The population of Drosera indica, a carnivorous plant, in a wetland of Taiwan is limited by its neighboring plants

Successful conservation of rare plants requires understanding of factors limiting their population growth. Drosera indica is a carnivorous annual herb. In Taiwan Island, the only stable population of the plant is currently found in the wetland of Lienhwa Temple and is maintained through manually removing neighboring non-carnivorous plants. This study investigated the effect of neighboring plants on D. indica in the wetland. We conducted both field and laboratory experiments to test two hypotheses: 1) The overgrowth of neighboring non-carnivorous plants in the wetland causes reduction in light availability for D. indica, which inhibits its population and 2) accompany plants reduce the effectiveness of prey capture by D. indica. Results of the field experiments showed that treatment plots, received mowing and mowing then plowing treatments, intercepted more light at the ground level and had a significantly higher occurrence of D. indica sprouts than control plots. No significant difference in leaf stable nitrogen isotopes ratio was found between D. indica plants sprouting from control and from treatment plots indicating they utilized similar sources of nitrogen. Control experiments revealed that D. indica seeds did not germinate in the dark or at 15/10 degrees C, and shading (with 20-30% transmittance of sunlight) caused a significant reduction in its growth and seed production. We therefore conclude that the overgrowth of neighboring non-carnivorous plants in the wetland limits light availability for D. indica seed germination, plant growth and seed production. Results of this study also provide management strategies for the conservation of this rare plant in Taiwan.

Automated summary

Successful conservation of rare plants requires understanding of factors limiting their population growth. The study on Drosera indica in Taiwan Island found that the overgrowth of neighboring non-carnivorous plants in the wetland limits light availability for D. indica seed germination, plant growth and seed production, providing valuable management strategies for the conservation of this rare plant.