scholarly journals Annelida (Oligochaeta and Aphanoneura) from the Natural Reserve of Isla Martín García (upper Río de la Plata estuary, Argentina): biodiversity and response to environmental variables

2014 ◽  
Vol 74 (1) ◽  
pp. 128-136 ◽  
Author(s):  
II César
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Sampling Period ◽  
Abundant Species ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Oxygen Conductivity ◽  
La Plata

The Island of Martín García – located in the Upper Río de la Plata, to the south of the Uruguay River – is an outcropping of the crystalline basement. Fourteen sampling sites were selected, five along the littoral section of the island and nine in inland ponds. Four major environmental variables were measured: water temperature, dissolved oxygen, electrical conductivity, and pH. A total of 34 species of Oligochaeta and Aphanoneura were found, 30 belonging to Naididae plus one species each of the Narapidae, Lumbricidae, Enchytraeidae, and Aeolosomatidae. The thirteen most frequent species were: A. leydigi (30%), N. bonettoi (13%), L. hoffmeisteri (11%), N. variabilis(10%), S. trivandrana (6.5%), A. pigueti (5.6%), D. sawayai (4.5%), D. digitata(3.5%), C. diastrophus (2.7%), A. costatus (2.5%), P. longiseta (2.0%), Enchytraeidae (1.5%), and A. p. paraguayensis(1.4%). UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. Canonic-correspondence analysis (CCA) was conducted with the 15 most frequent and abundant species in the 9 sampling sites and the 4 environmental variables. Results from the CCA revealed that the order of fluctuation of the environmental variables during the sampling period was, from the greatest to the least: dissolved oxygen, conductivity, pH, and water temperature. Approximately 97.6% of the correlations between species and environmental variables were expressed on axis 1 of the ordination diagram. Species richness correlated with the four environmental variables in the following order, from the weakest to the strongest: water temperature, pH, electrical conductivity, and dissolved oxygen.

scholarly journals Mollusks (Gastropoda and Bivalvia) of the Multiple-Use Reserve Martín García Island, Río de la Plata River: biodiversity and ecology

2012 ◽  
Vol 72 (1) ◽  
pp. 121-130 ◽  
Author(s):  
II César ◽  
SM Martín ◽  
A Rumi ◽  
M Tassara
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Sampling Period ◽  
Pomacea Canaliculata ◽  
Rio De La Plata ◽  
Multiple Use ◽  
Río De La Plata ◽  
Oxygen Conductivity ◽  
La Plata

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila , B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma, Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds.

scholarly journals Biodiversity and ecology of Hirudinea (Annelida) from the Natural Reserve of Isla Martín García, Río de la Plata, Argentina

2009 ◽  
Vol 69 (4) ◽  
pp. 1107-1113 ◽  
Author(s):  
II. César ◽  
SM. Martín ◽  
BS. Gullo ◽  
R. Liberto
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Natural Reserve ◽  
Species Groups ◽  
Floating Macrophytes ◽  
Measured Water

The Island of Martin Garcia lies at the confluence of the Uruguay and Paraná Rivers (upper Río de la Plata). This island is an outcrop of the crystalline basement. Due to basalt exploitation the island exhibits several ponds covered by carpets of free-floating macrophytes. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Eleven leech species were found, Helobdella striata, H. diploides, H. adiastola and H. hyalina were new records. UPGMA clustering of species based on their occurrence in different ecological conditions revealed three main species groups. Canonical Correspondence Analysis (CCA) explained 97.2% of the correlation between species and environmental variables. H. triserialis shows the widest range of tolerance, H. hyalina shows positive relationships to conductivity; H. diploides shows a high correlation with dissolved oxygen, H. striata, H. lineata, and S. similis are negatively correlated with water temperature, and H. simplex is positively correlated with pH. Relationships between the species richness (S) and the sampling sites were negatively correlated with water temperature and positively correlated with dissolved oxygen. Leech biodiversity from the water bodies of Martín García Island, shows a great diversity of species and a wide plasticity regarding the characteristics of the environmental factors considered.

scholarly journals Ecological classification of the freshwater Ostracoda (Crustacea) based on physicochemical properties of waters and habitat preferences

2018 ◽  
Vol 54 ◽  
pp. 26 ◽  
Author(s):  
Okan Külköylüoğlu ◽  
Mehmet Yavuzatmaca ◽  
Derya Akdemir ◽  
Ebru Çelen ◽  
Nurhayat Dalkıran
Keyword(s):  
Electrical Conductivity ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Habitat Preferences ◽  
Habitat Type ◽  
Alpha Diversity ◽  
Abundant Species ◽  
Critical Issue ◽  
Cosmopolitan Species

The relationship between ecological characteristic of freshwater ostracods and their habitat preferences has been a critical issue for understanding of both current and past aquatic conditions. To evaluate this idea, 121 water bodies with 11 different habitat types were randomly sampled in the province of Kütahya. Water quality measurements indicated high to low (Ca2+ > Mg2+ > Na+) cations and relatively low (SO42− > Cl− > F−) anion concentrations with Ca2+ being the dominant ion. Sixteen of 23 species were new reports for the area. Alpha diversity (H′ = 3.64) was found relatively high. Four most abundant species with ca. 93% of similarities contributed highest alpha values in warm to cooler (lower than 25 °C), alkaline (pH 8.22), and fresh to slightly brackish waters. Heterocypris salina and Ilyocypris bradyi also revealed the highest tolerances for electrical conductivity. Based on habitat type, species were clustered into three main groups (I–III). Canonical Correspondence Analyses explained about 57.4% of correlation between species and environmental variables. Redox potential, pH, water temperature and electrical conductivity were found to be the most effective factors on species occurrences while habitat type and dissolved oxygen were not effective. Total number of species showed strong negative and positive relationships with water temperature and dissolved oxygen, respectively. Results clearly showed that cosmopolitan species exhibited relatively wide tolerance ranges to different environmental variables. Accordingly, having wide tolerance ranges seems to provide advantages to cosmopolitan species, increasing their survival chances in a variety of habitats.

scholarly journals Population structure of Uncancylus concentricus (d'Orbigny, 1835) (Ancylidae, Pulmonata, Basommatophora) in the Multiple Use Reserve Martín García Island, Upper Río de la Plata, Argentina

2012 ◽  
Vol 72 (1) ◽  
pp. 65-70 ◽  
Author(s):  
SM Martín ◽  
AC Díaz
Keyword(s):  
Size Range ◽  
Sampling Period ◽  
Rio De La Plata ◽  
Multiple Use ◽  
Río De La Plata ◽  
La Plata ◽  
Natural Reserve ◽  
Variable Distribution ◽  
In The Wild ◽  
Uruguay River

The present work analyzes the population dynamics of Uncancylus concentricus in natural conditions in the northeastern coastal area of the Multiple Use Natural Reserve Isla Martín García (Beach of Basural), Buenos Aires, Argentina. Martín García Island is located in the Upper Río de La Plata, to the south of the mouth of the Uruguay River (34° 11' 25" S and 58° 15'38" W). Monthly collections were made from August 2005 to December 2006. The size frequency of the U. concentricus population throughout the sampling period ranges from 1.2 to 8.3 m. The changes in the size frequencies throughout the months surveyed indicate a variable distribution pattern because of the increase and decrease in water flow, but we observed a peak in the frequency of individuals within the size range 3.5 to 4.5 mm in the population. It can be concluded that this species lives for at least a year in the wild since the juveniles are highly abundant in spring and summer.

Geographic distribution of the short-tailed river stingray (Potamotrygon brachyura): assessing habitat loss and fishing as threats to the world’s largest obligate freshwater elasmobranch

2016 ◽  
Vol 67 (10) ◽  
pp. 1463 ◽  
Author(s):  
Luis O. Lucifora ◽  
Santiago A. Barbini ◽  
Sabina Llamazares Vegh ◽  
Pablo A. Scarabotti ◽  
Facundo Vargas ◽  
...  
Keyword(s):  
Water Temperature ◽  
Geographic Distribution ◽  
River Basins ◽  
Paraná River ◽  
Habitat Modification ◽  
Rio De La Plata ◽  
Fishing Pressure ◽  
Río De La Plata ◽  
La Plata ◽  
Parana River

Freshwater elasmobranchs are threatened but little is known about them. Potamotrygon brachyura is the world’s largest obligate freshwater elasmobranch. This makes it popular among fishermen and suggests a susceptibility to anthropogenic threats. We collected records of P. brachyura (n=70) from media, fishermen and scientific sampling, to estimate its global geographic distribution (using both generalised additive and MaxLike models). Then, we estimated the species’ exposure to habitat modification and fishing pressure, by applying multinomial ordinal models with threat levels as response and the presence or absence of P. brachyura as an independent variable. Distance to coast, depth, water temperature range, salinity range and mean water temperature were the main determinants of the distribution in the Río de la Plata. This resulted in a narrow coastal distribution. In the Uruguay and Paraná River basins, the probability of occurrence was positively associated with flow accumulation, percentage of open water and submerged vegetation, and lowland ecoregions, and negatively to wetness index and altitude. This limited the distribution to large lowland rivers. Approximately 41% of the range of P. brachyura in the Río de la Plata was subject to high habitat modification. In the Uruguay and Paraná River basins, this percentage reached 7%; however, the overlap with high fishing pressure was 59%. For conservation purposes, P. brachyura may function as an umbrella species.

scholarly journals Seasonal composition, abundance and biomass of the subestuarine fish assemblage in Solís Chico (Río de la Plata estuary, Uruguay)

2016 ◽  
Vol 77 (3) ◽  
pp. 622-631 ◽  
Author(s):  
A. Acuña Plavan ◽  
R. Gurdek ◽  
N. Muñoz ◽  
J. M. Gutierrez ◽  
M. Spósito ◽  
...  
Keyword(s):  
Fish Assemblage ◽  
Fish Community ◽  
Abundant Species ◽  
Estuarine Fish ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Juvenile Stages ◽  
Micropogonias Furnieri ◽  
First Time

Abstract The large estuaries can present long narrow branches called subestuaries or tidal creeks. These types of subsystems are distributed along the Uruguayan coast of the Río de la Plata estuary and are very important as nursery and refuge areas for fish. For the first time, the seasonal composition and abundance of the fish community of the Solís Chico subestuary was studied by using beach and gill nets. Fourteen species, mainly euryhaline (86%) presented a significant representation of juvenile stages. The fish community was dominated by Odontesthes argentinensis, Platanichthys platana, Mugil liza, Brevoortia aurea, Micropogonias furnieri and Paralichthys orbignyanus, similar to adjacent subestuaries. While Micropogonias furnieri and B. aurea were the most abundant species, some other species were rarely caught. A seasonal variation of the fish assemblage abundance was detected, with higher values in autumn showing a positive correlation with temperature. Species that complete their life cycle in the Río de la Plata estuary, some of which are relevant to fisheries (64% of the analyzed species) were captured in the Solís Chico subestuary. The importance of this environment as a transitional system for some estuarine fish species is advised.

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