Additive effects of genotype, nutrient availability and type of tissue damage on the compensatory response of Salix planifolia ssp. planifolia to simulated herbivory

Abstract

Plant responses to herbivory include tolerance (i.e. compensatory growth) and defense. Several factors influence the tolerance of a plant following herbivory, including plant genetic identity, site nutrient availability, and previous and/or concurrent herbivory. We studied the effects of these factors on the compensatory response of Salix planifolia ssp. planifolia, a shrub species common in the boreal and subarctic regions of North America. We cloned several genets of S. planifolia and submitted them to simulated root and/or leaf herbivory while varying the nutrient availability. Simulated leaf herbivory was more detrimental to the plant than simulated root herbivory, reducing both above- and below-ground tissue production. Leaf demography was unaffected by either simulated herbivory treatment. There was some compensatory growth following simulated leaf and root herbivory, but only the root compartment responded to increased nutrient availability. Simulated leaf herbivory increased leaf transpiration and reduced stomatal resistance, suggesting increased carbon fixation. The unexpected finding of the experiment was the absence of interactions among factors (genotype, nutrient availability and type of tissue damage) on the compensatory response of S. planifolia. These factors thus have additive effects on the species' compensatory ability.

Additive effects of herbivory, nectar robbing and seed predation on male and female fitness estimates of the host plant Ipomopsis aggregata

“…A central goal in ecology is to understand and predict the outcomes of these complex species interactions (Morris et al 2007). In some cases, the effects of multispecies interactions on host fitness will be additive and predictable from pairwise effects (Houle and Simard 1996;Maron 1998). However, in other cases, multispecies interactions are non-additive, and quantifying pairwise interactions is insufficient to predict the results of complex interactions (Wootton 1993).…”

Compensatory responses of an arid land crucifer, Chorispora tenella (Brassicaceae), to experimental flower removal

“…The availability of resources necessary for compensation may be depressed by competition from neighbouring plants (Dirzo, 1984;Price, 1991, Houle & Simard, 1996, thereby restricting plant regrowth and reproductive compensation (Coley et al, 1985;Maschinski & Whitham, 1989;Price, 1991;Belsky et al, 1993;HjaK lteH n et al, 1993;Sadras, 1996). Moreover, lowproductive habitats, like deserts, constrain the ability of plants to regrow after damage (Rosenthal & Kotanen, 1994;Strauss & Agrawal, 1999).…”

“…Many extrinsic factors influence a plant's ability to compensate for damage (Maschinski & Whitham, 1989;Houle & Simard, 1996). The availability of resources necessary for compensation may be depressed by competition from neighbouring plants (Dirzo, 1984;Price, 1991, Houle & Simard, 1996, thereby restricting plant regrowth and reproductive compensation (Coley et al, 1985;Maschinski & Whitham, 1989;Price, 1991;Belsky et al, 1993;HjaK lteH n et al, 1993;Sadras, 1996).…”

Response of artificially defoliated Betula pendula seedlings to additional soil nutrient supply

“…The tolerance is also related to other environmental factors, such as damage frequency and severity (Houle & Simard 1996, Wise & Abrahamson 2005, Pinkard et al 2007). Stevens et al (2008) reported a positive correlation of aspen tolerance with the proportion of biomass in stems under low-nutrient conditions and no defoliation event; however, it was correlated with greater allocation to stems under high-nutrient conditions and defoliation event.…”