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Shifting dominance from native C 4 to non‐native C 3 grasses: relationships to community diversity
Author(s) -
Miles Erin K.,
Knops Johannes M. H.
Publication year - 2009
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1111/j.1600-0706.2009.17718.x
Subject(s) - ecology , agropyron , biology , dominance (genetics) , plant community , andropogon , poa pratensis , species richness , species diversity , grassland , introduced species , poaceae , biochemistry , gene
Many field studies have examined how site fertility, soil differences and site history influence the diversity of a plant community. However, only a few studies have examined how the identity of the dominant species influences the diversity in grasslands. Plant species differ widely in phenology, growth form and resource uses; thus, communities dominated by different species are also likely to strongly differ in the environment that they create and in which the subdominant species exist. We examined the correlation between the four most dominant species and community diversity in 2100 plots, located in 21 abandoned agricultural fields in central Minnesota over a 23‐year period. The four most common species were two non‐native C 3 cool season species, Poa pratensis and Agropyron repens , and two native C 4 warm season species, Schizachyrium scoparium and Andropogon gerardii . We found that the differences in the dominants explained up to 27% of the community diversity. Thus, the identity of the dominant species can have a strong influence on community diversity and studies examining factors that influence plant community diversity need to incorporate the effect of the dominants. Secondly, we found that the non‐native C 3 grass dominated communities had lower overall and lower native species richness relative to the native C 4 grass dominated communities. Therefore, a shift in dominants from C 4 to C 3 may lead to a large community diversity decline. We found that Poa pratensis , the most abundant non‐native C 3 grass increased in abundance over the 23 years; thus, the negative influence of non‐natives on the community diversity is not decreasing over time and active management is required to restore native grassland plant communities.