The state of a nation’s health, wealth and happiness is measured by a wide variety of indicators. Such background information is essential for policy-makers. Data on the levels of disease prevalence, education and social cohesion all provide crucial background information to determine the demand for schools, hospitals and community facilities. Governments need to know how much to spend, where to spend it, what to spend it on and whether spending is effective or not. Setting, and obtaining agreement on, particular goals is a key approach taken to stimulate action. For example, eight Millennium Development Goals were set to focus and coordinate efforts to reduce extreme poverty over the period 2000–2015. Although the goals have not been fully met, they have arguably had a significantly positive impact at global, national and local levels (United Nations 2015).

South Africa has committed to several international environmental agreements, and to achieve their goals it has developed national policy frameworks and legislation to manage biodiversity loss. In particular, South Africa has produced a series of National Biodiversity Assessments (e.g. Driver et al. 2012). Although these includesections on the impact of the drivers of global change, biological invasions have not been a core focus of the reports.

In October 2014, the Regulations on Alien and Invasive Species (A&IS Regulations 2014) were made into law in terms of Section 97(1) of the National Environmental Management: Biodiversity Act (NEM:BA, Act 10 of 2004). Section 11(1)(a)(iii) of the regulations mandates the South African National Biodiversity Institute (SANBI) to submit a report on the status of biological invasions every three years (Box 1). The aim of the national status report is to consolidate information on the extent and impact of biological invasions as well as the effectiveness of interventions in a way that can be used to inform policy responses.

As part of initial efforts to gain input into the national status report, the DST-NRF Centre of Excellence for Invasion Biology and the SANBI convened a 3-day symposium (18–20 May 2016) in the Western Cape (Figure 1).

The symposium was one in a long line of very valuable and fruitful annual meetings. The first in this series of meetings was held in 1973 at Rhodes University and was attended by five people who discussed the science and practice of the biological control of weeds (Moran, Hoffmann & Zimmermann 2013). These symposia have expanded in size over time, and, particularly in the last decade, the scope of meetings has expanded – from an initial sole focus on biological control to research on the management of plant invasions more generally. The 2016 meeting was the first to cover all aspects of biological invasions, but it still included talks on technical aspects of the biological control of alien plants (Moran, Hoffmann & Hill 2011) and, to a lesser extent, alien plant incursion response planning (Wilson et al. 2013; Wilson, Panetta & Lindgren 2017).

The 173 delegates who attended the 2016 symposium represented 30 institutions including universities, governmental and non-governmental organisations, commercial partners and private individuals from across South Africa (Figure 1). Seventy-four presentations were given on topics ranging from pathogens to invasive birds to introduction pathways. Keynote talks focussed on scientific assessments, reporting on biological invasions and risk analyses. See Online Appendix 1 for the full programme and list of delegates (also available at http://www.invasives.org.za/events#abstracts).

Not since the inaugural research meeting of the Working for Water programme in 2003 (Macdonald 2004; van Wilgen 2004) has there been a national gathering that addressed the full spectrum of issues pertaining to the research and management of biological invasions across all taxa. Meetings like these bring special challenges, but they also provide unique opportunities for the exchange of ideas. Presenters were required to communicate their information to others from different and often unfamiliar disciplines, and to emphasise the implications of their work for managers. The focus on providing material and syntheses for the upcoming status report assisted in this process, resulting in a series of productive exchanges that promises to take the science forward in more trans-disciplinary ways.

Although the ‘43rd Annual Research Symposium on the Management of Biological Invasions in South Africa’ was somewhat of a departure from previous versions of this meeting, these meetings have always provided valuable opportunities to network and engage, and should remain a cornerstone in South Africa’s efforts to improve our understanding of biological invasions and their management. It remains to be seen whether such meetings would be more productive and cohesive if they were to revert to concentrating on alien plants or whether a wider remit of biological invasions (which includes non-plant taxa and aspects of policy development and management effectiveness) would be more valuable.

The symposium is, of course, not the only forum for discussing biological invasions in South Africa. Over time, there have been various regional meetings, including the C.A.P.E. Invasive Animal Working Group (Wilson et al. 2014) and the KZN Invasive Alien Species Forum. Two taxon-specific national working groups have also been established to focus research efforts and provide fora for stakeholders to discuss issues: the Cactus Working Group (Kaplan et al. 2017) and the Alien Grass Working Group (Visser et al. 2017). Such groups have been very effective in stimulating applied research and its uptake (e.g. both groups resulted in papers in this special issue), and there is an urgent need for other taxon- or theme-focussed groups (Packer et al. in press) that are also sustainably funded and facilitated.

In the initial planning of the national status report, it was clear that the report would need to be a collaborative exercise relying heavily on partnerships to deliver content. Although much relevant data on particular issues had been collected, much of it was not collated or published. It was decided to use a journal special issue as a means by which input into the status report could be facilitated. The aim of the special issue was to collate reports on as broad a range of topics relating to invasions in South Africa as possible. In particular, we felt it was important to gain insights from a range of approaches encompassing work on pathways, taxonomic groups, particular geographical areas and interventions at the various stages of the invasion process.

During the latter half of 2015, experts were asked if they would be prepared to write a paper on a particular topic, and an open call for paper proposals was distributed (to core team members of the Centre for Invasion Biology, to attendees of the previous symposium and through the South African invasives-l server, invasives@wordlink.co.za, see Online Appendix 2). Proposals for papers were evaluated by the editorial team, and submissions that were deemed relevant to the status report were accepted for inclusion in the symposium programme (34 out of 51 proposed papers were presented at the symposium). After the symposium, presenters were invited to submit manuscripts for consideration as papers in the special issue of Bothalia: African Biodiversity and Conservation. All papers were subjected to standard peer review. Of 23 papers that were eventually submitted, 4 were either withdrawn or rejected during review stage, leaving 19 papers in this special issue (Table 1).

There were several reasons that certain topics were not included. Firstly, some topics had already been recently comprehensively reviewed [e.g. marine invasions (Griffiths et al. 2010; Robinson et al. 2016) and the impact of invasive plants on water resources (Le Maitre et al. 2016)]. Secondly, some of the work presented at the symposium was published elsewhere (e.g. on management effectiveness, Fill et al. 2017; van Wilgen et al. 2016). Thirdly, although several proposals involved interesting case studies on particular species (e.g. Shackleton et al. 2017), these were not included as one of the main aims of the status report is to look broadly across groups or areas. However, we look forward to case studies being used extensively to test the proposed framework for monitoring and reporting on biological invasions. Finally, many issues were identified as critical for a status report, but there was simply not enough time to solicit a contribution for this special issue. We have summarised a few of the issues that still need to be addressed in Box 2. Whether these can be dealt with in depth in the first national status report remains to be seen, but they should be prioritised for future reports.

One of the key challenges given to authors and reviewers was that the papers should have a clear focus on ‘status’. This was particularly difficult as the framework for the status report itself was still in development, as were international standards for monitoring invasions (Latombe et al. in press). But based on our involvement in work conducted in terms of South Africa’s National Strategy for Biological Invasions (https://sites.google.com/site/wfwplanning/strategy), a recent book on incursion response planning (Wilson, Panetta & Lindgren 2017) and the development of the concept of invasion debt (Rouget et al. 2016), a logical basic framework has emerged. This framework suggests that any national status report on biological invasions should have sections dedicated to the status of pathways, species, areas and interventions [see also McGeoch et al. (2016)]. Authors were therefore requested to concentrate on producing headline statistics, for example, the number of alien taxa present, the impacts of invasions in terms of formal schemes (e.g. Blackburn et al. 2014) and whether management interventions have actually led to measurable effects on biological invasions. An additional request was to place the topic reviewed in South Africa both in the context of invasions elsewhere and in the context of other types of invasion in South Africa. We have summarised some of the key findings of the papers in this special issue in Table 1.

SANBI is required by the NEM:BA A&IS Regulations to compile a status report and to do the necessary research for informing it (Box 1). In reality, SANBI does not have the capacity to do everything required in this regard, and must rely on others, as was the case for the biodiversity assessments (Driver et al. 2012). Luckily, several ongoing initiatives provide strong support for the production of the status report, in particular atlas projects like the southern African Plant Invaders Atlas (Henderson & Wilson 2017) and those run by the University of Cape Town’s Animal Demography Unit, and the diverse work undertaken through the DST-NRF Centre of Excellence for Invasion Biology (van Wilgen, Davies & Richardson 2014). What is particularly challenging is measuring the effectiveness of management interventions, as few if any interventions are monitored (van Wilgen & Wannenburgh 2016), and what assessments there are tend to be sporadic and not strategic in nature (Fill et al. 2017; McConnachie et al. 2012; McConnachie et al. 2016; Shackleton et al. 2016; van Wilgen et al. 2012). Although this is not ideal, the fact that South Africa has a nationally mandated biodiversity institute and a government-funded centre of excellence focussing on biological invasions places it in a much better position to compile such a report than most other countries.

The information in the papers from the special issue will be combined with other published literature and substantial contributions from the scientific, management and regulatory communities where this information resides. Taking the ‘pathway, species, area, intervention’ framework, the data will then be organised into a series of sections of the report, with publication due in October 2017. The papers presented in this special issue therefore represent an important snap-shot in time. In some cases, they provide a base-line, in other cases an additional point in an existing time-series of data. By combining these over time, we can hope to ultimately be able to assess the scale of South Africa’s invasion debt (Rouget et al. 2016) and to be able to prioritise resources to the most effective interventions. For this to happen in practice, though, research and implementation should no longer be seen as processes that happen separate to the needs and concerns of the wider society (Toomey, Knight & Barlow in press). For example, if we are to effectively respond to new incursions, we should not have separate institutions mandated to detect the problems, develop the appropriate response and implement control. These functions need to be organised as a single integrated process (Wilson, Panetta & Lindgren 2017).