Designing a dragonfly trail in the National Botanical Gardens, Pietermaritzburg.

Abstract

Dragonfly assemblages and their biotope preferences in the National Botanical Gardens, Pietermaritzburg, South Africa were investigated. The information served as background for increasing public awareness and education by designing a dragonfly observation trail. Multivariate analyses of data, classified 20 a priori selected sampling units into four ecologically meaningful biotope types, each with characteristic dragonfly assemblages. These biotopes were: 'waterfall', 'forested river', 'shaded pond/stream' and 'open ponds/dam'. Species-environmental variables correlations were significantly high for six out of twelve, measured environmental variables: pH, percentage shade, vegetation (structural and compositional), ambient temperatures, water temperatures, and water depth. Sunlit ponds/dam had higher species richness and diversity than the other water bodies. The months of November to April were significantly high in species richness and diversity, and were characterized by both rare and abundant, and both localized and widespread species. The winter months (May to October), in contrast, were characterized by only the widespread and abundant species. Questionnaire responses were used to test the popularity of the concept of a dragonfly trail, and showed a high level of awareness and commitment on the part of respondents (visitors to the botanical gardens) across all age groups. There was a strong response to knowing more about dragonflies (using a trail) and to become involved in conserving them. The scientific results, the responses to the questionnaire, and practical feasibility, all indicated that the instigation of a trail was possible. After some preliminary trials, a full trail was designed, which is now being installed by the National Botanical Gardens for the benefit of a wide sector of the public and for heightening public awareness of the need for dragonfly and other invertebrate conservation. This study was partly in response to the IUCN Status Survey and Conservation Action Plan: Dragonflies, and to widen the value and appeal of the botanical gardens, which are an already well-established public asset.