Timing and extent of tissue removal affect reproduction characteristics of an invasive species Heracleum mantegazzianum

Abstract

Response of the invasive speciesHeracleum mantegazzianum to experimental removal of tissues was studied in the Czech Republic. The study aimed at determining (i) how efficiently plants respond, in terms of quantity and quality of produced fruit, to the removal of different amounts of generative and/or vegetative tissues; and (ii) whether regeneration ability depends on the time of treatment. Total number of fruits and their mean weight were reduced by removal of leaves, but germination percentage and rate of germination did not differ from control. More vigorous individuals compensated for the loss of tissues to a higher degree, and the advantage of being larger increased with severity of the treatment. Of 40 plants with umbels completely removed, 18 (45.0%) regenerated and produced on average 103.4 ± 220.1 (mean ± SD) fruits. Total fruit numbers and total fruit weight of regenerating plants significantly differed neither among treatments nor from the control, but some treatments resulted in poorer germination compared to the control. Umbels removed from plants at the beginning of fruit development and left at the locality produced 18.6% of fruit numbers of control plants, and 24% of these seeds germinated. Control by removing umbels from plants must ensure that they are collected and destroyed. From the management viewpoint, there is a trade-off between later umbel removal, resulting in more efficient reduction in fecundity but necessity to handle more developed fruits, and early treatment, leading to a high regeneration, that produces seed of sufficient quantity and very little affected in terms of quality.

How tidal regime and treatment timing influence the clipping frequency for controlling invasive Spartina alterniflora: implications for reducing management costs

“…The previous studies (Hobbs and Humphries 1995;Pysek et al 2007) have shown that the clipping timing is an important regulator of treatment efficiency. We also obtained similar results in this study (Tables 2,3,4,5;Figs.…”

“…Previous studies have indicated that treatment timing is the important regulator for enhancing control efficiency (Emery and Gross 2005;Gao et al 2009;Pysek et al 2007;Ruesink and Collado-Vides 2006). This can infer that treatment timing might determine the final MFD.…”

Public Reaction to Invasive Plant Species in a Disturbed Colorado Landscape

“…One way to inhibit the further spread of tall invasive Heracleum, such as Tromsø palm or H. mantegazzianum, is to cut the umbels when they begin to flower to prevent the plant from setting seeds (Nielsen et al 2005). However, while no such research has been done on H. persicum, research with H. mantegazzianum showed that, even if umbels are cut before seeds ripen, they are still able to develop viable seeds (Pyšek et al 2007a), so appropriate disposal of the umbels is important (Pyšek et al 2007b). To remove invasive Tromsø palm by mowing and cutting of the stems, it is important that the plants are treated at least three times during the growing season (Renna 2002) for not less than 5 yr, which exhausts the plant until it finally dies (Nielsen et al 2005).…”

“…Fewer respondents indicated that the plant waste was taken away from the parcel and deposited in the garbage/organic waste container (24.1%, n = 27) and/or the municipal waste disposal site (10.7%, n = 12). Leaving the plant waste on the parcel must be regarded as unfavorable, as it can contribute to the continued spread of the plant, which has been shown in the case of giant hogweed (Pyšek et al 2007a). …”

“…In addition, landowners could be better informed about disposal of cut plant parts in garbage bins or at the municipal waste disposal site to prevent further spread, based on findings about giant hogweed seed ripening by Pyšek et al (2007a). Authorities should also inform landowners about taking particular care of border areas and hidden or inaccessible spaces in their information campaigns and assistance programs.…”