Impact of drought on plant populations of native and invasive origins

Abstract

Invasive populations often shift phenotypically during introduction. Moreover, they are postulated to show an increased phenotypic plasticity compared with their native counterparts, which could be advantageous. However, less is known about trait selection across populations along the invasion gradient in response to environmental factors, such as increasing drought caused by climate change. In this study, we investigated the impacts of drought on growth, regrowth, and various leaf traits in plants of different origin. Therefore, seeds of 18 populations of the perennial Tanacetum vulgare were collected along the invasion gradient (North America, invasive; West Europe, archaeophyte; East Europe, native) and grown in competition with the grass Poa pratensis under control or dry conditions in a common garden. Above-ground biomass was cut once and the regrowth was measured as an indicator for tolerance over a second growth period. Initially, drought had little effects on growth of T. vulgare, but after cutting, plants grew more vigorously. Against expectations, phenotypic plasticity was not higher in invasive populations, but even reduced in one trait, which may be attributable to ecological constraints imposed by multiple stress conditions. Trait responses reflected the range expansion and invasion gradient and were influenced by the latitudinal origin of populations. Populations of invaded ranges may be subject to faster and more extensive genetic mixing or had less time to undergo and reflect selective processes.

Flower Production, Headspace Volatiles, Pollen Nutrients, and Florivory in Tanacetum vulgare Chemotypes

“…But since there are hardly any extensive field studies on trophic interactions with chemotypes, this remains to be a topic for future analyses. In fact, vegetative reproduction by ramets is an important growth strategy of this perennial species (Kleine et al, 2017). The shortest bloom periods were observed for the artemisia ketone and artemisia acetate mix-chemotypes, but within this short period, plants of these chemotypes produced the highest numbers of flower heads (Figure 2F).…”

Increased Plasticity in Invasive Populations of a Globally Invasive Cactus

“…Similarly, Sexton et al [ 17 ] found significant genetic variation among different ecotypes of Tamarix ramosissima populations across its introduced ranges in North America. On the other hand, a common garden drought experiment between the plant populations of Tanacetum vulgare from its native range in temperate Europe and the invasive range in North America showed no significant interaction between range and treatment and as a result did not support the evolution of increased phenotypic plasticity in invasive populations [ 19 ]. Some invasive species have also been found to create increased intrapopulation genetic diversity once they have established outside of their native ranges [ 20 ], thus increasing their survival and adaptability.…”

Annual Net Primary Productivity of Different Functional Groups as Affected by Different Intensities of Rainfall Reduction in the Semiarid Grasslands of the Gauteng Province in South Africa

“…Hence, increasers are considered more tolerant to grazing than decreasers. Drought may lead to physiological and morphological plant modifications [19]. However, most genotypes that survive in most arid regions are the ones that become dormant in winter [20,21].…”