Resource Allocation and Fecundity of Populations of Solidago sempervirens Along a Coastal Dune Gradient

Abstract

Four populations of a coastal goldenrod (S. sempervirens), varying in habitat and distance from the coast at Island Beach State Park, New Jersey [USA] were compared in growth, phenology, biomass allocation and reproductive characters. At increaseing distances from the coast, these populations were Primary Dune (PD), Dune Hollow (DH), Intermediate (INT) and Bayshore (BAY). Percentage reproductive effort (i.e., proportion of aboveground biomass in reproductive parts)in the field ranged from 13.9-28.3%. BAY plants were taller and heavier and had the greatest reproductive effort. The BAY population ranked highest in reproductive potential as indicated by the greatest number of inflorescences and achenes as well as achene weights. INT, the only population with even a partial tree cover, was lowest in weight and reproductive characteristics. High allocation to leaves at INT may be a response to shading. In general, those populations (BAY and PD) that occurred in the most unstable sites (subjected to frequent catastrophic events) had a greater reproductive effort and fecundity than those populations (DH and INT) that occurred in the more stable sites. Strong similarities among greenhouse-grown populations in growth, biomass allocation and fecundity indicated that most field differences were phenotypic products of the local genotype-environment interaction.