The Power of Movement in Plants
Drenovsky, Rebecca E. , James, Jeremy J. .
Plant invasions in rangelands: physiological traits underlying success.
Humans have deliberately or accidentally moved plant species around the globe, drastically altering plant communities. However, not all non-native species become invasive. Thus, understanding the traits that make some non-native species more competitive than others is an important first step in determining which species may become invasive. Our objective was to compare a suite of native and non-native perennial forbs with respect to their relative growth rates and physiological traits related to nutrient uptake and use. We predicted specific leaf area would be the key trait underlying faster relative growth rates in non-native species. Additionally, we hypothesized that non-native species would have a greater ability to exploit soil nutrient resources and have higher photosynthetic rates, biomass accumulation, and nutrient use efficiency compared to native species. As predicted, high relative growth rate in non-native species was due to primarily higher specific leaf area and leaf area ratio than to other factors. This result indicates faster growth was related to plants creating more leaf area per unit biomass allocated to leaves rather than differences in biomass partitioning between shoots and roots or differences in net assimilation rate. Non-native species also were able to more effectively exploit soil resources, having higher leaf nitrogen than native species. Additionally, non-native species had higher photosynthetic rates, higher photosynthetic nutrient use efficiencies, and biomass accumulation than native species. However, native species differed greatly in their relative growth rates, physiological traits, and biomass accumulation. These results suggest that (1) multiple traits contribute to the success of non-native species and (2) that native species within a functional group showed large trait variation. Thus, managing these communities should focus on functional traits rather than functional group composition.
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1 - John Carroll University, Biology Department, 20700 North Park Blvd, University Heights, Ohio, 44118, USA
2 - USDA-Agricultural Research Service, Eastern Oregon Agricultural Research Station, 67826-A Hwy 205, Burns, OR, 97720, U.S.A.
relative growth rate
Presentation Type: Symposium or Colloquium Presentation
Location: Ballroom 2/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 11:15 AM