Biological Invasions

, Volume 19, Issue 12, pp 3515–3526 | Cite as

Urban trees: bridge-heads for forest pest invasions and sentinels for early detection

  • Trudy PaapEmail author
  • Treena I. Burgess
  • Michael J. Wingfield


Urban trees have been increasingly appreciated for the many benefits they provide. As concentrated hubs of human-mediated movement, the urban landscape is, however, often the first point of contact for exotic pests including insects and plant pathogens. Consequently, urban trees can be important for accidentally introduced forest pests to become established and potentially invasive. Reductions in biodiversity and the potential for stressful conditions arising from anthropogenic disturbances can predispose these trees to pest attack, further increasing the likelihood of exotic forest pests becoming established and increasing in density. Once established in urban environments, dispersal of introduced pests can proceed to natural forest landscapes or planted forests. In addition to permanent long-term damage to natural ecosystems, the consequences of these invasions include costly attempts at eradication and post establishment management strategies. We discuss a range of ecological, economic and social impacts arising from these incursions and the importance of global biosecurity is highlighted as a crucially important barrier to pest invasions. Finally, we suggest that urban trees may be viewed as ‘sentinel plantings’. In particular, botanical gardens and arboreta frequently house large collections of exotic plantings, providing a unique opportunity to help predict and prevent the invasion of new pests, and where introduced pests with the capacity to cause serious impacts in forest environments could potentially be detected during the initial stages of establishment. Such early detection offers the only realistic prospect of eradication, thereby reducing damaging ecological impacts and long term management costs.


Biological invasions Biosecurity Invasion pathways Pathogens Pests Sentinel plants Urban trees 



This paper had its origins at a workshop on ‘Non-native species in urban environments’ hosted and funded by the DST-NRF Centre of Excellence for Invasion Biology (CIB) in Stellenbosch, South Africa, in November 2016. We thank Duccio Migliorini for useful discussion on the movement of pathogens through nursery stock. This work was funded by the South African National Department of Environmental Affairs.


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Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Trudy Paap
    • 1
    • 2
    Email author
  • Treena I. Burgess
    • 1
    • 3
  • Michael J. Wingfield
    • 1
    • 3
  1. 1.Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoriaSouth Africa
  2. 2.Invasive Species Programme, South African National Biodiversity InstituteKirstenbosch Research CentreCape TownSouth Africa
  3. 3.Centre for Phytophthora Science and Management, School of Veterinary and Life SciencesMurdoch UniversityPerthAustralia

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