Eucalyptus risdonii Known as the narrow-leafed black peppermint, this rare tree comes from southeastern Tasmania. It has recently been making headlines as it spreads its range northward because of climate change. It is only found on the warmer slopes of Risdon Reserve, south of Risdon Vale in Hobart’s eastern suburbs. Meanwhile, it’s a different story for other eucalypt species—many are failing to make it. Scientists say that the plant’s ability to respond to a changing environment—most importantly, to warmer and drier conditions—has been a major factor in its success.
Unlike most of the other members of its extensive family Eucalyptus risdonii stands out with unique blue-grey leaves and a scraggly but perky appearance. Its habit of holding onto this blue-grey juvenile foliage, unusual in eucalypts, adds to its ornamental appeal. According to noted developer and tree expert Rebecca Jones, the resulting tree canopy is “stunning.” She admits that’s not in keeping with the classic postcard view of a healthy tree.
Unique Characteristics and Adaptability
Eucalyptus risdonii is not only a beauty—it is a winner for its incredible resilience. The tree is characterized by thick leaves that are joined together along the stem. This dramatic fusion produces a single leaf structure, with the stalk popping up vertically through its middle. This showy adaptation, or perhaps more accurately mis-adaptation, could help it minimize water loss and survive periods of particularly harsh environmental extremes.
While these adaptations can give Eucalyptus risdonii a bizarre beauty, new research suggests that those peculiarities were actual adaptations evolved to survive in extreme environments. New research confirms this species is a master at surviving in extreme environments. As such, it is more suited than other eucalypts to meet the challenges posed by climate change.
Species distribution modeling predicts both the extent and number of areas climatically suitable for Eucalyptus risdonii will drastically expand by the end of this century. This hopeful forecast bodes well for this scarce species. Our forecast underscores the promise of this awesome tree to keep thriving in the face of changing climate, if only we give it the chance.
Role of Hybridisation in Expansion
Thais Ribeiro Pfeilsticker is a post-doctoral researcher joining the lab, who works on Eucalyptus risdonii. She explains that hybridization is critical to the tree’s developing range. Crucially, in her PhD thesis she provided a credible alternative explanation. This study confirms our hunch that hybridization is playing a critical role in expanding the distribution of this rare eucalypt. It is hoped that this process will give Eucalyptus risdonii the genetic diversity needed to adapt even more to a constantly changing environment.
At first the early explorers confused Eucalyptus risdonii with another species altogether because of its unusual traits. No one disputed its size and speed, but the failure to classify the creature correctly caused everyone a great deal of grief. Continued research has helped define its importance, character and distinct place within the eucalypt family.
Even as hybridisation enables the rapid spread of Eucalyptus risdonii, scientists are hopeful about the tree’s prospects. Its flexibility and durability provide important lessons. They are a potential template for efforts to learn how other plant species will adapt to climate change.
Conservation and Future Prospects
Given its limited range and important ecological role, conservation of Eucalyptus risdonii is essential. As more areas become suitable for this species, efforts must be made to protect its natural habitat from potential threats. Wildlife advocates and nature lovers alike highlight the ecological value of saving the unique ecosystems where Eucalyptus risdonii are found.
Climate change is remaking the world’s landscapes. Now more than ever, it is imperative to know about and advocate for hardy species such as Eucalyptus risdonii. For biodiversity, the growing range of this unusual eucalypt is good news. It can teach us important lessons about how we can continue to protect it, even in faster-changing landscapes.
