Microcrustacean assemblages composition and environmental variables in lakes and ponds of the Andean region - South of Chile (37-39° S)

Abstract

The zooplankton assemblages in Chilean Patagonian lakes are characterised mainly by their low biodiversity and high predominance of calanoids copepods, a pattern that has been studied for large and deep lakes between 38-51° S, and shallow ponds at 51° S. The aim of the present study was analyse the zooplankton assemblages in different water bodies located in coastal zones, middle valleys and mountain zones between 37-39° S. For this purpose, the following variables were considered: maximum depth, latitude, altitude, chlorophyll-a and species number, and to these variables, a Principal Component Analysis (PCA) was applied. A co-occurrence null model analysis was also applied for determining the existence of a random process in crustacean species associations. The results denoted low species richness, and different species associations for studied sites, and the null model analysis revealed the absence of a random process as regulator of species associations. Furthermore, a low species/genera ratio was identified, which denotes low productivity of the studied sites. These results were supported by a PCA analysis which denoted that the main determinant factors are chlorophyll concentration and species number that are directly associated. The obtained results are in agreement with descriptions in the literature for species diversity for lakes of Chilean Patagonia that describes oligotrophy as the main regulator of zooplankton assemblages. Other ecological and limnological topics are discussed in the present study.

Crustacean zooplankton communities in Lake General Carrera (46°S) and their possible association with optical properties

“…chilensis. Similar results were observed for other glacial, oligotrophic lakes in Torres del Paine National Park, such as Nordsdenkjold and Grey, where the Zooplankton communities consist of only two species {B. michaelseni and Tropocyclops prasinus (Fischer, I860)) (Soto et al, 1994;Soto & De los Ríos, 2006;De los Ríos-Escalante, 2010;De los Ríos-Escalante et al, 2011). This situation differs from that of another Patagonian lake with glacial influence.…”

“…In central and south Chilean Patagonia (46-51°S) there are numerous deep, oligotrophic lakes of glacial origin and/or with glaciers associated with their basins (Soto & Zúñiga, 1991;Soto et al, 1994;De los Ríos-Escalante, 2011), which contain Zooplankton communities with a low number of species and high calanoid dominance (Soto & Zúñiga, 1991;De los Ríos & Soto, 2006, 2007 De los Ríos-Escalante, 2010). This region is practically unpolluted and has been little studied due mainly to geographical difficulties -mountains, ice fields and fiords -and the weather, characterized by strong winds, especially in the southem spring and summer (October-February) (Soto et al, 1994;De los Ríos-Escalante, 2010).…”

Regulatory factors in crustacean zooplankton assemblages in mountain lakes of northern Chilean Patagonia (38 41°S): a comparison with Bulgarian counterparts (42°N)

“…The aim of the present study is to compare data obtained from the literature of chlorophyll-a concentration and crustacean zooplankton populations in North Patagonian mountain lakes and Bulgarian mountain lakes, considering the geographical and ecological differences between the two regions. Data about the trophic status and zooplanktonic crustacean and littoral species from Chilean mountain lakes were obtained from the literature (n = 8; Steinhart et al, 2002;De los Ríos-Escalante et al, 2011) and from field-work in Alerce Andino National Park. The data from Bulgaria (n = 9) were taken from the literature Hristozova et al, 2004).…”

Evidence of the Anthropic Impact on a Crustacean Zooplankton Community in Two North Patagonian Lakes

“…In South America, specifically in Chilean North Patagonia, there are lakes that were characterized by their morphology, physicochemical properties, environmental conditions, and biodiversity as oligotrophic lakes in the 1980s and 1990s [9][10][11][12][13][14][15][16]. However, in Chilean North Patagonia, a significant expansion of different economic activities has been observed in recent decades, such as agriculture, livestock, forestry, and aquaculture [17].…”