Quantifying the proportion of tile-drained land in large river basins. (original) (raw)
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Geology, Ecology and Landscape , 2019
Rapid urbanization in Addis Ababa and the surrounding area resulted in the rapid land use/ land cover (LULC) change that affected landscape structures and ecological functions. This study aimed at quantifying and mapping the spatial patterns of landscape structure for a sustainable city region landscape conservation planning and management. GIS and statistical tools were used to compute important landscape metrics. Pearson Correlation and factor analysis were also applied to reduce redundant indices and identify underlining factor of the landscape structure by network of hexagonal area. The analysis depicted four landscape and four class-level underlined metrics. Accordingly, as the region overall landscape was characterized by patch size and density, shape and texture (interspersion) index, the forest class also attributed by patch size and density, and shape metrics. The result shows that the region landscape planning and management schemes must emphasize on the level of patch fragmentation and landscape complexity to maintain the natural land cover habitat functioning, the amount of ecological process and extent of human intervention. This research will help scientific base decision-making in conservation planning and management of the tropical highland urban landscape in general, and the study area in particular. ARTICLE HISTORY
Landscape is " an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors " (Council of Europe, European Landscape Convention, 2000). The changing conditions of this complex factor, that determines the variability of our local and national contexts in Europe, can be effectively measured thanks to quantitative and qualitative indicators. These values could be calculated through procedures implemented thanks to Geographical information systems (GIS), using elements of geostatistics and numeric cartography. The speculative basics of the need of using GIS for the landscape analysis is strongly connected to the necessity of finding a steadier definition of its variability in time and space, mainly in a context like the European Union, that is in constant demand for procedures that could be standardized as best practices.
Using landscape structure to develop quantitative baselines for protected area monitoring.
Changes in habitat extent as well as landscape and habitat structure are often caused by human pressure within protected areas and at their boundaries, with consequences for biodiversity and species distributions. Thus quantitative spatial information on landscape mosaic arrangements is essential, for monitoring for nature conservation, as also specified by frameworks such as the Convention on Biological Diversity (CBD), and the European Union’s Habitat Directive. While measuring habitat extent is a relatively straightforward task, approaches for measuring habitat fragmentation are debated. This research aims to delineate a framework that enables the integration of different approaches to select a set of site- and scale-specific indices and synthetic descriptors and develop a comprehensive quantitative assessment of variations in human impact on the landscape, through assessment of habitat spatial patterns, which can be used as a baseline for monitoring. This framework is based on the use of established methodologies and free software, and can thus be widely applied across sites. For each landscape and observation scale, the framework permits the identification of the most relevant indices, and appropriate parameters for their computation. We illustrate the use of this framework through a case study in a protected area in Italy, to indicate that integrated information from multiple approaches can provide a more complete understanding of landscape and habitat spatial pattern, especially related to locations experiencing disturbance and pressure. First, identification of a parsimonious set of traditional LPIs for a specific landscape and spatial scale provides insights on the relation between landscape heterogeneity and habitat fragmentation. These can be used for both change assessment and ranking of different sections of the study area according to a fragmentation gradient in relation to matrix quality. Second, morphological spatial pattern analysis (MSPA), provides a pixel based structural characterisation of the landscape. Third, compositional characterisation of the landscape at the pixel level is provided by landscape mosaic analysis. These three approaches provide quantitative assessments through indices which can be used singly or in combination to derive three synthetic descriptors for a comprehensive quantitative baseline representation of landscape structure that can be used for monitoring: the first descriptor, landscape diversity profiling, based on the output of landscape mosaic analysis, at the landscape level, complements the evaluation which at the pixel level can be obtained by more complex modelling; the second descriptor, obtained combining of the outputs of MSPA and the landscape mosaic analysis, informs on the local structural pattern gradient across the landscape space; the third descriptor, derived from the integration of selected LPIs and those derived from MSPA into a discontinuities detection procedure, allows for the identification of “critical points” of transitions in management where threats to biodiversity and ecosystems integrity may be likely. The framework developed has significant potential to capture information on major landscape structural features, identify problematic areas of increased fragmentation that can be used to prioritise research, monitoring and intervention, and provide early warning signals for immediate response to pressures increasing habitat fragmentation, with the goal of facilitating more effective management.
Status and trend analysis in landscape pattern through field-based sampling data
Caspian Journal of Environmental Sciences, 2021
Traditionally, calculation of landscape metrics is commonly conducted on land cover/use maps of entire landscape which is created from remotely sensed data. An interesting approach, however, is to make use of sample data, without the use of wall-to-wall mapping. In the present review and case study, it is aimed to estimate three basic landscape metrics, namely Shannon's diversity (SH), forest edge length (E) and contagion (C) from field-based sampling data. It is also intended to estimate landscape change using time series datasets. Estimated variance (sampling error) was used to assess landscape metric estimators. For this purpose, sampling data from National Inventory in the Landscape of Sweden (NILS) is used. In this case study, the metrics are estimated with acceptable precision. In most cases, the estimated variance (sampling error) was less than 10 %. The largest sampling error was 28 % for forest edge length. We will be able to compare different landscape at a given time or a landscape over time using filed-based sampling data. Furthermore, in an ecological survey it may be possible to find a relationship between landscape pattern and ecological processes such as biodiversity. The methods applied in this study is very simple and there is no need for extra measurements.
Landscape metrics as a tool for evaluating scenarios for flood prevention and nature conservation
Landscape Online, 2011
Within the framework of the project "Flood Prevention and Nature Conservation in the Weisseritz area" ("HochNatur"), a method including landscape metrics was developed and applied to assess and to compare different land use scenarios with regard to flood prevention and nature conservation. For the analysis, two sub-catchments strongly differing in land use within the Weisseritz catchment (Eastern Erzgebirge, Saxony, Germany) were selected. The first step of the evaluation procedure was a biotope assessment using three assessment criteria (naturalness, substitutability, rareness/endangerment). However, the biotope assessment did not yield any information about spatial distribution or the structural composition of the landscape. Therefore, landscape metrics were applied to analyse the structural and biotope type diversity at the landscape scale. Different landscape metrics (Shannon/Weaver diversity index, mean patch size index, Interdispersion/Juxtaposition index) ...