Nitrogen deposition simulation in ant colony enclosures (Formicidae)

Knowledge graph centered on Nitrogen deposition simulation in ant colony enclosures (Formicidae) with 22 nodes and 91 connections. Top connected: Ligusticum porteri, Artemisia, mutualistic relationships, herbivory, trophic cascade.

Method synopsis

Factorial experiment testing effects of low-level nitrogen enrichment on trophic cascades using enclosed ant colonies with controlled fertilizer applications. Enclosures contained single ant nests and received either ambient or elevated N deposition treatments.

Synthesized from method descriptions across 1 paper using this protocol.

Procedure as described in the canonical source

Steps below were extracted from the paper that introduces this protocol — Short-term, low-level nitrogen deposition dampens a trophic cascade between bears and plants (2018), Ecology and Evolution. Implementations in other papers (listed below) may differ.

1. Establish ant enclosures
   Install 36 ant enclosures in the montane meadow during summer 2010. Each enclosure was 5 m in diameter and encircled a central F. obscuripes nest. Male fern rhizomes along landscape edges (15 cm tall) buried 5 cm deep. Plastic barriers were slippery for thatch ants, which could not crawl over the material, but foraging trails were occasionally dug underneath the barriers.
   Quantities: 36 enclosures total, 5 m diameter each, 15 cm tall barriers, buried 5 cm deepDuration: Summer 2010 installation, maintained each summer through 2012 by reinstalling barriers and removing bridging vegetationConditions: Montane meadow conditions
   Equipment: male fern rhizomes, plastic barriers
2. Apply nitrogen treatments
   Apply elevated N deposition (3.5 times ambient) in half of the ant enclosures. Total N deposition in the meadow was approximately 2 kg N ha⁻¹ year⁻¹ when study began in 2010. Apply 0.5 g N m⁻² of slow-release ammonium nitrate fertilizer once each summer to randomly-selected enclosures (n = 18) to mimic a total N deposition rate of 7 kg N ha⁻¹ year⁻¹.
   Quantities: 18 enclosures treated, 0.5 g N m⁻² application rate, targeting 7 kg N ha⁻¹ year⁻¹ total deposition rateDuration: Once each summer from 2010 to 2012Conditions: Applied to randomly-selected enclosures
   Equipment: slow-release ammonium nitrate fertilizer
3. Monitor bear foraging activity
   Allow bears to forage on ant nests within the enclosures from 2010 to 2012. Nests were considered inactive if no more than one ant-worker emerged when the ground next to the nest was beaten. Bear attacks on nests and nest inactivity occurred in all three sections of the study meadow and were unrelated to N additions according to binomial models.

Typical Equipment

• male fern rhizomes
• plastic barriers
• slow-release ammonium nitrate fertilizer
• ground beating assessment method

Output Measurements

• nitrogen addition effects
• ant nest activity
• plant-herbivore interactions

Papers Using This Protocol (1)

Species Studied With This Protocol