scholarly journals Monitoring of Urban Landscape Ecology Dynamics of Islamabad Capital Territory (ICT), Pakistan, Over Four Decades (1976–2016)

Land ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 123 ◽  
Author(s):  
Hammad Gilani ◽  
Sohail Ahmad ◽  
Waqas Ahmed Qazi ◽  
Syed Muhammad Abubakar ◽  
Murtaza Khalid
Keyword(s):  
Forest Fragmentation ◽  
Urban Landscape ◽  
Urban Forest ◽  
Rate Of Change ◽  
Rapid Expansion ◽  
Annual Rate ◽  
Tree Cover ◽  
Spatiotemporal Analyses ◽  
Urban Landscape Ecology ◽  
Landsat Satellite

In the late 1960s, the Islamic Republic of Pakistan’s capital shifted from Karachi to Islamabad, officially named Islamabad Capital Territory (ICT). In this aspect, the ICT is a young city, but undergoing rapid expansion and urbanization, especially in the last two decades. This study reports the measurement and characterization of ICT land cover change dynamics using Landsat satellite imagery for the years 1976, 1990, 2000, 2010, and 2016. Annual rate of change, landscape metrics, and urban forest fragmentation spatiotemporal analyses have been carried out, along with the calculation of the United Nations Sustainable Development Goal (SDG) indicator 11.3.1 Land Consumption Rate to the Population Growth Rate (LCRPGR). The results show consistent increase in the settlement class, with highest annual rate of 8.79% during 2000–2010. Tree cover >40% and <40% canopy decreased at an annual rate of 0.81% and 0.77% between 1976 to 2016, respectively. Forest fragmentation analysis reveals that ‘core forests of >500 acres’ class decreased from 392 km2 (65.41%) to 241 km2 (55%), and ‘patch forest’ class increased from 15 km2 (2.46%) to 20 km2 (4.54%), from 1976 to 2016. The LCRPGR ratio was 0.62 from 1976 to 2000, increasing to 1.36 from 2000 to 2016.

scholarly journals Quantifying Tree Cover Loss in Urban Forests within Nairobi City Metropolitan Area from Earth Observation Data

2020 ◽  
Vol 3 (1) ◽  
pp. 78
Author(s):  
Francis Oloo ◽  
Godwin Murithi ◽  
Charlynne Jepkosgei
Keyword(s):  
Land Cover ◽  
Metropolitan Area ◽  
Land Surface ◽  
Urban Forest ◽  
Urban Forests ◽  
Earth Observation ◽  
Tree Cover ◽  
Observation Data ◽  
Vegetation Health ◽  
Earth Observation Data

Urban forests contribute significantly to the ecological integrity of urban areas and the quality of life of urban dwellers through air quality control, energy conservation, improving urban hydrology, and regulation of land surface temperatures (LST). However, urban forests are under threat due to human activities, natural calamities, and bioinvasion continually decimating forest cover. Few studies have used fine-scaled Earth observation data to understand the dynamics of tree cover loss in urban forests and the sustainability of such forests in the face of increasing urban population. The aim of this work was to quantify the spatial and temporal changes in urban forest characteristics and to assess the potential drivers of such changes. We used data on tree cover, normalized difference vegetation index (NDVI), and land cover change to quantify tree cover loss and changes in vegetation health in urban forests within the Nairobi metropolitan area in Kenya. We also used land cover data to visualize the potential link between tree cover loss and changes in land use characteristics. From approximately 6600 hectares (ha) of forest land, 720 ha have been lost between 2000 and 2019, representing about 11% loss in 20 years. In six of the urban forests, the trend of loss was positive, indicating a continuing disturbance of urban forests around Nairobi. Conversely, there was a negative trend in the annual mean NDVI values for each of the forests, indicating a potential deterioration of the vegetation health in the forests. A preliminary, visual inspection of high-resolution imagery in sample areas of tree cover loss showed that the main drivers of loss are the conversion of forest lands to residential areas and farmlands, implementation of big infrastructure projects that pass through the forests, and extraction of timber and other resources to support urban developments. The outcome of this study reveals the value of Earth observation data in monitoring urban forest resources.

Urban Trees and Water Use in Arid Climates: Insights from an Integrated Bioeconomic-Health Model

2018 ◽  
Vol 04 (04) ◽  
pp. 1850022 ◽  
Author(s):  
Benjamin A. Jones ◽  
John Fleck
Keyword(s):  
Ecosystem Services ◽  
Water Use ◽  
Forest Canopy ◽  
Urban Forest ◽  
Economic Value ◽  
Urban Trees ◽  
Tree Cover ◽  
Arid Environments ◽  
Value Of Water ◽  
Health Model

Managing outdoor water use while maintaining urban tree cover is a key challenge for water managers in arid climates. Urban trees generate flows of ecosystem services in arid areas, but also require significant amounts of irrigation. In this paper, a bioeconomic-health model of trees and water use is developed to investigate management of an urban forest canopy when irrigation is costly, water has economic value, and trees provide ecosystem services. The optimal tree irrigation decision is illustrated for Albuquerque, New Mexico, an arid Southwest US city. Using a range of monetary values for water, we find that the tree irrigation decision is sensitive to the value selected. Urban deforestation is optimal when the value of water is sufficiently high, or alternatively starts low, but grows to cross a specific threshold. If, however, the value of water is sufficiently low or if the value of tree cover rises over time, then deforestation is not optimal. The threshold value of water where the switch is made between zero and partial deforestation is well within previously identified ranges on actual water values. This model can be applied generally to study the tradeoffs between urban trees and water use in arid environments.

scholarly journals Urban forest fragmentation impoverishes native mammalian biodiversity in the tropics

2018 ◽  
Vol 8 (24) ◽  
pp. 12506-12521 ◽  
Author(s):  
Sze Ling Tee ◽  
Liza D. Samantha ◽  
Norizah Kamarudin ◽  
Zubaid Akbar ◽  
Alex M. Lechner ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Urban Forest ◽  
The Tropics

scholarly journals Landscape Transformations in Rapidly Developing Peri-urban Areas of Accra, Ghana: Results of 30 years

2019 ◽  
Vol 11 (1) ◽  
pp. 172-182 ◽  
Author(s):  
George Ashiagbor ◽  
Clifford Amoako ◽  
Stephen B. Asabere ◽  
Jonathan A. Quaye-Ballard
Keyword(s):  
Landscape Structure ◽  
Urban Areas ◽  
Urban Governance ◽  
Urban Landscape ◽  
Urban Expansion ◽  
Edge Density ◽  
Aggregation Index ◽  
Intensity Index ◽  
Landsat Satellite ◽  
Landscape Transformations

Abstract Beyond the loss of peri-urban agricultural and forested land as a result of built-up expansion, not much information exists on the changes in the structure of the peri-urban landscape in Ghana. The aim of this paper is to examine the extent to which urban expansion is driving changes in landscape structure of the peri-urban fringes of Accra. We submit that rapid peri-urbanisation will fragment the existing agricultural and forested landscape with consequent ecological, socio-economic and urban governance implications. Using Landsat satellite images for the years 1985, 1991, 2002 and 2015 the study area was classified into four land cover classes. The study adopted the use of Urban Intensity Index (UII) and the Annual Rate of Urbanization (R) as measures of urbanization. Edge density (ED), largest patch index (LPI) and Aggregation index (AI) were used as proxies to measure landscape structural transformations. The study reveals substantial reductions and fragmentation in agricultural lands, riverine and open forests, while there has been over 200 percent increase in built-up areas. Beyond these revelations in spatiotemporal changes in landscape structure, the paper points to the ecological implications of the changes, and three key socio-economic and urban governance implications.

Socioeconomic Factors and Urban Tree Cover Policies in a Subtropical Urban Forest

2012 ◽  
Vol 49 (3) ◽  
pp. 428-449 ◽  
Author(s):  
Zoltan Szantoi ◽  
Francisco Escobedo ◽  
John Wagner ◽  
Joysee M. Rodriguez ◽  
Scot Smith
Keyword(s):  
Socioeconomic Factors ◽  
Urban Forest ◽  
Tree Cover ◽  
Urban Tree ◽  
Urban Tree Cover

scholarly journals Tree Species Diversity and Socioeconomic Perspectives of the Urban (Food) Forest of Accra, Ghana

2018 ◽  
Vol 10 (10) ◽  
pp. 3417 ◽  
Author(s):  
Bertrand Nero ◽  
Nana Kwapong ◽  
Raymond Jatta ◽  
Oluwole Fatunbi
Keyword(s):  
Land Use ◽  
Tree Species ◽  
Forest Cover ◽  
Food System ◽  
Food Policy ◽  
Urban Forest ◽  
Urban Forestry ◽  
Tree Cover ◽  
Land Use Types ◽  
The City

Urban and peri-urban forestry has emerged as a complementary measure to contribute towards eliminating urban hunger and improved nutritional security. However, there is scanty knowledge about the composition, diversity, and socioeconomic contributions of urban food trees in African cities. This paper examines the diversity and composition of the urban forest and food trees of Accra and sheds light on perceptions of urbanites regarding food tree cultivation and availability in the city. Using a mixed methods approach, 105 respondents in six neighborhoods of Accra were interviewed while over 200 plots (100-m2 each) were surveyed across five land use types. Twenty-two out of the 70 woody species in Accra have edible parts (leaves, fruits, flowers, etc.). The food-tree abundance in the city is about half of the total number of trees enumerated. The species richness and abundance of the food trees and all trees in the city were significantly different among land use types (p < 0.0001) and neighborhood types (p < 0.0001). The diversity of food-bearing tree species was much higher in the poorer neighborhoods than in the wealthier neighborhoods. Respondents in wealthier neighborhoods indicated that tree and food-tree cover of the city was generally low and showed greater interest in cultivating food (fruit) trees and expanding urban forest cover than poorer neighborhoods. These findings demonstrate the need for urban food policy reforms that integrate urban-grown tree foods in the urban food system/culture.

Land types and vegetation in the Luuq district of south-western Somalia

1985 ◽  
Vol 1 (1) ◽  
pp. 65-87 ◽  
Author(s):  
Ronald G. Wieland ◽  
M. J. A. Werger
Keyword(s):  
Construction Material ◽  
Ground Cover ◽  
Tree Cover ◽  
Department Of Agriculture ◽  
Agriculture Soil ◽  
Colour Image ◽  
The Us ◽  
Community Types ◽  
Landsat Satellite ◽  
Land Types

ABSTRACTA land use survey involving land typing and vegetation classification was conducted within the Luuq District Refugee Area (200,000 ha) in south-western Somalia. Average rainfall and annual temperature of the area are 310 mm and 30.5° C. The area is composed of limestone and basalt uplands, gypsiferous and alluvial interplains, and ancient and recent alluvial terraces of the Juba River.Land types were identified by aerial photo survey and ground observation and mapped on a 1:100,000 scale LandSat Satellite (colour) Image. Soil types were classified according to the method used by the US Department of Agriculture, Soil Conservation Service. Vegetation was sampled according to the Braun-Blanquet approach in 52 releves located within previously mapped land types, and analysed using the traditional phytosociological methods and the DECORANA and TWINSPAN computer programs. The results of these methods are compatible with one another. Most community types identify distinct land types: basalt and limestone uplands, gypsum and alluvial interplains, and depressions and gentle rises of the Juba River terrace.Commiphora and Acacia species dominate the open thorny bushland. They are mostly medium-sized shrubs and trees, 1 to 4 m in height. There is little herbaceous ground cover except in depressions and drainageways. Total shrub and tree cover averages 34%. Due to the large influx of refugees, there has been excessive cutting for fuelwood and construction material and notable bushland converted to cropland. Degradation of the vegetation and soils is prominent and is most evident on the upper and lower terraces of the Juba River.

Late Holocene forest contraction and fragmentation in central Africa

2017 ◽  
Vol 89 (1) ◽  
pp. 43-59 ◽  
Author(s):  
Jean Maley ◽  
Charles Doumenge ◽  
Pierre Giresse ◽  
Gil Mahé ◽  
Nathalie Philippon ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Late Holocene ◽  
Environmental Changes ◽  
Forest Disturbance ◽  
Central Africa ◽  
Thunderstorm Activity ◽  
Rapid Expansion ◽  
Sea Surface ◽  
Climatic Data ◽  
Solar Influence

AbstractDuring the warmer Holocene Period, two major climatic crises affected the Central African rainforests. The first crisis, around 4000 cal yr BP, caused the contraction of the forest in favor of savanna expansion at its northern and southern periphery. The second crisis, around 2500 cal yr BP, resulted in major perturbation at the forest core, leading to forest disturbance and fragmentation with a rapid expansion of pioneer-type vegetation, and a marked erosional phase. The major driver of these two climatic crises appears to be rapid sea-surface temperature variations in the equatorial eastern Atlantic, which modified the regional atmospheric circulation. The change between ca. 2500 to 2000 cal yr BP led to a large increase in thunderstorm activity, which explains the phase of forest fragmentation. Ultimately, climatic data obtained recently show that the present-day major rise in thunderstorms and lightning activity in Central Africa could result from some kind of solar influence, and hence the phase of forest fragmentation between ca. 2500 to 2000 cal yr BP may provide a model for the present-day global warming-related environmental changes in this region.

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