FrogLog 103 PDF here - Amphibian Specialist Group

Uncovering New Sites of a Cryptic KwaZulu-Natal
Endemic
By Jeanne Tarrant
Fig. 1: A juvenile of Hyperolius pickersgilli at Mount Moreland, Durban, South Africa. Photo: J. Tarrant.
Pickersgill’s reed frog Hyperolius pickersgilli was discovered
and described only in the early 1980s (1). Given this relatively
late discovery, and the fact that it occurred in a region
that was otherwise well-studied in terms of amphibian research,
gives an indication of this species’ obscurity. It is a small hyperoliid
(max SVL 29 mm; Fig 1) with an inconspicuous cricket-like call
(2). It is a habitat specialist, favouring densely vegetated (and as
such, inaccessible) coastal wetlands. At the time of its description,
it was known from just seven localities. Since then, only a few new
sub-populations have been reported, so that as of 2010 the species
was known officially from a total of 12 localities, between St Lucia
Estuary in the north and Warner Beach in the south (3). Within
this range, sub-populations are severely fragmented, and only two
(at Umlalazi Nature Reserve and iSimangaliso Wetland Park) are
statutorily protected. The remainder of localities occur in areas that
are sought after for coastal development, sugarcane and gum plantations
(4). As an artefact of these pervasive threats, much of the
historical habitat of H. pickergilli is likely to have been destroyed
(5).
As a result of its limited distribution and the ongoing threats to
much of its habitat, H. pickergilli was Red Listed as Critically
Endangered in 2010. The resultant strategy document from that
School of Environmental Sciences & Development, North-West University,
Potchefstroom Campus, South Africa.
20 | FrogLog 20 (4) | Issue number 103 (July 2012)
assessment (6) recognised H. pickergilli as having the highest conservation
priority for any frog species in South Africa and a high
priority for monitoring and surveillance. South Africa has few
herpetologists and little funding to support the conservation of its
amphibian fauna, and so species prioritization is necessary as well
as the listing of the associated information needs and the efficient
gathering of this information. To address some of these research
requirements, Jeanne Tarrant (as part of her PhD research with
North-West University, Potchefstroom) and Dr. Adrian Armstrong
(Ezemvelo KZN Wildlife), embarked on a three year project to survey
the entire range of H. pickergilli. Data of historical records was
obtained from the South African Frog Atlasing Project (2004) and
Biodiversity Database of Ezemvelo KZN Wildlife. All but two of the
historically known sites were revisited to verify species presence
during the survey period (spring and summer 2010-2011 and 2011-
2012). Historical occurrence records were used to model a predicted
distribution using MaxEnt and RAMAS GIS for H. pickergilli,
which in turn was surveyed during the same period.
Most of the historical sites were revisited and in some cases, suitable
habitat has been completely destroyed, including at the type
locality and site of original discovery. Some of the sites at which
the species still persists are in a precarious state. For example, the
site at Isipingo, is in the highly industrialised area of Durban South
and is surrounded on all sides by a highly transformed landscape
(Fig 2). Another site nearby at Prospecton, discovered during the