Researchers have identified the biggest threats to the only population of rare and endangered mule ear orchids in the US.
The Florida International University (FIU) orchid research team found that powerful hurricanes can wipe out these fragile plants, but an invasive species of leaf-eating scale insects is the main culprit for the concern.
The findings were published in ecosphere.
“The mule-ear orchids that we observed that had mealybugs were more likely to die,” said Haydee Borrero, lead author of the study and an FIU postdoctoral scientist. “This is an invasive species that has affected other types of orchids on the west coast of Florida. So it’s something we need to be concerned about.”
Borrero, along with FIU conservation ecologist Hong Liu, have long been sentinels of mule-eared orchids. These orchids grow exclusively throughout the Caribbean, with the largest populations scattered in remote regions of Cuba. Its northernmost range is the buttonwood hammocks of southern Florida in Everglades National Park.
As part of his Ph.D. In his job at FIU, Borrero traveled to Cuba to do field work to better understand these little-studied orchids and found that those in Cuba were devoid of the invasive mealybug known to cover the leaves of mule orchids in Florida.
Those leaves, as the name suggests, resemble the large floppy ears of a mule. When this species of mealybug attacks the leaves, it paralyzes the plant and causes it to shrink. When the team returned to a study site where mealybugs had been observed on orchids two years earlier, many of the affected plants were dead.
The loss of even a single adult mule-ear orchid can be devastating, Borrero said. That’s one less plant in an already small population to make the next generation of much-needed orchids, pushing them closer to extinction.
“This has been a very important and exciting project, because we were able to do an analysis using many years of data to better separate which impacts cause the most damage,” Liu said. “What we found is complex. It’s not simple. Yes, hurricanes are a threat. But herbivory is a bigger threat.”
In 2017, Hurricane Irma caused its share of damage as Category 3 storm surge swept through the southern Everglades. While the hurricane damaged the orchid population, it also did a lot of damage to the mealybug population. With fewer insects in the years after Irma, mule ear orchids went into recovery mode.
Borrero and Liu are monitoring and using this data to help design future management strategies and potential rescue strategies for the endangered orchid.
The healthiest populations in Cuba are something of a model because they also grow in coastal regions prone to hurricanes and flooding. However, the forests in which they live have a greater diversity of tree species. This important information may provide clues as to which areas of Florida with similar tree types might be a good choice for relocating and expanding Florida’s imperiled population.
“One of the reasons we did this research was so we could make more informed [conservation] recommendations, such as, what are the habitats like in Cuba? And do we have similar habitats in Florida where we can plant and introduce these plants?” Borrero said. “One idea is to look at the Royal Palm Hammock area [within the Everglades National Park]Have [habitat] characteristics that match populations [in] Cuba.”
Meanwhile, the FIU orchid team refuses to give up Florida mule ear orchids. For Borrero, the mission could not be easier.
“They will go extinct if we do nothing. If we help them, they will survive.”
Haydee Borrero et al, Populations of a tropical epiphytic orchid are disrupted in its peripheral range by a hurricane and an exotic herbivore, ecosphere (2023). DOI: 10.1002/ecs2.4355
Provided by Florida International University
Citation: Saving Florida’s Only Endangered and Rare Orchid Population from Extinction (January 25, 2023) Accessed January 26, 2023 at https://phys.org/news/2023-01-florida- population-rare-endangered-orchid.html
This document is subject to copyright. Apart from any fair dealing for private study or research purposes, no part may be reproduced without written permission. The content is provided for informational purposes only.