Search results for "Landscape"
showing 10 items of 1561 documents
Behavioural strategy of common bottlenose dolphins (Tursiops truncatus) in response to different kinds of boats in the waters of Lampedusa Island (It…
2013
Owing to the increase of boat-traffic in the ocean many studies have been conducted to determine the response of bottlenose dolphin (Tursiops truncatus) to this kind of disturbance. This species is affected by boats in various ways and the response depends on the behavioural state of the dolphin but also on the kind of vessel. This study aimed to determine the effect of motorboats and trawlers on dolphins' presence, permanence in the area and whistle parameters in Lampedusa waters (Italy). Sampling was carried out between May and December 2006 and between July and September 2009, using experimental passive acoustic monitoring systems (PAM); a total of 300 h of recordings and 3000 whistles w…
Predicting Heuristic Search Performance with PageRank Centrality in Local Optima Networks
2015
Previous studies have used statistical analysis of fitness landscapes such as ruggedness and deceptiveness in order to predict the expected quality of heuristic search methods. Novel approaches for predicting the performance of heuristic search are based on the analysis of local optima networks (LONs). A LON is a compressed stochastic model of a fitness landscape's basin transitions. Recent literature has suggested using various LON network measurements as predictors for local search performance.In this study, we suggest PageRank centrality as a new measure for predicting the performance of heuristic search methods using local search. PageRank centrality is a variant of Eigenvector centrali…
Plant hunting: exploring the behaviour of amateur botanists in the field
2021
We asked what are the behavioural and logistic preferences of professional and amateur botanists when exploring flora in the field. We extracted temporal and spatial data on vas- cular plant species occurrences from three datasets of Sicilian flora: a subset of iNaturalist, a dataset collected by a Facebook group focused on the flora of Sicily and a subset of the professional database European Vegetation Archive. We used the time span of individual contributor’s activity as a proxy of their commitment to collecting information about the flora of Sicily. Climate and landscape data were used to better characterize the spatial and temporal activity of data contributors. Finally, we assessed wh…
Ventricular Fibrillation and Tachycardia Detection Using Features Derived from Topological Data Analysis
2022
A rapid and accurate detection of ventricular arrhythmias is essential to take appropriate therapeutic actions when cardiac arrhythmias occur. Furthermore, the accurate discrimination between arrhythmias is also important, provided that the required shocking therapy would not be the same. In this work, the main novelty is the use of the mathematical method known as Topological Data Analysis (TDA) to generate new types of features which can contribute to the improvement of the detection and classification performance of cardiac arrhythmias such as Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT). The electrocardiographic (ECG) signals used for this evaluation were obtained from…
Sensitivity of soil processes in northern forest soils: are management practices a threat?
2000
Abstract There is evidence that forest management practices influence soil-decomposer communities. It is also established that changes in the trophic structure and composition of these communities can induce changes in soil-nutrient dynamics, thereby affecting plant growth. Whether forest productivity is affected by management-induced changes in, e.g. soil faunal structure, is, however, yet to be shown. The aim of this study was (1) to determine the resolution of the ecological hierarchy (e.g. species, functional groups, trophic levels) at which a change in soil fauna would alter biotically-controlled processes in soils, and (2) to examine the sensitivity of soil fauna of the boreal forest …
Short-term responses of soil decomposer and vegetation communities to stump harvesting in boreal forests
2011
Recently, in addition to logging residues, stumps have become an important component in energy production since there is growing global interest in the use of renewable energy sources in order to decrease anthropogenic carbon emissions. Harvesting of stumps influences the forest floor by changing vegetation and soil organic layers and exposing mineral soil across large areas. We studied whether stump harvesting after clear felling poses further short-term changes in boreal forest soil decomposer community (microbes and mesofauna) and vegetation when compared to the traditional site preparation practice (mounding). In general, stump harvesting caused decline in enchytraeid abundance but did …
Spot mounding and granulated wood ash increase inorganic N availability and alter key components of the soil food web in clear-cut Norway spruce fore…
2012
Abstract The interactive effects of site preparation (spot mounding) and fertilization (granulated wood ash) on soil properties, soil micro- and mesofauna and ground vegetation were studied in two Norway spruce plantations established in clear-cut forests in Central Finland. Half of the seedlings were planted on mounds created by the planting machine, and the rest on intact forest floor. Half of the seedlings on mounded and intact forest floor were fertilized by adding granulated wood ash to circular plots surrounding the seedlings. Initial samples were taken from mounded and intact soil immediately after planting in June. Samples were taken from all treated plots in the autumn in the first…
The implications of stand composition, age and spatial patterns of forest regions with different ownership type for management optimisation in northe…
2015
Abstract Forests with different ownership type often form complex mosaics of stands, thus adding new challenges to the spatial planning of sustainable management in forested landscapes. This study attempted to analyse the spatial patterns and age structures of forest regions with different ownership type and to formulate suggestions for the optimisation of tactical planning of forest management planning by addressing ecological functionality at the landscape level. We hypothesised that structure of forests of various ownership groups differs significantly. National forest inventory data from 2011 was used in this study to compare spatial patterns of forest stands and clearcuts, as well as f…
Forest types for biodiversity assessment at regional level: the case study of Sicily (Italy)
2007
Within Europe the question of plant coenosis is attracting growing interest. The quality and quantity of collected information on forest resources at a global level largely depends on the capacity to collect and analyse data at national and sub-national scale in a way compatible with those at global or continental levels. In Italy the acceptance of all the international agreements and protocols on the protection of the environment and management of natural resources, requires a standardization of collected information and statistics, with the aim to produce homogeneous and integrative data at global level. This need is reflected in the following points: (1) the adoption of a classification …
The role of traditional Erica arborea L. management practices in maintaining northeastern Sicily’s cultural landscape
2007
The tree heath (Erica arborea L.), a small evergreen tree found in the Mediterranean region and parts of Eastern and Central Africa, produces lignotubers that are highly valued for making smoking pipes. The Peloritani Mountains of northeastern Sicily are historically one of the most important areas in Italy for the production of these high quality lignotubers, known as briar root wood. In the past, tree heath shrublands were also an important source of charcoal. Erica arborea utilisation has declined dramatically during the past century, mostly due to the decreasing demand for smoking pipes, as well as the increasing frequency of wildfires and large-scale afforestation activities in this re…