Using dragonflies to monitor and prioritize lotic systems: a South African perspective
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REVIEW
Using dragonflies to monitor and prioritize lotic systems: a South African perspective John P. Simaika & Michael J. Samways
Received: 30 October 2011 / Accepted: 16 February 2012 / Published online: 17 August 2012 # Gesellschaft für Biologische Systematik 2012
Abstract The ever-worsening condition of streams due to local, regional, and global demands on water has resulted in the development of increasingly streamlined, rapid assessment methods using macroinvertebrates. Biotic indices in particular are versatile and robust, although not always easy to use. For example, the family-level South African Scoring System is an effective water quality measure, but is time-consuming and requires high-level expert training. The index could be used alongside the species-level Dragonfly Biotic Index (DBI), originally developed for monitoring habitat integrity, with which it is significantly and strongly correlated. We review here the relevant biotic indices in stream biomonitoring and their advantages and disadvantages, and present a new extension of the DBI, the Habitat Condition Scale (HCS). The HCS enables comparison and ranking of sites in terms of their habitat condition. Indeed, the DBI is a very flexible index, having been used in site selection and prioritization for conservation, as well as the measurement of habitat recovery. The theoretical framework behind the index demonstrates the potential of the index to track biotic changes due to climate change. The index could also be easily adapted for use in other biogeographical regions, given that species distributions, This is a contribution to the Festschrift for Michael L. May Electronic supplementary material The online version of this article (doi:10.1007/s13127-012-0104-4) contains supplementary material, which is available to authorized users. J. P. Simaika (*) Department of River Ecology and Conservation, Biodiversity and Climate Research Centre and Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen 63571, Germany e-mail: [email protected] J. P. Simaika : M. J. Samways Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
threat levels and sensitivities are well-known, and that there is an adequate number of endemic species. However, like all benthic macroinvertebrate indices, the DBI cannot always identify exactly which in-water impacts have an effect and to what extent. The real power of the DBI lies in being able to quantify community response to known physical changes on the riverscape and across the region. Keywords Mike May Festschrift . Aquatic insects . Freshwater . Conservation . Biomonitoring . Odonata . Dragonflies . Dragonfly Biotic Index
Introduction River ecosystems are the most threatened ecosystems of all (Abell 2002). Indeed, declines in biodiversity are estimated to be up to five times greater in some rivers than in the most degraded terrestrial ecosystems (Dudgeon et al. 2006). The worst impacts on rivers include the introduction of alien o
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