The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?

The distribution, abundance, size distribution and diurnal activity patterns of invasive land snails, Theba pisana, in the West Coast National Park (WCNP), South Africa, were investigated. The park was divided into 1 km2 grids, within each of which five 1 m2 quadrat counts of live snails were record...

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Main Authors: Lizelle J. Odendaal, Tanya M. Haupt, Charles L. Griffiths
Format: Article
Language:English
Published: AOSIS 2008-12-01
Series:Koedoe: African Protected Area Conservation and Science
Subjects:
Online Access:https://koedoe.co.za/index.php/koedoe/article/view/153
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author Lizelle J. Odendaal
Tanya M. Haupt
Charles L. Griffiths
author_facet Lizelle J. Odendaal
Tanya M. Haupt
Charles L. Griffiths
author_sort Lizelle J. Odendaal
collection DOAJ
description The distribution, abundance, size distribution and diurnal activity patterns of invasive land snails, Theba pisana, in the West Coast National Park (WCNP), South Africa, were investigated. The park was divided into 1 km2 grids, within each of which five 1 m2 quadrat counts of live snails were recorded. Of 106 grids sampled, 19% contained live snails. The average density of snails was 4.04 m-2 ± 24.9, significantly lower than in disturbed habitats adjacent to the park (57 m-2 ± 96.25), but very high densities were recorded at two sites. Snails were most abundant along roadsides and densities decreased dramatically with distance from roads. T. pisana in the WCNP appear to have an annual lifecycle, breeding in autumn to winter and growing to adult size of about 14 mm diameter by the end of the following summer. Snails were observed on a wide variety of endemic and introduced plant species and appeared to have a catholic diet. They are active mostly at night and especially during periods of high humidity, irrespective of temperature. Given the very high densities that T. pisana can attain at some sites, plus their apparently catholic feeding habits, their potential impact on the vegetation of the park is cause for concern and should be further investigated. Control of the main colonies should also be considered.
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spelling doaj.art-ed9c4348a50d4582b699275e679a2e7a2022-12-22T01:41:08ZengAOSISKoedoe: African Protected Area Conservation and Science0075-64582071-07712008-12-01501939810.4102/koedoe.v50i1.153633The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?Lizelle J. Odendaal0Tanya M. Haupt1Charles L. Griffiths2University of Cape TownUniversity of Cape TownUniversity of Cape TownThe distribution, abundance, size distribution and diurnal activity patterns of invasive land snails, Theba pisana, in the West Coast National Park (WCNP), South Africa, were investigated. The park was divided into 1 km2 grids, within each of which five 1 m2 quadrat counts of live snails were recorded. Of 106 grids sampled, 19% contained live snails. The average density of snails was 4.04 m-2 ± 24.9, significantly lower than in disturbed habitats adjacent to the park (57 m-2 ± 96.25), but very high densities were recorded at two sites. Snails were most abundant along roadsides and densities decreased dramatically with distance from roads. T. pisana in the WCNP appear to have an annual lifecycle, breeding in autumn to winter and growing to adult size of about 14 mm diameter by the end of the following summer. Snails were observed on a wide variety of endemic and introduced plant species and appeared to have a catholic diet. They are active mostly at night and especially during periods of high humidity, irrespective of temperature. Given the very high densities that T. pisana can attain at some sites, plus their apparently catholic feeding habits, their potential impact on the vegetation of the park is cause for concern and should be further investigated. Control of the main colonies should also be considered.https://koedoe.co.za/index.php/koedoe/article/view/153<i>Theba pisana</i>land snailinvasive speciesWest Coast National Parkimpact of alien species invasion
spellingShingle Lizelle J. Odendaal
Tanya M. Haupt
Charles L. Griffiths
The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
Koedoe: African Protected Area Conservation and Science
<i>Theba pisana</i>
land snail
invasive species
West Coast National Park
impact of alien species invasion
title The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
title_full The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
title_fullStr The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
title_full_unstemmed The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
title_short The alien invasive land snail <i>Theba pisana </i>in the West Coast National Park: Is there cause for concern?
title_sort alien invasive land snail i theba pisana i in the west coast national park is there cause for concern
topic <i>Theba pisana</i>
land snail
invasive species
West Coast National Park
impact of alien species invasion
url https://koedoe.co.za/index.php/koedoe/article/view/153
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