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Where Are We?


A screenshot of Dan and Winnie speaking to the virtual ATBC meeting. July 2021.

On July 23, 2021, Drs. Dan Janzen and Winnie Hallwachs participated in a panel discussion, "Janzen-Connell 50th Anniversary: Where Are We?" as part of the virtual meeting of the Association for Tropical Biology and Conservation (ATBC). The panel discussion also included two other prominent ecologists, Dr. Lissy Coley, a professor at the University of Utah, and Dr. John Terborgh, a professor Emeritus at Duke University. The purpose of the panel was to discuss the Janzen-Connell hypothesis, which is a widely accepted explanation, put forth, independently by Dan Janzen and Joseph Connell, for the maintenance of tree species biodiversity in tropical rain forests. Published in the early 1970s and today still very much relevant, the hypothesis proposes that specialist natural enemies, such as herbivores and pathogens, maintain diversity in plant communities by reducing survival rates on conspecific seeds and seedlings located close to reproductive adults or in areas of high conspecific diversity.

With Coley and Terborgh discussing more recent research on this topic, Dan and Winnie focused on the "Where Are We?" question, discussing the current state of affairs when it comes to biodiversity in the tropics, and said, "Sadly, we are still attempting to study the nature that is melting in front of our eyes, measuring the temperature in the burning building - wonderful data, but no building... The house is on fire for ALL tropical biodiversity. It needs thermometers less than it needs more global and place-based preventions." And, they added, addressing the viewers, "Biodiversity restoration from the surviving fragments [of this ecosystem] is in full swing, but it can no longer achieve the 'original' state while enduring the rapid climate change scenario we are living in. And it will have to live with the ongoing extinctions in its badly wounded ecosystems. Today's insect survivors, and all that come with them, are now tomorrow's colonists in their brave new world. Please be kind to them."

The video of the panel discussion is now available via the ATBC YouTube channel. It can be found here.