Consistent Effects of Disturbance and Forest Edges on the Invasion of a Continental Rain Forest by Alien Plants

Wayne Dawson, David F R P Burslem, Philip E. Hulme

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Continental tropical forests are thought to be resistant to alien plant invasion due to a lack of disturbance, or low propagule pressure from introduced species. We assessed the importance of disturbance and edge effects by surveying areas of submontane and lowland forest of Amani Nature Reserve in the East Usambara mountains, Tanzania. These areas are in the vicinity of Amani Botanic Garden (ABG)-a propagule source for many alien plant species. We surveyed three edges in the vicinity of the ABG plantations, using plots interspersed along multiple 250 m transects. Survey plots were either in secondary or seminatural forest, representing a difference in past disturbance). Alien plant species richness and abundance declined with increasing distance from forest edges, indicating that edge effects were important. In addition, the effect of distance on richness and abundance of alien species as adults was much smaller in seminatural than secondary forest, emphasizing that invasion of seminatural forest is less likely to occur. Abundance and occurrence of individual species showed broadly similar declines with increasing distance from the forest edge, and lower abundance in seminatural compared to secondary forest. Alien species were dominant in 15 percent of plots surveyed. As 28 percent of the Amani nature reserve forest is within 250 m of an edge, the importance of disturbance and edges could make a potentially large proportion of the forest vulnerable to alien species invasion.

Original languageEnglish
Pages (from-to)27-37
Number of pages11
JournalBiotropica
Volume47
Issue number1
Early online date21 Dec 2014
DOIs
Publication statusPublished - Jan 2015

Fingerprint

forest edge
introduced plants
edge effects
rain forests
introduced species
disturbance
secondary forests
botanical gardens
propagule
edge effect
secondary forest
conservation areas
nature reserve
garden
lowland forests
Tanzania
tropical forests
plantations
surveying
tropical forest

Keywords

  • East Africa
  • Exotic
  • Fragmentation
  • Invasive species
  • Protected area
  • Tree
  • Tropical forest
  • Weed

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

Cite this

Consistent Effects of Disturbance and Forest Edges on the Invasion of a Continental Rain Forest by Alien Plants. / Dawson, Wayne; Burslem, David F R P; Hulme, Philip E.

In: Biotropica, Vol. 47, No. 1, 01.2015, p. 27-37.

Research output: Contribution to journalArticle

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abstract = "Continental tropical forests are thought to be resistant to alien plant invasion due to a lack of disturbance, or low propagule pressure from introduced species. We assessed the importance of disturbance and edge effects by surveying areas of submontane and lowland forest of Amani Nature Reserve in the East Usambara mountains, Tanzania. These areas are in the vicinity of Amani Botanic Garden (ABG)-a propagule source for many alien plant species. We surveyed three edges in the vicinity of the ABG plantations, using plots interspersed along multiple 250 m transects. Survey plots were either in secondary or seminatural forest, representing a difference in past disturbance). Alien plant species richness and abundance declined with increasing distance from forest edges, indicating that edge effects were important. In addition, the effect of distance on richness and abundance of alien species as adults was much smaller in seminatural than secondary forest, emphasizing that invasion of seminatural forest is less likely to occur. Abundance and occurrence of individual species showed broadly similar declines with increasing distance from the forest edge, and lower abundance in seminatural compared to secondary forest. Alien species were dominant in 15 percent of plots surveyed. As 28 percent of the Amani nature reserve forest is within 250 m of an edge, the importance of disturbance and edges could make a potentially large proportion of the forest vulnerable to alien species invasion.",
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