Effects of competition and mowing on growth and reproduction of the invasive plant Erigeron annuus at two contrasting altitudes
Tóm tắt
Invasive plants are often abundant at frequently disturbed sites such as roadsides, because they benefit from reduced competition or increased nutrient availability. In Switzerland, roadsides are subjected to regular mowing, and to persist in these sites, plants must be able to compensate for the biomass removal. However, the ability to tolerate competition and mowing might decline under less favourable growth conditions, such as those at higher altitudes. I investigated how competition and mowing affect growth and reproduction of Erigeron annuus (L.) Pers., an invasive plant common on Swiss roadsides, and how these effects change with altitude. The experiment was replicated in common gardens at altitudes of 400 m and 1,000 m asl, representing growth conditions in the main distribution area of E. annuus and at its altitudinal limit, respectively. Vegetative growth was negatively affected by competition at both sites, but especially at 1,000 m. The number of capitula was not affected by competition at 400 m, but was reduced at 1,000 m. Plants regrew vigorously after mowing in both gardens. The effects of mowing on reproductive output were positive at 400 m, but negative at 1,000 m. These results imply that E. annuus is able to tolerate competition and mowing at low altitudes, but both of these factors hinder its reproduction at higher altitudes.
Tài liệu tham khảo
Becker T, Dietz H, Billeter R, Buschmann H, Edwards PJ (2005) Altitudinal distribution of alien plant species in the Swiss Alps. Perspect Plant Ecol Evol Syst 7:173–183
Brandon AL, Gibson DJ, Middleton BA (2004) Mechanisms for dominance in an early successional old field by the invasive non-native Lespedeza cuneata (Dum. Cours.). G Don Biol Invasions 6:483–493
Cano L, Escarre J, Sans FX (2007) Factors affecting the invasion success of Senecio inaequidens and S. pterophorus in Mediterranean plant communities. J Veg Sci 18:281–288
Connolly J, Wayne P, Bazzaz FA (2001) Interspecific competition in plants: how well do current methods answer fundamental questions? Am Nat 157:107–125
Daehler CC (2003) Performance comparisons of co-occurring native and alien invasive plants: implications for conservation and restoration. Annu Rev Ecol Evol Syst 34:183–211
Edwards PJ, Frey D, Bailer H, Baltisberger M (2006) Genetic variation in native and invasive populations of Erigeron annuus as assessed by RAPD markers. Int J Plant Sci 167:93–101
Fahnestock JT, Detling JK (2000) Morphological and physiological responses of perennial grasses to long-term grazing in the Pryor Mountains, Montana. Am Midl Nat 143:312–320
Frey D, Baltisberger M, Edwards PJ (2003) Cytology of Erigeron annuus s.l. and its consequences in Europe. Bot Helv 113:1–14
Gibson DJ, Connolly J, Hartnett DC, Weidenhamer JD (1999) Designs for greenhouse studies of interactions between plants. J Ecol 87:1–16
Huhta AP, Hellstrom K, Rautio P, Tuomi J (2000) A test of the compensatory continuum: fertilization increases and below-ground competition decreases the grazing tolerance of tall wormseed mustard (Erysimum strictum). Evol Ecol 14:353–372
Joshi J, Matthies D (1996) Effects of mowing and fertilization on succession in an old-field plant community. Bull Geobot Inst ETH 62:13–26
Kimball S, Schiffman PM (2003) Differing effects of cattle grazing on native and alien plants. Conserv Biol 17:1681–1693
Lennartsson T, Nilsson P, Tuomi J (1998) Induction of overcompensation in the field gentian, Gentianella campestris. Ecology 79:1061–1072
Maschinski J, Whitham TG (1989) The continuum of plant responses to herbivory: the influence of plant association, nutrient availability, and timing. Am Nat 134:1–19
Moreno DM, Nunez-Farfan J, Terrazas T, Muiz LD, Trinidad-Santos A, Trejo C, Larque-Saavedra A (1999) Plastic responses to clipping in two species of Amaranthus from the Sierra Norte de Puebla, Mexico. Genet Resour Crop Evol 46:225–234
Petryna L, Moora M, Nunes CO, Cantero JJ, Zobel M (2002) Are invaders disturbance-limited? Conservation of mountain grasslands in Central Argentina. Appl Veg Sci 5:195–202
Regehr DL, Bazzaz FA (1976) Low temperature photosynthesis in successional winter annuals. Ecology 57:1297–1303
Ross MA, Harper JL (1972) Occupation of biological space during seedling establishment. J Ecol 60:77–88
Sala A, Verdaguer D, Vila M (2007) Sensitivity of the invasive geophyte Oxalis pes-caprae to nutrient availability and competition. Ann Bot 99:637–645
Seastedt TR, Suding KN (2007) Biotic constraints on the invasion of diffuse knapweed (Centaurea diffusa) in North American grasslands. Oecologia 151:626–636
Stratton DA (1989) Competition prolongs expression of maternal effects in seedlings of Erigeron annuus (Asteraceae). Am J Bot 76:1646–1653
White VA, Holt JS (2005) Competition of artichoke thistle (Cynara cardunculus) with native and exotic grassland species. Weed Sci 53:826–833