No evidence for novel weapons: biochemical recognition modulates early ontogenetic processes in native species and invasive acacias

  • Florencia A. YannelliEmail author
  • Ana Novoa
  • Paula Lorenzo
  • Jonatan Rodríguez
  • Johannes J. Le Roux
Original Paper


The Novel Weapons Hypothesis postulates that the release of allelochemicals by alien plants can inhibit the growth of evolutionary naïve native plants. On the other hand, when species share a recent evolutionary history, recognition of phytochemicals from neighboring plants can have adaptive value by providing cues to signal suitable conditions conducive to establishment. This has been termed the Biochemical Recognition Hypothesis. We explored these two hypotheses by conducting germination experiments in South Africa and Spain and a growth experiment in South Africa, using invasive Australian acacias and native species from each region. The experiments exposed seeds of the selected recipient species to leachates collected under acacias, nearby uninvaded vegetation, or distilled water. We then measured total germination, and above and below ground biomass in the growth experiment. Our results did not support the Novel Weapons Hypothesis, but instead we found some leachates collected under acacias and uninvaded areas to stimulate the germination and early growth of some of our selected acacias and native species. Such effects occurred both at the intra- and interspecific level. In general, interspecific stimulatory effects between invasive acacias occurred irrespective of whether they had overlapping native ranges in Australia. We also found leachates from uninvaded areas in South Africa to have stimulatory effects on one invasive acacia and one native species. Hence, our results support the Biochemical Recognition Hypothesis, suggesting that chemically-induced signals may facilitate acacia establishment in sites that have already been transformed by acacias.


Allelopathy Phytochemicals Novel Weapons Hypothesis Biochemical Recognition Hypothesis Leachates 



FAY thanks Wolf-Christian Saul and Nitya Mohanty for assistance in the laboratory and field, Fiona Impson for seed material, Flower Valley (Mr Sean Privett) and Altydgedacht farm for providing access to their land. The authors acknowledge Ian J. Renne and an anonymous reviewer for their comments that significantly improved this manuscript. AN acknowledges funding from the South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme, EXPRO grant no. 19-28807X (Czech Science Foundation) and long-term research development project RVO 67985939 (The Czech Academy of Sciences). AN, FAY, and JJLR acknowledge the Stellenbosch University’s DST-NRF Centre of Excellence for Invasion Biology (C·I·B). FAY and JJLR also acknowledge the Working for Water Programme through the collaborative research project on ‘Research for Integrated Management of Invasive Alien Species’. PL was supported by a contract (SFRH/BPD/88504/2012; IT057-18-7248) from the Fundação para a Ciência e a Tecnologia (Portugal) and the European Social Fund. The experiment conducted with Spanish leachates was financed by FCT/MEC through national funds and the co-funding by the FEDER, within the PT2020 Partnership Agreement, and COMPETE 2020, within the project UID/BIA/04004/2013. PL thanks Parque Natural do Monte Aloia (Xunta de Galicia, Spain) for providing permission to collect acacia leachates. JR was supported by a research contract (GRC2015/012) from the Xunta de Galicia/FEDER, Consellería de Educación y Ordenación Universitaria (Autonomous Government of Galicia). JR acknowledges a short-term research grant awarded by University of Vigo to visit the DST-NRF Centre of Excellence for Invasion Biology (C·I·B), and funding from the Xunta de Galicia, Spain (CITACA Strategic Partnership, Reference: ED431E 2018/07).

Supplementary material

10530_2019_2110_MOESM1_ESM.docx (70 kb)
Supplementary material 1 (DOCX 70 kb)


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Botany and Zoology, Centre for Invasion BiologyStellenbosch UniversityMatielandSouth Africa
  2. 2.Department of Invasion Ecology, Institute of BotanyAcademy of Sciences of the Czech RepublicPrůhoniceCzech Republic
  3. 3.South African National Biodiversity InstituteKirstenbosch Research CentreClaremontSouth Africa
  4. 4.Department of Life Sciences, Centre for Functional Ecology - Science for People and the Planet (CFE)University of CoimbraCoimbraPortugal
  5. 5.Plant Ecophysiology Group, Department of Plant Biology and Soil ScienceUniversity of VigoVigoSpain
  6. 6.ECOEVO Lab, E. E. ForestalUniversity of VigoPontevedraSpain
  7. 7.Department of Biological SciencesMacquarie UniversitySydneyAustralia

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