Post-Border Forest Biosecurity in Australia: Response to Recent Exotic Detections, Current Surveillance and Ongoing Needs

Round 1

Reviewer 1 Report

This is a detailed and comprehensive review of the issues around biosecurity surveillance and eradication of forest pests and pathogens. While there’s not really any new insights in the discussion and conclusions, the detailed description of Australia’s forest biosecurity systems and the list of case study incursions make this a very worthwhile read, and I expect if published it will be widely referenced.

The discussion of the strengths and weaknesses of biosecurity surveillance is welcome. However, there is no mention of the need for qualitative, or ultimately quantitative, understanding of the sensitivity and specificity of different surveillance tools for different targets. We will never be able to optimise surveillance systems until we can model them convincingly, and this will require data. Work by Cindy Hauser and colleagues is a good example of how surveillance systems can be significantly improved by measuring the efficacy of the tools (or people) involved.

On line 504 the authors endorse generalist trapping, but fail to mention the problem which means this is rarely used – the issue of bycatch. Trappers may need to sort through hundreds, thousands or millions of bycatch specimens to find the one target exotic organism that really matters. Recent molecular “DNA soup” and eDNA technologies may prove a boon here, but only once biosecurity authorities are prepared to make decisions in the absence of an intact specimen. Regulators and researchers need to agree on standards for the sensitivity and specificity of such tools before the potential of generalised trapping can be fully realised. Incidentally, there are similar issues around other new detection and diagnostic technologies such as digital photographs sent in by the public.

On line 607, I think the point about social science needs to be taken further. Not only do we need to measure the social acceptability of biosecurity interventions, we ultimately need to understand what factors affect this, so that biosecurity authorities can educate and empower the public in the most effective way. Critical research is needed to assess the strengths and weaknesses of public vigilance for biosecurity surveillance.

The only other point I can really fault is the misspelling of my surname on line 65.  :-)

Author Response

We have taken on board all of Reviewer 1's suggestions and comments.

See attached.

Author Response File: Author Response.docx

Reviewer 2 Report

General comments

This manuscript reviews the literature dealing with the detection and eradication of forest insects and pathogens in Australia.

The review is well written and outcomes are of great relevance for management of invasive alien species in forest ecosystems. While the introduction well represents the Australian situation, I strongly suggest highlighting the importance of the Australian experience for other continents: how can lessons learned in Australia benefit other parts of the world? For example, Europe is now experiencing the implementation of a recent regulation on invasive alien species; can this article help towards increasing the detection and eradication performance?

Citation (I appreciate the possibility of seeing the classical citation) and reference style should be revised in accordance with Journal’s indications.

Specific comments

L116: Please specify why data are not comprehensive before 1996.

L128-130: I suggest clearly highlighting whether detection was made on exotic trees (or specify that all trees forming plantations are exotic).

L131: Did authors make reference to overall reviews (on insects and pathogens) or to specific documents for each detected species? Please give examples of the main literature resources.

Figure 1: Years are to compressed, please reduce dimension of the text or make it transversal. Please add a legend in the figure that enables direct recognition of different colours and symbols.

L281-282: Why is Arhopalus rusticus mentioned here? Is it because the monitoring of Bursaphelenchus hunanensis lead to its detection? In this case please make it clearer.

L294: Do Authors refer to Castanea spp. and Quercus spp. or to specific species?

L306vs.309, L321vs.324: Species number are sometimes abbreviated after first mention and sometimes not. Please be consistent.

L328-330: I suggest giving the information on B. hunanensis in the paragraph at L278-290. It seems to me a kind of repetition.

L366-373: I do not understand the link of this case (Ophiostoma ips + Ips grandicollis) with the previous part of the paragraph.

L414-416: What about the importance of knowing existing occurrence and infestation of pests? Based on section 2.3, I would add this aspect because the knowledge of the presence and diffusion of pests is important to decide whether to finance eradication actions and not waste resources in unnecessary eradication campaigns (many examples are reported in the review where an initial eradication action started but then stopped because of the spread of these species).

L416-418: Can authors give some more specifications on this curve?

L430-548: Really interesting. What about the role of early detection? Do authors assume that increasing cost/intensity of surveillance will result in more probable detection? It should be made clear, as I have understood from all the discussion around figure 4, that early detection probability strongly influences the probability of successful eradication. With a constant early detection probability, would the curve have the same trend as the one in figure 4?

L523-540: I think this paragraph should introduce the discussion related to the proposed curve (and not be positioned after it as it is now). In fact, the presented factors play a role in shaping the probability of eradication success. Furthermore, as mentioned in the previous point, I would stress the importance of early detection as an important factor in successful eradications.

L605-607: Double parenthesis makes it difficult to follow this sentence and the examples, I suggest using the common or the scientific names.

Table 1: I suggest deleting the term “responded” in the table’s caption. Species are reported regardless of the implementation of an eradication action.

Table 1: It would be important to have a more informative description of the groups and elements reported as integration to the text or as supplementary material.

Author Response

We have included most of the suggestions of Reviewer 2. 

See attached.

Author Response File: Author Response.docx