Search results for "Specie"
showing 10 items of 4389 documents
Species and genetic diversity relationships in benthic macroinvertebrate communities along a salinity gradient
2022
Background Species- and genetic diversity can change in parallel, resulting in a species-genetic diversity correlation (SGDC) and raising the question if the same drivers influence both biological levels of diversity. The SGDC can be either positive or negative, depending on whether the species diversity and the genetic diversity of the measured species respond in the same or opposite way to drivers. Using a traditional species diversity approach together with ultra-conserved elements and high throughput sequencing, we evaluated the SGDCs in benthic macrofauna communities in the Baltic Sea, a geologically young brackish water sea characterised by its steep salinity gradient and low species …
Homage to Proserpina, or: why did the charophytes of the Pergusa Lake vanish?
2020
An important bisexual population of the charophyte Chara canescens Loisel. (Characeae, Charales, Charophyceae) was reported in the XIX century for the Pergusa Lake (Sicily). A recent field survey to check its presence revealed that it has disappeared. After a bibliographic research to understand when and why this happened, the input of freshwater from outside the basin and the introduction of the carps were identified as the two main causes for its recent extinction. Some possible management measures to try to restore the lake ecosystem are proposed.
Effects of forest-fuel harvesting on the diversity of dead wood and epixylic macrolichens in clear-cuts
2016
Energiapuuta käytetään yhä enemmän uusiutuvan energian lähteenä. Energiapuun korjuussa hakkuutähteitä eli kantoja, oksia ja latvuksia kerätään päätehakkuun ja harvennuksen yhteydessä hakkuualoilta. Tämä vähentää erityisesti pienikokoisen lahopuun ja kantojen määrää. Lahopuu on tärkeä resurssi boreaalisissa metsissä, mutta sen määrä talousmetsissä on alhainen luonnonmetsiin verrattuna. Määrän väheneminen edelleen energiapuun korjuun seurauksena voi johtaa lahopuusta riippuvaisen monimuotoisuuden vähenemiseen, minkä vuoksi on tärkeää tutkia energiapuun korjuun monimuotoisuusvaikutuksia. Teoriat pinta-alan ja habitaatin heterogeenisyyden vaikutuksesta lajimäärään ovat yksiä tärkeimmistä lajimä…
Predicting valuable forest habitats using an indicator species for biodiversity
2020
Intensive management of boreal forests impairs forest biodiversity and species of old-growth forest. Effective measures to support biodiversity require detection of locations valuable for conservation. We applied species distribution models (SDMs) to a species of mature forest, the northern goshawk (Accipiter gentilis, goshawk), that is often associated with hotspots of forest biodiversity. We located optimal sites for the goshawk on a landscape scale, assessed their state under intensified logging operations and identified characteristics of goshawks' nesting sites in boreal forests. Optimal sites for the goshawk covered only 3.4% of the boreal landscape and were mostly located outside pro…
Do large‐scale associations in birds imply biotic interactions or environmental filtering?
2023
Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species association…
Species distributions models may predict accurately future distributions but poorly how distributions change: A critical perspective on model validat…
2023
Aim: Species distribution models (SDMs) are widely used to make predictions on how species distributions may change as a response to climatic change. To assess the reliability of those predictions, they need to be critically validated with respect to what they are used for. While ecologists are typically interested in how and where distributions will change, we argue that SDMs have seldom been evaluated in terms of their capacity to predict such change. Instead, typical retrospective validation methods estimate model's ability to predict to only one static time in future. Here, we apply two validation methods, one that predicts and evaluates a static pattern, while the other measures change…
gllvm : Fast analysis of multivariate abundance data with generalized linear latent variable models in R
2019
1.There has been rapid development in tools for multivariate analysis based on fully specified statistical models or “joint models”. One approach attracting a lot of attention is generalized linear latent variable models (GLLVMs). However, software for fitting these models is typically slow and not practical for large datsets. 2.The R package gllvm offers relatively fast methods to fit GLLVMs via maximum likelihood, along with tools for model checking, visualization and inference. 3.The main advantage of the package over other implementations is speed e.g. being two orders of magnitude faster, and capable of handling thousands of response variables. These advances come from using variationa…
Bright spots in the darkness of cancer: A review of starfishes-derived compounds and their anti-tumor action
2019
The fight against cancer represents a great challenge for researchers and, for this reason, the search for new promising drugs to improve cancer treatments has become inevitable. Oceans, due to their wide diversity of marine species and environmental conditions have proven to be precious sources of potential natural drugs with active properties. As an example, in this context several studies performed on sponges, tunicates, mollusks, and soft corals have brought evidence of the interesting biological activities of the molecules derived from these species. Also, echinoderms constitute an important phylum, whose members produce a huge number of compounds with diverse biological activities. In…
Marine reserves : fish life history and ecological traits matter
2010
Copyright by the Ecological Society of America
Effects of NIS on Mediterranean marine ecosystems: the case study of Egadi Island MPA (Sicily, Tyrrhenian Sea)
2018
Habitat modification and loss, climate change and the introduction of Non-Indigenous Species (NIS, i.e. organisms introduced outside of their natural, past or present, range and outside of their natural dispersal potential) are considered to be the main threats to Mediterranean marine biodiversity and natural ecosystem functioning. NIS may become invasive (IAS = Invasive Alien Species) and may have significant environmental, socio-economic and human health impacts. The Mediterranean Sea is one of the major hotspots for NIS introductions, with the total for these species having almost reached the 1,000 figure (equivalent to ca. 6% of the total flora and fauna). NIS are entering the Mediterra…