Dr Katja Rembold, a postdoc researcher on biodiversity, ecology and conservation of tropical rain forest ecosystems at the University of Goettingen, expounded on the “Ecology and Conservation of Nepenthes Pitcher Plants” as the topic for BIOTROP’s First Quarterly Public Seminar for 2018. The seminar was held on 15 February 2018 at the Centre’s headquarter in Bogor.
During her lecture, Dr Katja introduced the complex ecology, animal-plant interactions and conservation of Nepenthes pitcher plants. She informed the participants that the genus Nepenthes (Nepenthaceae) comprises about 160 species of carnivorous pitcher plants. The plants tend to grow in open areas, lowland forests, highland forests, Kerangas and white sands. Southeast Asia is the diversity center of Nepenthes, but some species spread as far as Madagascar, New Caledonia, China and Northern Australia.
Dr Katja explained that all Nepenthes species adapt the same capture mechanism: modified pitcher-shaped leaves consisting of attractive zone, slippery zone and digestion zone. They attract mainly arthropod prey by providing nectar, sweet fragrances and often a bright coloration on their attractive zone. The prey then slips and falls into a digestive liquid where it drowns. The plant is capable of absorbing the nutrients from digested prey animals via glands in the pitcher walls. She added, however, that many species have modified traps, often specializing on a certain prey. This carnivorous mechanism provides Nepenthes pitcher plants with an additional nutrient source that enables them to colonize extremely nutrient poor soils or to grow epiphytic.
While the Nepenthes pitchers are a death trap for some animals, Dr. Katja revealed that they also provide a habitat for others such as mosquitoes that spent at least certain stages of their live within the pitchers, which makes each pitcher a little ecosystem on its own. The pitchers also become a shelter for spiders to protect itself from predators. In addition, rats, birds and frogs are known to look for their preys around the flowering Nepenthes population. In terms of symbiosis, ants are well-known to have mutualism relationship with Nepenthes. The ants help the plants to digest the meals and supply more nitrogen through their feces, while the plants provide the ants with the food from the nectar.
At the end of her lecture, Dr Katja emphasized that wild collections and habitat loss become the main threats to these interesting plants of which many species are already under risk of extinction according to International Union for Conservation of Nature and Natural Resources (IUCN) Red List. In order to save and protect the plants, Dr. Katja encouraged several conservation efforts that need to be done such as collecting the seeds from wild plants and planting them in a conservation area such Botanic Garden as well as by using tissue culture technology.
Dr Katja completed her Biology studies with a master thesis on the ecology of Nepenthes madagascariensis at the University on Bonn (Germany), then, was responsible for the carnivorous plants working group at the Nees Institute for Biodiversity of Plants and for the carnivorous plant collection at the Botanical Gardens of Bonn. She finished her PhD on the conservation status of plants in East African rain forests at the University of Koblenz (Germany) in 2011 and got a position as project manager in an agroforestry project in Rwanda, Africa. Since 2012, she had a postdoc position in an international collaboration project investigating the consequences of rainforest transformation into agricultural systems for plant diversity in Sumatera, Indonesia.
The seminar was attended by 55 participants coming from various educational and research institutions in West Java.