The decline of the globally threatened Rudd's Lark in one of its last remaining core sites, the Wakkerstroom grasslands
type: CreativeWork
description: Abstract The Rudd's Lark Heteromirafra ruddi is a globally threatened species with a fragmented population occurring in one of the world's most poorly-protected biomes, the grasslands. This, together with its endemism to the Highveld of South Africa and climate envelope modelling which predicts a dramatic reduction in its available habitat, places the species firmly in the cross-hairs of extinction risk. This thesis aims to gain a better understanding of Rudd's Lark population trends, habitat preference and threats in one of its most important remaining core sites in the grasslands around Wakkerstroom, Mpumalanga Province, which are under private ownership and used predominantly for grazing. My objectives were, first, to determine whether the species has declined in the Wakkerstroom area since a survey conducted in 2002 by David Maphisa. Second, to determine what habitat variables predict Rudd's Lark incidence, whether there has been a change in its available habitat and in farm management practices, and whether the species has changed in its habitat selection since the previous survey. Finally, I aimed to investigate whether other grassland birds (particularly other threatened grassland endemics) also respond to fine-scale habitat variation and share habitat preference with the Rudd's Lark. I found both absolute lower numbers of Rudd's Larks (5 transects with Rudd's Lark present down from 9 in 2002; 9 individuals down from 32), and a lower probability of encounter (significantly lower in the case of individuals). Seven transects had been lost to crop production, two of which formerly contained Rudd's Larks. Forb and dead vegetation cover had significantly increased at a coarse scale, but vegetation variables did not explain any significant variation in Rudd's Lark incidence at either a fine or a coarse scale within 2016. However, Rudd's Larks appear to be occupying subtly different habitat now compared to 12 years ago: lark territories surveyed in 2016 had less bar…
abstract: Abstract The Rudd's Lark Heteromirafra ruddi is a globally threatened species with a fragmented population occurring in one of the world's most poorly-protected biomes, the grasslands. This, together with its endemism to the Highveld of South Africa and climate envelope modelling which predicts a dramatic reduction in its available habitat, places the species firmly in the cross-hairs of extinction risk. This thesis aims to gain a better understanding of Rudd's Lark population trends, habitat preference and threats in one of its most important remaining core sites in the grasslands around Wakkerstroom, Mpumalanga Province, which are under private ownership and used predominantly for grazing. My objectives were, first, to determine whether the species has declined in the Wakkerstroom area since a survey conducted in 2002 by David Maphisa. Second, to determine what habitat variables predict Rudd's Lark incidence, whether there has been a change in its available habitat and in farm management practices, and whether the species has changed in its habitat selection since the previous survey. Finally, I aimed to investigate whether other grassland birds (particularly other threatened grassland endemics) also respond to fine-scale habitat variation and share habitat preference with the Rudd's Lark. I found both absolute lower numbers of Rudd's Larks (5 transects with Rudd's Lark present down from 9 in 2002; 9 individuals down from 32), and a lower probability of encounter (significantly lower in the case of individuals). Seven transects had been lost to crop production, two of which formerly contained Rudd's Larks. Forb and dead vegetation cover had significantly increased at a coarse scale, but vegetation variables did not explain any significant variation in Rudd's Lark incidence at either a fine or a coarse scale within 2016. However, Rudd's Larks appear to be occupying subtly different habitat now compared to 12 years ago: lark territories surveyed in 2016 had less bar…
author: Gush, Wesley Gurney
language: eng
date published: 2017
date modified: 2026-07-22T22:23:34Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Percy FitzPatrick Institute of African Ornithology

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/25011