Search results for " CONSERVATION"

Spatiotemporal monitoring of the rare northern dragonhead (Dracocephalum ruyschiana, Lamiaceae) — SNP genotyping and environmental niche modeling her…

2022

The species we have studied the spatiotemporal genetic change in the northern dragonhead, a plant species that has experienced a drastic population decline and habitat loss in Europe. We have added a temporal perspective to the monitoring of northern dragonhead in Norway by genotyping herbarium specimens up to 200 years old. We have also assessed whether northern dragonhead has achieved its potential distribution in Norway. To obtain the genotype data from 130 herbarium specimens collected from 1820 to 2008, mainly from Norway (83) but also beyond (47), we applied a microfluidic array consisting of 96 SNP markers. To assess temporal genetic change, we compared our new genotype data with exi…

Host in reserve: The role of common shrews (Sorex araneus) as a supplementary source of tick hosts in small mammal communities influenced by rodent p…

2022

Rodents often act as important hosts for ticks and as pathogen reservoirs. At north -ern latitudes, rodents often undergo multi- annual population cycles, and the peri -odic absence of certain hosts may inhibit the survival and recruitment of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a sup -plementary host source to immature life stages (larvae and nymphs) of a generalist tick Ixodes ricinus and a small mammal specialist tick I. trianguliceps, during decreas-ing abundances of bank voles (Myodes glareolus). We used generalized mixed models to test whether ticks would have a propensity to parasitize a certain host species dependent on host populati…

FishSizer: Software solution for efficiently measuring larval fish size

2022

Length and depth of fish larvae are part of the fundamental measurements in many marine ecology studies involving early fish life history. Until now, obtaining these measurements has required intensive manual labor and the risk of inter- and intra-observer variability. We developed an open-source software solution to semi-automate the measurement process and thereby reduce both time consumption and technical variability. Using contrast-based edge detection, the software segments images of a fish larva into “larva” and “background.” Length and depth are extracted from the “larva” segmentation while taking curvature of the larva into consideration. The graphical user interface optimizes workf…

Recovery of macroinvertebrate communities from stream habitat restoration

1998

1. Many streams channelized for timber floating in Finland are now being restored to their original condition. The most frequently used restoration structures are boulder dams, flow deflectors, excavations and channel enlargements. By increasing substrate heterogeneity and leaf litter retention, restoration may enhance the formation of detritivore-dominated macroinvertebrate assemblages. In this study, macroinvertebrate communities in streams with differing recovery periods (from 0 to 16 years) from restoration, were compared with those in channelized and near-pristine streams. 2. Water depth and current velocity were lower, and relative bed roughness higher in restored than in dredged chan…

Forest Fragmentation Increases Nest Predation in the Eurasian Treecreeper

2004

We used long-term breeding data to monitor the influences of fragmentation and habitat composi- tion at different spatial scales on the reproductive success of Eurasian Treecreepers (Certhia familiaris) breeding in nest boxes. We collected data from the same forest patches (2.7-65.1 ha in size) during seven breeding sea- sons. Nest predation varied considerably over the years and was the primary cause of nesting failure (mean annual rate of 21.6 ± 12.8%). Nest predation explained most of the variation in fledgling production during the study period. Landscape-level fragmentation (radius of 500 m from territory center) affected nest predation more than did fragmentation on the territory scal…

Isoëtes sabatina (Isoëtaceae, Lycopodiopsida). Taxonomic distinctness and preliminary ecological insights

2021

1) Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres. 2) Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina. 3) To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species wa…

Bacteria, fungi and arthropod pests collected on modern human mummies

2011

A survey of opportunistic biocenosis (macro and micro organisms) associated with a rest of human mummy samples was carried out to characterise the biocenosis and to detect the potential of biodeteriogens. The rests of the human modern mummies come from a hypogeic site. Since mummies are relevant from a historic-artistic-scientific point of view, an aspect of this study was the identification and characterization of the biological systems related with biodeterioration of organic matter. In a first step, different sampling methods, according to the taxa, were applied. Technological procedures were combined in order to have an interdisciplinary approach to the conservation actions for testing …

Individual and Environmental Determinants of Daily Black Grouse Nest Survival Rates at Variable Predator Densities

2010

Nest predation in ground nesting black grouse (Tetrao tetrix) inhabiting managed boreal forests is arguably the single most important cause of nesting failure. Little is known, however, about indirect effects of other factors, such as maternal or environmental properties, and to what extent maternal and habitat qualities interact with varying levels of predator densities. Using an information-theoretical approach, we studied maternal and environmental determinants of daily nest survival rates under variable predator densities of 210 individual black grouse hens in central Finland. Environmental determinants were far more important than maternal ones, and the effects were more apparent at hi…

Loss of a freshwater copepod species from El Junco Lake, Galápagos following the introduction and eradication of the Nile tilapia

2021

An undescribed diaptomid copepod probably belonging to a new Mastigodiaptomus species has been discovered and was very abundant in El Junco Lake (San Cristóbal Island, Ecuador) from 1966 until 2004. The species was not found in samples from 2007, 2008 or 2018. The loss of this key species from the lake coincides with the illegal introduction of Nile tilapia to El Junco Lake in 2005 and its subsequent eradication in 2008. The disappearance of this biogeographically and ecologically important copepod population may be explained by direct mechanisms of predation and competition, by a combination of both processes, and by indirect mechanisms linked to alterations in the lake ecosystem. The effe…

2015

Songs in passerine birds are important for territory defense and mating. Speciation rates in oscine passerines are so high, due to cultural evolution, that this bird lineage makes up half of the extant bird species. Leaf warblers are a speciose Old-World passerine family of limited morphological differentiation, so that songs are even more important for species delimitation. We took 16 sonographic traits from song recordings of 80 leaf warbler taxa and correlated them with 15 potentially explanatory variables, pairwise, and in linear models. Based on a well-resolved molecular phylogeny of the same taxa, all pairwise correlations were corrected for relatedness with phylogenetically independe…