Propagule success of an invasive Poaceae depends on size of parental plants

Abstract

Aim Viability and successful colonization of propagules by an invasive species may depend on several factors, such as parental plant size and propagules’ fresh mass. Here, we tested (i) the effects of propagules’ origin (from large and small parental plants); (ii) the position in the parental stem (apical, intermediate and basal) on the early development of the new sprouts of Urochloa arrecta; and (iii) if the regeneration success of U. arrecta was related with propagule fresh mass that comes from large or small parental plants. Methods We selected 16 individuals of U. arrecta and separated them in two groups: (i) eight “large” (stem ± 1.5 m) and (ii) eight “small” (stem ± 0.6 m). For each individual, we cut three fragments with two nodes (considered as the “propagule”) from the apical, intermediate and basal portions of the stem and we measured the fresh mass (g), length (cm) and distance between the two nodes (cm) of all propagules of U. arrecta. In addition, after the experimentation, we measured the dry mass (g) and length (cm) of each new sprout of U. arrecta generated from each propagule. Results We found that large parental individuals produced sprouts with longer length and greater dry mass. In contrast, the position in the parental stem did not significant influence the development of sprouts in U. arrecta. In addition, the propagule fresh mass played a role in the development of sprouts just for propagules from small parental plants. Conclusions We found that the size of the parental individual is an important determinant of the development of new sprouts of this invasive species and the propagule fresh mass has a positive and significant influence in the success of U. arrecta only for propagules from smaller parental plants. We highlight that all propagules were viable, which could explain the reasons for this plant to be a successful invader.

Propagule resistance of an invasive Poaceae as a trait of its invasiveness

“…We then performed ANOVAs with permutations (given the lack of assumptions) to evaluate if measured traits were affected by treatments. Also, since propagule initial size can impact macrophyte growth and other traits development (Bando et al 2016), we considered initial propagule mean sizes as well as a random factor. Graphics and Fig.…”