Oenanthe aquatica (L.)Poir.: Seed reproduction, population structure, habitat conditions and distribution in Czechoslovakia

1992 ◽  
Vol 27 (3) ◽  
pp. 301-335 ◽  
Author(s):  
Zdenka Hroudová ◽  
Petr Zákravský ◽  
Lubomír Hrouda ◽  
Ivan Ostrý
Keyword(s):  
Population Structure ◽  
Habitat Conditions ◽  
Seed Reproduction ◽  
Oenanthe Aquatica

scholarly journals Struktur komunitas tiram dagingdi perairan estuaria Kuala Gigieng, Kabupaten Aceh Besar, Provinsi Aceh

DEPIK ◽  
2014 ◽  
Vol 3 (2) ◽  
Author(s):  
Chitra Octavina ◽  
Fredinan Yulianda ◽  
Majariana Krisanti
Keyword(s):  
Population Structure ◽  
Management Strategy ◽  
Anthropogenic Activities ◽  
Ostrea Edulis ◽  
Habitat Conditions ◽  
Intensive Exploitation ◽  
Small Class Size ◽  
Shellfish Farming ◽  
Sampling Locations ◽  
Aceh Province

Abstract. The oysters (Ostreidae) isone of economically important bivalves for urban community in Kuala Gigieng, Aceh Besar District. Presently, the quality and quantity of oyster is decreased over the years by intensive exploitation and water pollution. Therefore, theobjective of the present study was to analyze population structure and habitat condition of oystersin estuary area of Kuala Gigieng, Aceh Besar District, Aceh Province. The sampling was conducted at three locations during August to September 2013. The sampling locations were determined based on anthropogenic activities. A total of two genus of oysters were recorded during the study i.e Crossastrea with four species (C. gigas, C. iridescens, C. angulata, C. virginica) and and Ostrea edulis with one species (O. edulis). The highest density (>39 ind m-2)of oysters were found at undisturbed and less pressure environment. The distribution pattern of Ostreidae in the Kuala Gigieng water was clustered where frequency of occurrence wasin small class size of 24 mm to 37.20 mm with optimum harvested of 32.27 mm. The growth of the oysters was relatively slow as shown by the maximum length (Lmaks) that can only reach 37.91-72.81 mm within 0 to 3.42 years. Generally, oysters population structure and habitat conditions in Kuala Gigieng Water was declined over the yeras. Therefore, it is a crucially needed to plan a management strategy for oysters with regulation on fishing, shellfish farming and waste disposal regulation to ensure the oysters population remains sustain.Keywords : Environment factors; fishing, growth; Kuala Gigieng; Oyster; population structureAbstrak. Tiram daging (Ostreidae) merupakan salah satu kerang yang memiliki  nilai ekonomi penting bagi masyarakat Kuala Gigieng. Namun, kualitas dan kuantitas tiram menurun akibat eksploitasi dan pencemaran perairan. Penelitian ini bertujuan untuk menganalisis struktur populasi dan kondisi habitat tiram di perairan estuaria Kuala Gigieng Kabupaten Aceh Besar, Provinsi Aceh. Sampling dilakukan pada tiga lokasi selama bulan Agustus hingga September 2013.Hasil penelitian menunjukkan bahwa terdapat dua genus tiram di perairan Kuala Gigieng yaitu Crassostrea dan Ostrea dengan total 5 spesies (C. gigas, C. iridescens, C. angulata, C. virginica and O. edulis). Kepadatan tertinggi berada pada lokasi yang tekanan penangkapan dan lingkungannya yang rendah. Pola penyebaran tiram daging di Kuala Gigieng cenderung mengelompok. Frekuensi ukuran selang kelas tiram terbanyak yang ditemukan yaitu 24-37,20 mm dengan ukuran layak tangkap yaitu 32,27 mm. Pertumbuhan tiram daging di Kuala Gigieng tergolong lambat, hal ini ditunjukkan dengan panjang maksimal (Lmaks) yang mampu dicapai kerang ini hanya 37,91-72,81 mm dalam waktu 0-3,42 tahun. secara keseluruhan, struktur populasi tiram daging dan kondisi habitat di Kuala Gigieng mulai menurun. Oleh karen itu, diperluka pengaturan pengelolaan sumberdaya tiram dengan melakukan pengaturan penangkapan, budidaya tiram, dan pembuangan limbah agar sumberdaya tiram di Kuala Gigieng tetap lestari.Kata kunci : Faktor lingkungan; Kuala Gigieng; penangkapan; pertumbuhan; struktur populasi; tiram daging,

scholarly journals Polyvariation of the development Scutellaria L. species and the structure of their populations in Siberia

2019 ◽  
Vol 16 ◽  
pp. 00010
Author(s):  
Alexandra Guseva ◽  
Vera Cheryomushkina
Keyword(s):  
Spatial Structure ◽  
Life Form ◽  
Rocky Mountain ◽  
Life Forms ◽  
Living Conditions ◽  
Projective Cover ◽  
Habitat Conditions ◽  
Seed Reproduction ◽  
Number Of Species ◽  
Ontogenetic Structure

Structure of coenopopulations and polyvariance of the development of species of the genus Scutellaria in Siberia were described. Species of the genus are semi-wood and grassy life forms. The formation of different life forms is confined to specific habitats. In a number of species (S. galericulata, S. grandiflora и S. supina), the life form is changing. Dimensional polyvariance of individuals of S. scordiifolia in different habitats was found. The ontogenetic structure of coenopopulations is diverse; 3 types of spectrum are formed: left-sided, centered, and right-hand. In individuals of S. supina and S. tuvensis, the duration of ontogenesis and the duration of individual ontogenetic conditions are influenced by living conditions. The polyvariance of selfmaintenance was revealed in S. supina, the transition from completely seed self-maintenance to mixed − seed reproduction in combination with vegetative. The spatial structure and density of coenopopulations vary depending on the habitat conditions. The spatial structure of the studied species is also determined by the peculiarities of self-maintenance of coenopopulations. The change in density is also associated with the mobility of the substrate on steep, rocky mountain slopes in vegetatively stationary species and with projective cover in vegetatively mobile ones.

scholarly journals Population structure three species of Family Syngnathidae in Merowi River, Kecamatan Kembayan, Kabupaten Sanggau Kalimantan Barat

2021 ◽  
Vol 21 (3) ◽  
pp. 305-319
Author(s):  
Kasianus Krisye Firstantha ◽  
Tri Rima Setyawati ◽  
Riyandi Riyandi ◽  
Gema Wahyudewantoro
Keyword(s):  
Principal Component Analysis ◽  
Population Structure ◽  
Population Density ◽  
Principal Component ◽  
Ornamental Fish ◽  
Age Group ◽  
Habitat Conditions ◽  
Chi Square ◽  
The Status ◽  
Male To Female

Pipe fish is a type of freshwater fish that has potential as ornamental fish. The research objective was to determine the status and habitat conditions of the Merowi River pipe fish as a member of Syngnathidae. The research was conducted from July to December 2019. The research stations were determined based on differences in existing environmental bases.  Sampling had done randomly by using scoop net and umbrella fish trap. The data used include population density, age group,test Chi-Square and Principal Component Analysis (PCA). The results showed that 2 genera consisted of 3 species of pipe fish, as much 248 individu.  Doryichthys deokhatoides 26 individu (0.042 Catch/Unit Efort); D. martensii 209 individu (0.34 Catch/Unit Efort);  Microphis retzii 13 individu (0.02 Catch/Unit Efort). The length of the pipe fish ranged from 48.1 mm to 87.4 mm, and  the ratio of male to female is 1: 1 (balanced). The presence of members of Syngnathidae in the Merowi River was effect by temperature and current velocity.

scholarly journals Population structure of Liparis loeselii (L.) Rich. in relation to habitat conditions in the Warta River valley (Poland)

2016 ◽  
Vol 43 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Agnieszka Błońska ◽  
Dariusz Halabowski ◽  
Agnieszka Sowa
Keyword(s):  
Population Structure ◽  
Plant Height ◽  
River Valley ◽  
Peat Bog ◽  
Habitat Conditions ◽  
Demographic Structure ◽  
Percentage Cover ◽  
Liparis Loeselii ◽  
S Poland

Abstract The paper presents results of a study on the population structure of the orchid Liparis loeselii growing in the Warta River valley peat bog in Myszków (Woźnicko-Wieluńska Upland, S. Poland). Individuals of L. loeselii occurred in patches of Menyantho trifoliatae-Sphagnetum teretis and Eleocharitetum pauciflorae – associations. The demographic structure of L. loeselii populations was described by variations in plant height, the length and width of leaves and the number of flowers of the constituting individuals. It was observed that habitat conditions such as conductivity, pH and the percentage cover of tall perennials had the strongest effect on the structure of L. loeselii populations.

scholarly journals Population structure of Poecilia mexicana (native) and Poeciliopsis gracilis (non-native) in a subtropical river

2020 ◽  
Vol 48 (3) ◽  
pp. 357-369
Author(s):  
María Pamela Bermúdez-González ◽  
Arely Ramírez-García ◽  
Estefanía del Carmen Velázquez-García ◽  
Mónica Elisa Queijeiro-Bolaños ◽  
Juan Pablo Ramírez-Herrejón
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Habitat Quality ◽  
Size Structure ◽  
Habitat Characteristics ◽  
Habitat Conditions ◽  
Exotic Fish ◽  
Complete Structure ◽  
Poecilia Mexicana ◽  
Habitat Category

Despite the increase of exotic species in bodies of water, studies on the population structure of coexisting native and exotic fish species are rare. We evaluated the population structure of the native Poecilia mexicana and non-native Poeciliopsis gracilis species in an environmental gradient and its relation to the habitat characteristics in the Jalpan River, located in the state of Queretaro, Mexico. We calculated size structure, sex ratio, gonad stage, and condition factor for both species. Visual-based habitat quality, riparian quality, and physical and chemical characteristics of water were also evaluated. A total of 322 individuals of P. gracilis and 762 of P. mexicana were captured with different fishing nets due to the habitat heterogeneity. Study sites were classified into three categories of habitat conditions: poor, marginal, and sub-optimal. P. mexicana females showed a complete structure of sizes in the poor habitat category. P. gracilis did not show a complete structure in any habitat category. The sub-optimal category of habitat conditions had the lowest number of specimens for both species. Poor category showed a sex ratio of 1:1 (females: males) for P. mexicana while in P. gracilis, females were more abundant than males (sex ratio 5:1). Fulton's factor was higher for P. mexicana than for P. gracilis. Our results showed that habitat quality of the river affected size structure, stages of development, and sex ratio of the two species, but did not show conclusive evidence of favored species or reproductive competition.

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