Distribution and conservation status of the desert rain frog Breviceps macrops

Abstract

The desert rain frog, Breviceps macrops, is found along the greater Namaqualand coast, an area of acute conservation concern. We reconstruct the distribution of this species from museum specimens to the north and quantitative surveys in the south. In addition, a small (0.6 ha) study site near McDougall's Bay was searched on eight visits, each between two and seven nights long, between October 2002 and September 2007. The unique dorsal patterns of frogs were used as ‘marks’. Recaptured animals moved between 0 and 380 m (mean±SD = 29±73 m, n=26). The highest counts in September 2006 of 66 adults and 39 juveniles show the population at a density of 110 adults ha⁻¹. Voucher specimens held in museum collections were examined, and demonstrate the northernmost locality in Lüderitz, Namibia, with all 11 localities in white sandy habitat where coastal fog exceeds 100 days per year. The most southerly record from active searches was just south of Kleinzee in South Africa. A new threat to this species is housing development in prime coastal sand dunes.

Keywords:

• Conservation
• threats
• distribution
• Namaqualand
• mining
• frog

ACKNOWLEDGEMENTS

A number of institutions supported this work, for which we are grateful. This work was partially funded under subcontract 07-844 through Arizona State University, funded by the CEPF. The Critical Ecosystem Partnership Fund is a joint initiative of Conservation International, the Global Environment Facility, the Government of Japan, the MacArthur Foundation and the World Bank. A fundamental goal is to ensure civil society is engaged in biodiversity conservation. South African National Biodiversity Institute funding allowed us to closely examine the southern limit of the species distribution. The National Research Foundation provided partial support over a number of years. The University of the Western Cape provided funding and opportunities for fieldwork. Paul Kruger and Nadia Williams kindly arranged access into the mining areas at Kleinzee and Koiingnaas. Peter Carrick provided an opportunity to visit the active mines. Schalk Lange kindly facilitated our access to the Alexkor mining area, and Pieter van Wyk acted as a knowledgeable guide. We acknowledge the field assistance of André van Wyk, Marius Burger, Laurence Wahlberg and many groups of undergraduate students. Mike Griffin, Bill Branch and John Irish are thanked for their assistance with Namibian records. Additional information was provided by Wulf Haacke (Flagship Institution Pretoria), Shirley Hanrahan (University of the Witwatersrand), and LeFras Mouton (University of Stellenbosch). We thank M.-O. Rödel for drawing our attention to the Lüderitz specimens in the Berlin collection. Finally, two reviewers and an editor worked hard to turn our original manuscript into a form suitable for publication - we acknowledge their contributions.