scholarly journals Freshwater Invertebrates of Southwestern South America: Diversity, Biogeography, and Threats

2021 ◽  
Author(s):  
Claudio Valdovinos Zarges ◽  
Pablo Fierro ◽  
Viviana Olmos
Keyword(s):  
South America ◽  
Central Zone ◽  
The North ◽  
Current State ◽  
Strait Of Magellan ◽  
The Strait Of Magellan ◽  
Latitudinal Patterns ◽  
Diverse Groups ◽  
Biogeographic Analysis

This chapter reviews the current state of knowledge of invertebrates of rivers, lakes, and wetlands in western South America, from southern Peru to the Strait of Magellan in southern Chile. A characterization of the diverse groups of insects, mollusk crustaceans, and other smaller groups is presented, and a biogeographic analysis of them is made with emphasis on their main forcing factors, ecology, and threats in the Anthropocene. This fauna presents Gondwanic characteristics, with clear North–South latitudinal patterns, covering from the Desert of Atacama in the North, one of the most arid deserts of the world, to the rainy and cold regions of the southern end of South America. The central zone of this territory includes one of the global biodiversity “hot spots,” which currently presents serious threats associated with changes in habitat, introduction of invasive species, climate change, and overexploitation of aquatic resources.

scholarly journals Lymnaea Diaphana; a study of Topotypic specimens (Pulmonata: Lymnaeidae)

1984 ◽  
Vol 79 (1) ◽  
pp. 75-81 ◽  
Author(s):  
W. Lobato Paraense
Keyword(s):  
Ventral Surface ◽  
North Coast ◽  
Left Shoulder ◽  
Middle Line ◽  
The North ◽  
Strait Of Magellan ◽  
Nidamental Gland ◽  
The Strait Of Magellan ◽  
The Right ◽  
Pulmonary Cavity

A description of the species Lymnaea diaphana King, 1830 is presented, on the basis of material collected at its type-locality, San Gregorio, on the north coast of the Strait of Magellan, in the Chilean province of Magallanes. It may be identified by the following characters taken together: adult shell over 10 mm in length, whorls inflated, regularly convex, separated by a well-marked suture, aperture ovate occupying about half the shell length; renal organ forming an approximately right angle with the ureter; pouch of the oviduct well noticeable high on the right ventral surface and on the right side of the nidamental gland; uterus bent to the right into an approximately right angle; body of the spermatheca projected into the pulmonary cavity and adhered to the pericardium and to the roof of the pulmonary cavity; spermiduct highly sinuous, folding dorsalward between the left half of the oviduct and the left shoulder of the nidamental gland, and then winding on ventralward to reach the prostate on the middle line; prostate voluminous, convex on the left, pushed in on the right, with a deep dorsal furrow corresponding to a fold which projects into the prostatic lumen and is more developed at the fore half of the organ; apical end of the penial sheath with about six minute protuberances corresponding to inner chambers; prepuce from about as long about twice as long as the penial sheath, with some variation beyond those limits; lateral teeth of the radula basically tricuspid, with a usually simple ectocone which may show a bifid or trifid point. A diagnosis between lymnaea diaphana and three other lymnaeids which also occur in South America and were previously studied by the author - L. columella, L. viatrix and L. rupestris - is presented.

scholarly journals Caractérisation des pâturages herbacés sahéliens à accès limité : Cas du Centre Secondaire de Multiplication de Bétail de Sayam (Diffa).

2020 ◽  
Vol 156 ◽  
pp. 16095-16113
Author(s):  
Idrissa Issoufa ◽  
Morou boubé ◽  
Abdoulaye Diouf ◽  
Saley Karim ◽  
Ali Mahamane
Keyword(s):  
Central Zone ◽  
Floristic Composition ◽  
Mots Clés ◽  
Additional Information ◽  
Current State ◽  
Sont Respectivement ◽  
Palatable Species ◽  
Pastoral Value ◽  
Composition Floristique

Objectifs : Cette étude vise à caractériser l’état actuel des pâturages herbacés du Centre Secondaire de Multiplication de Bétail de Sayam. Méthodologie et Résultats : Quatre groupements pastoraux ont été identifiés et décrits à partir de 56 relevés linéaires réalisés sur un transect Sud - Nord. Au total 98 espèces herbacées réparties parmi 59 genres et 27 familles botaniques ont été répertoriées. Les genres suivants : Eragrostis, Ipomoea, Aristida, Cenchrus, Indigofera, Digitaria et Brachiaria ont été les mieux représentés. Ils représentent environ 50% du total et renferment l’essentiel des espèces de bonne valeur pastorale. Le recouvrement global, les valeurs pastorales brutes et nettes sont respectivement de 85,5%, 75,05% et 67,56%, celles-ci attestent que le pâturage du centre est de bonne qualité. La productivité globale en phytomasse herbacée a été estimée 2,26 tMS/ha avec une capacité de charge globale de 0,40 UBT/ha/an soit 2,5 ha/UBT/an. L’analyse du spectre fourrager indique que les espèces de bonne valeur pastorale et de faible valeur pastorale dominent le tapis herbacé. La première catégorie domine la zone centrale mieux protégée tandis que la dernière occupe les parties périphériques soumises à une forte exploitation du bétail. Conclusion et application des résultats : Le front de colonisation des espèces faiblement appétées (espèces qui ont IS = 0 ou IS = 1) progresse vers le centre sous l’effet de la forte pression pastorale. D’où l’urgence de clôturer l’ensemble du périmètre du centre afin d’éviter de créer un déséquilibre écologique préjudiciable à la survie de nombreuses espèces inféodées à ces milieux particuliers. Dans les perspectives d’une gestion durable des ressources fourragères des centres secondaire de multiplication de bétail, ce travail fournit des informations scientifiques fiables sur l’état actuel des pâturages herbacés de ce centre. Mots-clés : Kouri, composition floristique, groupements pastoraux, qualité pastorale, Sayam. Idrissa et al., J. Appl. Biosci. 2020 Caractérisation des pâturages herbacés sahéliens à accès limité : Cas du Centre Secondaire de Multiplication de Bétail de Sayam (Diffa). 16096 Characterization of Sahelian herbaceous pastures with limited access: Case of the Secondary Cattle Multiplication Center of Sayam (Diffa). ABSTRACT Objectives : This study aims to characterize the current state of the herbaceous pastures of the Sayam Secondary Cattle Multiplication Center. Methodology and Results : Four pastoral groups have been identified and described from 56 linear surveys carried out on a South - North transect. A total of 98 herbaceous species distributed among 59 genera and 27 botanical families have been listed. The best represented genera are: Eragrostis, Ipomoea, Aristida, Cenchrus, Indigofera, Digitaria and Brachiaria. They represent about 50% of the total and contain most of the species of good pastoral value. The overall recovery, the gross and net pastoral values are respectively 85.5%, 75.05% and 67.56%, these attest that the pasture of the center is of good quality. The overall productivity of herbaceous phytomass was estimated at 2.26 tMS / ha with an overall carrying capacity of 0.40 TLU / ha / year, ie 2.5 ha / TLU / year. Analysis of the forage spectrum indicates that species of good pastoral value and those of low pastoral value dominate the grass cover. The first category dominates the better protected central zone while the last occupies the peripheral parts subject to heavy livestock exploitation. Conclusion and applicability of results : The colonization front of poorly palatable species is progressing towards the center under the effect of strong pastoral pressure. Hence the urgency to enclose the entire perimeter of the center in order to avoid creating an ecological imbalance detrimental to the survival of many species dependent on these particular miles. With a view to the rehabilitation and sustainable management of these pastoral centers, this study provides additional information on the current state of the herbaceous pastures in this center. Keywords : Kouri, floristic composition, pastoral groups, pastoral quality, Sayam, Niger

scholarly journals Diagnosis of the Ghiss Nekor aquifer in order to elaborate the aquifer contract

2018 ◽  
Vol 37 ◽  
pp. 01006
Author(s):  
Wissal Baite ◽  
A. Boukdir ◽  
A. Zitouni ◽  
S. D. Dahbi ◽  
H. Mesmoudi ◽  
...  
Keyword(s):  
Urban Areas ◽  
Underground Water ◽  
North East ◽  
The North ◽  
Current State ◽  
Strategic Role ◽  
The Face ◽  
Over Exploitation ◽  
Al Hoceima

The Ghiss-Nekor aquifer, located in the north-east of the action area of the ABHL, plays a strategic role in the drinkable water supply of the city of Al Hoceima and of the neighboring urban areas. It also participates in the irrigation of PMH. However, this aquifer has problems such as over-exploitation and pollution. In the face of these problems, the only Solution is the establishment of a new mode of governance, which privileges the participation, the involvement and the responsibility of the actors concerned in a negotiated contractual framework, namely the aquifer contract. The purpose of this study is to diagnose the current state of the Ghiss Nekor aquifer, the hydrogeological characterization of the aquifer, the use of the waters of the aquifer, the Problem identification and the introduction of the aquifer contract, which aims at the participatory and sustainable management of underground water resources in the Ghiss- Nekor plain, to ensure sustainable development.

scholarly journals Glacial geomorphology of the Strait of Magellan ice lobe, southernmost Patagonia, South America

2020 ◽  
Vol 16 (2) ◽  
pp. 299-312 ◽  
Author(s):  
Rodrigo L. Soteres ◽  
Carly Peltier ◽  
Michael R. Kaplan ◽  
Esteban A. Sagredo
Keyword(s):  
South America ◽  
Glacial Geomorphology ◽  
Strait Of Magellan ◽  
The Strait Of Magellan

A Synopsis of Dicliptera (Acanthaceae) in Brazil, with the Description of Two New Species

2020 ◽  
Vol 45 (2) ◽  
pp. 340-348
Author(s):  
James Lucas da Costa-Lima ◽  
Earl Celestino de Oliveira Chagas
Keyword(s):  
New Species ◽  
South America ◽  
The State ◽  
Northeastern Brazil ◽  
Mato Grosso ◽  
The North ◽  
New Synonyms ◽  
Two New Species ◽  
Mato Grosso Do Sul ◽  
A New Species

Abstract—A synopsis of Dicliptera (Acanthaceae) for Brazil is presented. Six species are recognized: Dicliptera ciliaris, D. sexangularis, and D. squarrosa, widely distributed in South America; D. purpurascens, which ranges from the North Region of Brazil (in the state of Acre) to eastern Bolivia; D. gracilirama, a new species from the Atlantic Forest of northeastern Brazil; and D. granchaquenha, a new species recorded in dry and semideciduous forests in Bolivia and western Brazil, in the state of Mato Grosso do Sul. Furthermore, we propose new synonyms and designate lectotypes for eleven names. An identification key to the six accepted Dicliptera species in Brazil is provided.

CURRENT STATE AND DEVELOPMENT PERSPECTIVES OF THE CASPIAN SPRAT FISHERIES

2018 ◽  
pp. 69-75
Author(s):  
Tatiana Vasilievna Pomogaeva ◽  
Aliya Ahmetovna Aseinova ◽  
Yuriy Aleksandrovich Paritskiy ◽  
Vjacheslav Petrovich Razinkov
Keyword(s):  
Food Item ◽  
Growth Potential ◽  
North West ◽  
Marine Fishery ◽  
The North ◽  
Current State ◽  
West Part ◽  
Eggs And Larvae ◽  
Intensive Growth

The article presents annual statistical data of the Caspian Research Institute of Fishery. There has been kept track of the long term dynamics of the stocks of three species of Caspian sprat (anchovy, big-eyed kilka, sprat) and investigated a process of substituting a food item of sprats Eurytemora grimmi to a small-celled copepod species Acartia tonsa Dana. According to the research results, there has been determined growth potential of stocks of each species. Ctenophoran-Mnemiopsis has an adverse effect on sprat population by eating fish eggs and larvae. Ctenophoram - Mnemiopsis is a nutritional competitor to the full-grown fishes. The article gives recommendations on reclamation of stocks of the most perspective species - common sprat, whose biological characteristics helped not to suffer during Ctenophoram outburst and to increase its population during change of the main food item. Hydroacoustic survey data prove the intensive growth of common sprat biomass in the north-west part of the Middle Caspian. According to the results of the research it may be concluded that to realize the volumes of recommended sprat catch it is necessary to organize the marine fishery of common sprat at the Russian Middle Caspian shelf.

Sign in / Sign up

Export Citation Format

Share Document