Development of a grassland integrity index based on breeding bird assemblages

Area of Science:

• Ecology
• Conservation Biology
• Ornithology

Background:

• Mixed-grass prairies face fragmentation and woody encroachment, impacting avian communities.
• Long-term monitoring data is crucial for understanding ecological changes.

Purpose of the Study:

• To develop and validate a Grassland Integrity Index (GII) using avian assemblage data.
• To create an inexpensive and efficient tool for monitoring grassland health.

Main Methods:

• Utilized Breeding Bird Survey (BBS) data from 1965-1995 in Oklahoma.
• Developed a Grassland Disturbance Index (GDI) based on landscape variables (vegetation cover, patch size).
• Selected 13 avian assemblage metrics reflecting life history parameters to build the GII, scaled from 0-100.

Main Results:

• The GII effectively responded to landscape disturbances measured by the GDI.
• The index was derived from readily available, long-term BBS data.
• The GII demonstrated potential as a cost-effective monitoring tool.

Conclusions:

• The avian-based GII is a promising tool for assessing regional grassland conditions.
• This index offers an advantage over traditional habitat-based monitoring methods.
• The GII can be applied broadly to monitor ecological changes in grasslands.