By analyzing the different stages of an invasion (from introduction to expansion), researchers seek to identify the factors that influence the success of invasive species in different aquatic environments. The project aims to study the dynamics of biological invasions in aquatic ecosystems and offer a deeper understanding of how biological invasions impact ecosystems over time and in different geographical areas, and how these dynamics can be managed for the conservation of marine biodiversity.
In the 1950s, the field of ecology incorporated the gradient paradigm, which demonstrated that the structure and functionality of ecosystems are governed by spatial gradients of environmental conditions. The southern coast of Africa is home to one of the most dramatic environmental gradients in the world, largely governed by the confluence of two oceans in this region, but also by the influence of two opposing currents (the cold Benguela Current and the warm Agulhas Current). Therefore, within a relatively small region, one can range from ecosystems dominated by coral reefs (typical of tropical waters) on the southeast coast to ecosystems dominated by kelp (typical of cold waters) on the southwest coast. This makes the coasts surrounding present-day South Africa a unique natural laboratory in the world for studying the effects of environmental gradients on ecosystems.
One of the factors that most negatively impacts the world’s ecosystems is biological invasions (non-native species transported intentionally or unintentionally to new regions where they can have significant ecological and economic impacts). Recently, much progress has been made in the ecological understanding of biological invasions, but very little is known about the population dynamics of these biological invasions over time and space.
This project aims to study biological invasions over time and across environmental gradients along the South African coast. The South African coast contains a large number of marine protected areas and is frequented by a large number of vessels (directly or indirectly responsible for the transport of non-native species) each year. This study will be conducted by analyzing environmental DNA (eDNA) preserved in sediments from well-preserved estuarine areas. These areas are key points for the introduction of non-native marine species that are abundant and well-characterized along the coasts where this study will be conducted. eDNA research focuses on the detection of DNA found in ecosystems (e.g., in water or sediment) that can be isolated and sequenced (via metabarcoding). eDNA detection provides us with information on all the species found in the sampled ecosystem, from enormous whales to tiny bacteria. This approach is innovative (it has only recently been used for the detection of metazoans or animals) and revolutionary as it provides us with a resolution for estimating biodiversity patterns never seen before. The CEAB-CSIC research group is a national leader in the study of eDNA in marine coastal environments.
-Some Project Activities
Introductory Workshop on Environmental DNA (eDNA)
The Introductory Workshop on Environmental DNA (eDNA), held at Rhodes University in Makhanda (South Africa) from 6–8 July 2026, brought together 16 participants (mainly from several African countries, including Malawi, Botswana, Namibia and South Africa) for an intensive introduction to the theoretical and practical foundations of environmental DNA (eDNA) studies. The workshop was delivered by CEAB-CSIC researchers Marc Rius and Xavier Turon, together with Peter Teske (University of Johannesburg, South Africa) and his postgraduate research group. The programme covered metabarcoding survey design, laboratory procedures and the bioinformatics tools required for data analysis, culminating in a practical session focused on analysing a sample dataset.
The different sessions addressed key topics including primer selection, taxonomic resolution, diversity metrics, biological community analyses, and the applications of eDNA in biodiversity conservation, invasive species detection and ecological monitoring. Participants combined theoretical learning with hands-on exercises, including the processing of a mock dataset to reinforce the knowledge acquired during the workshop.
Feedback on the workshop was highly positive. Most attendees rated it as “excellent” and considered the balance between theoretical and practical content to be appropriate. Participants also highlighted the suitability of the level of the materials and presentations, reporting an improved understanding of sampling strategies and bioinformatics workflows. Several attendees particularly valued the discussions, case studies and networking opportunities with the lecturers and fellow participants.
Overall, the workshop successfully achieved its objectives, providing a strong foundation in eDNA methodologies and fostering collaboration among researchers and students. The combination of expert instruction, well-structured content and active participation helped equip attendees with the essential tools required to undertake environmental DNA studies.
This activity was funded through the CSIC I-COOP 2024 call (grant COOPB24022).
