SURICATA 2 Manual of Freshwater Assessment for South Africa: Dragonfly Biotic Index Michael J. Samways & John P. Simaika Pretoria 2016 SURICATA Suricata is the genus name of the suricate (meerkat), which is near-endemic to the arid western parts of southern Africa (occurring in Namibia, South Africa and Botswana; and just entering into a very small area in the extreme south of An- gola). Behaviourally, suricates are socially inclusive and innately inquisitive, symbolising the commitment of the South African National Biodiversity Institute (SANBI) to include all biodiversity and serve all of Africa, and the scientific curi- osity that precedes and drives research and publication of research results. Sister journal to SANBI’s Strelitizia, Suricata is a peer-reviewed journal and publishes original and applied research such as monographs, revisions, checklists, Red Lists, Atlases and Faunas of any taxa belonging to Regnum Animalia (the Animal Kingdom). Michael J. Samways Department of Conservation Ecology & Entomology, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa John P. Simaika Department of Soil Science, Faculty of AgriSciences, Stellenbosch University, Matieland 7602, South Africa EDITOR: Alicia Grobler PROOFREADER: Yolande Steenkamp COVER DESIGN & LAYOUT: Elizma Fouché COVER: One of the world’s rarest damselflies, the Amatola Mala- chite (Chlorolestes apricans) from the Eastern Cape. It is Red Listed as Endangered, and has the maximum Drag- onfly Biotic Index score of 9. (Photograph: Michael J. Samways). Recommended citation: SAMWAYS, M.J. & SIMAIKA, J.P. 2016. Manual of Freshwater Assessment for South Africa: Dragonfly Biotic Index. Suricata 2. South African National Biodiversity Institute, Pretoria. ISBN: 978-1-928224-05-1 Obtainable from: SANBI Bookshop, Private Bag X101, Pretoria, 0001 South Africa. Tel.: +27 12 843 5000 E-mail: [email protected] Website: www.sanbi.org Printed by: United Litho, 19 Beaufort Street, Troyville, Johannesburg, 2139 South Africa. Tel.: +27 11 402 0571. Copyright © 2016 by South African National Biodiversity Institute (SANBI) All rights reserved. No part of this book may be reproduced in any form without written permission of the copyright owners. The views and opinions expressed do not necessarily reflect those of SANBI. The authors and publisher have made their best efforts to prepare this book, and make no representation or warranties of any kind with regard to the completeness or accuracy of the contents herein. All images in this book have been reproduced with the knowledge and prior consent of the artists concerned and no responsibility is accepted by the publisher or printer for any infringement of copyright or otherwise arising from the contents of this publication. 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SURICATA 2 (2016) iii CONTENTS PREFACE ..................................................................... iv INTRODUCTION. 1 The use of adult dragonflies versus larvae, exuviae and water chemistry. 1 Some biogeographical considerations. 2 Dragonfly assessments in context ................................................. 3 Dragonfly biology ............................................................ 3 Ecoregions and their significance for dragonflies. 4 Threats to South African dragonflies . 5 Red List status of South African dragonflies. 5 The Dragonfly Biotic Index. 14 The DBI sub-indices . 15 Steps and recommendations for determining DBI values ............................... 16 Using the Dragonfly Biotic Index in practice. 30 Methods and techniques for dragonfly recognition, assessment and conservation ............. 31 Comparing the Dragonfly Biotic Index across geographical areas ......................... 33 SPECIES DESCRIPTIONS ......................................................... 37 CALOPTERYGIDAE ........................................................... 38 CHLOROCYPHIDAE .......................................................... 39 SYNLESTIDAE ............................................................... 43 LESTIDAE . 51 PLATYCNEMIDIDAE .......................................................... 58 COENAGRIONIDAE .......................................................... 64 AESHNIDAE ................................................................. 103 GOMPHIDAE. 114 CORDULIIDAE .............................................................. 130 LIBELLULIDAE . 138 CHECKLIST OF SOUTH AFRICAN DRAGONFLIES ..................................... 201 PHOTOGRAPH CREDITS AND ACKNOWLEDGEMENTS . 206 BIBLIOGRAPHY. 207 GLOSSARY. 209 INDEX ....................................................................... 212 iv SURICATA 2 (2016) PREFACE Overall, freshwater ecosystems are the most threat- the Dragonfly Biotic Index, which is based on drag- ened ecosystem type in the world. The scarce South onfly biogeography, their sensitivity to change, and African freshwaters are threatened by alien organ- the degree to which they are threatened. This index isms, high volumes of water abstraction, and pollu- is sensitive and robust and is suitable for assessing tion. Yet some South African freshwaters are being and monitoring freshwaters across the country. This restored to their former condition. It is important to manual explains how to use and apply the Dragon- monitor these systems and note whether they are fly Biotic Index, while also providing guidelines for declining or improving. One way to do this is to use species identification. Phyllomacromia picta (Darting Cruiser) SURICATA 2 (2016) 1 INTRODUCTION ‘Dragonflies’ is a broad term that covers the true is a pair of close-focus binoculars, a net for catch- and familiar dragonflies as well as the smaller and ing the occasional specimen for verification, and a usually more slender and delicate damselflies. As a hand lens to study their important morphological group, they are well-known insects that grace virtu- features. With practice at recognition, a freshwater ally every freshwater body, whether running or still body can be assessed in a relatively short period of water, throughout South Africa. To date, 162 species time – without entering the water. The assessment have been recorded from the country. This figure is can take place from the bank or the margin. There unlikely to be final, as occasional new records come are other taxa, such as mayflies, caddisflies and from species crossing the northern borders. Indeed, stoneflies, which can also be used for freshwater one such species, the Great Hooktail (Paragomphus assessment. However, they hold much bigger chal- magnus), was only discovered in South Africa in late lenges of recognition than is the case with dragon- 2012. Also, there is still a chance that species com- flies, and often the larvae have to be collected and pletely new to science will be discovered, which carefully scrutinised, which is not always practical may only be known from particular, localised areas. for many busy freshwater health practitioners. Species with restricted distribution ranges are known This guide is a handbook for freshwater managers as endemics, with about a fifth of the South Afri- who require an assessment of a water body, either can species falling into this category, i.e. they are at one moment in time, or over time as conditions restricted to South Africa and mostly to only a very change. This may, for example, be for assessing riv- small part of the country. These endemic species are er condition as alien invasive plants are removed important, often because they need conservation from the river bank. This guide is about using adult protection in their own right, as they are vulnerable dragonflies in freshwater health assessments. The to human impact. Often too, endemic species are recommendations given here have been developed also highly sensitive indicators of water quality. This over many years of rigorous research. is an important feature as fresh water is a scarce and diminishing resource in South Africa, and one that In summary, this is a handbook for the assessment of constantly needs conservation management for fu- freshwater bodies using a visible group of insects to ture human health and security. apply a practical, straightforward method. Further- more, the undertaking of this type of assessment is Overall, dragonflies are good indicators of freshwa- not overly arduous, as, in principle, it is no different ter quality and conservation. This presents a major from going birdwatching. Similarly, it requires some opportunity for using them to measure the extent to initial practice at recognition and identification, but which a freshwater body is deteriorating, or, where competency soon develops, making it a very easy conservation action has been taken, to assess how and effective means of assessing freshwater quality. well the freshwater body is returning to its original This handbook introduces the procedure to follow or reference condition. Dragonflies are particularly and notes on interpreting the results for optimal con- useful for the task of assessment and monitoring as servation management. there is a sufficient number of species with different, yet specific habitat requirements to provide for a range of descriptive characteristics for any freshwa- ter habitat, type and quality. In fact, it is the change The use of adult dragonflies in the species assemblages that enables us to meas- versus larvae, exuviae ure the state of the water body. The emphasis here really