Indices of plant competition

Journal of Ecology

Volumn 91, Issue 5, 2003, Pages 707-720

  Weigelt, Alexandra ^a,c   Jolliffe, Peter ^b  

^a BIELEFELD UNIVERSITY   (Germany)

^b UNIVERSITY OF BRITISH COLUMBIA   (Canada)

^c UNIVERSITY OF BAYREUTH   (Germany)

Author keywords

Competition indices; Competition intensity; Competitive effects; Competitive responses; Outcome of competition

Indexed keywords

COMPETITION (ECOLOGY); INDEX METHOD; PLANT;

EID: 0141889783     PISSN: 00220477     EISSN: None     Source Type: Journal    
DOI: 10.1046/j.1365-2745.2003.00805.x     Document Type: Review

References (150)

1. Aarssen, L.W. (1985) Interpretation of the evolutionary consequences of competition in plants: an experimental approach. Oikos, 45, 99-109.
2. Austin, M.P. (1982) Use of relative physiological performance value in the prediction of performance in multispecies mixtures from monoculture performance. Journal of Ecology, 70, 559-570.
3. Austin, M.P., Fresco, L.F.M., Nicholls, A.O., Groves, R.H. & Kaye, P.E. (1988) Competition and relative yield: estimation and interpretation at different densities and under various nutrient concentrations using Silybum marianum and Cirsium vulgare. Journal of Ecology, 76, 157-171.
4. 2. Ecology, 69 (4), 937-946.
5. Begon, M., Harper, J.L. & Townsend, C.R. (1996) Ecology. Blackwell Science, Oxford.
6. Belcher, J.W., Keddy, P.A. & Twolan-Strutt, L. (1995) Root and shoot competition intensity along a soil depth gradient. Journal of Ecology, 83, 673-682.
7. Berendse, F. (1982) Competition between plant populations with different rooting depths. III. Field experiments. Oecologia, 53, 50-55.
8. Berendse, F. (1983) Interspecific competition and niche differentiation between Plantago lanceolata and Anthoxanthum odoratum in a natural hayfield. Journal of Ecology, 71, 379-390.
9. Berkowitz, A.R., Canham, C.D. & Kelly, V.R. (1995) Competition vs facilitation of tree seedling growth and survival in early successional communities. Ecology, 76 (4), 1156-1168.
10. Biging, G.S. & Dobbertin, M. (1992) A comparison of distance-dependent competition measures for height and basal area growth of individual conifer trees. Forest Science, 38, 695-720.
11. Bonser, S.P. & Reader, R.J. (1995) Plant competition and herbivory in relation to vegetation biomass. Ecology, 76 (7), 2176-2183.
12. Cahill, J.F. (1999) Fertilization effects on interactions between above- and belowground competition in an old field. Ecology, 80, 466-480.
13. Campbell, B.D. & Grime, J.P. (1992) An experimental test of plant strategy theory. Ecology, 73 (1), 15-29.
14. Cheplick, G.P. (1997) Responses to severe competitive stress in a clonal plant: differences between genotypes, Oikos, 79, 581-591.
15. Cheplick, G.P. & Gutierrez, C.M. (2000) Clonal growth and storage in relation to competition in genets of the rhizomatous perennial Amphibromus scabrivalvis. Canadian Journal of Botany, 78, 537-546.
16. Chetty, C.K.R. & Reddy, M.N. (1984) Staple land equivalent ratio for assessing yield advantage from intercropping. Experimental Agriculture, 20, 171-177.
17. Connolly, J. (1986) On difficulties with replacement series methodology in mixture experiments. Journal of Applied Ecology, 23, 125-137.
18. Connolly, J. (1987) On the use of response models in mixture experiments. Oecologia, 72, 95-103.
19. Connolly, J. (1997) Substitutive experiments and the evidence for competitive hierarchies in plant communities. Oikos, 80 (1), 179-182.
20. Connolly, J. & Wayne, P. (1996) Asymmetric competition between plant species. Oecologia, 108, 311-320.
21. Connolly, J., Wayne, P. & Bazzaz, F.A. (2001) Interspecific competition in plants: how well do current methods answer fundamental questions? The American Naturalist, 157 (2), 107-125.
22. Connolly, J., Wayne, P. & Murray, R. (1990) Time course of plant-plant interactions in experimental mixtures of annuals: density, frequency and nutrient effects. Oecologia, 82, 513-526.
23. Cousens, R. (1985) A simple model relating yield loss to weed density. Annals of Applied Biology, 107, 239-252.
24. Cousens, R. (1996) Design and interpretation of interference studies: are some methods totally unacceptable? New Zealand Journal of Forestry Science, 26 (1/2), 5-18.
25. Cousens, R. & O'Neill, M. (1993) Density dependence of replacement series experiments. Oikos, 66 (2), 347-352.
26. Davis, M.A., Wrage, K.J. & Reich, P.B. (1998) Competition between tree seedlings and herbaceous vegetation: support for a theory of resource supply and demand. Journal of Ecology, 86, 652-661.
27. Dietz, H.J., Steinlein, T. & Ullmann, I. (1998) The role of growth form and correlated traits in competitive ranking of six perennial ruderal plant species grown in unbalanced mixtures. Acta Oecologia, 19 (1), 25-36.
28. Dormann, C.F., Van der Wal, R. & Bakker, J.P. (2000) Competition and herbivory during salt marsh succession: the importance of forb growth strategy. Journal of Ecology, 88 (4), 571-583.
29. Elberse, W.Th & Kruyf, H.N. (1979) Competition between Hordeum vulgare and Chenopodium album with different dates of emergence of Chenopodium album. Netherlands Journal of Agricultural Science, 27, 13-26.
30. Facelli, E. & Facelli, J.M. (2002) Soil phosphorus heterogeneity and mycorrhizal symbiosis regulate plant intra-specific competition and size distribution. Oecologia, 133, 54-61.
31. Firbank, L.G. & Watkinson, A.R. (1985) On the analysis of competition within two-species mixtures of plants. Journal of Applied Ecology, 22, 503-517.
32. Firbank, L.G. & Watkinson, A.R. (1990) On the effects of competition: from monocultures to mixtures. Perspectives on Plant Competition (eds J.B. Grace & D. Tilman), pp. 165-192. Academic Press, San Diego.
33. Ford, E.D. & Diggle, P.J. (1981) Competition for light in a plant monoculture modelled as a spatial stochastic process. Annals of Botany, 48, 481-500.
34. Foster, B.L. (2000) Competition at the population level along a standing crop gradient: a field experiment in successional grassland. Plant Ecology, 151, 171-180.
35. Fowler, N.L. (1982) Competition and coexistence in a North Carolina grassland. III. Mixture of component species. Journal of Ecology, 70, 77-92.
36. Fowler, N.L. (2002) The joint effects of grazing, competition, and topographic position on six savanna grasses. Ecology, 83 (9), 2477-2488.
37. Fransen, B., De Kroon, H. & Berendse, F. (2001) Soil nutrient heterogeneity alters competition between two perennial grass species. Ecology, 82 (9), 2534-2546.
38. Freckleton, R.P. & Watkinson, A.R. (1997) Measuring plant neighbour effects. Functional Ecology, 11, 532-536.
39. Freckleton, R.P. & Watkinson, A.R. (1999) Themis-measurement of plant competition. Functional Ecology, 13, 285-287.
40. Freckleton, R.P. & Watkinson, A.R. (2000) Design for greenhouse studies of interactions between plants: an analytical perspective. Journal of Ecology, 88, 386-391.
41. Garnier, E., Navas, M.-L., Austin, M.P., Lilley, J.M. & Gifford, R.M. (1997) A problem for biodiversity-productivity studies: how to compare the productivity of multispecific plant mixtures to that of monocultures? Acta Oecologia, 18 (6), 657-670.
42. Gibson, D.J., Connolly, J., Hartnett, D.C. & Weidenhamer, J.D. (1999a) Designs for greenhouse studies of interactions between plants. Journal of Ecology, 87, 1-16.
43. Gibson, K.D., Foin, T.C. & Hill, J.E. (1999b) The relative importance of root and shoot competition between water-seeded rice and Echinochloa phyllopogon. Weed Research, 39, 181-190.
44. Gilliver, B. & Pearce, S.C. (1983) A graphical assessment of data from intercropping factorial experiments. Experimental Agriculture, 19, 23-31.
45. Goldberg, D.E. (1987) Neighborhood competition on an old-field plant community. Ecology, 68 (5), 1211-1223.
46. Goldberg, D.E. (1990) Components of resource competition in plant communities. Perspectives on Plant Competition (eds J.B. Grace & D. Tilman), pp. 26-49. Academic Press, San Diego.
47. Goldberg, D.E. (1994) Influence of competition at the community level: an experimental version of the null models approach. Ecology, 75 (5), 1503-1506.
48. Goldberg, D.E. & Fleetwood, L. (1987) Competitive effect and response in four annual plants. Journal of Ecology, 15, 1131-1143.
49. Goldberg, D.E. & Landa, K. (1991) Competitive effect and response: hierarchies and correlated traits in the early stages of competition. Journal of Ecology, 79, 1013-1030.
50. Goldberg, D.E., Rajaniemi, T., Gurevitch, J. & Stewart-Oaten, A. (1999) Empirical approaches to quantifying interaction intensity competition and facilitation along productivity gradients. Ecology, 80 (4), 1118-1131.
51. Goldberg, D.E. & Scheiner, S.M. (1993) ANOVA and ANCOVA: field competition experiments. Design and Analysis of Ecological Experiments (eds S.M. Scheiner & J. Gurevitch), pp. 69-93. Chapman & Hall, New York.
52. Goldberg, D.E. & Werner, P.A. (1983) Equivalence of competitors in plant communities: a null hypothesis and a field experimental approach. American Journal of Botany, 70 (7), 1098-1104.
53. Grace, J.B. (1985) Juvenile versus adult competitive abilities in plants: size-dependence in cattails (Typha). Ecology, 66 (5), 1630-1638.
54. Grace, J.B. (1988) The effects of plant age on the ability to predict mixture performance from monoculture growth. Journal of Ecology, 76, 152-156.
55. Grace, J.B. (1995) On the measurement of plant competition intensity. Ecology, 76 (1), 305-308.
56. Grace, J.B., Keough, J. & Guntenspergen, G.R. (1992) Size bias in traditional analyses of substitutive competition experiments. Oecologia, 90, 429-434.
57. Greiner la Peyre, M.K., Grace, J.B., Hahn, E. & Mendelssohn, I.A. (2001) The importance of competition in regulating plant species abundance along a salinity gradient. Ecology, 82 (1), 62-69.
58. Gurevitch, J., Wilson, P., Stone, J.L., Teese, P. & Stoutenburgh, R.J. (1990) Competition among old-field perennials at different levels of soil fertility and available space. Journal of Ecology, 78, 727-744.
59. Harper, J.L. (1977) Population Biology of Plants. Academic Press, London.
60. Hedges, L.V., Gurevitch, J. & Curtis, P.S. (1999) The metaanalysis of response ratios in experimental ecology. Ecology, 80(4), 1150-1156.
61. Hooper, D.U. (1998) The role of complementarity and competition in ecosystem responses to variation in plant diversity. Ecology, 79 (2), 704-719.
62. Howard, T.G. (2001) The relationship of total and per-gram rankings in competitive effect to the natural abundance of herbaceous perennials. Journal of Ecology, 89 (1), 110-117.
63. Howard, T.G. & Goldberg, D.E. (2001) Competitive response hierarchies for germination, growth, and survival and their influence on abundance. Ecology, 82 (4), 979-990.
64. Hunt, R. (1982) Plant Growth Curves. The Functional Approach to Plant Growth Analysis, Edward Arnold, London.
65. Inouye, B.D. (2001) Response surface experimental designs for investigating interspecific competition. Ecology, 82 (10), 2696-2706.
66. Jasienski, M. & Bazzaz, F.A. (1999) The fallacy of ratios and the testability of models in biology. Oikos, 84 (2), 321-326.
67. Jolliffe, P.A. (1997) Are mixed populations of plant species more productive than pure stands? Oikos, 80, 595-602.
68. Jolliffe, P.A. (2000) The replacement series. Journal of Ecology, 88, 371-385.
69. Jolliffe, P.A., Minjas, A.N. & Runeckles, V.C. (1984) A reinterpretation of yield relationships in replacement series experiments. Journal of Applied Ecology, 21, 227-243.
70. Jolliffe, P.A. & Wanjau, F.M. (1999) Competition and productivity in crop mixtures: some properties of productive intercrops. Journal of Agricultural Science, 132, 425-435.
71. Kadmon, R. (1995) Plant competition along soil moisture gradients: a field experiment with the desert annual Stipa capensis. Journal of Ecology, 83, 253-262.
72. Keddy, P.A., Fraser, L.H. & Wisheu, I. (1998) A comparative approach to examine competitive response of 48 wetland plant species. Journal of Vegetation Science, 9, 777-786.
73. Keddy, P.A., Gaudet, J.P. & Fraser, L.H. (2000) Effects of low and high nutrients on the competitive hierarchy of 26 shoreline plants. Journal of Ecology, 88, 413-423.
74. Keddy, P.A., Twolan-Strutt, L. & Wisheu, I. (1994) Competitive effect and response rankings in 20 wetland plants: are they consistent across three environments? Journal of Ecology, 82, 635-643.
75. Law, R. & Watkinson, A.R. (1987) Response-surface analysis of two-species competition: an experiment on Phleum arenarium and Vulpia fasciculata, Journal of Ecology, 75, 871-886.
76. Lepš, J. (1999) Nutrient status, disturbance and competition: an experimental test of relationships in a wet meadow. Journal of Vegetation Science, 10, 219-230.
77. Loreau, M. (1998) Separating sampling and other effects in biodiversity experiments. Oikos, 82 (3), 600-602.
78. Mack, R. & Harper, J.L. (1977) Interference in dune annuals: spatial pattern and neighbourhood effects. Journal of Ecology, 65, 345-363.
79. Markham, J.H. (1997) Measuring and modelling plant neighbour effects: a reply to Freckleton and Watkinson. Functional Ecology, 11, 534-535.
80. Markham, J.H. & Chanway, C.P. (1996) Measuring plant neighbour effects. Functional Ecology, 10, 548-549.
81. McGilchrist, C.A. (1965) Analysis of competition experiments. Biometrics, 21, 975-985.
82. McGilchrist, C.A. & Trenbath, B.R. (1971) A revised analysis of plant competition experiments. Biometrics, 27, 659-671.
83. McLellan, A.J., Law, R. & Fitter, A.H. (1997) Response of calcareous grassland plant species to diffuse competition: results from a removal experiment. Journal of Ecology, 85, 479-490.
84. Mead, R. (1979) Competition experiments. Biometrics, 35, 41-54.
85. Mead, R. & Willey, R.W. (1980) The concept of a 'land equivalent ratio' and advantages on yields from intercropping. Experimental Agriculture, 16, 217-228.
86. Miller, T.E. (1994) Direct and indirect species interactions in an early old-field plant community. The American Naturalist, 143(6), 1007-1025.
87. Miller, T.E. (1996) On quantifying the intensity of competition across gradients. Ecology, 77 (3), 978-981.
88. Miller, T.E. & Werner, P.A. (1987) Competitive effects and responses between plant species in a first-year old-field community. Ecology, 68 (5), 1201-1210.
89. Moen, J. & Meurk, C.D. (2001) Competitive abilities of three indigenous New Zealand plant species in relation to the introduced plant Hieracium pilosella. Basic and Applied Ecology, 2, 243-250.
90. Mynhardt, J.E. (1994) Competitive ability of two grass species: Anthephora pubescens and Eragrostis curvula. 1. Yield and biomass allocation. South African Journal of Botany, 60 (5), 261-268.
91. Newton, P.F. & Jolliffe, P.A. (1998) Assessing processes of intraspecific competition within spatially heterogeneous black spruce stands. Canadian Journal of Forest Research, 28, 259-275.
92. Nienaber, G.W. (1999) Stand and tree dynamics in uneven-aged interior Douglas-fir stands. PhD dissertation. The University of British Columbia, Vancouver.
93. Parrish, J.A.D. & Bazzaz, F.A. (1982) Competitive interactions in plant communities of different successional ages. Ecology, 63(2), 314-320.
94. Peltzer, D.A. (1999) Measuring plant neighbour effects in different systems. Functional Ecology, 13, 283-284.
95. Peltzer, D.A. (2001) Plant responses to competition and soil origin across a prairie-forest boundary. Journal of Ecology, 89, 176-185.
96. Peltzer, D.A. & Köchy, M. (2001) Competitive effects of grasses and woody plants in mixed-grass prairie. Journal of Ecology, 89, 519-527.
97. Peltzer, D.A., Wilson, S.D. & Gerry, A.K. (1998) Competition intensity along a productivity gradient in a low-diversity grassland. The American Naturalist, 151 (5), 465-476.
98. Purves, D.W. & Law, R. (2002) Experimental derivation of functions relating growth of Arabidopsis thaliana to neighbour size and distance. Journal of Ecology, 90, 882-894.
99. Reader, R.J., Wilson, S.D., Belcher, J.W., Wisheu, I., Keddy, P.A., Tilman, D. et al. (1994) Plant competition in relation to neighbor biomass: an intercontinental study with Poa pratensis. Ecology, 75 (6), 1753-1760.
100. Rebele, F. (2000) Competition and coexistence of rhizomatous perennial plants along a nutrient gradient. Plant Ecology, 147, 77-94.
101. Rejmanek, M., Robinson, G.R. & Rejmankova, E. (1989) Weed-crop competition: experimental design and models for data analysis. Weed Science, 37, 276-284.
102. Riley, J. (1985) Examination of the staple and effective land equivalent ratios. Experimental Agriculture, 21, 369-376.
103. Rösch, H., Van Rooyen, M.W. & Theron, G.K. (1997) Competitive effect and response of ten Namaqualand ephemeral plant species at two nutrient levels. South African Journal of Botany, 63 (4), 210-215.
104. Roush, M.L., Radosevich, S.R., Wagner, R.G., Maxwell, B.D. & Petersen, T.D. (1989) A comparison of methods for measuring effects of density and proportion in plant competition experiments. Weed Science, 37, 268-275.
105. Roxburgh, S.H. & Wilson, J.B. (2000) Stability and coexistence in a lawn community: mathematical prediction of stability using a community matrix with parameters derived from competition experiments. Oikos, 88, 395-408.
106. Sackville Hamilton, N.R. (2001) Measurement of competition and competition effects in pastures. Competition and Succession in Pastures (eds P.G. Tow & A. Lazenby), pp. 15-42. CABI Publishing, Wallingford, UK.
107. Sammul, M., Kull, K., Oksanen, L. & Veromann, P. (2000) Competition intensity and its importance: results of field experiments with Anthoxanthum odoratum. Oecologia, 125, 18-25.
108. Silander, J.A. Jr & Antonovics, J. (1982) Analysis of interspecific interactions in a coastal plan community - a perturbation approach. Nature, 298, 557-560.
109. Silander, J.A. Jr & Pacala, S.W. (1985) Neighbourhood predictors of plant performance. Oecologia, 66, 256-263.
110. Snaydon, R.W. (1991) Replacement or additive design for competition studies? Journal of Applied Ecology, 28, 930-946.
111. Snaydon, R.W. & Satorre, E.H. (1989) Bivariate diagrams for plant competition data: modifications and interpretation. Journal of Applied Ecology, 26, 1043-1057.
112. Spitters, C.T.J. (1983) An alternative approach to analysis of mixed cropping experiments. I. Estimation of competitive effects. Netherlands Journal of Agricultural Science, 31, 1-11.
113. Stoll, P., Weiner, J. & Schmid, B. (1994) Growth variation in a naturally established population of Pinus sylvestris. Ecology, 75 (3), 660-670.
114. Suding, K.N. & Goldberg, D. E. (1999) Variation in the effects of vegetation and litter on recruitment across productivity gradients. Journal of Ecology, 87, 436-449.
115. Suding, K.N. & Goldberg, D.E. (2001) Do disturbances alter competitive hierarchies? Mechanisms of change following gap creation. Ecology, 82 (8), 2133-2149.
116. Taylor, D.R. & Aarssen, L.W. (1990) Complex competitive relationships among genotypes of three perennial grasses: implications for species coexistence. The American Naturalist, 136 (3), 305-327.
117. Taylor, D.R., Aarssen, L.W. & Loehle, C. (1990) On the relationship between r/K selection and environmental carrying capacity: a new habitat templet for plant life history strategies. Oikos, 58, 239-250.
118. Tielbörger, K. & Kadmon, R. (2000a) Temporal environmental variation tips the balance between facilitation and interference in desert plants. Ecology, 81 (6), 1544-1553.
119. Tielbörger, K. & Kadmon, R. (2000b) Indirect effects in a desert plant community: is competition among annuals more intense under shrub canopies? Plant Ecology, 150, 53-63.
120. Trenbath, B.R. (1976) Plant interactions in mixed crop communities. American Society of Agronomy, Special Publication, 27, 129-169.
121. Turkington, R. & Jolliffe, P.A. (1996) Interference in Trifolium repens - Lolium perenne mixtures: short- and long-term relationships. Journal of Ecology, 84, 563-571.
122. Turkington, R. & Klein, E. (1993) Interactive effects of nutrients and disturbance: an experimental test of plant strategy theory. Ecology, 74 (3), 863-878.
123. Twolan-Strutt, L. & Keddy, P.A. (1996) Above- and below-ground competition intensity in two contrasting wetland plant communities. Ecology, 77 (1), 259-270.
124. Vandermeer, J. (1989) The Ecology of Intercropping. Cambridge University Press, Cambridge.
125. Wagner, R.G. & Radosevich, S.R. (1998) Neighborhood approach for quantifying interspecific competition in coastal Oregon forests. Ecological Applications, 8, 779-794.
126. Wardle, D.A. & Barker, G.M. (1997) Competition and herbivory in establishing grassland communities: implications for plant biomass, species diversity and soil microbial activity. Oikos, 80, 470-480.
127. Warren, J., Wilson, F. & Diaz, A. (2002) Competitive relationships in a fertile grassland community - does size matter? Oecologia, 132, 125-130.
128. Weigelt, A., Röttgermann, M., Steinlein, T. & Beyschlag, W. (2000) Influence of water availability on competitive interactions between plant species on sandy soils. Folia Geobotanica, 35, 169-178.
129. Weigelt, A., Steinlein, T. & Beyschlag, W. (2002) Does plant competition intensity rather depend on biomass or on species identity? Basic and Applied Ecology, 3, 85-94.
130. Weiner, J. (1982) A neighborhood model of annual-plant interference. Ecology, 63 (5), 1237-1241.
131. Weiner, J. (1984) Neighbourhood interference amongst Pinus rigida individuals. Journal of Ecology, 12, 183-195.
132. Weiner, J. (1990) Asymmetric competition in plant populations. Trends in Ecology and Evolution, 5 (11), 360-364.
133. Weiner, J. & Thomas, S.C. (1986) Size variability and competition in plant monocultures. Oikos, 47, 211-222.
134. Weiden, C.W. & Slauson, W.L. (1986) The intensity of competition versus its importance: an overlooked distinction and some implications. The Quarterly Review of Biology, 61 (1), 23-44.
135. Wetzel, RR. & Van der Valk, A.G. (1998) Effects of nutrient and soil moisture on competition between Carex stricta, Phalaris arundinacea, and Typha latifolia. Plant Ecology, 138(2), 179-190.
136. Willey, R.W. & Heath, S.B. (1969) The quantitative relationships between plant population and crop yield. Advances in Agronomy, 21, 281-321.
137. Willey, R.W. & Osiru, D.S.O. (1972) Studies on mixtures of maize and beans (Phaseolus vulgaris) with special reference to plant population. Journal of Agricultural Science, 79, 519-529.
138. Willey, R.W. & Rao, M.R. (1980) A competitive ratio for quantifying competition between intercrops. Experimental Agriculture, 16, 117-125.
139. Wilson, J.B. (1988) Shoot competition and root competition. Journal of Applied Ecology, 25, 279-296.
140. Wilson, S.D. (1993) Competition and resource availability in heath and grassland in the Snowy Mountains of Australia. Journal of Ecology, 81, 445-451.
141. Wilson, S.D. & Keddy, P.A. (1986a) Measuring diffuse competition along an environmental gradient: results from a shoreline plant community. The American Naturalist, 127, 862-869.
142. Wilson, S.D. & Keddy, P.A. (1986b) Species competitive ability and position along a natural stress/disturbance gradient. Ecology, 67(5), 1236-1242.
143. Wilson, S.D. & Tilman, D. (1991) Components of plant competition along an experimental gradient of nitrogen availability. Ecology, 72 (3), 1050-1065.
144. Wilson, S.D. & Tilman, D. (1993) Plant competition and resource availability in response to disturbance and fertilization. Ecology, 74 (2), 599-611.
145. Wilson, S.D. & Tilman, D. (1995) Competitive responses of eight old-field plant species in four environments. Ecology, 76(4), 1169-1180.
146. de Wit, C.T. (1960) On competition. Verslagen Landbouwkundige Onderzoekigen, 66, 1-82.
147. de Wit, C.T. & Van den Bergh, J.P. (1965) Competition between herbage plants. Netherlands Journal of Agricultural Science, 13(2), 212-221.
148. Wright, A.J. (1981) The analysis of yield-density relationships in binary mixtures using inverse polynomials. Journal of Agricultural Science, 96, 561-567.
149. Yates, F. & Dutton, S.J. (1988) A simple procedure for the analysis of experiments on mixtures of varieties or species of agronomic interest. Journal of Agricultural Science, 110, 13-24.
150. Zamfir, M. & Goldberg, D.E. (2000) The effect of initial density on interactions between bryophytes at individual and community levels. Journal of Ecology, 88, 243-255.