First Report of the Larva of a Vulnerable Damselfly in Nigeria, With Some Ecological Notes: A Case for Umbrella Species Conservation Approach

Abstract

Background and Research: Lack of information on the distribution of threatened aquatic species impedes their conservation, thus predisposing them to extinction risk before being reported. Hence, this study reports in Nigeria, for the first time, the occurrence and habitat specificity of the larva of Pentaphlebia stahli (Zygoptera: Pentaphlebiidae) a vulnerable damselfly. Methods: Samples of P. stahli were collected in July and December 2020 from a rural stream situated at the Ekor Waterfalls in the Cross River State of Nigeria and very close to the Nigeria–Cameroon border. Some water quality parameters were also measured in each sampling period. Results: A total of 27 larvae of P. stahli and 1 teneral adult emerging from its exuvia were recorded in the two sampling periods. The habitat was a forested stream characterized by rapids, falls, and dark rock substrata. Water flows at a fast rate of 1 m in 3 or 4 seconds, thus characterizing a rifle and headwater stream. Dissolved oxygen concentration was between 8.05 and 8.09 mg/L, while dissolved oxygen saturation was ∼98%. Biological oxygen demand was between 1.04 and 1.08 mg/L, while pH ranged from 7.28 and 7.56. Conclusion: The stream could be described as having high ecological integrity as evidenced in its optimum range of values for the investigated water parameters and the presence of a threatened species. Implications for Conservation: Based on habitat specificity, P. stahli is considered an umbrella species required for conserving other co-occurring species in the tropical stream and its riparian forest.