Contrasting effects of clipping and nutrient addition on reproductive traits of Heteropappus altaicus at the individual and population levels
- 225 Downloads
This study was conducted to examine the effects of clipping and nutrient addition on plant traits of a dominant perennial forb species, Heteropappus altaicus (Willd.) Novopokr. (Compositae), at both the individual and population levels in a temperate steppe in northern China. A nested experimental design was used with clipping as the main factor and nutrient, including nitrogen (N), phosphorus (P) and both, addition as the second factor. The main effect of clipping reduced plant height, aboveground biomass (AGB) per plant, and pollen production per floret by 15.8, 34.3, 28.0% (all p < 0.05), respectively, but enhanced reproductive allocation and population density by 8 and 28.2% (both p < 0.05), respectively, suggesting contrary effects of clipping on H. altaicus traits at the individual and population levels. N addition significantly stimulated plant height, AGB per plant, reproductive allocation, pollen diameter, and pistil length, but decreased population density. The main effects of P addition also stimulated the plant traits at individual level, but did not change population traits. The significant interactions of clipping and nitrogen addition were observed on AGB per plant, pollen production, and population density. The differential responses of H. altaicus at the individual and population levels to clipping and nutrient addition indicate that the future dynamics of H. altaicus in the temperate steppe are uncertain and need long-term research to demonstrate.
KeywordsClipping Heteropappus altaicus Inflorescence Nitrogen Phosphorus Pollen Population Temperate steppe
This study was conducted as part of a comprehensive research project (Global Change Multi-factor Experiment-Duolun) sponsored by the Institute of Botany, Chinese Academy of Sciences. This study was financially supported by the Ministry of Science and Technology (2007CB106803), Chinese Academy of Sciences (Hundred Talents Program), and State Key Laboratory of Vegetation and Environmental Change.
- Aizen MA, Raffaele E (1998) Flowering-shoot defoliation affects pollen grain size and postpollination pollen performance in Alstroemeria aurea. Ecology 79:2133–2142Google Scholar
- Allee WC, Emerson AE, Park O, Park T, Schmidt KP (1949) Principals of animal ecology. W.B. Saunders, PhiladelphiaGoogle Scholar
- Ashman TL, Knight TM, Steets JA, Amarasekare P, Burd M, Campbell DR, Dudash MR, Johnston MO, Mazer SJ, Mitchell RJ, Morgan MT, Wilson WG (2004) Pollen limitation of plant reproduction: ecological and evolutionary causes and consequences. Ecology 85:408–421Google Scholar
- Fu HC (1989) Flora of Inner Mongolia, 2nd edn, vol 3. Inner Mongolia People’s Press, Huhehot, pp 235–238Google Scholar
- Hambäck PA (2001) Direct and indirect effects of herbivory: feeding by spittlebugs affects pollinator visitation rates and seedset of Rudbeckia hirta. Ecoscience 8:45–50Google Scholar
- Lehtilä K, Strauss SY (1999) Effects of foliar herbivory on male and female reproductive traits of wild radish, Raphanus raphanistrum. Ecology 80:116–124Google Scholar
- Mothershead K, Marquis RJ (2000) Fitness impacts of herbivory through indirect effects on plant–pollinator interactions in Oenothera macrocarpa. Ecology 81:30–40Google Scholar
- Wu E, Xia QM, Gao W, Xing Q (2006) Phosphorus nutrition problems and their solutions in Inner Mongolia grassland. Inner Mongolia Prataculture 18:4–7Google Scholar