On the slopes of a spring-fed lake in the Wasatch Mountains in the western United States lives a single gigantic organism that sustains an entire ecosystem on which plants and animals have depended for thousands of years. “Pando” is a 106-acre aspen clone that can be found in Utah.
Pando (Latin for "I spread") is actually made up of 47.000 genetically identical stems that emerge from an interconnected network of roots. Despite appearing to be a woodland of individual trees, with their striking white bark and tiny leaves that flutter in the slightest breeze, the Pando is actually a genetically diverse group of fungi.
The weight of this single genetic human is almost 6.000 metric tons. It is the largest organism on Earth in terms of mass.
Although poplar trees elsewhere often grow in clonal stands, Pando is unique for its size. In North America, clonal aspen stands are quite small, with stands in the western US averaging only 3 acres.
Although most stems only live for about 130 years, the pando has existed for thousands of years—possibly up to 14.000 years. Due to its age and isolation, an entire ecosystem of 68 plant species and various animals has developed and grown under its shadow.
The continuation of the health and stability of aspen is very important for this entire ecosystem. However, protected by the US National Forest Service and not at risk of cutting, the Pando is still threatened with extinction due to a number of other problems.
The newest "trees" are being eaten by deer.
One of the most important problems is overgrazing by deer and roe deer. The packs were originally kept in check by wolves and cougars, but these predators are no longer present and the packs have grown significantly.
Due to the protection provided by the forest area, elk and elk also congregate frequently in Pando because there is no hunting risk there.
When old trees die or fall, light reaches the forest floor and encourages the growth of new clonal trunks. However, these animals perish when they consume the crowns of the newly formed stems. This indicates that most of the Pando is not fresh growth.
The exception is an area that was fenced off several decades ago so that dead trees can be removed. A “bamboo garden” is a fenced area where fresh clonal stems grow and reproduce successfully despite the absence of deer and roe deer.
Plant diseases and climate change
At least three diseases also affect older stems in Pando, including leaf spot, conch fungal disease, and sooty barkworm.
Despite the fact that plant diseases have evolved and developed in poplar stands for thousands of years, it is not known what the long-term impact on the ecosystem might be given the lack of new growth and the large number of additional stressors on the clonal giant.
Climate change is the fastest growing threat. Pando emerged towards the end of the last ice age and has struggled with a mostly stable environment ever since.
It is true that he lives in an alpine region surrounded by desert, so he is accustomed to hot weather and drought. But the tree's size, lifespan, and the entire ecosystem it supports are threatened by climate change.
Although Pando is not the subject of specific scientific study, poplar stands are under pressure from climate change-related factors such as reduced water availability and higher temperatures earlier in the year, resulting in loss of coverage.
Pando will undoubtedly find it difficult to adapt to these rapidly changing conditions while maintaining its size, with increased competition for dwindling water resources, the threat of more intense wildfires, and the nearby Fish Lake being out of reach of the tree's root system.
after 14.000 years
But Pando is resilient and has long since weathered rapid environmental changes, particularly with the arrival of European settlers in the 19th century or the rise of recreational activities in the 20th century. It is still the world's largest scientifically confirmed creature and has previously survived disease, wildfire, and grazing.
For all reasons for concern, there is hope because researchers are helping us discover the mechanisms underlying Pando's resilience, and conservation agencies and the U.S. Forest Service strive to protect this tree and the environment it is a part of. Also, a brand new organization called Friends of Pando aims to make the tree widely accessible by creating 360-degree video recordings.
source: sciencealert
📩 10/03/2023 17:45