeds in different areas of planting year. This study used a sampling method carried out on two mature areas (18 years and 8 years) and an immature area (1 year), with the direct observation method. Every planting area is made of 2 large plots with a size of 20 m x 60 m at interrow of palm, then inside there are made 6 small plots with a size of 2 x 2 m. Data were analyzed with SDR (Summed Dominance Ratio) value to determine the dominant weed species. The diversity of weeds from each area is varied, there are 29 species of weeds and 20 families, nevertheless, there are 5 species of weeds found in all areas of study; O. nodusa, Poaceae; C. kyllingia, Cyperaceae; A. comressus, Poaceae; P. Niruri, Phyllanthaceae; A. spinous, Amaranthaceae. The dominant weeds in the immature area are E. indica, Poaceae while in the mature areas are O. nodosa, Poaceae.

Identifikasi Keragaman dan Dominansi Gulma pada Lahan Pertanaman Kedelai

<p>The diversity and dominance of weeds is the first step in determining the success of weed control. This study aimed to identify the diversity and dominance of weeds in the cultivation of soybean under the shade of oil palm that have not produced (1 year). This research was conducted in October 2018 to January 2019. Sampling used a phrase with a frame size of 1 x 1 m. Weed samples were collected and identified per species according to weed groups, then counted with Summed Dominance Ratio to get weed dominance at each location. There were 10 weed families in soybean cultivation consisting of two types of weed grass, seven types of broadleaf weeds, and two types of weed puzzles. The dominant weed family in soybean cultivation was found in the Poaceae family, with <em>Imperata cylindrica</em> species.</p>

Effects of benthivorous fish disturbance and snail herbivory on water quality and two submersed macrophytes

Benthivorous fish disturbance and snail herbivory are two important factors that determine the community structure of submersed macrophytes. We conducted an outdoor mesocosm experiment to examine the separate and combined effects of these two factors on water quality and the growth of two mixed-cultivation submersed macrophytes, Vallisneria natans and Hydrilla verticillata, with different growth forms. The experiment involved two levels of fish (Misgurnus anguillicaudatus) disturbance crossed with two levels of snail (Radix swinhoei) intensity. The results revealed that fish activity rather than snail activity significantly increased the overlying water concentrations of total suspended solids (TSS), total nitrogen (TN), ammonia nitrogen (N-NH4), total phosphorus (TP) and phosphate phosphorus (P-PO4). However, no differences among treatments were observed for chlorophyll a (chl a) concentrations. Fish disturbance or snail herbivory alone did not affect the relative growth rate (RGR) of H. verticillata, but their combined effects significantly decreased the RGR of H. verticillata. Although snail herbivory alone did not affect the RGR of V. natans, fish disturbance alone and the combined effects of these factors drastically reduced its RGR. Both species exhibited increased free amino acid (FAA) contents and decreased ramet numbers, soluble carbohydrate (SC) contents and starch contents in the presence of the fish. Moreover, compared to H. verticillata, V. natans showed exceedingly low ramet numbers and starch contents in the presence of the fish. H. verticillata had a higher RGR and summed dominance ratio (SDR2) than V. natans in all treatments; H. verticillata also displayed a larger competitive advantage in the presence of fish disturbance. The present study suggests that (1) fish disturbance rather than snail activity increases water nutrient concentrations, (2) low snail density may be harmful to submersed macrophyte growth when the plants are under other abiotic stress conditions and (3) the competitive advantage of H. verticillata over V. natans is more preponderant in a turbid environment.