Details

Autor(en) / Beteiligte

• Gherlenda, Andrew N
• Crous, Kristine Y
• Moore, Ben D
• Haigh, Anthony M
• Johnson, Scott N
• Riegler, Markus

Titel

Precipitation, not CO2 enrichment, drives insect herbivore frass deposition and subsequent nutrient dynamics in a mature Eucalyptus woodland

Ist Teil von

• Plant and soil, 2016-02, Vol.399 (1-2), p.29-39

Ort / Verlag

Cham: Springer International Publishing

Erscheinungsjahr

2016

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• BACKGROUND AND AIMS: Herbivorous insects are important nutrient cyclers that produce nutrient-rich frass. The impact of elevated atmospheric [CO₂] on insect-mediated nutrient cycling, and its potential interaction with precipitation and temperature, is poorly understood and rarely quantified. We tested these climatic effects on frass deposition in a nutrient-limited mature woodland. METHODS: Frass deposition by leaf-chewing insects and its chemical composition was quantified monthly over the first 2 years at the Eucalyptus free-air CO₂ enrichment experiment and contrasted with leaf nitrogen concentration, rainfall and temperature. RESULTS: Leaf-chewing insects produced yearly between 160 and 270 kg ha⁻¹ of frass depositing 2 to 4 kg ha⁻¹ of nitrogen. Frass quantity and quality were influenced by rainfall and average maximum temperatures. In contrast, elevated CO₂ did not impact nitrogen concentrations in fully expanded leaves and frass deposition to the woodland floor. CONCLUSIONS: Two years of elevated CO₂ did not alter nutrient transfer by leaf-chewing insects. This may be due to the low nutrient status of this ecosystem, duration of CO₂ fumigation or climatic conditions. However, rainfall co-occurring with seasonally higher temperatures exerted strong effects on nutrient cycling, potentially through shifts in leaf phenology with consequences for insect population dynamics and insect-mediated nutrient transfer.