Are environmental transitions more prone to biological invasions?

Show simple item record Janse Van Rensburg, Berndt Hugo, Sanet Levin, Noam Kark, Salit 2013-06-28T07:05:17Z 2014-03-31T00:20:06Z 2013-03
dc.description.abstract AIM To examine whether at a subcontinental-scale ecotonal areas of transition between vegetation communities are at higher risk of plant invasion. LOCATION South Africa and Lesotho. METHODS Using plant data on native and established alien species in South Africa, we examined the relationship between plant richness (native and alien) in each grid cell (quarter-degree resolution) in the study area and the distance of the grid cell to the nearest ecotone between vegetation communities. We used a residual analysis to estimate each grid cell’s relative invasibility (i.e. susceptibility to invasion) relative to its ecotone distance. We further explored the relative importance of ecotones in relation to large-scale environmental variation, and the importance of ecotonal spatial heterogeneity, in structuring alien species richness patterns. RESULTS Both alien and native richness patterns become higher with declining distance to ecotones, suggesting that transitional environments are more susceptible to invasion than areas located farther away; however, levels of invasibility vary across South Africa. The negative relationship between ecotone distance and alien species richness remained negative and significant for the whole of South Africa, grassland and Nama-Karoo, after controlling for environmental variables. Several sources of environmental heterogeneity, which were shown here to be associated with ecotones, were also found to be important determinants of alien species richness. MAIN CONCLUSIONS While most of the current conservation efforts at the regional and global scales are currently directed to distinct ecosystems, our results suggest that much more effort should be directed to the transitions between them, which are small in size and have high native richness, but are also under greater threat from invasive alien species. Understanding how alien species richness and invasibility change across transitions and sharp gradients, where environmental heterogeneity is high, is important for ongoing conservation planning in a biogeographical context. en
dc.description.librarian hb2013 en
dc.description.librarian ab2013
dc.description.sponsorship B.J.v.R. and S.H. acknowledge the support from the University of Pretoria and the DST-NRF Centre of Excellence for Invasion Biology. en
dc.description.uri en
dc.identifier.citation Van Rensburg, BJ, Hugo, S, Levin, N & Kark, S 2013, 'Are environmental transitions more prone to biological invasions?', Diversity and Distributions, vol. 19, no. 3, pp. 341-351. en
dc.identifier.issn 1366-9516 (print)
dc.identifier.issn 1472-4642 (online)
dc.identifier.other 10.1111/ddi.12026
dc.language.iso en en
dc.publisher Wiley-Blackwell en
dc.rights © 2013 Blackwell Publishing Ltd. The definite version is available at en
dc.subject Alien plants en
dc.subject Ecotones en
dc.subject Invasibility en
dc.subject Native biodiversity en
dc.subject Subcontinental scale en
dc.subject.lcsh Environmentalism en
dc.subject.lcsh Biological invasions en
dc.subject.lcsh Plant invasions en
dc.title Are environmental transitions more prone to biological invasions? en
dc.type Postprint Article en

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