Cattle browsing impacts on stunted Avicennia marina mangrove trees

  • Published source details Hoppe-Speer S.C.L. & Adams J.B. (2015) Cattle browsing impacts on stunted Avicennia marina mangrove trees. Aquatic Botany, 121, 9-15.


This study is summarised as evidence for the following.

Action Category

Exclude or remove livestock from historically grazed brackish/saline swamps

Action Link
Marsh and Swamp Conservation
  1. Exclude or remove livestock from historically grazed brackish/saline swamps

    A replicated, paired, controlled study in 2010–2012 in an estuary in South Africa (Hoppe-Speer & Adams 2015) reported that excluding cattle increased the height and growth rate of grey mangrove Avicennia marina. After two years, grey mangroves were 91 cm tall in plots that had been fenced to exclude cattle (vs 77 cm in plots left open to cattle; statistical significance not assessed). Over the two years, trees in exclusion plots grew more than trees in open plots in three of four metrics: plant height (exclusion: 5.4; open: −0.2 cm/year), plant diameter (exclusion: 7.1; open: 2.0 cm/year) and crown volume (exclusion: 0.5; open: 0.1 m3/year). Circumference growth did not significantly differ between treatments (exclusion: 26; open: 15 cm). In the second year, a total of 75 grey mangrove seedlings appeared in exclusion plots (vs 35 in open plots). Methods: In 2010, five pairs of 25-m2 plots were established within stunted, shrubby, estuarine mangroves. In each pair, one plot was fenced to exclude cattle whilst the other remained open to cattle (3–11 cows/ha). Grey mangrove trees were measured and seedlings were counted three times after setting up the experiment, in July 2010, 2011 and 2012.

    (Summarised by: Nigel Taylor)

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