Designing Standardized and Optimized Surveys to Assess Invertebrate Biodiversity in Tropical Irrigated Rice Using...

Area of Science:

• Agricultural Entomology
• Ecology
• Biodiversity Assessment

Background:

• Effective insect pest management relies on standardized, rapid, and reliable sampling methods.
• Optimizing sampling techniques is crucial for accurate invertebrate fauna characterization in agricultural ecosystems.
• Previous studies have not fully explored structured inventory and optimization approaches for rice field invertebrates.

Purpose of the Study:

• To evaluate and optimize seven field sampling methods for invertebrate fauna in Philippine irrigated rice.
• To compare the effectiveness of different sampling techniques for canopy and floodwater invertebrates.
• To utilize species richness models for assessing inventory completeness and guiding sampling effort allocation.

Main Methods:

• Conducted intensive, repetitive sampling of canopy and floodwater invertebrates across 600 quadrats in Philippine rice fields over two cropping seasons.
• Employed seven field methods, including D-Vac, plant dissections (PD), FARMCOP, Blower-Vac, sweep-net, area collector, and strainer-net.
• Utilized species richness models to estimate inventory completeness and determine optimal sampling effort allocation for different methods.

Main Results:

• All four tested methods captured only 25% (canopy) and 50% (floodwater) of the observed invertebrate richness.
• Estimated inventory completeness reached an average of 82% (canopy) and 98% (floodwater) when all methods were pooled.
• Sampling optimization recommended prioritizing D-Vac and PD for canopy sampling and the area collector for floodwater sampling.

Conclusions:

• Structured inventory and species richness models are valuable tools for optimizing sampling strategies in crop-invertebrate assemblages.
• These approaches provide reliable criteria for setting stopping rules in sampling protocols.
• The findings enable more informative biodiversity comparisons and enhance insect pest management in rice ecosystems.