A new digital method of data collection for spatial point pattern analysis in grassland communities

Area of Science:

• Plant Ecology
• Spatial Statistics
• Ecological Methodology

Background:

• Understanding spatial distribution patterns of plant species is crucial in plant ecology.
• Spatial point pattern analysis is a valuable tool but hindered by data collection challenges in grasslands.
• Previous studies have limited the application of point pattern analysis in grassland ecosystems.

Purpose of the Study:

• To develop and test a novel, convenient sampling method for collecting spatial point pattern data in grassland communities.
• To analyze the spatial patterns of *Stipa grandis* in grazed and ungrazed temperate steppe ecosystems.
• To investigate the ecological interactions (competition vs. facilitation) driving spatial patterns in *S. grandis* populations.

Main Methods:

• Developed a new method using digital photography and a geographical information system (GIS) to record individual plant coordinates.
• Applied the method to measure *Stipa grandis* coordinates in grazed and ungrazed communities in a Chinese temperate steppe.
• Utilized the pair correlation function *g(r)* and homogeneous/heterogeneous Poisson processes for spatial pattern analysis.

Main Results:

• Individuals of *Stipa grandis* exhibited overdispersion at 0-0.16 m in the ungrazed community (homogeneous Poisson process).
• Individuals of *Stipa grandis* showed clustering at 0.19 m in the grazed community (homogeneous and heterogeneous Poisson processes).
• The results indicate a shift from competitive to facilitative interactions between grazed and ungrazed conditions.

Conclusions:

• The new digital photography and GIS-based method provides a convenient and effective way to collect spatial point pattern data in grasslands.
• Spatial patterns of *Stipa grandis* differ significantly between grazed and ungrazed conditions, reflecting distinct ecological processes.
• Competitive interactions dominate in ungrazed *S. grandis* communities, while facilitative interactions are more prominent in grazed communities.