| dc.contributor.author | van Rensburg, Berndt J. | eng |
| dc.contributor.author | Peacock, Derick S. | eng |
| dc.contributor.author | Robrtson, Mark P. | eng |
| dc.coverage.spatial | South Africa -- Pretoria | eng |
| dc.date.issued | 2009 | eng |
| dc.description | Based on a gradient of urbanization identified in the Pretoria region, the capital city of South Africa, we aimed to examine whether biotic homogenization within the bird community is indeed taking place within the wider urban exploiter, adapter and avoider framework (see Blair, 1996; Kark et al., 2007), and if so, define which species belong to each category. We examine these trends for three groups of birds: all species, alien species and the Common Myna. We propose and test the following hypotheses. 1. All species: There will be an increase in biotic homogenization with an increase in the level of urbanization. 2. Alien species: Alien species richness and abundance will be higher in the urban exploiter community compared to the avoider community. 3. Common Myna: Compared to all the alien species examined, the Common Myna will be the most dominant (abundance and spatial distribution) species along the urbanization gradient. As in most cities, Pretora's land-cover varies from high-rise offices and apartment buildings in the city centre, through residential suburbs with schools, universities and urban green areas within the city limits, to stock and crop farming agricultural land and smallholdings at the city's edge and semi-natural vegetation outside the city limits. The Pretoria region is therefore an ideal study area with its well defined urbanization gradient. The region also has well established alien bird populations, and is home to approximately 2.0-2.2 million people living at an average density of approximately 946-2389 people/km2 (Anon., 2001). In addition, this study will address some of the geographical and taxonomic biases occurring in invasion biology, as no detailed studies have focused on a particular invasive bird species in Africa (Richardson and Pysek, 2008). | eng |
| dc.description.abstract | Similar to the process seen in invasion biology, urbanized environments lead to biotic homogenization with a few species, often alien, dominating the urban habitat. We investigated avian communities across an urban gradient in Pretoria (South Africa). We defined three urbanization zones: urban, suburban and semi-natural, based on land-cover. We conducted point counts of all species at each of 13 sites in these zones over a 4-month period. We found significantly more species in the semi-natural zone than the urban zone but abundance was significantly lower in semi-natural than urban. The increase in abundance was mainly as a result of alien species with the three most abundant species in the urban zone being all alien. Semi-natural contained fewer alien species than urban and significantly fewer than suburban. The Common Myna Acridotheres tristis was the only alien species that was observed in all three urbanization zones and was the second most abundant species in the suburban and urban zones. Our study supports the process of biotic homogenization, where an increase in alien species occurs in the urban compared to semi-natural zone. Although the suburban zone made an important contribution towards native bird abundance in a larger city environment, this environment was also an important environment for alien species, especially for the Common Myna. | eng |
| dc.identifier.citation | van Rensburg BJ, Peacock DS, Robertson MP. 2009. Biotic homogenization and alien bird species along an urban gradient in South Africa. Landscape Urban Plan 92, 233-241. | eng |
| dc.identifier.uri | https://hdl.handle.net/10355/67024 | |
| dc.language | English | eng |
| dc.publisher | Elsevier | eng |
| dc.relation.ispartofcollection | Urban Biodiversity Research Coordination Network (UrBioNet) (MU) | eng |
| dc.subject | Urban Ecology | eng |
| dc.subject | Native | eng |
| dc.subject | Exotic | eng |
| dc.subject | Biodiversity | eng |
| dc.subject.lcsh | Birds | eng |
| dc.title | Bird data : South Africa, Pretoria | eng |
| dc.title.alternative | Biotic homogenization and alien bird species along an urban gradient in South Africa | eng |
| dc.type | Dataset | eng |
