Research at the C·I·B explores the impacts of biological invasions on biodiversity, and aims to improve our understanding of how interactions among global change drivers might further influence the impacts of invasions, and to facilitate and formulate appropriate policy interventions (Fig. 1). Investigations are taking place across a wide range of disciplines, taxa, and spatial and temporal scales. C·I·B publications on ISI Web of Science (2005-2011) are listed under 39 “subject areas”; the top-five subject areas are: Ecology, Biodiversity Conservation, Environmental Science, Plant Sciences and Zoology.

Several themes that characterise the core of the C·I·B’s research programme are discussed below. Links are provided to web pages, reports and key publications that showcase findings to date and provide further details of particular projects.

Long-term research

A. Long-term change in insect assemblages

This work involves the investigation of invertebrate diversity along several major spatial transects in different areas of South Africa: the Cederberg (Western Cape), Drakensberg (KwaZulu-Natal) and Soutpansberg mountains (Limpopo). Results from this work are also contributing to the Formicidae Barcode of Life project.

B. Long-term changes to the Prince Edward Islands ecosystem

The C·I·B has a strong research presence on the sub-Antarctic islands of the Southern Ocean. Long-term work on the Prince Edward Islands involves repeated measurement of sites that were investigated many years ago, providing multiple data points in a lengthy time series. The research includes elevational surveys of indigenous and alien plants, and effects of environmental change, including interactive effects of climate change and predation by introduced house mice. Past and current research projects on the islands are summarized in the popular book “Marion and Prince Edward: Africa’s Southern Islands”.

Short-term collaborative research

A. Biodiversity foundations

Biological invasions and the consequences of human activities are not clearly separable from other natural processes, but rather form a clearly identifiable component thereof. Consequently, the impacts of biological invasions on biodiversity cannot be comprehended without a sound understanding of the patterns in and mechanisms structuring biodiversity. The development of comprehensive understanding and predictive capability of biological invasions requires information from a wide variety of fields. For a flavour of recent and ongoing research on “biodiversity foundations” at the C·I·B click here.

B. Biodiversity dynamics through space and time

Spatial and temporal processes drive biological invasions by influencing how populations establish and then move over time and space. Thus, investigations of biological invasions are an extension of the concerns that ecology has long had with the determinants of species abundance and distribution. Some prominent themes from recent and ongoing research at the C·I·B are discussed further here.

C. Molecular ecology and genetics of invasions

To address the biodiversity consequences of biological invasions from an evolutionary point if view, the C·I·B has embarked on a range of studies incorporating molecular ecology. This research field entails using population genetics, phylogeographic and phylogenetic approaches to explore ecological processes. Major topics of this research are discussed here.

D. Global environmental change, biological invasions, ecosystem services and sustainability

The Millennium Ecosystem Assessment (MA) identified five major drivers of biodiversity loss: habitat alteration, climate change, invasive species, overexploitation and pollution. Understanding how these drivers have led to biodiversity loss, how they are likely to continue doing so both in isolation and through synergistic interactions, and what actions need to be taken to mitigate and adapt to their effects, are thought to be among the most significant questions facing humanity. Thus, these topics are key features of the research undertaken by the C·I·B. Some recent and ongoing facets of work in this area are set out here.

E. Detection, deterioration, restoration and re-introduction

Once alien species have established and become invasive, their costs to biodiversity, ecosystem functioning and society are typically high. These costs may be either in the form of direct impacts, or partly as a result of control interventions. In consequence, ensuring early detection of potentially invasive species, and developing cost-effective and efficient strategies for documenting and controlling changes in species abundances and distributions are key elements of reducing the rates of biological invasions. Some research activities in these themes are discussed here.

F. Risk assessment, indicators and policy

From the perspective of biodiversity conservation, the introduction and subsequent establishment of alien species represent a potential risk. However, non-indigenous species are also of considerable value to national economies. Ensuring the right balance between individual gain and public good requires informed risk assessments prior to the introduction of non-indigenous species and prior to the translocation of species already present in a given region. Details of research on this theme appear here.

G. Invasion, science, and society

Biological invasions have large impacts on society, either directly, by affecting ecosystem services, or indirectly by interacting with other environmental change drivers to affect ecosystem service delivery. However, society may also accrue positive benefits from biological invasions, either as a consequence of job creation through their removal, direct use of the invasive species, or more indirectly through the environments non-indigenous species create. The C·I·B investigates the social dimensions of environmental change and in particular of biological invasions and their remediation. The main research topics in this regard are discussed here.

H. Research for the Integrated Management of Invasive Alien Species in collaboration with the Working for Water Programme (Natural Resources Management Programmes)

Using various approaches such molecular genetics, impact and risk assessments, and the collection of spatial and distributional data for a wide range of invasive species, this project aims to provide information to facilitate improved management of some of the worst invasive species in South African ecosystems. The project has had a strong focus on aspects of the invasion ecology of Australian wattles. This group (1,020 species in the subgenus Phyllodineae of Acacia native to Australia) provides a superb model system for exploring all aspects of invasion science for one of the world’s most important invasive plant taxa. An international workshop on the theme “Human-mediated introductions of Australian Acacia species—a global experiment in biogeography” was held in Stellenbosch in November 2011 and a special issue of the journal Diversity and Distributions was published in September 2011. Detailed studies are underway on the molecular ecology of Acacia pycnantha and A. saligna.

I. Invasion Biology in Support of Environmental Sustainability during Times of Change

The bulk of work on this theme is being conducted as part of Stellenbosch University’s HOPE Project. Overarching goals of the work are to undertake cutting-edge research in biology and to develop the policy implications and social dimensions of this work, with biological invasions forming the core around which the research revolves. To reach these goals, several projects have started and fit in two main strategies:

• Environmental change effects on species of direct concern to humans: tsetse flies and climate change, climate change and the South African vectors of malaria, and climate change effects on the biocontrol agent of the invasive aquatic plant Salvinia molesta.
• Habitat alteration and climate change effects on biodiversity