Assessing avian habitat fragmentation in urban areas of Hong Kong (Kowloon) at high spatial resolution using spectral unmixing

Nichol, Janet Elizabeth; Wong, Man Sing; Corlett, Richard T.; Nichol, D.

doi:10.1016/j.landurbplan.2009.12.002

Cited by 28 publications

(21 citation statements)

References 37 publications

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“…This finding was supported by claims that sub-pixel classification is more advantageous than per-pixel classification, because it relaxes the assumption that pixels are homogenous [46,47]. Many studies, especially urban studies characterizing artificial surfaces with remote sensing data, have been successful in using sub-pixel classification to develop fractional maps of land cover types [19,48,49]. For other classes, the preference of sub-pixel vs. per-pixel classification remains a debate, because the producer's and user's accuracies were not consistently higher for one classification over the other (Figure 3).…”

Section: Land Cover Map and Accuracymentioning

confidence: 90%

Land Cover Heterogeneity Effects on Sub-Pixel and Per-Pixel Classifications

Tran

Julian

Beurs

2014

IJGI

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Abstract:Per-pixel and sub-pixel are two common classification methods in land cover studies. The characteristics of a landscape, particularly the land cover itself, can affect the accuracies of both methods. The objectives of this study were to: (1) compare the performance of sub-pixel vs. per-pixel classification methods for a broad heterogeneous region; and (2) analyze the impact of land cover heterogeneity (i.e., the number of land cover classes per pixel) on both classification methods. The results demonstrated that the accuracy of both per-pixel and sub-pixel classification methods were generally reduced by increasing land cover heterogeneity. Urban areas, for example, were found to have the lowest accuracy for the per-pixel method, because they had the highest heterogeneity. Conversely, rural areas dominated by cropland and grassland had low heterogeneity and high accuracy. When a sub-pixel method was used, the producer's accuracy for artificial surfaces was increased by more than 20%. For all other land cover classes, sub-pixel and per-pixel classification methods performed similarly. Thus, the sub-pixel classification was only advantageous for heterogeneous urban landscapes. Both creators and users of land cover datasets should be aware of the inherent landscape heterogeneity and its potential effect on map accuracy.

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Section: Land Cover Map and Accuracymentioning

confidence: 90%

Land Cover Heterogeneity Effects on Sub-Pixel and Per-Pixel Classifications

Tran

Julian

Beurs

2014

IJGI

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“…The abundance of human-associated species increase as the amount of building cover increased [15]. Feeding guild (granivores) was higher in developed areas and sometimes found in areas with greater intensity of land use [30].Road70Along with all routes, most birds were observed in trees and appeared to be either foraging, nesting or singing, with little evidence of the routes being used as flyways [42].Waterbody20Marked preference for breeding sites adjacent to aquatic habitats over sites on farmland associated with wetland habitats, breeding season preference for areas containing water bodies [43].…”

Section: Methodsmentioning

confidence: 99%

“…Built up area90Rarely found in non-vegetation areas [28].Road80Recognises only dense trees, lower tree fractions equal to no trees [42]. Prefer denser trees but can traverse non-tree as last resort [42].Waterbody10Yellow-vented bulbul ( Pycnonotus goiavier ) was recorded the highest densities in the open waterbody habitat [51].…”

Section: Methodsmentioning

confidence: 99%

“…Larger parks with more visitors could support more omnivores in the breeding season [30]. Increasing random extinction with decreasing habitat size [57].Patch distanceMaximum distance 1000 mSeed food within 1 km of the nest-site influenced nest-site choice or affected productivity [43].All tree fractions equally suitable; avoids gaps [42].Birds choose the least-cost (optimum) path, encounter fewer hazards, would spend less time in traveling, and travel through habitat with higher probability of containing food and cover [42].The importance of seed and food resources to the persistence of Eurasian tree sparrow populations. Operates on a larger spatial scale due to the greater mobility in the non-breeding season [43].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Ecological connectivity networks in rapidly expanding cities

Nor

Corstanje

Harris

et al. 2017

Heliyon

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Urban expansion increases fragmentation of the landscape. In effect, fragmentation decreases connectivity, causes green space loss and impacts upon the ecology and function of green space. Restoration of the functionality of green space often requires restoring the ecological connectivity of this green space within the city matrix. However, identifying ecological corridors that integrate different structural and functional connectivity of green space remains vague. Assessing connectivity for developing an ecological network by using efficient models is essential to improve these networks under rapid urban expansion. This paper presents a novel methodological approach to assess and model connectivity for the Eurasian tree sparrow (Passer montanus) and Yellow-vented bulbul (Pycnonotus goiavier) in three cities (Kuala Lumpur, Malaysia; Jakarta, Indonesia and Metro Manila, Philippines). The approach identifies potential priority corridors for ecological connectivity networks. The study combined circuit models, connectivity analysis and least-cost models to identify potential corridors by integrating structure and function of green space patches to provide reliable ecological connectivity network models in the cities. Relevant parameters such as landscape resistance and green space structure (vegetation density, patch size and patch distance) were derived from an expert and literature-based approach based on the preference of bird behaviour. The integrated models allowed the assessment of connectivity for both species using different measures of green space structure revealing the potential corridors and least-cost pathways for both bird species at the patch sites. The implementation of improvements to the identified corridors could increase the connectivity of green space. This study provides examples of how combining models can contribute to the improvement of ecological networks in rapidly expanding cities and demonstrates the usefulness of such models for biodiversity conservation and urban planning.

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“…Distance from urban-rural boundary was generated for each point count location from the official City of Reno growth boundary, available at the Washoe County GIS site. FragStats was used to calculate patch shape and area to represent possible edge effects and describe the core area (Mason, Moorman, Hess, & Sinclair, 2007) as well as proximity and nearest neighbor index to represent isolation/connectivity effects (Fernandez-Juricic & Jokimaki, 2001;Nichol, Wong, Corlett, & Nichol, 2010) within a 10 km radius of each point count location. The 10 km search radius was chosen in order to incorporate all patches in the landscape, although patches very far away receive very little weight (McGarigal et al, 2002).…”

Section: Environmental Variablesmentioning

confidence: 99%