Consequences of Prescribed Fire and Grazing on Grassland Ant Communities

• Published in: Environmental entomology 2009-04, Vol.38 (2), p.325-332
• Main Authors: Underwood, Emma C, Christian, Caroline E
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Ants - physiology; Behavior, Animal; Biodiversity; Biological and medical sciences; Brachymyrmex; California; cattle; COMMUNITY AND ECOSYSTEM ECOLOGY; conservation management; Conservation of Natural Resources - methods; ecological disturbance; ecological impact; environmental impact; Feeding Behavior; Fires; Formicidae; Fundamental and applied biological sciences. Psychology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; grasslands; grazing; habitat disturbance; habitats; insect communities; mediterranean ecosystems; Poaceae; Population Density; Population Dynamics; prescribed burning; restoration; species diversity; Synecology; Terrestrial ecosystems; vegetation
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1603/022.038.0204

Prescribed fire and livestock grazing are used for the management and restoration of native grasslands the world over; however, the effects of these management techniques on ant communities are unclear. We examined the response of ants to these disturbances in grasslands in northern California. Twenty-four 30 by 30 m plots were established across two sites that received one of four treatments: grazing, fire, grazing and fire, or no treatment. Ants were censused using 240 pitfall traps with one preburn and two postburn samples (14 d and 1 yr after burning). We analyzed ant abundance using broadly defined groups based on feeding habit and/or habitat use and detected no grazing effect but a significant fire effect that differed by group. Immediate postfire sampling showed an increase in cryptic species (particularly Brachymyrmex depilis). One year after the fire, no response was detected for cryptic species, but burned plots had greater abundance of seed harvesters. Analysis of vegetation showed burned plots had significantly greater forb cover, which might have provided greater food resources, and also lower biomass, which might have facilitated foraging. Understanding the effects of these management tools on ant abundance complements our understanding of their effect on vegetation and assists conservation practitioners effectively manage grassland ecosystems both in California and beyond.