Light reduction predicts widespread patterns of dominance between asters and goldenrods

Abstract

Here we investigate the long-cited pattern that throughout the eastern United States, Solidago species (goldenrods), and in particular S. canadensis displace Aster species and dominate old-field communities. Theory predicts that such a ubiquitous pattern of repeated dominance should be linked to competitive ability for a limiting resource. However, no one has investigated this possibility in old-fields, representing a potentially significant gap in our understanding of a common human-altered environment. We tested the hypothesis that S. canadensis is the superior competitor for light compared to other common co-occurring goldenrod species, and that the goldenrods in general are the superior competitors for light compared to coexisting aster species, which are typically less abundant. We tested this hypothesis by comparing the light attenuation abilities of four goldenrod species, S. canadensis, S. rugosa, S. gigantea, and Euthamia graminifolia, and three aster species, Aster novae-angliae, A. pilosus, and A. prenanthoides. Consistent with our hypothesis, S. canadensis had a greater ability to attenuate light than any of the other goldenrods at higher densities, and the goldenrods overall had a greater ability to attenuate light than the asters. By conducting a census in our study area, we verified that S. canadensis is locally the most abundant goldenrod and that goldenrods are more locally abundant than asters. Furthermore, by conducting a literature survey we found evidence that S. canadensis replaces A. pilosus through time. Thus we found a close correspondence between relative abundance in the field and light attenuation ability in field experiments. These results are consistent with theory predicting that competition for limiting resources, in this case light, explains patterns of dominance and relative abundance in oldfield plant communities.

Rainfall variability counteracts N addition by promoting invasiveLonicera maackiiand extending phenology in prairie

“…Thus, plot characteristics associated with the aboveground and belowground competitive ability of the herbaceous community (e.g., LAI and root abundance, respectively) might be expected to differ between treatments based on forb dominance. Although we were unable to detect a response of root abundance to either IRV or N addition, LAI was greater under each of these treatments, consistent with our expectation of greater competition for light with higher forb cover (Banta et al 2008). However, when we included LAI or metrics of herbaceous community composition (i.e., C 4 grass cover, clonal forb cover, or grass : forb ratio) in our analyses, either in addition to or in lieu of rainfall variability and N availability terms, they were never significant predictors of seedling growth or any other seedling response.…”

“…Although we were unable to detect a response of root abundance to either IRV or N addition, LAI was greater under each of these treatments, consistent with our expectation of greater competition for light with higher forb cover (Banta et al 2008). Seedlings were planted into experimental communities that had already undergone 2 yr of change in response to our treatments.…”

Selective alteration of soil food web components by invasive giant goldenrod Solidago gigantea in two distinct habitat types

“…Solidago gigantea renders invaded plots unfit for most resident native plants. At least in part this could be attributed to the high efficiency of S. gigantea in the immobilization of minerals such as P and C (Vanderhoeven et al 2006, Scharfy et al 2009) From June onwards, the stems and leaves of S. gigantea can become increasingly dense and compete successfully for light (Weber and Jakobs 2005, Banta et al 2008). Moreover, S. gigantea releases large amounts of furanoid compounds and acidic compounds in the rhizosphere (Weber and Jakobs 2005).…”

California annual grass invaders: the drivers or passengers of change?

“…Wedin & Tilman 1993; HilleRisLambers et al. 2004; Harpole & Tilman 2006; Vojtech, Turnbull & Hector 2007; Banta et al. 2008; Violle et al.…”