Leaf Phenology and Seasonal Carbon Gain in the Invasive Plant, Bunias orientalis L.

Abstract

In two potentially competing herbaceous plants, the invasive Bunias orientalis L. (Brassicaceae) and the native Picris hieracioides L. (Asteraceae), seasonal changes in leaf CO2 gas exchange and plant growth were studied over an entire growing season from February 1998 to December 1998 in two experimental fields. The study was motivated by the hypothesis that pre‐adaptive phenological displacement of alien species relative to the native flora may be an important reason for the observed expansion of B. orientalis in central Europe. We quantified the importance of phenological differences for annual carbon gain in both species by estimating total leaf carbon gain from the results of leaf CO2 exchange and changes in plant leaf area. Bunias orientalis achieved almost half of its annual carbon gain in the time between early September and December, when competition for light by other species, like P. hieracioides, is low. Our quantitative approach corroborates the notion that the phenological shift of a relatively poor competitor, such as B. orientalis, could be of great importance for the success as an invasive species.

Phenology of the dioecious shrubBaccharis halimifoliaalong a salinity gradient: Consequences for the invasion of Atlantic subhalophilous communities

“…Phenology can play an important role in invasion success (De Falco et al 2007;Wolkovich & Cleland 2010) since it may determine the nature and the extent of the biotic interactions established in the recipient ecosystem. For instance, early or extended vegetative activity of invaders can contribute to their competitive superiority over their native neighboring plants (Zotz et al 2000;Park & Blossey 2008). Different flowering phenology of invaders compared with natives can also promote successful invasion through the filling of an empty temporal niche by the invaders (Lloret et al 2005;Andrew & Ustin 2009;Godoy et al 2009;Wolkovich & Cleland 2010).…”

Seasonal variation of temperature response of respiration in invasive Berberis thunbergii (Japanese barberry) and two co-occurring native understory shrubs in a northeastern US deciduous forest

“…One potential explanation is that these plants have a relative C balance advantage over the co-occurring natives. Early leafing, which leads to a significant spring C subsidy by stimulating photosynthetic C gain when high irradiance is available, has been proposed to be an important mechanism of invasion in temperate deciduous forests (Harrington et al 1989;Myers and Anderson 2003;Zotz et al 2000). However, plant C balance is determined as the net equilibrium between C gain and C loss.…”

Leaf phenology and seasonal variation of photosynthesis of invasive Berberis thunbergii (Japanese barberry) and two co-occurring native understory shrubs in a northeastern United States deciduous forest

“…An important mechanism of invasion in the forest understory can be longer leaf longevities than co-occurring native plants (Harrington et al 1989;Myers and Anderson 2003;Zotz et al 2000). Many successful understory invaders produce leaves earlier than their native counterparts and/or defoliate later (Harrington et al 1989;Myers et al 2005;Nelson et al 1982;Schierenbeck and Marshall 1993;Zotz et al 2000).…”