Climbing capacity of the invasive vine Mikania micrantha Kunth on vertical artificial poles
Hu L; Li M
Climbing capacity of invasive climbers is an important parameter to evaluate in the species invasive potential and processes in forests. However this feature has not attracted the attention of invasion biologists. In the present study we assessed the climbing traits and capacity of Mikania micrantha; a herbaceous invasive stem-twiner by supplying artificial vertical supports of different sizes ranging from 1.0 to 8.0 cm in diameter. We also calculated the theoretical maximum usable host size of a M. micrantha shoot based on confirm of the hypothesis that curvature of M. micrantha shoots will remain constant and not affected by support pole size. A total 164-tested M. micrantha shoots ascended the supports successfully. Shoot success rate declined significantly when support diameter exceeded 5.0 cm. The largest pole M. micrantha ascended successfully was 6.6 cm while the theoretical value is 7.5 cm on average. Curvature declined significantly with increasing shoot diameter. However no significant correlation was detected between curvature and support diameter and most M. micrantha shoots maintained relatively constant curvature within a small fluctuation range (0.1–0.2 cm-1) near the average value (0.16 cm-1). We compared our results with the only two similar studies available and concluded that climbing shoot ascent angle on supports decreased with increasing support diameter while curvature remained constant which was not affected by support size. These appear to be common attributes for herbaceous stem-twiners. Maximum usable host size was an important factor for successful M. micrantha ascent. We recommend this as a vital criterion in species management.