1,721,035 research outputs found
Landscape metrics and topographical determinants of large-scale forest dynamics in a Mediterranean landscape
No full textThe analysis of land-use and land-cover change has long been a key topic in Landscape Ecology. In particular, forest fragmentation is known to affect species composition and diversity, thus threatening the integrity of forest habitats. This paper examines the forest cover dynamics in a Mediterranean area (the Province of Siena, central Italy), by comparing historical (1933) and recent forest maps (2000). The historical map has been geo-referenced, digitised in a GIS environment, and classified in three forest classes: broad-leaved, conifer and mixed forests. The same classification was used for the recent forest map. Image processing techniques and landscape pattern metrics were applied to quantify the changes in forest cover patterns, while appropriate statistical descriptors were adopted to investigate the relationship between land-cover changes and topographical factors. A general afforestation process was detected in the investigated area over the period 1933-2000, resulting in a high landscape transformation overall considering zones with higher elevation and slope. The forest landscape structure changed in terms of decreased fragmentation and patchiness. The general trend observed in this area was in line with previous results achieved in similar ecological situations, thus reinforcing the need to link landscape change patterns with appropriate management decisions
Human activity impact on the heterogeneity of a Mediterranean landscape
No full textThe Mediterranean area is one of the most significantly altered hotspots on Earth, since it has been intensively affected by human activity for millennia. As a result, only 4.7% of its primary vegetation remained unaltered and the landscape has been repeatedly transformed. In this paper, we aimed at detecting both the direction and the rate of landscape change focusing on the effects of human activity on the environmental heterogeneity of the Mediterranean landscape under study. In particular, we carried out an analysis of landscape changes occurred in a Mediterranean area from 1954 to 2000, by means of a comparative examination of a historical and a recent land use map. Land use changes have been quantified by landscape metrics coupled with topographical information. Results underline: i) a general homogenisation of the landscape, ii) modification of the arrangements for exploitation of the territory, particularly in the plain areas, iii) a trend of recovery of the territory by the forest to the detriment of semi-natural and agricultural areas in hilly and mountain parts. The analysis of the complex phenomena related to land use changes can be a useful tool to define effective strategies for natural resources management and biodiversity conservation. (C) 2009 Elsevier Ltd. All rights reserved
PANDORA 3.0 plugin: A new biodiversity ecosystem service assessment tool for urban green infrastructure connectivity planning
No full textEcosystem services related to landscape connectivity are of paramount importance for biodiversity conservation.
However, due to the complexity of urban systems, both landscape connectivity assessment and the analysis
of ecosystem services related to landscape connectivity are often inadequately conducted, or even completely
lacking, in urban planning. The PANDORA 3.0 model, developed as a QGIS plugin and illustrated here with a
study case, is the first free, open-source tool for an integrated evaluation of ecosystem services related to
landscape connectivity for biodiversity conservation purposes in urban contexts. The PANDORA 3.0 model
plugin aims to be a versatile and innovative tool for assessing Green Infrastructure value in terms of ecological
connectivity and biodiversity, useful for the planning of sustainable and resilient landscapes and cities. Its open
code availability means that users, scientists, developers and planners involved in urban and landscape ecology
will have the opportunity to test the PANDORA 3.0 model in several contexts and even contribute further
improvements
Recovering historical vegetational database to study the forest biodiversity in Trentino
No full textThe biodiversity data of a forest ecosystem can be applied to provide useful information about a territory. The presence and distribution of living organisms to interpret and synthesize the characteristics of a territory has been used for a long time and in various contexts. In past years, considerable investigations have been carried out to describe of biodiversity richness and vegetation dynamics in forest ecosystems of Trentino, in particular, the database used for the construction of “Schmid’s vegetational belts”, owned by the Fondazione Edmund Mach. The archive had been thought in order to determine the main vegetational belts in the province of Trento and was made along 20 years, since the beginning of the 70s until the early 90s. The database was not designed to be consulted and accessible since developed by obsolete tools and technologies no longer exploitable. In the framework of the FORCING project, a comprehensive process of database recovering has been carried out: an analysis of the data structure has been performed in order to reverse engineering the database structure, missing data were digitized from historical maps, still preserving paper-based maps and documents. This work aimed to bringing together and homogenizing the
datasets of 16 forest districts representing the whole archive, restoring and modernizing the architecture of the original database
and removing any redundancy. Also, all the maps and the related 8000 detected transect have been georeferenced, in order to geographically enable the whoile database and to evaluat the possibility to perform comparative samplings on up-to-date datasets.
At the same time, it has been pursuing the aim of achieving fully accessible data and metadata, to provide the greatest number of project-related information. Despite the fact that over the years the scientific community has established the obsolescence of the “Schmid’s vegetational belts” system, the floristic data the raw data used at that time still retain an important and irreplaceable information value useful not only as a historical memory, but for many other applications. The amount and structure
of the archive is as follows: (1) More than 600 serial lines are evenly distributed across the Trentino. (2) More than 8000
surveys of the transects running along the 600 series lines, placed every 50 m of altitude, presents on average ca. 25 plant species, including trees, shrubs and herbaceous. (3) About 8 ha of land under survey. (4) More than 15 detectors that have taken place along the 20 years of investigation. Five detectors were stable throughout the period of the project. (5) About 1300 different species identified only in the forest ranges (out of ca. 2.300 spp. estimated by Dalla Fior in Trentino). (6) About 200000 specific identification, for each of them are present frequency indices. (7) Thousands of color slides that illustrate the identified species. The data recovery may be useful for following accomplishments: (a) to have a database freely accessible to the scientific
community with a web-oriented interface accessible to other stakeholders for consultation and information processing; (b)
recovering and ordering of the data and the geo-localization of the transects it is possible to run new survey on the same areas
with modern methodologies, using the presence and frequency of over 1300 plant species such as bioindicators, to assess potential impacts due to climate change and/or anthropogenic pressure on forests of Trentino; (c) evaluation of the introgression
of invasive and alien species in Trentino; (d) evaluating of care and protection system for species placed in the red list; (e) assess the land use changes in the last twenty years in Trentin
The contribution of historical vegetational database recovery to the study of forest biodiversity in Trentino (Italy)
No full textThe biodiversity data of a forest ecosystem can be applied to provide useful information about a territory. The presence and distribution of living organisms to interpret and synthesize the characteristics of a territory has been used for a long time and in various contexts.
In past years, considerable investigations have been carried out to describe of biodiversity richness and vegetation dynamics in forest ecosystems of Trentino, in particular, the database used for the construction of "Schmid’s vegetational belts", owned by the Fondazione Edmund Mach. The archive had been thought in order to determine the main vegetational belts in the province of Trento and was made along 20 years, since the beginning of the 70s until the early 90s.
The database was not designed to be consulted and accessible since developed by obsolete tools and technologies no longer exploitable. In the framework of the FORCING project, a comprehensive process of database recovering has been carried out: an analysis of the data structure has been performed in order to reverse engineering the database structure, missing data were digitized from historical maps, still preserving paper-based maps and documents. This work aimed to bringing together and homogenizing the datasets of 16 forest districts representing the whole archive, restoring and modernizing the architecture of the original database and removing any redundancy. Also, all the maps and the related 8,000 detected transect have been georeferenced, in order to geographically enable the whoile database and to evaluat the possibility to perform comparative samplings on up-to-date datasets. At the same time, it has been pursuing the aim of achieving fully accessible data and metadata, to provide the greatest number of project-related information. Despite the fact that over the years the scientific community has established the obsolescence of the “Schmid’s vegetational belts" system, the floristic data the raw data used at that time still retain an important and irreplaceable information value useful not only as a historical memory, but for many other applications.
The amount and structure of the archive is as follows:
- More than 600 serial lines are evenly distributed across the Trentino.
- More than 8,000 surveys of the transects running along the 600 series lines, placed every 50 m of altitude, presents on average ca. 25 plant species, including trees, shrubs and herbaceous.
- About 8 ha of land under survey
- More than 15 detectors that have taken place along the 20 years of investigation. Five detectors were stable throughout the period of the project.
- About 1,300 different species identified only in the forest ranges (out of ca.2.300 spp. estimated by Dalla Fior in Trentino)
- About 200,000 specific identification, for each of them are present frequency indices.
- Thousands of color slides that illustrate the identified species.
The data recovery may be useful for following accomplishments:
- To have a database freely accessible to the scientific community with a Web oriented interface accessible to other stakeholders for consultation and information processing.
- Recovering and ordering of the data and the geo-localization of the transects it’s possible to run new survey on the same areas with modern methodologies, using the presence and frequency of over 1300 plant species such as bioindicators, to assess potential impacts due to climate change and/or anthropogenic pressure on forests of Trentino.
- Evaluation of the introgression of invasive and alien species in Trentino.
- Evaluating of care and protection system for species placed in the red list.
- Assess the land use changes in the last twenty years in Trentino
Fuzzy and boolean forest membership: on the actual separability of land cover classes
No full textForests are among the most important habitats of the Earth for several ecological reasons and their management is a prior task when dealing with landscape conservation. Thematic maps and remote sensing data are powerful tools to be used in landscape planning and forest management; nevertheless, most of the European and Mediterranean forest monitoring and conservation programs do not take into account the continuity of the variation of habitats within the landscape but they only rely on boolean classification methods. The utilisation of a classification method that applies a continuity criterion is fundamental because it is expected to better represent the ecological gradients within a landscape. The aim of this paper is to assess the amount of classification uncertainty related to crisp (boolean) classes, particularly focusing on forest identification uncertainty. Forest fuzzy membership of the Tuscany region (Italy) derived from a Landsat ETM+ image scene was compared with the widely used crisp datasets in European forests management and conservation practices, i.e. the European JRC Forest/Non-Forest map, the CORINE Land Cover 2000 (levels 1 and 2), as well as the Global Land Cover 2000, in order to qualitatively and quantitatively assess the separability of crisp classes with respect to forest fuzzy membership. A statistically significant (p < 0.001) forest fuzzy membership separability among the considered crisp classes was found. Despite the crisp dataset and hierarchical level taken into account, both forest and non-forest crisp classes showed a high degree of forest fuzzy membership variability. Therefore, given the intrinsic mixture of crisp land cover classes, ecological studies on forestal ecosystems should rigorously take into account the classification uncertainty related to a crisp view of ecological entities which are being mapped. RI Neteler, Markus/C-6328-200
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Biodiversity, roads, & landscape fragmentation: two Mediterranean cases
No full textThe most pervasive threats to biological diversity are directly or indirectly linked to the road networks. For this reason, over the last few decades, interest in the study of the ecological characteristics of the edges associated with roads has increased. This work aims to investigate the effect of roads as a human-induced disturbance on the plant diversity in two managed Mediterranean forest sites, focusing on the responses of plants species richness, evenness, composition and taxonomic diversity.
A stratified random sampling was performed in two protected areas located in Tuscany, Central Italy. The species richness, composition and abundance were measured in 53 20x20 m plots. Ordinary Least Square and quantile regressions were used to study the effect of the roads on species richness, evenness and taxonomic distinctness, and redundancy analysis was used to examine the species composition. Generalized linear models in conjunction with an Information Criterion-based approach to model selection were used to test the role of road distance in the structure of forest plant biodiversity.
Our findings indicated a clear relationship between road distance and different plant biodiversity facets, which showed its maximum effect in the first 0-20 m forest-to-road segment and a mitigation after the 200 m threshold. Furthermore, the presence and abundance of many key forest species, such as Fagus sylvatica and Abies alba, were influenced more by the road distance than by other environmental gradients. The few remnants of core forest habitats in the Mediterranean basin highlight the need to recognize that road construction and maintenance have several ecological implications and accordingly require long-term monitoring programs
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