Grantee Research Project Results
2002 Progress Report: A Hierarchical Patch Dynamics Approach to Regional Modeling and Scaling
EPA Grant Number: R827676Title: A Hierarchical Patch Dynamics Approach to Regional Modeling and Scaling
Investigators: Wu, Jianguo , Green, Douglas
Institution: Arizona State University - West
EPA Project Officer: Packard, Benjamin H
Project Period: October 15, 1999 through October 14, 2002
Project Period Covered by this Report: October 15, 2001 through October 14, 2002
Project Amount: $629,540
RFA: Regional Scale Analysis and Assessment (1999) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration
Objective:
The main objective of this research project is to conduct field work as well as landscape pattern analysis and modeling. Significant insights have been obtained from these studies, which are summarized below.
Progress Summary:
We made significant progress toward achieving the project objectives in Year 3 of the project. Several major findings have emerged from our studies, which cover a variety of topics including: (1) quantitative analysis of historical land use change in the Phoenix region; (2) a gradient analysis of the landscape pattern of urbanization in the Phoenix metropolitan area; (3) scaling relations of the spatial pattern of the Phoenix urban landscape; and (4) integrating land use and land cover change with ecosystem dynamics. Our study of the historical land use change showed that urbanization in the metropolitan Phoenix region has resulted in dramatic increases in patch density, edge density, patch and landscape shape complexity, and sharp decreases in the largest and mean patch size, desert habitat area, and landscape connectivity. The general pattern of urbanization was that the increasingly urbanized areas became more compositionally diverse, more geometrically complex, and more ecologically fragmented. Our results suggest that the same resolution (and extent) must be used for analyzing the same landscape over time or comparing different landscapes at a given time due to scale effects. In addition, our results supported the hypothesis that, with increasing urbanization, patch density increases, while patch size and landscape connectivity decrease. However, our results on patch shape seemed to reject the hypothesis that patch shape becomes more regular as human modification to landscapes intensifies.
Our landscape gradient analysis showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be precisely and consistently identified with multiple indices. Different land use types exhibited distinctive, but not necessarily unique, spatial signatures that were dependent on specific landscape metrics. The changes in landscape pattern along the transect have important ecological implications, and quantifying the urbanization gradient is an important first step to linking patterns with processes in urban ecological studies. Our multiple-scale landscape pattern analysis suggested that, to adequately quantify spatial heterogeneity, metric scalograms (the response curves of metrics to changing scale), instead of single-scale measures, should be used.
Based on the hierarchical patch dynamics paradigm and the scaling ladder concept, we have developed a spatially hierarchical modeling approach to study complex urban landscape systems, and a hierarchical modeling platform (HPD-MP)-a software package-from which multiscale ecological models can be developed and integrated in an efficient and coherent manner. Refining the ecosystem models and integrating them with land use change models using HPD-MP is the focus of our current research.
Our field work revealed that: (1) total C was higher in mesic residential soils (0.9 to 1.9 percent) than xeric residential and desert (TC 0.5 to 1.2 percent); (2) organic C was higher in mesic residential soils (0.6 to 1.7 percent) than xeric residential and desert (0.3 to 0.7 percent); (3) neither total C nor organic C differed among soil associations at each site; (4) inorganic C (which varied from 0.1 to 0.5 percent overall) was higher in xeric residential (0.4 percent) than desert (0.2 percent) sites; (5) extractable P was higher in mesic residential soils (7.5 to 35.3 mg kg-1) than xeric residential and desert sites (5.8 to 19.1 mg kg-1); (6) conductivity was lower in soils at undeveloped desert (0.18 to 0.42 dS m-1) versus mesic and xeric residential sites (0.54 to 2.12 dS m-1), indicating that salt build up may be occurring as a result of irrigation and evapotranspiration; (7) C:N ratios were highest (24:1) in soils at xeric residential sites; (8) organic C (in mesic, r2 = 0.22), total N (in mesic, r2 = 0.28), and conductivity (in xeric, r2 = 0.20) all had a positive linear relationship with age of the residential development, suggesting that they had increased over time since development. Total N (in xeric, r2 = 0.12) showed a trend (P = 0.07) in the same direction; (9) the urban soils in the Phoenix area seem to have experienced a moderate increase in soil C, with a soil organic C density of 2.3 to 6.3 kg m-2 (to a 1-m depth), which is at the lower end of soil C storage for world soils (within the range of values expected for desert soils); and (10) the percentage of clay was significantly higher in the residential than the desert soils in two of the four main soil associations sampled, indicating a decrease in soil particle size due to residential development.
Future Activities:
We will continue to conduct field work and to perform landscape pattern analysis and modeling until the project is complete.
Journal Articles on this Report : 8 Displayed | Download in RIS Format
| Other project views: | All 73 publications | 44 publications in selected types | All 33 journal articles |
|---|
| Type | Citation | ||
|---|---|---|---|
|
|
He FL, Gaston KJ, Wu JG. On species occupancy-abundance models. Ecoscience 2002;9(1):119-126. |
R827676 (2002) R827676 (Final) |
Exit Exit |
|
|
Luck M, Wu J. A gradient analysis of urban landscape pattern: a case study from the Phoenix metropolitan region, Arizona, USA. Landscape Ecology 2002;17(4):327-339. |
R827676 (2002) R827676 (Final) |
Exit Exit |
|
|
Musacchio LR, Wu J. Collaborative landscape-scale ecological research: emerging trends in urban and regional ecology. Urban Ecosystems 2004;7(3):175-178. |
R827676 (2000) R827676 (2001) R827676 (2002) R827676 (2003) R827676 (Final) |
Exit Exit |
|
|
Wu J, Hobbs R. Key issues and research priorities in landscape ecology: an idiosyncratic synthesis. Landscape Ecology 2002;17(4):355-365. |
R827676 (2002) R827676 (Final) |
Exit Exit |
|
|
Wu J, David JL. A spatially explicit hierarchical approach to modeling complex ecological systems: theory and applications. Ecological Modeling 2002;153(1-2):7-26. |
R827676 (2001) R827676 (2002) R827676 (Final) |
Exit Exit Exit |
|
|
Wu J, Marceau D. Modeling complex ecological systems: an introduction. Ecological Modelling 2002;153(1-2):1-6. |
R827676 (2002) R827676 (Final) |
Exit Exit Exit |
|
|
Wu J, Shen W, Sun W, Tueller PT. Empirical patterns of the effects of changing scale on landscape metrics. Landscape Ecology 2002;17(8):761-782. |
R827676 (2002) R827676 (Final) |
Exit Exit |
|
|
Zhang H, Wu J. A statistical thermodynamic model of the organizational order of vegetation. Ecological Modelling 2002;153(1-2):69-80. |
R827676 (2002) R827676 (Final) |
Exit Exit Exit |
Supplemental Keywords:
land, soil, urban, stressors, ecosystem, regionalization, scaling, terrestrial, habitat, integrated assessment, sustainable development, ecology, modeling, Landsat, remote sensing, field measurements, Southwest, Arizona, AZ, agriculture, urbanization., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Air, Geographic Area, State, Ecosystem Protection, Ecology, Environmental Chemistry, Regional/Scaling, Ecological Effects - Environmental Exposure & Risk, climate change, Environmental Monitoring, regional survey data, scaling methods, urbanization, hierarchical patch dynamics, ecosystem, remote sensing imagery, ecological exposure, scaling, anthropogenic, land use, field measurements, agriculture, functional complexity, modeling, spatial scaleRelevant Websites:
http://LEML.asu.edu/EPASTAR-Proj/ Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.