Clonal mechanisms that matter in Agave fourcroydes and A. sisalana
invasions in drylands: implications for their management

Año Publicación:  2023
detalles
Responsable: María J. Salinas-Bonillo, M. Trinidad Torres-García, M. Mar Paniagua, M. Mar Sánchez and Javier Cabello
Journal, Volumen y páginas:
Management of Biological Invasions (2023) Volume 14

Autores

María J. Salinas-Bonillo, M. Trinidad Torres-García, M. Mar Paniagua, M. Mar Sánchez and Javier Cabello

Abstract


Clonal species Agave fourcroydes and A. sisalana from ancient crops have become
invasive in Mediterranean drylands, posing a severe threat to ecologically valuable
native plant communities. However, we barely know the relative contribution of
clonal mechanisms underlying their invasive behaviour. Therefore, environmental
managers must face this problem without scientific evidence on the most effective
methods to eradicate or control these invasions. In this study, we monitored populations
of A. fourcroydes and A. sisalana and carried out field and experimental plantings
(in situ and under controlled environmental conditions) to assess the efficacy of
three clonal mechanisms: shoots from rhizomes, shoots from rosettes, and aerial
bulbils from floral scapes). Both species showed very similar performance in their
clonal expansion. Shoot production from rhizomes was the primary mechanism for
densifying Agave populations, emerging to the soil 1.5 ± 2.1 shoots per individual.
Moreover, we did not observe mortality of new shoots from rhizomes. These new
clonal individuals seemed to ensure their survival by connecting to the mother plant
(clonal integration). In addition, contractile roots, only recorded in shoots from
rhizomes, could represent an advantage allowing them to react to harsh environmental
conditions. Regarding shoots from rosettes, individuals produced 0.63 ± 1.01 shoots
on average, with no mortality recorded, but without guaranteeing the replacement
of mother plants. Finally, bulbil production and their rooting under controlled and
favourable conditions were very high, although their establishment success under
arid conditions proved irrelevant. These results suggest that management actions
should focus on the removal of shoots from rhizomes. This approach could be an
efficient, feasible, and cost-effective medium- to long-term habitat management
strategy to control these Agave invasions, with widespread application worldwide
in similar invasion processes.
Key words: aerial bulbils, arid la

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