Dryland management regimes alter forest habitats and understory arthropod communities

Johnson, S. N. and Lopaticki, G. and Aslam, T. J. and Barnett, K. and Frew, A. and Hartley, S. E. and Hiltpold, I. and Nielsen, U. N. and Ryalls, J. M. W. (2018) Dryland management regimes alter forest habitats and understory arthropod communities. Annals of Applied Biology, 172 (3). pp. 282-294. ISSN 0003-4746

Abstract

Dryland forests, those characterised as having low precipitation and soil nutrients, account for over a quarter of forests globally. Increasing their productivity often relies on irrigation and fertilisation, but the impacts on the wider habitat are largely unknown. Understory invertebrates, in particular, play key roles in forest systems (e.g. nutrient cycling), but their responses to dryland forest management practices are untested. We investigated the impacts of irrigation, fertilisation and a combination of both on soil chemistry, understory vegetation, tree growth and understory arthropod communities in a Eucalyptus plantation to establish linkages between dryland management and ecosystem responses. Fertilisation increased all soil nutrients (N, NO3N, P and K) with similar effects on the chemical composition of understory grasses. Fertilisation also caused declines in foliar silicon concentrations, an important herbivore defence in grasses. Irrigation increased growth of both understory plants (+90%) and trees (+68%). Irrigation increased the abundance of ground‐dwelling arthropods by over 480% relative to control plots, but depressed higher level taxon arthropod diversity by 15%, declining by a further 7% (−22%) in combined treatment plots. Irrigation also caused a surge in the abundance of Collembola (+1300%) and Isopoda (+323%). Fertilisation drove increases in the abundance of Isopoda (+196%) and Diptera (+63%), whereas fertilisation combined with irrigation increased populations of Thysanoptera (+166%) and Acarina (+328%). Airborne arthropods were less affected, but fertilisation increased the abundance of Apocrita (+95%) and depressed populations of Thysanoptera (−77%). Diptera abundance was positively related to understory vegetation growth, whereas the abundance of other groups (Collembola, Isopoda, Thysanoptera and Acarina) correlated positively with tree growth. We proposed that the large increases in populations of key detritivores, Collembola and Isopoda, were linked to increased leaf litter from enhanced tree growth in irrigated and combined treatment plots. Our findings suggest that dryland management can increase both plant productivity and abundance of arthropods, but cause arthropod diversity at the higher taxon level to decline overall.


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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 05:31
Last Modified: 21 Nov 2019 04:40
Uncontrolled Keywords: agroecosystems; arthropods; detritivores; eucalypt; fertilisation; grasses; insects; irrigation; plantation; silicon
Fields of Research : 06 Biological Sciences > 0602 Ecology > 060208 Terrestrial Ecology
07 Agricultural and Veterinary Sciences > 0705 Forestry Sciences > 070504 Forestry Management and Environment
05 Environmental Sciences > 0502 Environmental Science and Management > 050205 Environmental Management
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960906 Forest and Woodlands Land Management
Identification Number or DOI: 10.1111/aab.12419
URI: http://eprints.usq.edu.au/id/eprint/37294

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