The Plight of the Red Mulberry
The red mulberry is truly a fascinating subject. This is our only native mulberry created when the super continent, Pangea, broke apart. Over the course of millions of years of geographic isolation, the red mulberry evolved.
The plight of the red mulberry started as far back as 1610. Settlers in Jamestown, USA, brought silkworms over and introduced them to the red mulberry. This silk creating experience proved unsuccessful since the silkworms preferred the white, Asian, mulberry. Subsequently, the white mulberry was introduced to North America to further silk production attempts.
Silk production schemes quickly died but the introduced white mulberry did not. As with any introduced non native species, it readily multiplied in the landscape since there were no natural predators or diseases to halt its’ spreading.
Here is where the story gets interesting. This is not just a story of the red mulberry simply being outnumbered by the Asian mulberry. The actual genetics and uniqueness of the red mulberry has also aided to its peril. How do you ask? I call it genetic ‘swamping’.
Millions of years ago geographic separation created our mulberry. However, even with this separation the red mulberry was still very closely related to its 9 Asian cousins. In the course of 200 years, we have effectively brought closely related species together, created hybrids and now we are at the brink of witnessing these closely related species becoming one again.
Today, with all this genetic ‘swamping’ and hybridization, the red mulberry is now listed as endangered in it occurrence in Canada. Only about 200 trees were inventoried in 2000. In attempts to save the species, we have tried to geographically isolate these pure, red mulberry in a number of preserves. White mulberry and hybrids have been removed from these areas. Even with these efforts, the native mulberry seldom reproduces true to type seeds.
The story goes from bad to worse. As if hybridization is not disastrous enough but the following factors have made recovery plans and efforts next to impossible.
- The natural environment is absolutely polluted with hardy mulberry hybrids and there are no controls with the horticultural system to stop selling non native mulberry.
- The actual nature of the native mulberry is working against recovery efforts. First of all, the red mulberry does not consistently produce true to type seeds. Secondly, in order to do any recoveries of trees at these preserves, they must be found young. Why? Because this tree actually sex changes, which is really cool. The University of Guelph has determined that the trees start out as male flowering while young then goes through a transition to a hermaphrodite stage in which male and female flowers are on the same tree. Lastly, the tree ages to a female.
- The habitat in which these trees are trying to reproduce is imbalanced. It is over run with mice and deer. It is extremely difficult for seeds to germinate and grow into viable trees when rodents and deer clearly love browsing on them.
The end result is that in these preserves the red mulberry colonies are not truly increasing in size due to our best efforts.
Leaving things to natural chance on these preserves clearly is not working. Are there any new recovery ideas on the horizon? I say with the lack of success and no new, innovative recovery plans coming to light, we start planting mulberry again. Why? I think we are truly witnessing the merging of cousins back together to a common mulberry species. Mulberry has fantastic wildlife value. Birds find the fruit irresistible and the fruit ripens over a long time (2 months) assuring a steady supply of food.
Considering so many birds, mammals and insects are under stress due to an imbalanced, non bio diverse, poor environment, why are we denying them the mulberry? The whole story is food for thought but in the end will you consider planting the red mulberry?