Do eucalypt plantation management practices create understory reservoirs of scarab beetle pests in the soil?

Frew, Adam and Nielsen, Uffe N. and Riegler, Markus and Johnson, Scott N. (2013) Do eucalypt plantation management practices create understory reservoirs of scarab beetle pests in the soil? Forest Ecology and Management, 306. pp. 275-280. ISSN 0378-1127

Abstract

Eucalypt management practices can affect the population dynamics of defoliating insects. To date, research has focused on how these practices alter eucalypt physiology and chemistry, which in turn affect canopy herbivores. Management practices such as irrigation and fertilisation, however, could also shape the understory plant community and potentially improve habitats for grass root-feeding scarab beetle larvae that later can become defoliators as adults. Using a large scale factorial field experiment comprising 2560 Eucalyptus saligna, we investigated the effects of irrigation and fertilisation on the understory ecology of a eucalypt plantation. We specifically focussed on grass communities and populations of scarab beetles and their natural enemies (entomopathogenic nematodes, EPNs). Irrigation and fertilisation increased grass coverage by 40% and 42%, respectively, and affected grass species composition. In particular, fertilisation favoured colonisation with C3 grasses (e.g. Microlaena stipoides) that have higher nitrogen concentrations over lower quality C4 grasses (e.g. Setaria incrassata). Fertilisation increased the nitrogen concentration of grasses by 30% on average. Scarab abundance increased by 52% in fertilised plots, potentially due to higher nutritional quality of host plants and the dominance of nutritionally superior species. Irrigation increased soil water content, but did not promote scarab larvae abundance. The presence of EPNs, however, was 78% higher in irrigated plots, which suggests scarab larvae populations may have been controlled by EPNs. This study illustrates how plantation management practices can affect understory communities of both plants and soil invertebrates with potential for creating ‘reservoirs’ of scarab beetle pests.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 20 Nov 2019 01:39
Last Modified: 20 Nov 2019 04:41
Uncontrolled Keywords: fertilisation, grass understory, irrigation, nematodes, rRoot herbivores
Fields of Research : 05 Environmental Sciences > 0502 Environmental Science and Management > 050209 Natural Resource Management
06 Biological Sciences > 0602 Ecology > 060202 Community Ecology(excl. Invasive Species Ecology)
05 Environmental Sciences > 0503 Soil Sciences > 050303 Soil Biology
Socio-Economic Objective: D Environment > 96 Environment > 9604 Control of Pests, Diseases and Exotic Species > 960414 Control of Plant Pests, Diseases and Exotic Species in Forest and Woodlands Environments
Identification Number or DOI: 10.1016/j.foreco.2013.06.051
URI: http://eprints.usq.edu.au/id/eprint/37281

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