Population structure of Rudgea parquioides (Rubiaceae), a shade-tolerant shrub species, in Southern Brazil

Abstract

The expectations that shade-tolerant forest species show 1) a population structure composed by a high amount of small individuals, and 2) biomass allocation for diameter higher than for height growth, were tested for Rudgea parquioides, a typical shrub in Southern Brazil. We described the size structure (height and stem diameter) and allometrical relations of a R. parquioides population by counting and measuring all the individuals in a 725m 2 area in the municipality of Curitiba (25 • 25 S; 49 • 19 W). A total of 916 individuals (12,634 ind.ha −1 ) were recorded in the area. The first expectation was supported, since distribution by height and diameter classes showed a predominance of small individuals (skewness coefficients > 1). On the other hand, the regression between height and stem base diameter showed slope β < 1, which indicates that growth in height is higher than in diameter, not supporting the second expectation. These results show that life strategies in shade-tolerant species may imply in more trade-off combinations than previously described.

Demography of the endangered tree species Ocotea porosa (Lauraceae) along a gradient of forest disturbance in southern Brazil

“…For example, trees adapted to survive in shaded areas have traits that increase light interception and persistence by allocating more biomass to diameter growth than to height gain. In contrast, gap-dependent species allocate their biomass to efficient height growth and pass through the understory to reach the high-light environment of the canopy (King 1990;Gelder et al 2006;Cardoso et al 2010). Considering that selective logging and the effects of fragmentation can increase the light availability in the understory of a fragment, it is expected that individuals will tend to allocate more resources to growth in height than to growth in diameter.…”