Monitoring of the eggs of the Karkloof blue butterfly, &lt;i&gt;Orachrysops ariadne&lt;/i&gt;, for its conservation management

Adrian J Armstrong,Sharon L Louw

doi:10.4102/koedoe.v55i1.1150

Abstract

The Endangered Orachrysops ariadne (Butler 1898) (Karkloof blue butterfly) is endemic to the Endangered Moist Midlands Grassland in KwaZulu-Natal, South Africa, and is extant at four sites. The results from the monitoring of the eggs laid by O. ariadne in a grassland area that is frequently burnt by poor rural people to ensure that palatable grass is available to their livestock, suggested the implementation of management interventions (fencing and firebreak burning) to prevent the local extinction of the butterfly. The number of eggs at the monitoring site declined dramatically between 2002 and 2003 and fluctuated after the management interventions were initiated properly in 2008, but had nearly reached the target number of 250 by 2013. An index count method for the monitoring of O. ariadne eggs at the other three known colonies, where plant invasion rather than uncontrolled burning is a major threat, was developed and shown to be efficient with regard to time relative to the number of eggs sampled. The host ant Camponotus natalensis (F. Smith 1858) (Natal sugar ant) was found to be present in all the host-plant patches at one colony site, indicating that all host-plant patches are likely to be breeding areas for the butterfly. Invasive plant control at and appropriate burning of the habitat of O. ariadne should assist in ensuring the survival of these colonies.Conservation implications: Adaptive monitoring and management of threatened endemic invertebrates and their habitats may be crucial for their continued survival. The development of efficient methods for the monitoring of such species is required where resources are limited, as threats to the species may cause sudden and irreversible declines in population size.

Highlights

Endangered species should not lose any more of their habitat if they are to survive in the wild in the long term (Pfab, Victor & Armstrong 2011)
A decline in the number of I. woodii var. laxa was recorded between 2004 and 2006, when fewer than half the number of host plants surveyed in 2003 were visible owing to the uncontrolled fires (Figure 5)
This study indicated that adaptive monitoring and management of threatened and endemic invertebrate species, with the cooperation of the owners, occupiers or managers of the land on which the species occur, may be crucial for the successful conservation of such species

Summary

Introduction

Endangered species should not lose any more of their habitat if they are to survive in the wild in the long term (Pfab, Victor & Armstrong 2011). Adaptive monitoring that enables adaptive management interventions to be initiated as and when appropriate, and that informs managers of the nature of the threats to the species and potential counters to those threats, would be very useful (Campbell et al 2002; Greenwood & Robinson 2006; Lindenmayer & Likens 2009; Lindenmayer et al 2011). Monitoring of lepidoteran species needs to be long term, as responses of threatened butterflies to management interventions may not be immediate and may depend on other interacting factors such as weather conditions (Murphy & Weiss 1988; Smee et al 2011; Thomas 2005). Long-term monitoring of threatened butterfly species is well established on other continents (e.g. Swengel et al 2011; Thomas 2005), but is only in its infancy in Africa (for South Africa, see Edge et al 2013; McGeoch et al 2011)

Objectives

Methods

Results

Discussion

Conclusion