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Maintaining understory vegetation in oil palm plantations supports higher assassin bug numbers

Published version
Peer-reviewed

Repository DOI


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Authors

Advento, AD 
Aryawan, AAK 
Caliman, JP 

Abstract

jats:titleAbstract</jats:title>jats:p jats:list

jats:list-itemjats:pThe expansion of oil palm agriculture across Southeast Asia has caused significant biodiversity losses, with the reduction in habitat heterogeneity that accompanies the conversion of forest to oil palm being a major contributing factor. However, owing to their long commercial lifespan, oil palm plantations can support relatively high levels of vegetation complexity compared to annual crops. There is therefore potential for the implementation of management strategies to increase vegetation complexity and associated within‐plantation habitat heterogeneity, enhancing species richness and associated ecosystem functioning within productive oil palm landscapes.</jats:p></jats:list-item>

jats:list-itemjats:pThis study focusses on two species of asassin bugs jats:italicCosmolestes picticeps and Sycanus dichotomus</jats:italic>, which are important agents of pest control within oil palm systems. Using a Before‐After Control‐Impact experimental manipulation in Sumatra, Indonesia, we tested the effect of three alternative herbicide spraying regimes and associated vegetation complexity treatments on assassin bug numbers. Our treatments encompass a range of current understory vegetation management practices used in oil palm plantations and include removing vegetation only in areas key to harvesting (“Normal”), removing all understory vegetation (“Reduced”), and allowing native vegetation to regrow naturally (“Enhanced”). We assessed both the long‐term (18 months) and short‐term (within 2 weeks) effects of our treatments following herbicide spraying.</jats:p></jats:list-item>

jats:list-itemjats:pPre‐treatment, we found high numbers of assassin bugs of both species in all plots. Long‐term post‐treatment, the abundance of both jats:italicC. picticeps</jats:italic> and jats:italicS. dichotomus</jats:italic> declined in reduced understory plots, although this decline was only significant for jats:italicC. picticeps</jats:italic> (98%). In contrast, there were no significant differences in the post‐treatment abundance of either species in the short‐term.</jats:p></jats:list-item>

jats:list-itemjats:pThese results suggest that the long‐term decline in assassin bug abundance was likely to be caused by loss of vegetation, rather than any immediate effects of the herbicide spraying. Our findings have clear management implications as they demonstrate that maintaining vegetation in oil palm understories can benefit an important pest control agent.</jats:p></jats:list-item> </jats:list> </jats:p>

Description

Publication status: Published


Funder: Biotechnology and Biological Sciences Research Council; doi: http://dx.doi.org/10.13039/501100000268; Grant(s): USN: 304338625


Funder: Gates Cambridge Trust; doi: http://dx.doi.org/10.13039/501100005370


Funder: Golden Agri Resources


Funder: International Conference of Oil Palm and Environment (ICOPE)


Funder: Isaac Newton Trust; doi: http://dx.doi.org/10.13039/501100004815


Funder: Marshall Aid Commemoration Commission; doi: http://dx.doi.org/10.13039/100014014

Keywords

31 Biological Sciences, 3103 Ecology

Journal Title

Ecological Solutions and Evidence

Conference Name

Journal ISSN

2688-8319
2688-8319

Volume Title

4

Publisher

Wiley
Sponsorship
Natural Environment Research Council (NE/P00458X/1)
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