Breeding biology and ecological niche of the Knysna leaf-folding frog (Afrixalus knysnae)
Abstract
Amphibians as a vertebrate class are under tremendous extinction risk. At the time of finalising this document, 41% of all amphibians worldwide face this prospect (IUCN, 2018). CHAPTER ONE discusses these threats and challenges worldwide and places them in a South African context. The realities of extinction are discussed as they relate to Afrixalus knysnae and its habitats within the Southern Cape region of South Africa. CHAPTER TWO expands on the localities of A. knysnae as reported in literature, metadata and local information. Investigating historical sites and employing Ecological Niche Modelling (ENM) as a technique to determine other probable localities are described. Surveys using Passive Acoustic Monitoring are discussed with its applicability within the region and as tool for a sole investigator to verify ENM results. Historical sites are reviewed, recent verified sites updated to the IUCN and a new site reported.
CHAPTER THREE describes and analyses the call structure of A. knysnae. The two-part call structure is spectrally and temporally measured to determine finer scale attributes and then compared to other conspecific and congeneric species within relatively close geographic areas. Analysis of this aspect may assist in future taxonomic studies and also more comprehensively understand reproductive behaviour and biology. CHAPTER FOUR is wholly dedicated to the description of the tadpole with some ancillary notes
on the early larvae development and resource use by breeding adults. This description is the first known detailed description of the tadpole of A. knysnae, and as such was published in the peer reviewed journal, ZOOTAXA, November 2018. CHAPTER FIVE reaches some conclusions regarding the current status of the habitats of the species, new localities and possible discovery of future sites using modern technology. The call mode and structures are compared to sympatric species with which it shares habitat while the habitat suitability for tadpoles are placed in context with the vegetation available. All of this is discussed with a view to emphasise conservation efforts to be undertaken and expanded.