Search results for "SYSTEMATICS"
showing 10 items of 6702 documents
Risk of inbreeding : problem of mate choice and fitness effects?
2016
Mating with close kin may cause inbreeding depression with negative consequences to offspring and local populations. There exist mechanisms like kin-recognition or sex-specific dispersal to avoid mating with kin. In fluctuating population densities, like in many small mammals, both very low and very high densities provide conditions for inbreeding, if kin males are prone to stay in their natal area. Females are choosy and male dominance is thought to be the key feature when selecting mating partners. The aim of this study was to test the possible discrepancy in mate choice and negative fitness effects of inbreeding in two experiments, one in the laboratory and one in field enclosures. We as…
Biogeochemical cycling and ecological thresholds in a High Arctic lake (Svalbard)
2019
Lakes are a dominant feature of the Arctic landscape and a focal point of regional and global biogeochemical cycling. We collected a sediment core from a High Arctic Lake in southwestern Svalbard for multiproxy paleolimnological analysis. The aim was to find linkages between the terrestrial and aquatic environments in the context of climate change to understand centennial-long Arctic biogeochemical cycling and environmental dynamics. Two significant thresholds in elemental cycling were found based on sediment physical and biogeochemical proxies that were associated with the end of the cold Little Ice Age and the recent warming. We found major shifts in diatom, chironomid and cladoceran comm…
Harvest‐induced evolution and effective population size
2016
Much has been written about fishery-induced evolution (FIE) in exploited species, but relatively little attention has been paid to the consequences for one of the most important parameters in evolutionary biology-effective population size (N-e). We use a combination of simulations of Atlantic cod populations experiencing harvest, artificial manipulation of cod life tables, and analytical methods to explore how adding harvest to natural mortality affects N-e, census size (N), and the ratio N-e/N. We show that harvest-mediated reductions in N-e are due entirely to reductions in recruitment, because increasing adult mortality actually increases the N-e/N ratio. This means that proportional red…
Temporal turnover of the soil microbiome composition is guild-specific.
2021
Although spatial and temporal variation are both important components structuring microbial communities, the exact quantification of temporal turnover rates of fungi and bacteria has not been performed to date. In this study, we utilised repeated resampling of bacterial and fungal communities at specific locations across multiple years to describe their patterns and rates of temporal turnover. Our results show that microbial communities undergo temporal change at a rate of 0.010-0.025 per year (in units of Sorensen similarity), and the change in soil is slightly faster in fungi than in bacteria, with bacterial communities changing more rapidly in litter than soil. Importantly, temporal deve…
Sea temperature effects on depth use and habitat selection in a marine fish community.
2021
14 pages, 7 figures, 2 tables.-- Open access
PERSPECTIVE: Underutilized resources for studying the evolution of invasive species during their introduction, establishment, and lag phases
2010
The early phases of biological invasions are poorly understood. In particular, during the introduction, establishment, and possible lag phases, it is unclear to what extent evolution must take place for an introduced species to transition from established to expanding. In this study, we highlight three disparate data sources that can provide insights into evolutionary processes associated with invasion success: biological control organisms, horticultural introductions, and natural history collections. All three data sources potentially provide introduction dates, information about source populations, and genetic and morphological samples at different time points along the invasion trajector…
Phytoplankton assemblages respond differently to climate warming and eutrophication : A case study from Pyhäjärvi and Taihu
2016
Abstract Long-term monitoring data from two lakes located at different latitudes were used to test the hypothesis that phytoplankton communities respond differently to environmental changes (e.g., global warming and anthropogenic activities, mainly eutrophication). Lake Pyhajarvi (temperate area) and Lake Taihu (subtropical area) are both shallow and productive lakes. Presence/absence data indicated that phytoplankton taxa present did not change significantly in the two lakes over the last two decades. However, biomass data showed that dominance relationships of species changed in both lakes. Results of assemblage ordination indicated that climate change played a vital role in mediating phy…
Responses of small mammal communities to environment and agriculture in a rural mosaic landscape
2018
Intensification of agriculture is an increasing threat for biodiversity. Central Romania still preserves a traditional rural landscape with a matrix of small plots of crops and large surfaces covered by grasslands and forests, but its biodiversity is very poorly studied. Small mammals are key components of agrarian and semi-natural ecosystems but rodents are also viewed as major pests. Knowledge of the driving factors of small mammal communities in agricultural landscapes may enable taking management measures that pursue both conservation and economic goals. Here we evaluate the response of small mammals to environmental variables, including vegetation characteristics, land use and geograph…
CHANGES IN COLLEMBOLA RICHNESS AND DIVERSITY ALONG A GRADIENTOF LAND-USE INTENSITY : A pan European study
2006
Changes in Collembola richness and diversity along a land-use intensity gradient were studied in eight European countries (Portugal, Spain, France, Switzerland, Hungary, UK, Ireland and Finland). In each country a set of six 1 km2 land-use units (LUUs) were selected forming a gradient ranging from natural forest to agricultural dominated landscapes, passing through mixed-use ones. In addition to data on Collembola, detailed information regarding landscape diversity and structure was collected for each LUU. A total of 47,774 individuals were identified from 281 species. Collembola reacted not only to changes in the diversity of the landscape, but also to the composition of that diversity and…
Population size and breeding performance of the Lanner Falcon Falco biarmicus in Sicily: conservation implications
2017
Capsule: We report a significant reduction in population size and breeding success for the Lanner Falcon Falco biarmicus in Sicily, its biggest stronghold in Europe, since the latest coordinated survey. Aims: To provide updated information on current population size of Lanner Falcon in Sicily and to compare breeding parameters with those obtained in previous studies. Methods: We performed an intensive coordinated field survey and literature review of breeding success parameters across the species range. Results: Overall, we monitored 126 territories throughout Sicily where the species had been reported in the last 15 years. Lanner Falcons were present only in 60 of them. Mean nest productiv…