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Assessing landscape structure and pattern fragmentation in semiarid ecosystems using patch-size distributions
Mariano Moreno-de Las Heras1, Patricia M Saco, Garry R Willgoose
1Faculty of Engineering and Built Environment, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia. Mariano.Morenodelasheras@newcastle.edu.au
Summary
Vegetation patch-size distribution in semiarid ecosystems is complex. Preserving large vegetation patches is crucial for maintaining ecosystem structure and function, especially under disturbance.
Area of Science:
- Ecology
- Remote Sensing
- Geomorphology
Background:
- Spatial vegetation patterns offer insights into semiarid ecosystem health, especially concerning climate and land use change.
- Previous studies suggested power-law metrics for dryland vegetation patch-size distribution, indicating desertification signs.
- Modeling approaches questioned universal power-law applicability, identifying characteristic scales in periodic landscapes.
Purpose of the Study:
- To analyze the relationship between vegetation fragmentation and patch-size distributions in semiarid landscapes with varying periodicity.
- To investigate the influence of analysis methodology and landscape traits on vegetation pattern assessment.
- To identify reliable indicators for monitoring desertification and ecosystem health.
Main Methods:
- Utilized remote sensing data of Australian Mulga shrublands with varying disturbance levels.
- Applied patch-size probability density and cumulative probability distribution functions.
- Conducted both nondirectional and downslope analyses to account for landscape anisotropies.
Main Results:
- Vegetation patch-size distribution shape varies with analysis methodology and landscape traits, challenging universal power-law metrics.
- Characteristic scale lengths were detected in periodic ecosystems using downslope transects.
- Disturbance leads to a decrease in large vegetation patches, a common fragmentation signal.
Conclusions:
- The universal applicability of power-law metrics for vegetation patch-size distribution in drylands is limited.
- Cumulative probability distributions are sensitive indicators of vegetation fragmentation in semiarid ecosystems.
- Maintaining large vegetation patches is vital for semiarid ecosystem structure and functionality.
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