Topographic controls on the invasion of Pteronia incana (Blue bush) onto hillslopes in Ngqushwa (formerly Peddie) district, Eastern Cape, South Africa

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Show simple item record Kakembo, V Rowntree, K Palmer, A 2009-06-26T04:11:08Z 2007-01
dc.identifier.citation Catena, 2007, 70 (2), pp. 185 - 199
dc.identifier.issn 0341-8162
dc.identifier.other C1 en_US
dc.description.abstract The role of topographic factors in the invasion of hillslopes by Pteronia incana, an unpalatable shrub, was investigated. The study combined field observations with image analysis based on high-resolution infrared imagery. A Digital Elevation Model (DEM) of 20 m spatial resolution was used to derive terrain parameters. The Topographic Wetness Index (WI), a component of the TOPMODEL, was derived from the DEM and its relationship with the spatial distribution of P. incana was explored. The absence/presence of P. incana was noted to be strongly influenced by slope angle and aspect. The probability for P. incana occurrence increased with slope steepness and southerly slope orientation. Abandoned and grazing lands were identified as the main invasion hotspots on hillslopes. The combined influence of slope gradient and aspect, and land use was noted to have promoted the invasion. This is borne out by the concentration of the invasion on abandoned steep slopes with a southerly orientation. The WI confirmed the bearing local topographic variations have on P. incana spatial distribution such that, P. incana was associated with the low WI values of convexities. The coupling between local topography and soil surface crusting underpins soil moisture variability. This in turn determines the competition between the patchy P. incana and grass species and the eventual replacement of the latter by the former. Restoration efforts of the invaded lands should focus on trapping of sediment and litter, and moisture retention on the inter-patch bare areas.
dc.publisher Elsevier
dc.relation.isbasedon 10.1016/j.catena.2006.08.005
dc.title Topographic controls on the invasion of Pteronia incana (Blue bush) onto hillslopes in Ngqushwa (formerly Peddie) district, Eastern Cape, South Africa
dc.type Journal Article
dc.parent Catena
dc.journal.volume 2
dc.journal.volume 70
dc.journal.number 2 en_US
dc.publocation Amsterdam, The Netherlands en_US
dc.identifier.startpage 185 en_US
dc.identifier.endpage 199 en_US DVCRch.Institute for Water & Environmental Resource Mgmnt en_US
dc.conference Verified OK en_US
dc.for 0406 Physical Geography and Environmental Geoscience
dc.personcode 995490
dc.percentage 100 en_US Physical Geography and Environmental Geoscience en_US
dc.classification.type FOR-08 en_US
dc.description.keywords Vegetation invasion; Land abandonment; Slope; Aspect; Wetness index en_US
dc.description.keywords Vegetation invasion
dc.description.keywords Land abandonment
dc.description.keywords Slope
dc.description.keywords Aspect
dc.description.keywords Wetness index
pubs.embargo.period Not known
pubs.organisational-group /University of Technology Sydney
pubs.organisational-group /University of Technology Sydney/Faculty of Science
utslib.copyright.status Closed Access 2015-04-15 12:17:09.805752+10
utslib.collection.history General Collection (ID: 346) [2015-05-15T14:11:16+10:00]
utslib.collection.history Closed (ID: 3)

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