Variation in growth rate in shoot populations of the clonal dwarf shrub Linnaea borealis

Publisher Website
Google Scholar
Abstract
This study was based on two years of field observations of aLinnaea borealispopulation in a coniferous forest in Sweden. Detailed information on performance and survivorship of shoots were gathered from consecutively made drawings of 90 individually marked shoot systems ofLinnaeadistributed among 15 plots in the forest. Branching of the shoot systems was correlated to growth of the main shoot. Increasing light flux negatively affected growth ofLinnaea. A tendency for a competitive effect onLinnaeaofVacciniumspp. was also found. In contrast, the surrounding mosses, and intraspecific density ofLinnaeahad no significant effect on the shoot systems. The growth rate of the shoot population was analysed by matrix models. Population growth rate was most dependent on survivorship and growth of main shoots inLinnaea, while the survivorship of lateral shoots was of less importance. In spite of an average decrease in the population size as revealed by the matrix model simulation, the incorporation of the observed spatial variation in shoot growth increment, branching and shoot survivorship, yielded varying population growth rates. Parts of the population increased in size. The importance of choice of spatial scale in population analyses of forest understory plants is emphasized.