Great Basin Naturalist


A two-year field experiment was conducted to investigate factors hypothesized to affect the reproductive potential of Astragalus kentrophyta var. implexus and to test the importance of trade-offs between growth and reproduction in this species. Levels of mineral nutrients, water, herbivory, and competition were manipulated. Seed output and growth of individuals in treatment groups were compared against control plants. Neither water nor mineral nutrients alone were shown to affect growth or reproduction. Herbivory was shown to be similarly unimportant in affecting growth and reproduction. Competition with other species influenced growth but not reproduction. No significant trade-offs between growth and reproduction were detected within years. However, there did appear to be a trade-off between these major fitness components when compared between years.