Species‐specific responses of plant communities to altered carbon and nutrient availability

Abstract

Summary In a field microcosm experiment, species‐specific responses of aboveground biomass of two California annual grassland communities to elevated CO2 and nutrient availability were investigated. One community grows on shallow, nutrient‐poor serpentine‐derived soil whereas the other occurs on deeper, modestly fertile sandstone/greenstone‐derived substrate. In most species, CO2 effects did not appear until late in the growing season, probably because the elevated CO2 increased water‐use‐efficiency easing, the onset of the summer drought. Responses of aboveground biomass to elevated CO2 differed depending on nutrient availability. Similarly, biomass responses to nutrient treatments differed depending on the CO2 status. For the majority of the species, production increased most under elevated CO2 with added nutrients (N,P,K, and micro nutrients). Some species were losers under conditions that increased overall community production, including Bromus hordeaceus in the serpentine community (negative biomass response under elevated CO2) and Lotus wrangelianus in both communities (negative biomass response with added nitrogen). Treatment and competitive effects on species‐specific biomass varied in both magnitude and direction, especially in the serpentine community, significantly affecting community structure. Individual resource environments are likely to be affected by neighbouring plants, and these competitive interactions complicate predictions of species' responses to elevated CO2.

Elevated CO2 influences nutrient availability in young beech-spruce communities on two soil types

“…The reason for the dependency of the CO 2 effects from soil types might be that the availability of nutrients becomes limiting for one of the species under elevated CO 2 (here beech), while for the other (here spruce), the nutrient supply is still adequate. The increasing nutrient limitation under CO 2 enrichment for beech might be either imposed by the larger CO 2 sensitivity of the competitor (spruce) or it might be caused indirectly by a greater nutrient immobilization at elevated CO 2 (Joel et al 2001). However, under adequate resource availability (here on the calcareous sand), the response of tree species to CO 2 enrichment depends solely on the responsiveness of each tree species itself.…”

“…In diverse plant communities, the responsiveness of various plants to elevated CO 2 can be different, which may lead to changes in plant community composition and biodiversity (Leadley et al 1999;Körner 2000;Joel et al 2001). Differences in the species-level growth response to elevated CO 2 may be driven, by and large, by differences in the ability to acquire nutrients (Berntson et al 1998).…”

“…In addition, elevated atmospheric CO 2 can also change the competitiveness of plants indirectly by increasing or decreasing the availability of nutrients in soils. Therefore, soil fertility is probably one important co-factor determining shifts in competitiveness of different species under CO 2 enrichment (Joel et al 2001).…”

Global‐scale environmental control of plant photosynthetic capacity

“…Many empirical studies have shown that V c,25 and J 25 correlate with leaf nitrogen content (e.g., Ryan 1995, Reich et al 1998, Medlyn et al 1999, Kattge et al 2009, Rogers 2014 and this relationship forms the basis of many ESM estimations of V c,25 (Kattge et al 2009, Rogers 2014 and J 25 (Kattge and Knorr 2007). Variation in V c,25 and J 25 is substantial (Wullschleger 1993, Medlyn et al 1999) and occurs with growth conditions (Reich et al 1998, Cai et al 2007, season (Wilson et al 2000, and among species (Wohlfahrt et al 1999, Joel et al 2001. In view of these large variations, it is well recognized that current ESM parameterization of V c,25 and J 25 oversimplifies the representation of this model input, and that refined representation of variables that control V c,25 and J 25 is critical for improving model simulations of landatmosphere carbon exchange (Bonan et al 2011, Bauerle et al 2012, Rogers 2014.…”

Seedling Growth of Two Honey Mesquite Varieties Under CO2 Enrichment

“…The relative responsiveness of these 2 honey mesquite varieties to CO 2 enrichment may indicate which will more aggressively encroach into rangelands in the future. Previous investigations have identified speciesspecific (e.g., Joel et al 2001;Goverde et al 2002) and genotype-specific (e.g., Roumet et al 2002) responses of plants to CO 2 enrichment. Dissimilar growth responses to CO 2 for these 2 honey mesquite varieties may be manifested in differential rates of shrub encroachment in arid and more mesic rangelands (Polley 1997;Polley et al 1997).…”