Effects of nutrient addition and clipping on biomass production of invasive and native annual Asteraceae plants

Abstract

Invasive plants dominate many habitats and cause significant harm to native plants, agriculture and the wider environment. Clipping by mowing machines has been a common method to control invasive plants, but whether it can reduce the performance of invaders and increase the performance of co-occurring natives is not known. This study examined the effects of soil nutrient conditions and clipping on the performance of three invasive and three co-occurring native annual Asteraceae plants under either isolated or competitive conditions. Clipping tended to reduce the aboveground biomass of the invasive plants more than that of the native plants under low, but not under high nutrient conditions. However, invasive plants still produced an aboveground biomass equal to, or larger than, that of native plants under the low nutrient and clipping treatment combination. Nutrient addition increased the aboveground biomass of the invasive plants more than that of the native plants, although this was only marginally significant under competitive conditions. Clipping did not reduce the performance advantage of invaders over natives under high soil nutrient conditions. The ability of invaders to benefit more from nutrient addition, along with its ability to perform equally well, or better than, the native plants after human mechanical control (i.e. clipping), may explain their high abundance and dominance in many habitats.

Comparative performance of the highly invasive Mimosa invisa and its less invasive subspecies under different nutrient and light conditions

“…The tilth soil had a pH value of 6.04, an organic matter content of 5.11 g kg −1 , an available nitrogen concentration of 48.692 mg kg −1 , an available phosphorus concentration of 3.44 mg kg −1 and an available potassium concentration of 52.30 mg kg −1 . The methods for measuring these soil variables were the same as those in a previous study (Huang et al ., ).…”

“…The effect of species shows whether M. invisa and M. invisa var. inermis differ in biomass production, R/S and plant height, and the effect of population (nested within species) shows whether the two populations from the same species differ in performance (Huang et al ., ). An interactive effect of species and nutrient or light treatment on R/S and plant height indicates that the two species differ in trait plasticity (Richards et al ., ).…”

“…In the field, a plant often grows in competition with neighbouring plants, and the performance of individual growth may not predict the performance in competitive environments (Dawson et al ., 2012a; Verlinden et al ., ). Several previous studies have shown that invasive plants outperformed natives only under competitive conditions (Verlinden et al ., ; Huang et al ., ). However, few studies have compared the performance of highly invasive and less invasive species under both competitive and isolated conditions (Dawson et al ., 2012a), and no such comparison has been made at the subspecies level.…”

“…The habitats the two species invade are subject to varying levels of light and soil nutrient conditions. In agricultural land, soil nutrient conditions may be significantly elevated because of frequent fertilisation and disturbance (Huang et al ., ). In disturbed forests and human plantations, the light levels are low.…”

“…Plants may plastically change their physiological and morphological traits and biomass production in response to varying light and soil nutrient conditions. For example, the biomass and plant height of invasive plants increased (Huang et al ., ; Chen & Chen, ), and the ratio of root to shoot decreased with increasing soil nutrient availability (Huang et al ., ). Under the condition of low light, the biomass and ratio of root to shoot decreased significantly (Hou et al ., ; Huang et al ., ; Yasin et al ., ).…”