Mass occurance and sporadic distribution of Corynocera ambigua Zetterstedt (Diptera, Chironomidae) in Danish lakes. Neo- and palaeolimnological records     

Klaus Peter Brodersen  Claus Lindegaard 《Journal of Paleolimnology》1999,22(1):41-52

The chironomid Corynocera ambigua (Tanytarsini) is commonly reported as a cold-stenothermal species living in shallow lakes in arctic and subarctic regions. In palaeoecological studies of temperate lakes, larval remains of C. ambigua are usually found in late-glacial sediments from the Allerød and Younger Dryas periods, and often in association with subfossil Chara oospores. During a surface sampling program of chironomid head-capsules in 41 Danish temperate lakes, C. ambigua was found to comprise 25% of the chironomid assemblages in two lakes, and was sporadically found in 8 other lakes (0.5-10%). A 70 cm palaeo-stratigraphy from the shallow (max depth 1.2 m) and eutrophic (total phosphorus = 150 g P l^-1) Lake Stigsholm showed that C. ambigua has been abundant in the last 4-5 centuries. At a sediment level of 25 cm (~year 1925, ²¹⁰Pb dating), C. ambigua began to decrease in frequency while Chironomus plumosus, Procladius sp., Cladotanytarsus gr. mancus and Tanytarsus spp. increased, suggesting an increased nutrient loading and an approach to eutrophic conditions. In 1995 C. ambigua was still very abundant in Lake Stigsholm but in early March 1997 no living larvae were found. An extremely heavy growth of Elodea, Enteromorpha and filamentous algae in the summers of 1995 and 1996, with following degradation in the fall, might have influenced the invertebrate population dynamics. No significant distinguishing characteristics were found for the lakes supporting C. ambigua. Its occurrence in warm (~20°C) Danish lakes brings into question the perception of the species as being cold-stenothermal.  相似文献   

Spatial and seasonal distribution of macroinvertebrates in high altitude reservoir (Beyler Reservoir, Turkey)     

zlem FINDIK 《中国海洋湖沼学报》2013,31(5):994-1001

A highland reservoir in the West Black Sea region of Turkey which belongs to the Mediterranean climatic zone was examined.Both littoral and profundal zones were sampled from October 2009 to September 2010,to determine taxonomic composition,biodiversity and abundance of benthic invertebrates as well as the seasonal variation of these measures.A total of 35 taxa were identified,of which 12 belong to Chironomidae and 10 to Oligochaeta groups.The highest diversity and abundance of benthic macroinvertebrates were found at the littoral stations.Macroinvertebrates showed significant positive correlations with water temperature and NO₂ and NO₃ concentrations,and negative correlation with dissolved oxygen.  相似文献   

Notes on the presence of the brown mudfish (Neochanna apoda günther) on the west coast of the south Island of New Zealand     

G. A. Eldon 《新西兰海洋与淡水研究杂志》2013,47(1):37-48

Two visits to the West Coast revealed that Neochanna apoda Giinther is present in six clearly defined types of habitat examined between Oparara and Whataroa.

The location of habitats varied from heavily forested country to open pakihi bog, between sea level and 200 m. A Neochanna apoda habitat was generally uninhabited by any other species of fish; occasionally short‐finned eels (Anguilla australis) and, once, banded kokopu (Galaxias fasciatus) were present. An association with freshwater crayfish (Paranephrops planifrons) was often noted.

Neochanna apoda was found in all stages of development from fry to adults over 150 mm in length, and all size ranges were present in some places.  相似文献