Increasing tree invasion on Isla Victoria: 10 years after the original “gringos en el bosque” study

MOYANO, JAIME; SIMBERLOFF, D.; RELVA, M. A.; NUÑEZ, M.

BIOLOGICAL INVASIONS

SPRINGER

Lugar: Berlin; Año: 2023 vol. 25 p. 3025 - 3031

1387-3547

Knowing which species will becomeinvasive has been the holy grail of invasion biology.A survey of woody plants was conducted in 2001on an island (Isla Victoria) where 135 non-nativewoody plant species had been introduced 80 yearspreviously. The survey showed that nearly 10% ofintroduced species had spread further than 100 mfrom the original sites. For some introduced specieson this island longer time lags between introductionand invasion (or further spread) could be at play. Totest if new invasions have begun since the originalsurvey or if ongoing invasions have spread further,we repeated the survey a decade later. The proportionof introduced species that became invasive didnot increase between surveys, suggesting that longertime lags may not reveal major invasions from newspecies on this island. However, we found that therelative frequency of taller individuals (above 2 m)has increased, suggesting a change in age structureof these invasive populations. Further, we found thatwoody invader densities and maximum heights haveincreased since the original survey, suggesting thatwoody plant invasion is progressing, and for somespecies even accelerating. These results highlightthe importance of research on how long invasions oflong-lived woody plants can take, providing key datato guide long-term monitoring of sites with multiplenon-native plant introductions.