Search results for "Finland"
showing 10 items of 1724 documents
Late-Holocene variability in chironomid functional assemblages and carbon utilization in a tundra lake food web
2020
AbstractHigh latitude freshwater systems are facing changes in catchment-mediated allochthonous input, as well as physical and chemical controls triggered by on-going climate change, which may alter their carbon processing and ecological characteristics. To explore changes in chironomid functional responses and carbon utilization in relation to long-term environmental change, we studied a sediment core covering ca. 2000 years from a tundra lake in northern Finland, which was analysed for sediment geochemistry, isotopic composition of chironomid remains and their functional assemblages. We aimed to relate changes in chironomid functional feeding assemblages and resource utilization, based on…
Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake.
2010
Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus were studied in a deep, ultra-oligotrophic lake in subarctic Finland from both stomach contents and the stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope compositions of muscle and liver tissues. Both diet and isotope results indicated that the S. alpinus population relied mainly on littoral benthic energy sources. The strong littoral reliance appeared largely independent of season or fish size, although the data lacked small (total length, L(T),130 mm) and young (3 years) S. alpinus. Liver isotope values of intermediate-sized S. alpinus (200-350 mm), however, suggested exploitation of the increase in …
Freshwater mussels (Anodonta anatina) reduce transmission of a common fish trematode (eye fluke, Diplostomum pseudospathaceum)
2017
SUMMARYRecent results suggest that bivalves can play an important role in restraining the spread of various aquatic infections. However, the ability of mussels to remove free-living stages of macroparasites and reduce their transmission is still understudied, especially for freshwater ecosystems. We investigated the influence of the common freshwater mussel (Anodonta anatina) on the transmission of a trematode (eye fluke, Diplostomum pseudospathaceum), which frequently infects fish in farms and natural habitats. In our experiments, mussels caused a significant decrease (P < 0·001) in the abundance of trematode free-living stages, from 6520 to 1770 cercariae L−1 on average (about 4-fold i…
Increasing water temperature and disease risks in aquatic systems: Climate change increases the risk of some, but not all, diseases
2010
Global warming may impose severe risks for aquatic animal health if increasing water temperature leads to an increase in the incidence of parasitic diseases. Essentially, this could take place through a temperature-driven effect on the epidemiology of the disease. For example, higher temperature may boost the rate of disease spread through positive effects on parasite fitness in a weakened host. Increased temperature may also lengthen the transmission season leading to higher total prevalence of infection and more widespread epidemics. However, to date, general understanding of these relationships is limited due to scarcity of long-term empirical data. Here, we present one of the first long…
Habitat quality is more important than matrix quality for bird communities in protected areas
2018
Protected areas are meant to preserve native local communities within their boundaries, but they are not independent from their surroundings. Impoverished habitat quality in the matrix might influence the species composition within the protected areas through biotic homogenization. The aim of this study was to determine the impacts of matrix quality on species richness and trait composition of bird communities from the Finnish reserve area network and whether the communities are being subject of biotic homogenization due to the lowered quality of the landscape matrix. We used joint species distribution modeling to study how characteristics of the Finnish forest reserves and the quality of t…
Lake restoration influences nutritional quality of algae and consequently Daphnia biomass
2020
AbstractFood quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on th…
Lichen communities on Populus tremula are affected by the density of Picea abies
2021
Questions Aspen (Populus tremula) is declining in the old‐growth forests of boreal Fennoscandia. This threatens the numerous taxa that are dependent on old aspens, including many epiphytic lichens. Potential methods to aid epiphytic lichens on aspen are centered around treatments which affect the density of Norway spruce (Picea abies). In this study, we investigated how epiphytic lichen communities on aspen are affected by the variation of spruce density in the immediate vicinity of the focal aspen. Location Southern boreal forests in Finland. Methods We recorded the occurrence of lichens from 120 aspens in 12 semi‐natural forest sites. We used spruce basal area as the measure for spruce de…
The effect of buffer strip width and selective logging on streamside plant communities
2019
Background Riparian forests surrounding streams host high biodiversity values, but are threatened by clear-cut logging. Narrow buffer strips of about 15 m are commonly left between the stream and the clear-cut, but studies suggest that the buffer width should be at least 30 m to protect riparian plant communities. Moreover, selective logging is often allowed on the buffer strips in order to increase economic gain. We used an experiment of 43 riparian sites where buffer strip width and selective logging within the strip were manipulated and supplemented with unlogged control sites. We report the short-term changes in the community composition of vascular plants and mosses near the stream (0–…
A new species of Arctoseius Thor, 1930 (Acari: Ascidae) from taiga regions of the Palaearctic, with a key to Arctoseius species of Fennoscandia, NW E…
2017
A new mesostigmatid mite species belonging to the genus Arctoseius Thor, 1930, is described based on material from subarctic coniferous forests, Finland, and Altai highlands, Russia. Arctoseius ambiguus sp. nov. is similar to Arctoseius venustulus (Berlese, 1916), but can be distinguished from the latter by its larger size, wider dorsal shield, weakly sclerotized presternal platelets, pronounced differences in the length of opisthonotal setae, and distinct punctation of the anal shield. A key for 15 Arctoseius species recorded in continental North-Western Europe (Fennoscandia) is given. The Fennoscandian fauna of Arctoseius species is rather specialised. It includes four European temperate …
Active hiding of social information from information-parasites
2014
Background: Coevolution between pairs of different kind of entities, such as providers and users of information, involves reciprocal selection pressures between them as a consequence of their ecological interaction. Pied flycatchers ( Ficedula hypoleuca ) have been shown to derive fitness benefits (larger clutches) when nesting in proximity to great tits ( Parus major ), presumably because they this way discover and obtain information about nesting sites. Tits suffer from the resulting association (smaller clutches). An arms race between the tits (information host) and the flycatchers (information parasite) could thus result . Great tits often cover eggs with nesting material before, but no…