Search results for "Littoral"
showing 10 items of 118 documents
Range Shifts of Mouse Lemurs in South-Eastern Madagascar: Evidence from Mitochondrial Genetic Data
2012
The gray mouse lemur, Microcebus murinus, occurs mainly in dry forests in western Madagascar, but its distribution extends into humid littoral forests in the south-eastern Anosy Region. We sequenced the mitochondrial hypervariable region 1 for 282 M. murinus individuals from 13 south-eastern study sites. The spatial distribution of mitochondrial haplotypes and the varying genetic distances within two haplotype clades indicated a trend of decreasing genetic diversity towards the south-eastern margin of the range. Rufous mouse lemurs, Microcebus cf. rufus, have a complementary distribution in south-eastern Madagascar which does not overlap with that of M. murinus. Taken together, the spatial …
Males Benefit from Mating with Outbred Females in Drosophila littoralis: Male Choice for Female Genetic Quality?
2015
The evolution and expression of mate choice behaviour in either sex depends on the sex-specific combination of mating costs, benefits of choice and constraints on choice. If the benefits of choice are larger for one sex, we would expect that sex to be choosier, assuming that the mating costs and constraints on choice are equal between sexes. Because deliberate inbreeding is a powerful genetic method for experimental manipulation of the quality of study organisms, we tested the effects of both male and female inbreeding on egg and offspring production in Drosophila littoralis. Female inbreeding significantly reduced offspring production (mostly due to lower egg-to-adult viability), whereas m…
Inbreeding rate modifies the dynamics of genetic load in small populations
2012
The negative fitness consequences of close inbreeding are widely recognized, but predicting the long-term effects of inbreeding and genetic drift due to limited population size is not straightforward. As the frequency and homozygosity of recessive deleterious alleles increase, selection can remove (purge) them from a population, reducing the genetic load. At the same time, small population size relaxes selection against mildly harmful mutations, which may lead to accumulation of genetic load. The efficiency of purging and the accumulation of mutations both depend on the rate of inbreeding (i.e., population size) and on the nature of mutations. We studied how increasing levels of inbreeding …
Inter-annual variation in macroinvertebrate communities in a shallow forest lake in eastern Finland during 1990–2001
2003
As a part of the Integrated Monitoring (IM) Programme of Air Pollution Effects on Ecosystems, the macroinvertebrate community of a pristine forest lake was monitored from 1990 up to the present. Lake Iso Hietajarvi is a small and shallow, weakly stratified oligotrophic headwater lake situated in Patvinsuo National Park, eastern Finland. Benthic macroinvertebrates were sampled annually, once in autumn at depths of 3 - 4 m (sublittoral zone) and at 7 m (profundal zone). The water quality of the lake and meteorological characteristics in the area were monitored during the same period. The inter-annual variation in macroinvertebrate abundance and taxonomic composition in the lake unaffected by …
Benthic foraminiferal response to trace element pollution. The case study of the Gulf of Milazzo, NE Sicily (Central Mediterranean Sea).
2013
The response of benthic foraminiferal assemblages to trace element pollution in the marine sediments of the Gulf of Milazzo (north-eastern Sicily) was investigated. Since the 1960s, this coastal area has been a preferred site for the development of two small marinas and a commercial harbour as well as for heavy industry. Forty samples collected in the uppermost 3-4 cm of an undisturbed layer of sediment in the littoral environment were used for this benthic foraminiferal analysis. The enrichment factors (EFs) of selected trace elements (As, Co, Cr, Cu, Mn, Ni, Pb and Zn) were also calculated. Changes both in benthic foraminiferal assemblages and in some trace elements concentrations have pr…
The distribution of sexual reproduction of the geographic parthenogenEucypris virens(Crustacea: Ostracoda) matches environmental gradients in a tempo…
2013
Niche segregation may prevent competitive exclusion and promote local coexistence. This typically results in the occupation of different habitats. In the freshwater ostracod Eucypris virens (Jurine, 1820), the distribution of sexual and parthenogenetic populations in the temporary Lake Caracuel, central Spain, was not homogeneous. Parthenogens were found everywhere including the littoral, whereas sexuals were restricted to the centre. We investigated the hypothesis that spatial distribution responded to ecological differences. We studied the ecological significance of this segregation by linking environmental data to male presence, sexual fraction, ploidy, and genetic structure of our model…
The Chironomidae (Diptera) in Two Polyhumic Reservoirs in Western Finland
1980
ABSTRACT Composition and distribution of chironomid and other benthic fauna was studied at two adjacent 15 years old polyhumic reservoirs in western Finland by taking benthic and emergence samples. The littoral (0.5 m) coarse debris habitats, previously coniferous forest, had considerably less chironomid larvae (6–7 types, maximally 800 individuals or 0.1 g, AFDW/m2) than the mossgrown habitats, previously peatland (9–10 types, maximally 4000 individuals or 3·4 g/m2). The Chironomus larvae which were dominant at the moss sites were almost lacking at the coarse debris sites. Zalutschia zalutschicola Lipina and Tonytarsus larvae were found only at the deepest areas at 6 m. Altogether 17 speci…
Stigmatized cohabitation in the Latvian region of the eastern Baltic littoral: nineteenth and twentieth centuries
2014
The social history of coresidence arrangements in the Latvian region suggests that forms of cohabitation without marriage were present in the Latvian population since the eighteenth century when empirical evidence became available. Before the twentieth century, however, these forms remained marginal and seldom involved choice. The subject of severe criticism until the 1960s–1970s, such forms become more widespread thereafter as the Latvian population began to exhibit many key features of a second demographic revolution. Post-Soviet censuses now suggest that such coresidence patterns in the Latvian population approach the levels of those in most western European states, including the Scandin…
Effects of temperature and sediment properties on benthic CO2production in an oligotrophic boreal lake
2010
Summary 1. Temperature and many other physical and chemical factors affecting CO2 production in lake sediments vary significantly both seasonally and spatially. The effects of temperature and sediment properties on benthic CO2 production were studied in in situ and in vitro experiments in the boreal oligotrophic Lake Paajarvi, southern Finland. 2. In in situ experiments, temperature of the water overlying the shallow littoral sediment varied seasonally between 0.5 and 15.7 °C, but in deep water (≥20 m) the range was only 1.1–6.6 °C. The same exponential model (r2 = 0.70) described the temperature dependence at 1.2, 10 and 20 m depths. At 2.5 and 5 m depths, however, the slopes of the two re…
Hydrology is reflected in the functioning and community composition of methanotrophs in the littoral wetland of a boreal lake
2010
In lake ecosystems a major proportion of methane (CH4) emissions originate from the littoral zone, which can have a great spatial variability in hydrology, soil quality and vegetation. Hitherto, spatial heterogeneity and the effects it has on functioning and diversity of methanotrophs in littoral wetlands have been poorly understood. A diagnostic microarray based on the particulate methane monooxygenase gene coupled with geostatistics was used to analyse spatial patterns of methanotrophs in the littoral wetland of a eutrophic boreal lake (Lake Kevaton, Eastern Finland). The wetland had a hydrology gradient with a mean water table varying from −8 to −25 cm. The wettest area, comprising the h…