Ecological role of benthic crustaceans in Chilean north Patagonian lakes and rivers (Araucania region, 39°S) (original) (raw)
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Ecology of benthic crustaceans in the Cautin river (38°S, Araucania region, Chile)
Crustaceana, 2017
The Cautin river is located in the Araucania region, Chile (38°S), and is characterized by alterations through human interference in its surrounding basin, by the presence of introduced salmonids, and by its mixed regime, which originates from melting snow in summer and rains in winter. The fauna of this river includes an invertebrate fauna composed of both endemic and widespread species, which has, however, been only poorly studied until now. The aim of the present study was to make a review of the ecological role of the benthic inland water crustaceans of the River Cautin, in order to understand their importance in the ecosystem of the river. The literature revealed the presence of abundant populations of amphipods and freshwater crabs as well as of aquatic insects along the river’s course. Many of these crustaceans are prey for both introduced salmonids and native fishes. Similar results have been reported for other southern Argentinean and Chilean Patagonian rivers.
Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile)
Brazilian Journal of Biology, 2017
The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second wi...
Evidence of the Anthropic Impact on a Crustacean Zooplankton Community in Two North Patagonian Lakes
Sustainability
Lately, agriculture, livestock, forestry, and aquaculture activities have been greatly developed in Chilean North Patagonia, negatively impacting the balance of the environmental conditions in lakes and affecting the development and survival of several native species. The aim of this study was to assess the anthropic impact on a zooplankton community in two North Patagonian lakes. We collected samples from four sites belonging to Lake Icalma and Lake Llanquihue, including four replicates per site. Water samples were analyzed for physicochemical characteristics and zooplankton communities. We focused on the presence of Daphnia pulex, a species of zooplanktonic crustacean that performs a key role in capturing energy from primary producers to deliver it to final consumers such as fish. We found that Llanquihue showed higher total phosphorus, nitrogen, copper, iron, manganese, total dissolved solids (TDS), and conductivity (EC) than Icalma. Furthermore, ecological variables were greatly...
Latin American Journal of Aquatic Research
Chilean Patagonia has protected mountainous areas with evergreen native forests; in which the lakes and rivers, of volcanic or glacial origin, are oligotrophic. In Bulgaria, there are mountainous zones with native forests and associated lakes of volcanic origin. The aim of the present study is to carry out a preliminary comparison of zooplanktonic crustaceans in lake ecosystems associated with native forests of Chilean Patagonia and of Bulgarian mountains. The study revealed that the lakes studied in Chilean Patagonia are associated mainly with Nothofagus forests; they are oligotrophic, with a low number of zooplanktonic crustacean species. Similar results were observed for Bulgarian mountain lakes associated with Fagus forests. A null model analysis of species co-occurrence was applied to the two groups of lakes, and the result revealed the absence of regulatory factors in species associations. These studies agree with similar descriptions of lakes in Andean Patagonia and New Zealand. They highlight the important role of native Nothofagus forests in Argentina and Chile, and of Fagus forests with associated soil properties in Bulgaria, in the oligotrophy of the lakes studied.
Zoogeography of Chilean inland water crustaceans
Latin American Journal of Aquatic Research, 2013
The Chilean inland water crustaceans are characterized by a combination of endemic and cosmopolitan species: some occur throughout the territory of continental Chile, while others are restricted to specific latitudinal regions. This study examined the zoogeographical patterns exhibited by Chilean inland water crustaceans. We considered six regions: Northern Chile (18º-27°S), North-Central Chile (27º-30°S), Central Chile (30º-38°S), Northern Patagonia (38°-41°S), Central Patagonia (41º-51°S), and Southern Patagonia (51º-55°S), and these were identified based on literature records of inland water crustaceans. The classification analysis generated dendrograms for the following groups considered in this categories: all inland water crustaceans (Branchiopoda, Copepoda and Malacostraca), the zooplanktonic crustaceans (Branchiopoda and Copepoda), the Malacostraca alone, and each group separately. Analysis of total data and of the zooplankton group taxa alone revealed the existence of a main grouping consisting of the three Patagonian zones plus Central Chile, that is distinct from that of Northern Chile and North-Central Chile. Similarly, analysis of the malacostracan data revealed the existence of two main groups, one comprising the three Patagonian zones plus Central Chile, contrasted with a second group of Northern and North-Central Chile combined. Our results are in agreement with other panbiogeographical studies of South American crustaceans and insects. Possible factors responsible for generating this pattern are the dispersal and colonization potential of zooplanktonic crustaceans and the marked endemism of the malacostracans.
Annales De Limnologie-international Journal of Limnology, 2006
Populations are dynamic in space and time. Abundance of organisms can increase or decrease, having a similar influence on the density-dependent processes and the stochastic events . Moreover, animal populations have certain synchronization between their fluctuations and the different environmental factors , Ruetz et al. 2005 which have a direct influence on density, sex ratio and recruitment. The study of biotic interrelationships such as those occurring in planktonic groups or those of invertebrates living in macrophytes, requires the knowledge of change rate, response time and the possibility for a population or community to repeat these conditions through time . In rivers with floodplains, such us the Paraná River, different highly dynamic habitats are recognizable, where stability and diversity are primarily conditioned by hydrology and flow of materials. The flooding pulse results in the coupling between the river and floodplain. Moreover, this basin provide shelters, foods and connectivity among different waterbodies . Therefore, relationships among populations of aquatic organisms like crabs, are subject to the variations of the river.