Lobelia telekii Herbivory, Mortality, and Size at Reproduction: Variation with Growth Rate

Size—specific life tables are often used in plant and animal demography when age—specific tables cannot be assembled or are less predictive. However, age x stage interactions may confuse the interpretation of size—specific life tables. I demonstrate here several age x stage interactions in the demography of Lobelia telekii, a long—lived semelparous rosette plant on Mount Kenya. Analysis of 4 yr of demographic data indicated that slower growing plants were more subject to herbivory, more likely to die, and tended to flower at a smaller size, than faster growing plants in the same population. If overlooked, these effects would cause overestimation of both plant age and the variance in generation time, when such estimates are based on size—specific life tables. Because these patterns parallel large—scale temporal and spatial trends in L. teleki demography related to soil moisture availability, I suggest that slow—growing plants occupied less favorable microsites than fast—growing plants.