Dragonfly Freshwater Health Tool
Water is essential to all life, yet humans continue to devastate freshwater habitats. This problem is particularly acute in Africa where the world’s driest and most unpredictable tropical climate, combined with a fast-growing human population, will make future impacts especially severe. Africa’s resources face increasing exploitation, and aquatic systems are particularly vulnerable, for example, to mining, damming, and agricultural conversion. Tools to evaluate impacts of human activities on freshwater biodiversity are urgently needed to enable the effective management of Africa’s natural resources. Dragonflies are a good indicator group of ecosystem health; they are easy to identify and to record, sensitive to change, and informative proxies for overall biodiversity. Dragonflies also couple aquatic and terrestrial habitats, using both at different parts of their lifecycle. This project aims to use dragonfly status as a management and conservation indicator throughout Africa. The health of dragonfly communities can inform environmental impact assessments and serve as a metric of ecosystem change in response to development and mitigation measures.
Key Objectives and Activities
The project objective is to improve freshwater health assessment across Africa, using dragonflies as environmental sentinels, by providing a robust assessment method based on rigorous ecological and taxonomic information. The estimated 700 to 800 species of dragonflies in Africa is a manageable number to characterize, and large enough to provide relatively high-resolution assessment potential. The Dragonfly Biotic Index (DBI), already developed as a freshwater management tool in South Africa, is a practical measure of habitat quality based on the community of dragonflies present at a site, compared to their known range, ecological sensitivity, and habitat requirements. The Stellenbosch team has the data and expertise to now expand the DBI across the African continent. This JRS award will be used to complete species identification tools and distribution data, to document the ecological sensitivity of all species, and to deploy these data to improve freshwater health assessment.
Planned Outputs and Outcomes
The primary output will be an easy-to-use tool for assessment of freshwater ecosystem health, built on a comprehensive review of dragonfly taxonomy and ecology that will be applicable Africa-wide and remain current with advancing knowledge in the field. The effort will synthesize ecological and observational record databases, and experts’ knowledge into a Dragonfly Biotic Index based on habitat specificity, range, and threat status for each species. The tool will be shared with environmental organizations, conservation authorities, museums, and the public through peer-reviewed publications, workshops, and a dedicated website providing details of species’ identification, conservation status, distribution, and ecology (available in 2015).
Last Updated: February 28th, 2017
Results to Date
The project has been remarkably successful in addressing the need to explore and assess the diversity of Odonata in Africa. They have described and named 60 species new to science, increasing the number of known dragonflies and damselflies in Africa by nearly 10% (download information on the new species).
The database for African dragonflies has surpassed 127,000 records, exceeding the project goal by more than 20%. The project’s most significant milestone to date was the experts’ workshop held 6-8 November 2013 at Stellenbosch University. Fifteen delegates provided the greatest concentration of field experience in African dragonflies ever assembled. Together, the group assessed ecological preferences for the nearly 800 species now known on the continent, based on more than 20 variables (such as water body and landscape type). Filling some 16,000 cells of a matrix with so much expertise required a great deal of discussion, the group worked to achieve consensus. This uniquely rich dataset helped highlight gaps in knowledge about dragonfly ecology, particularly in the early life stages, which occur under water, and provided the basis for updates to the IUCN listing status for all of the known species in Africa. Such a comprehensive approach also enabled the group to incorporate sub-indices into the DBI that will provide greater precision in assessment capability.
The project is now gearing up for a workshop in February 2016 where accepted attendees from across the continent will be trained in the use of the DBI. Lastly, the content of the website is very nearly complete, and awaits uploading to the skeleton site constructed under the umbrella of the Animal Demography Unit at the University of Cape Town.
Primary Software Platforms
Database records are consistent with Darwin Core so that they can be incorporated into global databases. The website will be housed under the Animal Demography Unit of the University of Cape Town, as they have most local expertise on collecting and sharing biodiversity information.
Undertaking any comprehensive taxonomic and ecological effort on a continental scale is undeniably ambitious. However, the focus group for this project, Odonata, dragonflies and damselflies, offers a system that is not only tractable in terms of numbers, but also ecologically relevant to the applied issue of freshwater ecosystem health, and a rich opportunity for research. The community of experts on this group is small enough that they could be assembled in a workshop, synthesizing the vast majority of what is known about African dragonflies. Doing so was a great opportunity to enrich the investigations that each expert is doing in his or her own subfield. For example, discussions about habitat use of various species revealed that some species apparently use different habitats over their ranges, which can be extremely large. This type of information is also critical to an ecological assessment tool, which must be relevant on a local scale to be useful.
One of the larger challenges to the completion of the DBI is the inability to directly observe ecological sensitivity for many species. Estimates or observations of ecological sensitivity rely either on extensive opportunistic data, or on experimentation, either of which can be difficult to come by. The group has had to develop proxies for each species, based on how specific their habitat requirements are and the likelihood that those habitats will be negatively impacted by human activities. However, the database of records is also rich enough that it can start to answer questions about which species might be most sensitive to climate change. This effort will have substantial value to conservation and management efforts now and well into the future.
- Dijkstra, K-DB; V Clausnitzer (2014) The dragonflies and damselflies of eastern Africa: Handbook of all Odonata from Sudan to Zimbabwe. Studies in Afrotropical Zoology. Vol 298. Belgian Royal Museum for Central Africa. (link to description and purchase)
- Suhling, F; G Sahlén; S Gorb; VJ Kalkman; K-DB Dijkstra: J van Tol. (2014) “Order Odonata”. In: Thorp, J., Rogers, D.C. (Eds.), Thorp and Covich’s Freshwater Invertebrates: Ecology and General Biology. (893–932) London: Academic Press – Elsevier.
Project Director Biography
KD (Klaas-Douwe) B. Dijkstra grew up in Egypt, drawing and describing his first dragonflies when he was 12 years old. Finding The Netherlands’ first Vagrant Emperor, Anax epihippiger, an African wanderer, in 1995 focused his passion. He has since spent more than 1,000 field days in 20 African countries, finding 80% of all 770 species of dragonfly and damselfly and describing 78 of them as new to science. He has authored several handbooks and identification guides to dragonflies and damselflies in Africa and Europe, and is honorary research associate at the Naturalis Biodiversity Center (The Netherlands) and the University of Stellenbosch (South Africa).
Notes from JRS
JRS often describes a “value chain” for data that begins with the primary taxonomy and field observations and includes databases, access to data, analysis and analytic tools and ends with conservation actions and policy change. The grant to the Stellenbosch University team began as one of our few investments in the “tools” category that aspires to synthesize biodiversity data to guide freshwater ecosystem management and conservation. We were interested to learn – and to support – how such a tool that is developed with a high level of technical expertise within and academic institution can be disseminated to conservation actors and refined for their users’ needs. 2015 was a fantastically productive year in terms of taxonomic characterization of dragonflies, publications, and collaboration among the expert team. As the project heads into its final phase, we are certain of significant contributions to the knowledge of African dragonflies, however the development of an applicable tool for field use remains an uncertain result.