Dioscorea bulbifera is a serious invader of various ecosystems in Florida, where plants generated by its two morphotypes climb aggressively and smother supporting vegetation. There is a dearth of published research on its invasive biological attributes including vine growth and biomass production by plants generated from bulbils. Herein, we assessed these parameters in common garden studies by planting bulbils from four biomass categories (PBBCs I–IV) of both morphotypes. Vine lengths, longevity-based growth rates (VLGR), biomass, and quantities of leaves and daughter bulbils in both morphotypes showed positive correlation with the biomass of planted parental bulbils. This indicated similarity between corresponding attributes in two morphotypes. Total vine length showed strong positive correlation with VLGR, biomass, and quantities of leaves and bulbils. Overall vine longevity among plants from PBBCs I–IV did not significantly differ whereas the total vine lengths, VLGRs, number of branches, and quantities of leaves and bulbils increased with the biomass of the parental bulbils. Plants recruited by smaller bulbils allocated more biomass to leaves and tubers compared to stems and bulbils, whereas the plants recruited by larger bulbils allocated more biomass to leaves and bulbils compared to tubers and stems. Higher proportion of biomass allocation to leaves and bulbils presumably ensures immediate faster growth, longer vines, and a greater number of daughter bulbils for future recruitment of new plants. Vine length (associated with faster growth rate, capable of blanketing supporting structures and producing large quantities of bulbils) has been noted as the primary invasive biological attribute that facilitates D. bulbifera's status as a noxious exotic weed in Florida. Control measure that can reduce vine length should reduce or eliminate the invasive behavior of D. bulbifera in Florida.
Nomenclature: Air-potato, Dioscorea bulbifera L.
Management Implications: The exotic invasive air potato vine D. bulbifera has become a serious problem for public and private land managers across Florida and beyond by blanketing and smothering native vegetation. Despite its common occurrence in Florida, there are no published research data related to the role of propagule biomass on the resulting vines' growth rate, biomass, and invasive biological traits. We conducted common garden studies using vegetative propagules (parent bulbils) ranging from small to large biomass and examined the growth and biomass of the plants generated from these bulbils. Biomass of the parent bulbils of both morphotypes was positively correlated with total vine lengths, growth rates, and the number of branches, leaves, and bulbils. The vine longevity of plants generated by bulbils of all sizes was not significantly different. However, the total vine length, vine growth rates, and the number of branches, leaves, and bulbils increased with the biomass of the parent bulbils. Plants recruited by smaller bulbils allocated a major proportion of total biomass to leaves and tubers compared to the stems and bulbils, whereas the larger bulbils allocated a greater proportion of total biomass to bulbils and leaves compared to tubers and stems. Total vine length was positively correlated with the total plant biomass. Reduced vine length should have concomitant negative impacts on leaf and bulbil production. These reductions should, in turn, negatively affect (1) plant biomass and the number of branches and leaves that are responsible for causing smothering effects on invaded plant communities and (2) bulbil production that will have direct negative impact on plant recruitment and invasion of the new areas. Therefore, control measures that reduce seasonal vine length should reduce the quantity of bulbils and hence invasiveness of D. bulbifera vines in Florid
