Differential seedling growth response to nutrient additions among tree species in a tropical forest in Panama
P 2.2 in Biodiversität: Verbreitung, Funktion und Erhaltung
Ecological sorting caused by niche differentiation may be important for maintaining species diversity. Patterns of tree distribution in tropical forests are often associated to variation in soil nutrients where tropical soils are highly diverse with variable nutrient status. In a recent study along the Isthmus of Panama, which encompasses a strong soil nutrient gradient, demonstrated that soil nutrients play an important role in limiting species ranges. Here we present a study to experimentally assess species’ responses to potentially limiting nutrients with the objective to identify the mechanisms underlying these patterns.
A common garden fertilization experiment has been implemented on a low nutrient forest site in Panama to evaluate the seedlings’ performance in response to nutrient additions. A number of 60 plots (30 fertilized, 30 control) were installed. Forty different species naturally associated to different nutrient contents were selected. Monthly fertilizations with complete nutrients, and trimonthly assessment of seedling growth and mortality were carried out.
The nutrient effects on the growth of various species were assessed on seedlings as relative growth rate and growth response ratio. Preliminary results show that growth differed among species however no strong effect of nutrients is observed, indicating that species do not respond to nutrients. The linkage between species responses to nutrients and their distribution patterns is important for the understanding of the diversity and ecology of plant species with implications for their responses under a changing climate.