Pliuraite V.,Institute of Ecology of Nature Research Center
Fresenius Environmental Bulletin | Year: 2011
The status of three Lithuanian medium-sized streams: a forested natural stream, an agricultural natural stream and a straightened stream, receiving diffused pollution from agricultural lands, was evaluated in spring, summer and autumn 2008 using selected physicochemical variables and macroinvertebrate analysis. Taxonomie composition of invertebrate macrofauna was used for calculation of the following biotic indices: the Danish Stream Fauna Index (DSFI), Hilsenhoff Biotic Index (HBI), Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), Belgian Biotic Index (BBI) and Extended Biotic Index (IBE). The data obtained show that water quality was of class 1 in the forested natural stream, of class 3 in the agricultural natural stream and of class 4 in the agricultural channelized stream (on a five-class scale), according to NO3-N and N total values. It was concluded that BMWP, ASPT, BBI and IBE indices tend to assign stream water to a higher water quality class than DSFI and HBI do. According to BMWP, BBI and IBE indices, good water quality was found even in the agricultural natural stream, where water quality was moderate according to NO 3-N and NT values. © by PSP.
Nika N.,Klaipeda University |
Virbickas T.,Institute of Ecology of Nature Research Center
Journal of Fish Biology | Year: 2010
Reproductive interaction between sympatric lampreys and salmonids was studied. The superimposition of brown trout Salmo trutta redds by spring-spawning river lamprey Lampetra fluviatilis and brook lamprey Lampetra planeri was examined in a small lowland stream of western Lithuania. A high superimposition rate of S. trutta redds by both L. fluviatilis (up to 83%) and L. planeri (up to 48%) was found, when the spawning intensity of Lampetra spp. was high. The occurrence of this phenomenon is the result of the overlap in the spawning habitat preferences at the reach-scale and at the microhabitat scale for the three species. One of the main requirements for Lampetra spp. spawning site selection was the negative streambed slope, an essential trait of the pool-riffle transitional zone. The structure of the salmonid redd created a considerable negative microhabitat slope suitable for Lampetra spp. spawning, which put the redds under a higher susceptibility to be superimposed. The timing of Lampetra spp. spawning overlapped closely with the emergence of S. trutta fry, suggesting a probable ecological effect of superimposition on S. trutta in the pre-emergent and emerging stages. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.
Balciauskas L.,Institute of Ecology of Nature Research Center |
Balciauskiene L.,Institute of Ecology of Nature Research Center
North-Western Journal of Zoology | Year: 2012
A single specimen of the Mediterranean water shrew (Neomys anomalus) was trapped in west Lithuania in 2009. Characteristics of N. anomalus shared by this specimen include: the keel on the ventral side of the tail only extending to the proximal third of the tail length, and the hind foot length and several skull measurements being significantly smaller than N. fodiens. The habitat of the specimen was flooded sedge meadows and reeds. A review of the skull collection at the Nature Research Centre (Vilnius, Lithuania) and its associated biometric data yielded two more N. anomalus individuals from the west of the country. These records extend the species' distribution by over 350 km to the north and represent a new mammal species for Lithuania and the Baltic countries. © NwjZ, Oradea, Romania, 2012.
Juskaitis R.,Institute of Ecology of Nature Research Center |
Baltrunaite L.,Institute of Ecology of Nature Research Center
Folia Zoologica | Year: 2013
The diet of the forest dormouse, Dryomys nitedula, was studied in Lithuania, which is situated on the north-western edge of its range. The diet composition of D. nitedula changes constantly over the activity period. From late April until mid-July, food of animal origin dominates the diet, while vegetable food prevails from mid-July until early September. Over the entire activity season, food of animal origin comprises on average 63 % of dormouse diet by volume estimates. Four main food groups - birds, adult insects, insect larvae and millipedes - dominate, but their proportions vary over the course of the season, as does the composition of vegetable food used by D. nitedula. Among vegetable food, dormice feed on blossoms of Norway spruce, oak and aspen in May, cones of Norway spruce during June-August, raspberries, birch seeds and fruits of glossy buckthorn in July and August and oak acorns in late August and early September. The composition of vegetable food used by D. nitedula in Lithuania is rather specific in comparison to other parts of the range and shows high dormouse adaptability to local conditions. In different years, the proportions of vegetable and animal food, as well as their compositions, vary in the dormouse diet. Dormice can accumulate sufficient fat reserves for hibernation feeding on both vegetable and animal food.
Pliuraite V.,Institute of Ecology of Nature Research Center |
Kesminas V.,Institute of Ecology of Nature Research Center
Fresenius Environmental Bulletin | Year: 2010
The present study contains the results of an investigation of the taxonomic diversity of common groups of benthic macrofauna, collected in the natural and channelized sites of the large river, receiving diffused pollution from agricultural lands. Channelization impacts on macroinvertebrate communities ranged from a negative influence to no effect. Total species richness (SR) in the natural river site was higher in comparison with that of the channelized river site. The sensitive Plecoptera are missing. There were no significant statistical differences for total Ephemeroptera and Trichoptera (ET) richness between the natural and the channelized river site. The data obtained showed that the natural site differed from the channelized one in the dominance of individual taxa. The data of this investigation showed that the share of Trichoptera was significantly higher in the natural site while the share of Chironomidae was higher in the channelized river site. According to Hilsenhoff biotic index, the ecological status during all seasons in natural river site is good and in channelized site fair. © by PSP.