Page 7 - EER-2-1

Explora: Environment

and Resource

REVIEW ARTICLE
Prioritizing scientific data over expert opinion

in the valid assessment of Australian Acacia
biocontrol success

Ruan Veldtman 1,2,3 * and Matthys Strydom 4

1 South African National Biodiversity Institute, Cape Town, Western Cape, South Africa
2 National Institute for Theoretical and Computational Science, Stellenbosch, Western Cape, South
Africa
3 Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, Western Cape,
South Africa
4 Academy for Environmental Leadership SA, Upington, Northern Cape, South Africa

Abstract

Invasive species are such a pervasive problem that, in many cases, the management
of this global change driver appears close to impossible. Biological control using
natural enemies from these invasive species’ native ranges is an attractive option to
restore the balance in the invaded environment. The biological control of Australian
Acacia spp. in South Africa is a lauded example of textbook biological control of
invasive species management. However, we propose that this apparent success of
*Corresponding author: biological control agents in reducing population levels of the alien trees is largely
Ruan Veldtman unfounded, as it is not based on ecological data but rather on scientific assumptions
(veldtman@sun.ac.za)
by experts. We argue that the fundamental question, “Does biocontrol reduce
Citation: Veldtman R, Strydom M. the impact of invasive tree populations?” is not being asked. Instead, the onus is
Prioritizing scientific data over
expert opinion in the valid on researchers to prove that biological control agents do not work. If experts act
assessment of Australian Acacia as reviewers for work that shows the contrary to their expert opinion, we have a
biocontrol success. Explora Environ potential conflict of interest. The result of this dispute is that contrary empirical data
Resour. 2025;2(1):5876.
doi: 10.36922/eer.5876 are slow to enter the policy decision-making sphere. The status quo of producing
policy recommendations to manage biological invasions is based on expert opinion
Received: November 12, 2024
from the scientists who released the biocontrol agents. We propose that an overhaul
1st revised: January 20, 2025 of this approach is urgently needed. The scientific burden of proof should not be
2nd revised: February 14, 2025 on whether biocontrol agents are not effective but rather on whether they are
effectively reducing the impacts of the host plant. Any corrective management to
Accepted: March 3, 2025
solve environmental problems should be based on open, multidisciplinary science
Published online: March 13, 2025 that provides the necessary supporting evidence. Our case study on biological
Copyright: © 2025 Author(s). control of Australian Acacia spp. is an illustrative example of why scientific data
This is an Open-Access article should guide decision-making for sustainable environmental management.
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution, Keywords: Invasive species; Classical biological control; Acacia; Seed-reducing agents
and reproduction in any medium,
provided the original work is
properly cited.
Publisher’s Note: AccScience
Publishing remains neutral with 1. Introduction
regard to jurisdictional claims in
published maps and institutional Invasive species are such a pervasive problem that, in many cases, the management of
1,2
affiliations. this global change driver appears close to impossible. Biological control (“biocontrol”)

Volume 2 Issue 1 (2025) 1 doi: 10.36922/eer.5876