جستجوی مقالات مرتبط با کلیدواژه « landscape ecology » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Rising temperatures and the formation of Urban Heat Islands (UHI) are the main consequences of population growth and uncontrolled expansion of cities. Green infrastructures are one of the nature based solutions. These infrastructures can be considered as an important strategy to reduce the damages caused by urban development and increase the quality of citizens’s life. Landscape ecology and its metrics are among the methods of evaluating green infrastructure in urban environments. Hence, the main objective of this research is to evaluate changes in urban green infrastructure during the period of 2013-2019 in Qazvin city. To do so, green infrastructures changes were investigated using remote sensing data and landscape metrics including presence (Class Area), stability (Mean Patch Size) and distribution (Patch Density, Mean Euclidean Distance Neighbor) in three regions of Qazvin. The results showed a decrease of 73.71 hectares in the Class Area (presence) and an increase of 0.1061 hectares in their Mean Patch Size (stability). Furthermore, the density of green infrastructures has experienced 0.8075 decrease per 100 hectares while the Mean Euclidean distance neighbor has increased about 5.5846 meters. These results indicate the conversion of small classes of green infrastructures to bigger classes and increase their stability despite the decrease in their presence. Therefore, planning and management by creating and expansion of green lands seems necessary in order to reduce the effects of urban development, improve the quality of citizen’s life and preserving green infrastructures of Qazvin.

The growth of urbanization has changed the ecological structure by changing the land use and cover, creating urban heat islands (UHI) and has been caused climate changes in the last decades. City of Neyshabuor has experienced the above mentioned changes; thus, studying and analysis of changes may lead to improve the ecological conditions. The main question in this research is how the ecological elements and structure affects heat islands patterns in Neyshabuor urban area. The present study is based on Landscape Ecology approach and metrics that were used to evaluate the ecological structure of Neyshabuor urban area. The purpose of the research is to analysis the relationship between ecological structure of Neyshabuor city, land surface temperature and heat islands pattern. Satellite images related to ETM sensor of Landsat satellite have been used in August 2010 to evaluate heat islands. The results indicate that there is significant correlation between landscape metrics and LST pattern. Accordingly, the composition and configuration of landscape metrics have significantly negative correlation with UHI. It suggests that the landscape elements such as, green spaces, gardens, farmlands and etc. can mitigate the effect on LST and UHI in our case study. Although, characteristics of landscape spatial structure have different correlation with LST and UHI, but positive synergy in ecological elements can help to decrease or preventing of LST and UHI effects in build up area.

Landscape ecology is one of theyoungest branches of ecology science, and especially deals on the study of landscape composition, structure and function. Landscape elements are such as patches, corridors, matrixalong the border and ecotons. Landscape metrics are algorithms for quantifying thespatial characteristics of patches, classes or entire landscape mosaics, and thebest way to compare different landscape requirements. Due to this, the aim of this study was to quantifylandscape patterns and the possibility of breakdown of plant communities usinglandscape metrics. Metrics that were used in this study thenumber of patch, class area proportion in the landscape, mean patch size, edge density, mean shape index, mean patch fractal dimension and total edgein the class level and Shannon diversity index in the landscape level. Metrics listed for vegetationmap and morphology units were calculated using the patch analyst extension for Poshtkooh rangelands of Yazd. Then, using the principal component analysis were determined the important metrics for the separation of plant communities. The resultsof the principal component analysis for the separation of class in morphology units map showed that edge density metric have thegreatest impact but in the vegetation map landscape metrics, were equally important and more importance metric could not be determined and compared to separation the units of land shape in the morphology units map were less separation. Finally, with using of discriminate analysis, wasdetermined thedifferentiation function and metrics that create separation between the plant communities and land classes. Discriminate analysis showed that thenumber of patch metric, edge density and mean patch fractal dimension can beseparated plant communities and classes in the map, units are less resolution.

Assessing effects of land use spatial pattern on hydrologic characteristics and variation of flow hydrograph can provide new information leading more effective decision-making and integrated watershed management. However, less attention has been relatively paid to this subject. The emphasis of this research is to quantify the contribution and effects of different land use types and spatial pattern on flood hydrographs in Galaz Watershed (103 km2 area), located in West-Azarbaijan Province, Iran. In the present study, the Clark's Time-Area model has been employed for simulation of hydrograph. The Time Area Histogram (TAH) of the study watershed has been derived based on a spatially distributed travel time approach, and the flow hydrograph was simulated in incorporating with the different land use types and design rainfall. The hydrograph has been routed to the watershed outlet. Then, the distribution of flow hydrograph and the peak discharge were analysed considering different land uses between isochrones. According to the results, the effect of land use types and patterns led to variations of time area histograms and the resulted hydrograph. Based on the results, the higher peak discharge were determined for rangeland, agriculture and forest land use types, respectively. The generated runoff volume of the rangeland, agriculture, and forest land use types were 84, 12, and 4%, respectively. The implemented method can be used to simulate the effects of land use changes in storm basis to study the temporal flow variations and also to quantify the components of flow hydrograph

Development of remote sensing (RS) and GIS techniques and that of landscape metrics in the late 1980s have caused to introduce a new dimension in the landscape ecology arena (the relationship between spatial patterns and ecological processes). However, scale dependence of some of landscape metrics and RS systems of different spatial resolution has resulted in particular attention into selection of an appropriate scale in the landscape ecology studies and correct interpretation of ecological processes. Hence, the present study has investigated the behaviors of some landscape metrics in relation to changes in scale. Accordingly, the effects of the scale (pixel size and extent) on those landscape metrics which indicate trends of vegetation cover class was discussed applying Landsat images in Isfahan city and its surrounding (an area of ​​960 thousand hectares). For this purpose, behavior of NP, PD, LSI, MPS, ED, MNN, MSI and TCAI have studied through changing the size from 30 m to 60, 120, 240 and 480 and extent from 300 ha to 600, 1200, 2400 and 4800. The results of this study indicated sensitivity of these metrics except TCAI in relation to the scale factor. This type of studies and attention to the spatial scale have indicated that it could play an important role in identifying the impacts of ecological processes, predicting the ecological functions (landscape modeling) and reducing the uncertainty in landscape ecology studies.

Urban growth has been an important social and economic phenomenon that affects severely on function of ecological systems. Hence، understanding and analyzing the spatial patterns of urban growth using remote sensing، GIS and landscape metrics can play a fundamental role in urban land use management and planning and subsequently reduction in environmental problems and challenges among them. Therefore، in present study we examined urban growth in Sari city and its surrounding. For this purpose، satellite images of 1992، 1998، 2002 and 2009 of the study area was processed to generate land use\ cover maps. Accordingly، different types of urban growth have been quantified using post classification method (map overlay)، applying a set of landscape metrics at class level including PD، MPS، ED، LPI and ENN and developing R metric at patch level applying ArcGIS 9. 3. The results show that، urban development is associated with the growth of old patches in the study area. While the outlying growth type became the dominant pattern، the infilling growth decreased over the entire study period.

Landscape ecology as a modern interdisciplinary science offers new concepts, theories, and methods for land evaluation and management. A main part of landscape ecology is describing patterns in the landscape and interpreting the ecological effects of these patterns on flora, fauna, flow of energy and materials. Remote sensing and GIS techniques have a high ability for landscape researchers to specify maps and analyze landscape patterns. We can use the trends in indices to our management decisions. In this study, landscape patterns were quantified by the number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated by GIS approaches and compared for 35 years, in order to reinforce the management efforts of Mouteh wildlife refuge in Iran. The results showed increasing destructions with regards to unplanned human activities, while some natural landscape improvements occurred in the core protected area.