Biodiversity and Conservation

, Volume 20, Issue 12, pp 2729–2743

Predicting Acacia invasive success in South Africa on the basis of functional traits, native climatic niche and human use

  • P. Castro-Díez
  • T. Langendoen
  • L. Poorter
  • A. Saldaña-López
Original Paper

DOI: 10.1007/s10531-011-0101-5

Cite this article as:
Castro-Díez, P., Langendoen, T., Poorter, L. et al. Biodivers Conserv (2011) 20: 2729. doi:10.1007/s10531-011-0101-5

Abstract

Australian Acacia species have been widely planted worldwide for different purposes. Some of them have spread and altered the native ecosystem functions to the extent of being considered economic and ecologic threats. Understanding factors that allow these species to become invasive is an important step for mitigating or preventing the damaging effects of invasive species. We aimed to test the importance of native niche climatic width and average, plant functional traits (plant height, leaf area, seed mass and length of flowering season) and anthropogenic factors (number of uses, time since introduction) for predicting invasive success, in terms of abundance and range, of 16 Australian Acacia species in South Africa. By using multiple regression analysis, we constructed one different model for each type of predicting factors. When more than two predicting variables were available in a category, they were reduced to a maximum of two predictors by means of principal component analysis. Acacia spp. abundance and range in South Africa were highly correlated. The anthropogenic model (using number of human uses as predictor) was the best to explain both abundance and range of acacias in South Africa. This may be attributed to the importance of humans as dispersal vectors and to the relatively recent introduction of these species (circa 150 years). The functional traits model was the next best model explaining Acacia range, but not abundance, acacias with higher height and leaf area being more widespread in South Africa. Taller plants may disperse their seeds more efficiently by attracting dispersal agents, such as birds. The climatic affinities model was the following in the ranking explaining both range and abundance, acacias coming from moister, cooler and less seasonal regions in Australia being more successful in South Africa. This pattern may be attributed to the fast growth genotype generally selected for under low climatic stress conditions. Acacias with wide climatic niche in the native region were also more widespread and abundant in South Africa, probably because the same traits that allow them to be widespread in Australia, also contribute to overcome the climatic filters to establish throughout South Africa. This study provides managers with tools to identify those exotic Acacia ssp. having more chances to become successful invaders in South Africa.

Keywords

Abundance Australian acacia Climatic amplitude Exotic range Generalised linear models Human use Plant functional traits Residence time 

Abbreviations

FL

Length of flowering time

H

Plant mean height

LA

Leaf area

No.uses

Number of uses

Pm.range

Annual precipitation range

Pm

Annual precipitation

Pseas.range

Precipitation seasonality range

Pseas

Precipitation seasonality

RT

Mean residence time

SM

Mean seed mass

Tm.range

Annual temperature range

Tm

Annual temperature

Tseas.range

Temperature seasonality range

Tseas

Temperature seasonality

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • P. Castro-Díez
    • 1
  • T. Langendoen
    • 1
    • 2
  • L. Poorter
    • 2
  • A. Saldaña-López
    • 1
  1. 1.Departamento de EcologíaUniversidad de Alcalá, Campus UniversitarioAlcalá de Henares, MadridSpain
  2. 2.Forest Ecology and Management Group, Centre for Ecosystem Studies, Wageningen University and Research CentreWageningenThe Netherlands

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