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Citation. Reichman, O. J. 1988. Comparison of the effects of crowding and pocket gopher disturbance on mortality, growth and seed production of Berteroa incana. The American Midland Naturalist 120(1):58-69. [1124 LTERCC]
Abstract. This study examines the effects of plant competition and pocket gopher (Geomys bursarius) disturbances on the mortality, growth, biomass and seed production of Berteroa incana, a weedy old-field plant. Experimental plants were transplanted over simulated burrows, vacant natural burrows, active burrows and onto mounds cast during burrow excavations. The simulated burrows were excavated in pocket gopher exclosures which contained a natural old-field plant community, and in devegetated exclosures. The results reveal: (1) the presence of competing plants had a more significant effect on plant yield components of B. incana than pocket gopher disturbance (2) any effects of pocket gopher disturbance on plant yield components were accentuated where the plants experienced increased competitive pressures, and (3) the most significant effect of pocket gophers on B. incana was mortality rather than changes in plant yield components. Plants growing on pocket gopher mounds had much higher mortality than adjacent controls, but those that survived grew larger and produced many more seeds than control plants off the mounds. The average seed mass, total number of seeds produced by a plant and the number of seeds per fruit were significantly correlated with total plant biomass.