Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.

Bracken fern (Pteridium aquilinum [L.] Kuhn) is an indigenous invasive plant and it is known to have a negative impact on biodiversity. This research focuses on infestations of bracken fern in two areas within the uKhahlamba Drakensberg Park World Heritage Site; the Royal Natal National Park and the...

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Main Author: Singh, Kaveer.
Other Authors: Forbes, Angus M.
Language:en_ZA
Published: 2013
Subjects:
Online Access:http://hdl.handle.net/10413/9903
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spelling ndltd-netd.ac.za-oai-union.ndltd.org-ukzn-oai-http---researchspace.ukzn.ac.za-10413-99032014-02-08T03:49:15ZChange detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.Singh, Kaveer.Invasive plants--KwaZulu-Natal.Invasive plants--Biological control--KwaZulu-Natal.Theses--Surveying.Bracken fern (Pteridium aquilinum [L.] Kuhn) is an indigenous invasive plant and it is known to have a negative impact on biodiversity. This research focuses on infestations of bracken fern in two areas within the uKhahlamba Drakensberg Park World Heritage Site; the Royal Natal National Park and the Rugged Glen Nature Reserve. Prior change detection research on bracken fern were constrained due to the low resolution satellite imagery and the inability of hard classification techniques to account for the mixtures of land cover types that occur within pixels of low resolution imagery. To overcome these constraints this research applied the fuzzy image classification technique to multispectral digital aerial imagery of 0.5 m spatial resolution. Multi date imagery used for image classification was captured in the mid-winter of 2009 and mid-spring of 2011. Thereafter post-classification change detection analysis was conducted using the fuzzy classified images. The classified images were verified using ground truth surveys. The 2009 and 2011 fuzzy classified images produced overall accuracies of 81.4% and 94.4% with Kappa coefficients of 0.63 and 0.89 respectively. This research found that the distinct seasonal development pattern of bracken fern and the time of year imagery were captured were significant factors in its detection. As bracken fern was found to be more spectrally distinct in spring as compared to winter, due to the plant growth of bracken fern, grass and other shrubbery. These classified images were used in post-classification change detection analysis which revealed that the bracken fern infestation in the Royal Natal National Park and Rugged Glen Nature Reserve had increased at a rate of 24 % and 27 % per annum respectively. This showed that bracken fern is spreading in the Royal Natal National Park and Rugged Glen Nature Reserve, as expected. Fire regimes, slope and aspect were found as factors that could be promoting the spread of bracken fern, 67.5 % and 75 % of the bracken fern infestation in the Park and Reserve respectively, occurred in areas that were burnt by fire regimes and have gentle to moderately gentle slopes facing east, south east and south.Thesis (M.Sc.Sur.)-University of KwaZulu-Natal, Durban, 2013.Forbes, Angus M.Akombelwa, Mulemwa.2013-11-06T06:43:52Z2013-11-06T06:43:52Z20132013Thesishttp://hdl.handle.net/10413/9903en_ZA
collection NDLTD
language en_ZA
sources NDLTD
topic Invasive plants--KwaZulu-Natal.
Invasive plants--Biological control--KwaZulu-Natal.
Theses--Surveying.
spellingShingle Invasive plants--KwaZulu-Natal.
Invasive plants--Biological control--KwaZulu-Natal.
Theses--Surveying.
Singh, Kaveer.
Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
description Bracken fern (Pteridium aquilinum [L.] Kuhn) is an indigenous invasive plant and it is known to have a negative impact on biodiversity. This research focuses on infestations of bracken fern in two areas within the uKhahlamba Drakensberg Park World Heritage Site; the Royal Natal National Park and the Rugged Glen Nature Reserve. Prior change detection research on bracken fern were constrained due to the low resolution satellite imagery and the inability of hard classification techniques to account for the mixtures of land cover types that occur within pixels of low resolution imagery. To overcome these constraints this research applied the fuzzy image classification technique to multispectral digital aerial imagery of 0.5 m spatial resolution. Multi date imagery used for image classification was captured in the mid-winter of 2009 and mid-spring of 2011. Thereafter post-classification change detection analysis was conducted using the fuzzy classified images. The classified images were verified using ground truth surveys. The 2009 and 2011 fuzzy classified images produced overall accuracies of 81.4% and 94.4% with Kappa coefficients of 0.63 and 0.89 respectively. This research found that the distinct seasonal development pattern of bracken fern and the time of year imagery were captured were significant factors in its detection. As bracken fern was found to be more spectrally distinct in spring as compared to winter, due to the plant growth of bracken fern, grass and other shrubbery. These classified images were used in post-classification change detection analysis which revealed that the bracken fern infestation in the Royal Natal National Park and Rugged Glen Nature Reserve had increased at a rate of 24 % and 27 % per annum respectively. This showed that bracken fern is spreading in the Royal Natal National Park and Rugged Glen Nature Reserve, as expected. Fire regimes, slope and aspect were found as factors that could be promoting the spread of bracken fern, 67.5 % and 75 % of the bracken fern infestation in the Park and Reserve respectively, occurred in areas that were burnt by fire regimes and have gentle to moderately gentle slopes facing east, south east and south. === Thesis (M.Sc.Sur.)-University of KwaZulu-Natal, Durban, 2013.
author2 Forbes, Angus M.
author_facet Forbes, Angus M.
Singh, Kaveer.
author Singh, Kaveer.
author_sort Singh, Kaveer.
title Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
title_short Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
title_full Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
title_fullStr Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
title_full_unstemmed Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
title_sort change detection of invasive bracken fern (pteridium aquilinum [l.] kuhn) in the royal natal national park and rugged glen nature reserve.
publishDate 2013
url http://hdl.handle.net/10413/9903
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