AN INVERTEBRATE ECOSYSTEM ENGINEER UNDER THE UMBRELLA OF SAGE-GROUSE CONSERVATION

Area of Science:

• Ecology
• Conservation Biology
• Entomology

Background:

• The umbrella species concept is widely used in conservation, but its application for protecting invertebrates via vertebrates is understudied.
• Sage-grouse (Centrocercus spp.) are a high-priority species in western North American rangelands, often considered an umbrella species.
• Harvester ants are crucial ecosystem engineers in rangeland environments.

Purpose of the Study:

• To investigate the potential of Greater Sage-Grouse as an umbrella species for conserving harvester ants.
• To determine the relationship between Greater Sage-Grouse abundance and harvester ant mound abundance in central Wyoming.

Main Methods:

• Compared abundance indices of western harvester ants (Pogonomyrmex occidentalis) and Greater Sage-Grouse (Centrocercus urophasianus) at 72 sites.
• Utilized regression modeling to identify predictors of harvester ant mound abundance, including habitat characteristics and sage-grouse abundance indicators (pellets).

Main Results:

• Harvester ant mound abundance was best predicted by a combination of local habitat and sage-grouse abundance.
• Areas with more sage-grouse pellets showed higher ant mound abundance, even after controlling for habitat factors.
• No relationship was found between broad-scale breeding sage-grouse density and ant mound abundance.

Conclusions:

• Fine-scale measures of sage-grouse abundance and non-breeding habitat are critical for their utility as an umbrella species for harvester ants.
• Sage-grouse may serve as a viable umbrella species for conserving harvester ants and their ecological roles in rangelands.